[PATCH 0/6] refs: provide detailed error messages when using batched update

[PATCH 0/6] refs: provide detailed error messages when using batched update

[Karthik Nayak]

The refs namespace uses an error buffer to capture details about failed
reference updates. However when we added batched update support to
reference transactions, these messages were never propagated, instead
only an error code pertaining to the type of failure was propagated.

Currently, there are three regions which utilize batched updates:

  - git update-ref --batch-updates
  - git fetch
  - git receive-pack

While 'git update-ref --batch-updates' was a newly introduced flag, both
'git fetch' and 'git receive-pack' were pre-existing. Before using
batched updates, they provided more detailed error messages to the user,
but this changed with the introduction of batched updates. This is a
regression in their workings.

This patch series fixes this, by passing the detailed error message and
utilizing it whenever available. The regression was reported by Elijah
Newren [1] and based on the patch submitted by Jeff King [2].

[1]: https://lore.kernel.org/all/CABPp-BGL2tJR4dPidQuFcp-X0_VkVTknCY-0Zgo=jHVGv_P=wA@mail.gmail.com/
[2]: https://lore.kernel.org/all/20251224081214.GA1879908@coredump.intra.peff.net/

---
 builtin/fetch.c         |  9 +++++---
 builtin/receive-pack.c  |  9 ++++++--
 builtin/update-ref.c    | 13 +++++++-----
 refs.c                  | 56 ++++++++++++++++++++++++++++++-------------------
 refs.h                  |  1 +
 refs/files-backend.c    |  3 ++-
 refs/packed-backend.c   |  9 +++++---
 refs/refs-internal.h    |  4 +++-
 refs/reftable-backend.c |  3 ++-
 t/t1400-update-ref.sh   | 26 +++++++++++------------
 t/t5510-fetch.sh        |  8 +++----
 t/t5516-fetch-push.sh   | 15 +++++++++++++
 12 files changed, 102 insertions(+), 54 deletions(-)

Karthik Nayak (6):
      refs: remove unused header
      refs: attach rejection details to updates
      refs: add rejection detail to the callback function
      update-ref: utilize rejected error details if available
      fetch: utilize rejected ref error details
      receive-pack: utilize rejected ref error details



base-commit: 8745eae506f700657882b9e32b2aa00f234a6fb6
change-id: 20260113-633-regression-lost-diagnostic-message-when-pushing-non-commit-objects-to-refs-heads-17786b20894a

Thanks
- Karthik

[PATCH 1/6] refs: remove unused header

[Karthik Nayak]

Some of the headers in 'refs.c' are no longer required, let's remove
them.

Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
---
 refs.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/refs.c b/refs.c
index e06e0cb072..965b232a06 100644
--- a/refs.c
+++ b/refs.c
@@ -15,7 +15,6 @@
 #include "iterator.h"
 #include "refs.h"
 #include "refs/refs-internal.h"
-#include "run-command.h"
 #include "hook.h"
 #include "object-name.h"
 #include "odb.h"
@@ -26,7 +25,6 @@
 #include "strvec.h"
 #include "repo-settings.h"
 #include "setup.h"
-#include "sigchain.h"
 #include "date.h"
 #include "commit.h"
 #include "wildmatch.h"

-- 
2.51.2

Re: [PATCH 1/6] refs: remove unused header

[Junio C Hamano]

Karthik Nayak <karthik.188@gmail.com> writes:

> Some of the headers in 'refs.c' are no longer required, let's remove
> them.
>
> Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
> ---
>  refs.c | 2 --
>  1 file changed, 2 deletions(-)

One thing to note is that The resulting file refs.c still includes
hook.h and because of that, the removal of run-command.h from here
has no effect.

> diff --git a/refs.c b/refs.c
> index e06e0cb072..965b232a06 100644
> --- a/refs.c
> +++ b/refs.c
> @@ -15,7 +15,6 @@
>  #include "iterator.h"
>  #include "refs.h"
>  #include "refs/refs-internal.h"
> -#include "run-command.h"
>  #include "hook.h"
>  #include "object-name.h"
>  #include "odb.h"
> @@ -26,7 +25,6 @@
>  #include "strvec.h"
>  #include "repo-settings.h"
>  #include "setup.h"
> -#include "sigchain.h"
>  #include "date.h"
>  #include "commit.h"
>  #include "wildmatch.h"

Re: [PATCH 1/6] refs: remove unused header

[Karthik Nayak]

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Junio C Hamano <gitster@pobox.com> writes:

> Karthik Nayak <karthik.188@gmail.com> writes:
>
>> Some of the headers in 'refs.c' are no longer required, let's remove
>> them.
>>
>> Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
>> ---
>>  refs.c | 2 --
>>  1 file changed, 2 deletions(-)
>
> One thing to note is that The resulting file refs.c still includes
> hook.h and because of that, the removal of run-command.h from here
> has no effect.
>

Good point, let me modify the commit message to explain this better.
Perhaps:

-->8--

refs: drop unnecessary header includes

The 'sigchain.h' header isn't being used and can be removed.

Similarly, 'run-command.h' serves no direct purpose here. While it gets
pulled in transitively through 'hook.h', we can still drop the explicit
include for clarity.

>> diff --git a/refs.c b/refs.c
>> index e06e0cb072..965b232a06 100644
>> --- a/refs.c
>> +++ b/refs.c
>> @@ -15,7 +15,6 @@
>>  #include "iterator.h"
>>  #include "refs.h"
>>  #include "refs/refs-internal.h"
>> -#include "run-command.h"
>>  #include "hook.h"
>>  #include "object-name.h"
>>  #include "odb.h"
>> @@ -26,7 +25,6 @@
>>  #include "strvec.h"
>>  #include "repo-settings.h"
>>  #include "setup.h"
>> -#include "sigchain.h"
>>  #include "date.h"
>>  #include "commit.h"
>>  #include "wildmatch.h"

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[PATCH 2/6] refs: attach rejection details to updates

[Karthik Nayak]

The implementation of batched updates in 23fc8e4f61 (refs: implement
batch reference update support, 2025-04-08) added rejection error codes
to each reference update. This allowed batching of updates, however
while each rejection is linked to a rejection code, the already present
user readable error message is simply dropped.

Make necessary changes to ensure that the rejection detail is also added
to the reference update. In upcoming commits, we'll utilize this field
to provide better error message to users, namely in:

  - git update-ref --batch-updates
  - git fetch
  - git receive-pack

We move the error message creation right above
`ref_transaction_maybe_set_rejected()`, so that the error message is
available and also reset the error message if utilized to avoid
un-expected concatination.

Co-authored-by: Jeff King <peff@peff.net>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
---
 refs.c                  | 52 ++++++++++++++++++++++++++++++++-----------------
 refs/files-backend.c    |  3 ++-
 refs/packed-backend.c   |  9 ++++++---
 refs/refs-internal.h    |  4 +++-
 refs/reftable-backend.c |  3 ++-
 5 files changed, 47 insertions(+), 24 deletions(-)

diff --git a/refs.c b/refs.c
index 965b232a06..991bd8e6ee 100644
--- a/refs.c
+++ b/refs.c
@@ -1222,6 +1222,7 @@ void ref_transaction_free(struct ref_transaction *transaction)
 		free(transaction->updates[i]->committer_info);
 		free((char *)transaction->updates[i]->new_target);
 		free((char *)transaction->updates[i]->old_target);
+		free((char *)transaction->updates[i]->rejection_details);
 		free(transaction->updates[i]);
 	}
 
@@ -1236,7 +1237,8 @@ void ref_transaction_free(struct ref_transaction *transaction)
 
 int ref_transaction_maybe_set_rejected(struct ref_transaction *transaction,
 				       size_t update_idx,
-				       enum ref_transaction_error err)
+				       enum ref_transaction_error err,
+				       const char *details)
 {
 	if (update_idx >= transaction->nr)
 		BUG("trying to set rejection on invalid update index");
@@ -1262,6 +1264,8 @@ int ref_transaction_maybe_set_rejected(struct ref_transaction *transaction,
 			   transaction->updates[update_idx]->refname, 0);
 
 	transaction->updates[update_idx]->rejection_err = err;
+	if (details)
+		transaction->updates[update_idx]->rejection_details = xstrdup(details);
 	ALLOC_GROW(transaction->rejections->update_indices,
 		   transaction->rejections->nr + 1,
 		   transaction->rejections->alloc);
@@ -2657,30 +2661,35 @@ enum ref_transaction_error refs_verify_refnames_available(struct ref_store *refs
 			if (!initial_transaction &&
 			    (strset_contains(&conflicting_dirnames, dirname.buf) ||
 			     !refs_read_raw_ref(refs, dirname.buf, &oid, &referent,
-						       &type, &ignore_errno))) {
+						&type, &ignore_errno))) {
+
+				strbuf_addf(err, _("'%s' exists; cannot create '%s'"),
+					    dirname.buf, refname);
+
 				if (transaction && ref_transaction_maybe_set_rejected(
 					    transaction, *update_idx,
-					    REF_TRANSACTION_ERROR_NAME_CONFLICT)) {
+					    REF_TRANSACTION_ERROR_NAME_CONFLICT, err->buf)) {
 					strset_remove(&dirnames, dirname.buf);
 					strset_add(&conflicting_dirnames, dirname.buf);
-					continue;
+					strbuf_reset(err);
+					goto next;
 				}
 
-				strbuf_addf(err, _("'%s' exists; cannot create '%s'"),
-					    dirname.buf, refname);
 				goto cleanup;
 			}
 
 			if (extras && string_list_has_string(extras, dirname.buf)) {
+				strbuf_addf(err, _("cannot process '%s' and '%s' at the same time"),
+					    refname, dirname.buf);
+
 				if (transaction && ref_transaction_maybe_set_rejected(
 					    transaction, *update_idx,
-					    REF_TRANSACTION_ERROR_NAME_CONFLICT)) {
+					    REF_TRANSACTION_ERROR_NAME_CONFLICT, err->buf)) {
 					strset_remove(&dirnames, dirname.buf);
-					continue;
+					strbuf_reset(err);
+					goto next;
 				}
 
-				strbuf_addf(err, _("cannot process '%s' and '%s' at the same time"),
-					    refname, dirname.buf);
 				goto cleanup;
 			}
 		}
@@ -2711,13 +2720,16 @@ enum ref_transaction_error refs_verify_refnames_available(struct ref_store *refs
 				    string_list_has_string(skip, iter->ref.name))
 					continue;
 
+				strbuf_addf(err, _("'%s' exists; cannot create '%s'"),
+					    iter->ref.name, refname);
+
 				if (transaction && ref_transaction_maybe_set_rejected(
 					    transaction, *update_idx,
-					    REF_TRANSACTION_ERROR_NAME_CONFLICT))
-					continue;
+					    REF_TRANSACTION_ERROR_NAME_CONFLICT, err->buf)) {
+					strbuf_reset(err);
+					goto next;
+				}
 
-				strbuf_addf(err, _("'%s' exists; cannot create '%s'"),
-					    iter->ref.name, refname);
 				goto cleanup;
 			}
 
@@ -2727,15 +2739,19 @@ enum ref_transaction_error refs_verify_refnames_available(struct ref_store *refs
 
 		extra_refname = find_descendant_ref(dirname.buf, extras, skip);
 		if (extra_refname) {
+			strbuf_addf(err, _("cannot process '%s' and '%s' at the same time"),
+				    refname, extra_refname);
+
 			if (transaction && ref_transaction_maybe_set_rejected(
 				    transaction, *update_idx,
-				    REF_TRANSACTION_ERROR_NAME_CONFLICT))
-				continue;
+				    REF_TRANSACTION_ERROR_NAME_CONFLICT, err->buf)) {
+				strbuf_reset(err);
+				goto next;
+			}
 
-			strbuf_addf(err, _("cannot process '%s' and '%s' at the same time"),
-				    refname, extra_refname);
 			goto cleanup;
 		}
+next:;
 	}
 
 	ret = 0;
diff --git a/refs/files-backend.c b/refs/files-backend.c
index 6f6f76a8d8..8d22a2e8e3 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -2983,7 +2983,8 @@ static int files_transaction_prepare(struct ref_store *ref_store,
 					  head_ref, &refnames_to_check,
 					  err);
 		if (ret) {
-			if (ref_transaction_maybe_set_rejected(transaction, i, ret)) {
+			if (ref_transaction_maybe_set_rejected(transaction, i,
+							       ret, err->buf)) {
 				strbuf_reset(err);
 				ret = 0;
 
diff --git a/refs/packed-backend.c b/refs/packed-backend.c
index 4ea0c12299..535200db01 100644
--- a/refs/packed-backend.c
+++ b/refs/packed-backend.c
@@ -1437,7 +1437,8 @@ static enum ref_transaction_error write_with_updates(struct packed_ref_store *re
 						    update->refname);
 					ret = REF_TRANSACTION_ERROR_CREATE_EXISTS;
 
-					if (ref_transaction_maybe_set_rejected(transaction, i, ret)) {
+					if (ref_transaction_maybe_set_rejected(transaction, i,
+									       ret, err->buf)) {
 						strbuf_reset(err);
 						ret = 0;
 						continue;
@@ -1452,7 +1453,8 @@ static enum ref_transaction_error write_with_updates(struct packed_ref_store *re
 						    oid_to_hex(&update->old_oid));
 					ret = REF_TRANSACTION_ERROR_INCORRECT_OLD_VALUE;
 
-					if (ref_transaction_maybe_set_rejected(transaction, i, ret)) {
+					if (ref_transaction_maybe_set_rejected(transaction, i,
+									       ret, err->buf)) {
 						strbuf_reset(err);
 						ret = 0;
 						continue;
@@ -1496,7 +1498,8 @@ static enum ref_transaction_error write_with_updates(struct packed_ref_store *re
 					    oid_to_hex(&update->old_oid));
 				ret = REF_TRANSACTION_ERROR_NONEXISTENT_REF;
 
-				if (ref_transaction_maybe_set_rejected(transaction, i, ret)) {
+				if (ref_transaction_maybe_set_rejected(transaction, i,
+								       ret, err->buf)) {
 					strbuf_reset(err);
 					ret = 0;
 					continue;
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index c7d2a6e50b..60d9f015cf 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -128,6 +128,7 @@ struct ref_update {
 	 * was rejected.
 	 */
 	enum ref_transaction_error rejection_err;
+	const char *rejection_details;
 
 	/*
 	 * If this ref_update was split off of a symref update via
@@ -153,7 +154,8 @@ int refs_read_raw_ref(struct ref_store *ref_store, const char *refname,
  */
 int ref_transaction_maybe_set_rejected(struct ref_transaction *transaction,
 				       size_t update_idx,
-				       enum ref_transaction_error err);
+				       enum ref_transaction_error err,
+				       const char *details);
 
 /*
  * Add a ref_update with the specified properties to transaction, and
diff --git a/refs/reftable-backend.c b/refs/reftable-backend.c
index 4319a4eacb..a9c9ceebf3 100644
--- a/refs/reftable-backend.c
+++ b/refs/reftable-backend.c
@@ -1401,7 +1401,8 @@ static int reftable_be_transaction_prepare(struct ref_store *ref_store,
 					    &refnames_to_check, head_type,
 					    &head_referent, &referent, err);
 		if (ret) {
-			if (ref_transaction_maybe_set_rejected(transaction, i, ret)) {
+			if (ref_transaction_maybe_set_rejected(transaction, i,
+							       ret, err->buf)) {
 				strbuf_reset(err);
 				ret = 0;
 

-- 
2.51.2

Re: [PATCH 2/6] refs: attach rejection details to updates

[Jeff King]

On Wed, Jan 14, 2026 at 04:40:43PM +0100, Karthik Nayak wrote:

> @@ -1262,6 +1264,8 @@ int ref_transaction_maybe_set_rejected(struct ref_transaction *transaction,
>  			   transaction->updates[update_idx]->refname, 0);
>  
>  	transaction->updates[update_idx]->rejection_err = err;
> +	if (details)
> +		transaction->updates[update_idx]->rejection_details = xstrdup(details);

I guess this could use xstrdup_or_null(), but probably doesn't matter
much either way. I do wonder if anybody actually passes a NULL value. I
think in my hacky patch there were some spots that did, but here you're
always setting the "err" buf (which is good, as we'll always have
details then).

> @@ -2657,30 +2661,35 @@ enum ref_transaction_error refs_verify_refnames_available(struct ref_store *refs
>  			if (!initial_transaction &&
>  			    (strset_contains(&conflicting_dirnames, dirname.buf) ||
>  			     !refs_read_raw_ref(refs, dirname.buf, &oid, &referent,
> -						       &type, &ignore_errno))) {
> +						&type, &ignore_errno))) {
> +
> +				strbuf_addf(err, _("'%s' exists; cannot create '%s'"),
> +					    dirname.buf, refname);
> +
>  				if (transaction && ref_transaction_maybe_set_rejected(
>  					    transaction, *update_idx,
> -					    REF_TRANSACTION_ERROR_NAME_CONFLICT)) {
> +					    REF_TRANSACTION_ERROR_NAME_CONFLICT, err->buf)) {
>  					strset_remove(&dirnames, dirname.buf);
>  					strset_add(&conflicting_dirnames, dirname.buf);
> -					continue;
> +					strbuf_reset(err);
> +					goto next;
>  				}
>  
> -				strbuf_addf(err, _("'%s' exists; cannot create '%s'"),
> -					    dirname.buf, refname);
>  				goto cleanup;
>  			}

OK, so this is a case where we re-ordered the "err" handling so that
it's available for the non-atomic case. Makes sense. We end up
formatting into err, then copying it via xstrdup(), and then resetting
the buffer, which is an extra copy. I think you could probably get
around that by passing in the strbuf to set_rejected() and using
strbuf_detach() to pull the value out. It's probably not worth worrying
about optimizing out the copy for an error path like this, but I wonder
if it would be more ergonomic (the caller does not have to remember to
strbuf_reset() then).

I notice that you "goto next" now instead of "continue". So I was
curious what happens in "next" now, but...

> +next:;
>  	}

...the answer is nothing. ;) I guess maybe you were going to
strbuf_reset() down here at one point? If the 'next' label remains
empty, I think I'd prefer to keep these as 'continue'. But maybe you use
it later in the series. I'll read on.

> [...]

The rest of the conversions all looked sensible to me. And you fixed my
memory leak, which is good. ;)

-Peff

Re: [PATCH 2/6] refs: attach rejection details to updates

[Karthik Nayak]

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Jeff King <peff@peff.net> writes:

> On Wed, Jan 14, 2026 at 04:40:43PM +0100, Karthik Nayak wrote:
>
>> @@ -1262,6 +1264,8 @@ int ref_transaction_maybe_set_rejected(struct ref_transaction *transaction,
>>  			   transaction->updates[update_idx]->refname, 0);
>>
>>  	transaction->updates[update_idx]->rejection_err = err;
>> +	if (details)
>> +		transaction->updates[update_idx]->rejection_details = xstrdup(details);
>
> I guess this could use xstrdup_or_null(), but probably doesn't matter
> much either way. I do wonder if anybody actually passes a NULL value. I
> think in my hacky patch there were some spots that did, but here you're
> always setting the "err" buf (which is good, as we'll always have
> details then).

That's correct, I did ensure that there were no NULLs passed through, we
could definitely drop the check. But I was being defensive. I think
`xstrdup_or_null()` is the better option here.

>> @@ -2657,30 +2661,35 @@ enum ref_transaction_error refs_verify_refnames_available(struct ref_store *refs
>>  			if (!initial_transaction &&
>>  			    (strset_contains(&conflicting_dirnames, dirname.buf) ||
>>  			     !refs_read_raw_ref(refs, dirname.buf, &oid, &referent,
>> -						       &type, &ignore_errno))) {
>> +						&type, &ignore_errno))) {
>> +
>> +				strbuf_addf(err, _("'%s' exists; cannot create '%s'"),
>> +					    dirname.buf, refname);
>> +
>>  				if (transaction && ref_transaction_maybe_set_rejected(
>>  					    transaction, *update_idx,
>> -					    REF_TRANSACTION_ERROR_NAME_CONFLICT)) {
>> +					    REF_TRANSACTION_ERROR_NAME_CONFLICT, err->buf)) {
>>  					strset_remove(&dirnames, dirname.buf);
>>  					strset_add(&conflicting_dirnames, dirname.buf);
>> -					continue;
>> +					strbuf_reset(err);
>> +					goto next;
>>  				}
>>
>> -				strbuf_addf(err, _("'%s' exists; cannot create '%s'"),
>> -					    dirname.buf, refname);
>>  				goto cleanup;
>>  			}
>
> OK, so this is a case where we re-ordered the "err" handling so that
> it's available for the non-atomic case. Makes sense. We end up
> formatting into err, then copying it via xstrdup(), and then resetting
> the buffer, which is an extra copy. I think you could probably get
> around that by passing in the strbuf to set_rejected() and using
> strbuf_detach() to pull the value out. It's probably not worth worrying
> about optimizing out the copy for an error path like this, but I wonder
> if it would be more ergonomic (the caller does not have to remember to
> strbuf_reset() then).

That's a great idea, let me do that instead.

>
> I notice that you "goto next" now instead of "continue". So I was
> curious what happens in "next" now, but...
>
>> +next:;
>>  	}
>
> ...the answer is nothing. ;) I guess maybe you were going to
> strbuf_reset() down here at one point? If the 'next' label remains
> empty, I think I'd prefer to keep these as 'continue'. But maybe you use
> it later in the series. I'll read on.
>

I should have explained this, there are two loops here in play. An outer
loop going through refnames to check availability for. An inner loop to
breakdown the path of each refname to check for path conflicts.

With continue, we'd skip the inner loop, but would still perform other
checks for the refname, this can lead to error details being overridden.
So while we could replace s/goto next/continue for the code in the outer
loop, it would still be needed for the inner loop.

>> [...]
>
> The rest of the conversions all looked sensible to me. And you fixed my
> memory leak, which is good. ;)
>
> -Peff

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Re: [PATCH 2/6] refs: attach rejection details to updates

[Jeff King]

On Thu, Jan 15, 2026 at 02:02:15AM -0800, Karthik Nayak wrote:

> >> +	if (details)
> >> +		transaction->updates[update_idx]->rejection_details = xstrdup(details);
> >
> > I guess this could use xstrdup_or_null(), but probably doesn't matter
> > much either way. I do wonder if anybody actually passes a NULL value. I
> > think in my hacky patch there were some spots that did, but here you're
> > always setting the "err" buf (which is good, as we'll always have
> > details then).
> 
> That's correct, I did ensure that there were no NULLs passed through, we
> could definitely drop the check. But I was being defensive. I think
> `xstrdup_or_null()` is the better option here.

I don't mind the extra defensiveness here, but I was wondering whether
this would also mean that ref_transaction_for_each_rejected_update_fn
callbacks could assume that "details" is always non-NULL. But maybe it
is better to be defensive there, too.

> > I notice that you "goto next" now instead of "continue". So I was
> > curious what happens in "next" now, but...
> >
> >> +next:;
> >>  	}
> >
> > ...the answer is nothing. ;) I guess maybe you were going to
> > strbuf_reset() down here at one point? If the 'next' label remains
> > empty, I think I'd prefer to keep these as 'continue'. But maybe you use
> > it later in the series. I'll read on.
> 
> I should have explained this, there are two loops here in play. An outer
> loop going through refnames to check availability for. An inner loop to
> breakdown the path of each refname to check for path conflicts.
> 
> With continue, we'd skip the inner loop, but would still perform other
> checks for the refname, this can lead to error details being overridden.
> So while we could replace s/goto next/continue for the code in the outer
> loop, it would still be needed for the inner loop.

Ah, thanks, I totally missed that it was jumping to the outer loop.

It's curious that the original did a "continue" from that inner loop,
rather than a "break". Once we see that "refs/heads/foo" is a conflict
for a particular update and mark it as failed, there is no point in
looking at "refs/heads/foo/bar" at all. So I suspect we were wasting
a tiny bit of processing in this error case before, but never doing the
wrong thing.

Likewise, if we did "break" from the loop, shouldn't we "continue" to
the next ref immediately? There is no need to do further checks.

Your new goto solves both of those; it's just subtle. So two possible
suggestions for making this more clear:

  - if we are going to use a label, call it next_ref or something, to
    make it clear we are jumping to the outer loop over the refs.

  - switch to the goto as a preparatory patch. It's the right thing even
    before changing the "err" handling, and the change will be more
    obvious that way.

There is another way of writing it, which is to break out of the inner
loop, and then notice that we did so. Either with an explicit flag, or
in this case we can do it by checking slash. Like this:

diff --git a/refs.c b/refs.c
index 965b232a06..a3dafdb58b 100644
--- a/refs.c
+++ b/refs.c
@@ -2663,7 +2663,7 @@ enum ref_transaction_error refs_verify_refnames_available(struct ref_store *refs
 					    REF_TRANSACTION_ERROR_NAME_CONFLICT)) {
 					strset_remove(&dirnames, dirname.buf);
 					strset_add(&conflicting_dirnames, dirname.buf);
-					continue;
+					break;
 				}
 
 				strbuf_addf(err, _("'%s' exists; cannot create '%s'"),
@@ -2676,7 +2676,7 @@ enum ref_transaction_error refs_verify_refnames_available(struct ref_store *refs
 					    transaction, *update_idx,
 					    REF_TRANSACTION_ERROR_NAME_CONFLICT)) {
 					strset_remove(&dirnames, dirname.buf);
-					continue;
+					break;
 				}
 
 				strbuf_addf(err, _("cannot process '%s' and '%s' at the same time"),
@@ -2685,6 +2685,13 @@ enum ref_transaction_error refs_verify_refnames_available(struct ref_store *refs
 			}
 		}
 
+		/*
+		 * We didn't finish our loop over the components, which means
+		 * we hit a conflict. Bail to the next ref now.
+		 */
+		if (slash)
+			continue;
+
 		/*
 		 * We are at the leaf of our refname (e.g., "refs/foo/bar").
 		 * There is no point in searching for a reference with that


That's more "structured" in that we avoid the goto. But I'm not sure it
is any easier to understand than a "next_ref" label. So I'm happy with
either approach. ;)

-Peff

Re: [PATCH 2/6] refs: attach rejection details to updates

[Karthik Nayak]

[-- Attachment #1: Type: text/plain, Size: 5467 bytes --]

Jeff King <peff@peff.net> writes:

> On Thu, Jan 15, 2026 at 02:02:15AM -0800, Karthik Nayak wrote:
>
>> >> +	if (details)
>> >> +		transaction->updates[update_idx]->rejection_details = xstrdup(details);
>> >
>> > I guess this could use xstrdup_or_null(), but probably doesn't matter
>> > much either way. I do wonder if anybody actually passes a NULL value. I
>> > think in my hacky patch there were some spots that did, but here you're
>> > always setting the "err" buf (which is good, as we'll always have
>> > details then).
>>
>> That's correct, I did ensure that there were no NULLs passed through, we
>> could definitely drop the check. But I was being defensive. I think
>> `xstrdup_or_null()` is the better option here.
>
> I don't mind the extra defensiveness here, but I was wondering whether
> this would also mean that ref_transaction_for_each_rejected_update_fn
> callbacks could assume that "details" is always non-NULL. But maybe it
> is better to be defensive there, too.
>

Since I've moved to passing in the strbuf instead of the 'char *', this
is now removed!

>> > I notice that you "goto next" now instead of "continue". So I was
>> > curious what happens in "next" now, but...
>> >
>> >> +next:;
>> >>  	}
>> >
>> > ...the answer is nothing. ;) I guess maybe you were going to
>> > strbuf_reset() down here at one point? If the 'next' label remains
>> > empty, I think I'd prefer to keep these as 'continue'. But maybe you use
>> > it later in the series. I'll read on.
>>
>> I should have explained this, there are two loops here in play. An outer
>> loop going through refnames to check availability for. An inner loop to
>> breakdown the path of each refname to check for path conflicts.
>>
>> With continue, we'd skip the inner loop, but would still perform other
>> checks for the refname, this can lead to error details being overridden.
>> So while we could replace s/goto next/continue for the code in the outer
>> loop, it would still be needed for the inner loop.
>
> Ah, thanks, I totally missed that it was jumping to the outer loop.
>
> It's curious that the original did a "continue" from that inner loop,
> rather than a "break". Once we see that "refs/heads/foo" is a conflict
> for a particular update and mark it as failed, there is no point in
> looking at "refs/heads/foo/bar" at all. So I suspect we were wasting
> a tiny bit of processing in this error case before, but never doing the
> wrong thing.
>

With the previous situation of not resetting strbuf after rejecting an
update, we ended up adding more errors to the same strbuf and since we
kept rejecting the same reference again and again, this causes the last
rejection with multiple messages appended to the strbuf to be displayed
to the user.

This is moot now, considering we reset the strbuf, but that's how I
noticed it.

> Likewise, if we did "break" from the loop, shouldn't we "continue" to
> the next ref immediately? There is no need to do further checks.
>
> Your new goto solves both of those; it's just subtle. So two possible
> suggestions for making this more clear:
>

Yes, I agree with it not being explicit.

>   - if we are going to use a label, call it next_ref or something, to
>     make it clear we are jumping to the outer loop over the refs.
>

This is a good suggestion, makes it much nicer to comprehend.

>   - switch to the goto as a preparatory patch. It's the right thing even
>     before changing the "err" handling, and the change will be more
>     obvious that way.
>

This is a fair point too, I'll do this.

> There is another way of writing it, which is to break out of the inner
> loop, and then notice that we did so. Either with an explicit flag, or
> in this case we can do it by checking slash. Like this:
>

This is an interesting approach, but it is very a bit harder to read in
my opinion since the final logic is collation of 'break' + 'continue if
slash'.

> diff --git a/refs.c b/refs.c
> index 965b232a06..a3dafdb58b 100644
> --- a/refs.c
> +++ b/refs.c
> @@ -2663,7 +2663,7 @@ enum ref_transaction_error refs_verify_refnames_available(struct ref_store *refs
>  					    REF_TRANSACTION_ERROR_NAME_CONFLICT)) {
>  					strset_remove(&dirnames, dirname.buf);
>  					strset_add(&conflicting_dirnames, dirname.buf);
> -					continue;
> +					break;
>  				}
>
>  				strbuf_addf(err, _("'%s' exists; cannot create '%s'"),
> @@ -2676,7 +2676,7 @@ enum ref_transaction_error refs_verify_refnames_available(struct ref_store *refs
>  					    transaction, *update_idx,
>  					    REF_TRANSACTION_ERROR_NAME_CONFLICT)) {
>  					strset_remove(&dirnames, dirname.buf);
> -					continue;
> +					break;
>  				}
>
>  				strbuf_addf(err, _("cannot process '%s' and '%s' at the same time"),
> @@ -2685,6 +2685,13 @@ enum ref_transaction_error refs_verify_refnames_available(struct ref_store *refs
>  			}
>  		}
>
> +		/*
> +		 * We didn't finish our loop over the components, which means
> +		 * we hit a conflict. Bail to the next ref now.
> +		 */
> +		if (slash)
> +			continue;
> +
>  		/*
>  		 * We are at the leaf of our refname (e.g., "refs/foo/bar").
>  		 * There is no point in searching for a reference with that
>
>
> That's more "structured" in that we avoid the goto. But I'm not sure it
> is any easier to understand than a "next_ref" label. So I'm happy with
> either approach. ;)
>
> -Peff

I think the 'next_ref' approach with a separate commit chalked out for
it, seems like the best approach. Thanks

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[PATCH 3/6] refs: add rejection detail to the callback function

[Karthik Nayak]

The previous commit started storing the rejection details alongside the
error code for rejected updates. Pass this along to the callback
function `ref_transaction_for_each_rejected_update()`. Currently the
field is unused, but will be integrated in the upcoming commits.

Co-authored-by: Jeff King <peff@peff.net>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
---
 builtin/fetch.c        | 1 +
 builtin/receive-pack.c | 1 +
 builtin/update-ref.c   | 1 +
 refs.c                 | 2 +-
 refs.h                 | 1 +
 5 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/builtin/fetch.c b/builtin/fetch.c
index 288d3772ea..d427adea61 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -1649,6 +1649,7 @@ static void ref_transaction_rejection_handler(const char *refname,
 					      const char *old_target UNUSED,
 					      const char *new_target UNUSED,
 					      enum ref_transaction_error err,
+					      const char *details UNUSED,
 					      void *cb_data)
 {
 	struct ref_rejection_data *data = cb_data;
diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index ef1f77be8c..94d3e73cee 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -1813,6 +1813,7 @@ static void ref_transaction_rejection_handler(const char *refname,
 					      const char *old_target UNUSED,
 					      const char *new_target UNUSED,
 					      enum ref_transaction_error err,
+					      const char *details UNUSED,
 					      void *cb_data)
 {
 	struct strmap *failed_refs = cb_data;
diff --git a/builtin/update-ref.c b/builtin/update-ref.c
index 195437e7c6..0046a87c57 100644
--- a/builtin/update-ref.c
+++ b/builtin/update-ref.c
@@ -573,6 +573,7 @@ static void print_rejected_refs(const char *refname,
 				const char *old_target,
 				const char *new_target,
 				enum ref_transaction_error err,
+				const char *details UNUSED,
 				void *cb_data UNUSED)
 {
 	struct strbuf sb = STRBUF_INIT;
diff --git a/refs.c b/refs.c
index 991bd8e6ee..ad1898598f 100644
--- a/refs.c
+++ b/refs.c
@@ -2880,7 +2880,7 @@ void ref_transaction_for_each_rejected_update(struct ref_transaction *transactio
 		   (update->flags & REF_HAVE_OLD) ? &update->old_oid : NULL,
 		   (update->flags & REF_HAVE_NEW) ? &update->new_oid : NULL,
 		   update->old_target, update->new_target,
-		   update->rejection_err, cb_data);
+		   update->rejection_err, update->rejection_details, cb_data);
 	}
 }
 
diff --git a/refs.h b/refs.h
index d9051bbb04..4fbe3da924 100644
--- a/refs.h
+++ b/refs.h
@@ -975,6 +975,7 @@ typedef void ref_transaction_for_each_rejected_update_fn(const char *refname,
 							 const char *old_target,
 							 const char *new_target,
 							 enum ref_transaction_error err,
+							 const char *details,
 							 void *cb_data);
 void ref_transaction_for_each_rejected_update(struct ref_transaction *transaction,
 					      ref_transaction_for_each_rejected_update_fn cb,

-- 
2.51.2

Re: [PATCH 3/6] refs: add rejection detail to the callback function

[Jeff King]

On Wed, Jan 14, 2026 at 04:40:44PM +0100, Karthik Nayak wrote:

> The previous commit started storing the rejection details alongside the
> error code for rejected updates. Pass this along to the callback
> function `ref_transaction_for_each_rejected_update()`. Currently the
> field is unused, but will be integrated in the upcoming commits.

Splitting it out like this seems reasonable.

> Co-authored-by: Jeff King <peff@peff.net>
> Signed-off-by: Karthik Nayak <karthik.188@gmail.com>

In case it matters, you can add my:

  Signed-off-by: Jeff King <peff@peff.net>

to this and any other patches which were derived from my earlier
attempt.

-Peff

Re: [PATCH 3/6] refs: add rejection detail to the callback function

[Karthik Nayak]

[-- Attachment #1: Type: text/plain, Size: 753 bytes --]

Jeff King <peff@peff.net> writes:

> On Wed, Jan 14, 2026 at 04:40:44PM +0100, Karthik Nayak wrote:
>
>> The previous commit started storing the rejection details alongside the
>> error code for rejected updates. Pass this along to the callback
>> function `ref_transaction_for_each_rejected_update()`. Currently the
>> field is unused, but will be integrated in the upcoming commits.
>
> Splitting it out like this seems reasonable.
>
>> Co-authored-by: Jeff King <peff@peff.net>
>> Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
>
> In case it matters, you can add my:
>
>   Signed-off-by: Jeff King <peff@peff.net>
>
> to this and any other patches which were derived from my earlier
> attempt.
>
> -Peff

Thanks, will add in the next version.

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[PATCH 4/6] update-ref: utilize rejected error details if available

[Karthik Nayak]

When git-update-ref(1) received the '--update-ref' flag, the error
details generated in the refs namespace wasn't propagated with failed
updates. Instead only an error code pertaining to the type of rejection
was noted.

This missed detailed error message which the user can act upon. The
previous commits added the required code to propagate these detailed
error messages from the refs namespace. Now that additional details are
available, use them instead of the generic error message based of the
error code. Fix the tests to also accommodate these error messages.

Reported-by: Elijah Newren <newren@gmail.com>
Co-authored-by: Jeff King <peff@peff.net>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
---
 builtin/update-ref.c  | 14 ++++++++------
 t/t1400-update-ref.sh | 26 +++++++++++++-------------
 2 files changed, 21 insertions(+), 19 deletions(-)

diff --git a/builtin/update-ref.c b/builtin/update-ref.c
index 0046a87c57..800e380d32 100644
--- a/builtin/update-ref.c
+++ b/builtin/update-ref.c
@@ -573,16 +573,18 @@ static void print_rejected_refs(const char *refname,
 				const char *old_target,
 				const char *new_target,
 				enum ref_transaction_error err,
-				const char *details UNUSED,
+				const char *details,
 				void *cb_data UNUSED)
 {
 	struct strbuf sb = STRBUF_INIT;
-	const char *reason = ref_transaction_error_msg(err);
 
-	strbuf_addf(&sb, "rejected %s %s %s %s\n", refname,
-		    new_oid ? oid_to_hex(new_oid) : new_target,
-		    old_oid ? oid_to_hex(old_oid) : old_target,
-		    reason);
+	if (details)
+		strbuf_addf(&sb, "%s\n", details);
+	else
+		strbuf_addf(&sb, "rejected %s %s %s %s\n", refname,
+			    new_oid ? oid_to_hex(new_oid) : new_target,
+			    old_oid ? oid_to_hex(old_oid) : old_target,
+			    ref_transaction_error_msg(err));
 
 	fwrite(sb.buf, sb.len, 1, stdout);
 	strbuf_release(&sb);
diff --git a/t/t1400-update-ref.sh b/t/t1400-update-ref.sh
index db7f5444da..6cd6b45411 100755
--- a/t/t1400-update-ref.sh
+++ b/t/t1400-update-ref.sh
@@ -2100,7 +2100,7 @@ do
 			echo $head >expect &&
 			git rev-parse refs/heads/ref2 >actual &&
 			test_cmp expect actual &&
-			test_grep -q "invalid new value provided" stdout
+			test_grep -q "trying to write ref ${SQ}refs/heads/ref2${SQ} with nonexistent object" stdout
 		)
 	'
 
@@ -2126,7 +2126,7 @@ do
 			echo $head >expect &&
 			git rev-parse refs/heads/ref2 >actual &&
 			test_cmp expect actual &&
-			test_grep -q "invalid new value provided" stdout
+			test_grep -q "trying to write non-commit object $head_tree to branch ${SQ}refs/heads/ref2${SQ}" stdout
 		)
 	'
 
@@ -2148,7 +2148,7 @@ do
 			git rev-parse refs/heads/ref1 >actual &&
 			test_cmp expect actual &&
 			test_must_fail git rev-parse refs/heads/ref2 &&
-			test_grep -q "reference does not exist" stdout
+			test_grep -q "cannot lock ref ${SQ}refs/heads/ref2${SQ}: unable to resolve reference ${SQ}refs/heads/ref2${SQ}" stdout
 		)
 	'
 
@@ -2172,7 +2172,7 @@ do
 			test_cmp expect actual &&
 			echo $head >expect &&
 			test_must_fail git rev-parse refs/heads/ref2 &&
-			test_grep -q "reference does not exist" stdout
+			test_grep -q "cannot lock ref ${SQ}refs/heads/ref2${SQ}: reference is missing but expected $head" stdout
 		)
 	'
 
@@ -2198,7 +2198,7 @@ do
 			echo $head >expect &&
 			git rev-parse refs/heads/ref2 >actual &&
 			test_cmp expect actual &&
-			test_grep -q "expected symref but found regular ref" stdout
+			test_grep -q "cannot lock ref ${SQ}refs/heads/ref2${SQ}: expected symref with target ${SQ}refs/heads/nonexistent${SQ}: but is a regular ref" stdout
 		)
 	'
 
@@ -2223,7 +2223,7 @@ do
 			echo $head >expect &&
 			git rev-parse refs/heads/ref2 >actual &&
 			test_cmp expect actual &&
-			test_grep -q "reference already exists" stdout
+			test_grep -q "cannot lock ref ${SQ}refs/heads/ref2${SQ}: reference already exists" stdout
 		)
 	'
 
@@ -2248,7 +2248,7 @@ do
 			echo $head >expect &&
 			git rev-parse refs/heads/ref2 >actual &&
 			test_cmp expect actual &&
-			test_grep -q "incorrect old value provided" stdout
+			test_grep -q "cannot lock ref ${SQ}refs/heads/ref2${SQ}: is at $head but expected $old_head" stdout
 		)
 	'
 
@@ -2269,7 +2269,7 @@ do
 			echo $old_head >expect &&
 			git rev-parse refs/heads/ref/foo >actual &&
 			test_cmp expect actual &&
-			test_grep -q "refname conflict" stdout
+			test_grep -q "${SQ}refs/heads/ref/foo${SQ} exists; cannot create ${SQ}refs/heads/ref${SQ}" stdout
 		)
 	'
 
@@ -2290,7 +2290,7 @@ do
 			echo $old_head >expect &&
 			git rev-parse refs/heads/foo >actual &&
 			test_cmp expect actual &&
-			test_grep -q "refname conflict" stdout
+			test_grep -q "${SQ}refs/heads/ref/foo${SQ} exists; cannot create ${SQ}refs/heads/ref${SQ}" stdout
 		)
 	'
 
@@ -2316,7 +2316,7 @@ do
 			echo $old_head >expect &&
 			git rev-parse refs/heads/ref >actual &&
 			test_cmp expect actual &&
-			test_grep -q "reference conflict due to case-insensitive filesystem" stdout
+			test_grep -e "cannot lock ref ${SQ}refs/heads/Foo${SQ}: Unable to create" -e "Foo.lock" stdout
 		)
 	'
 
@@ -2358,7 +2358,7 @@ do
 
 			format_command $type "delete refs/heads/symbolic" "$head" >stdin &&
 			git update-ref $type --stdin --batch-updates <stdin >stdout &&
-			test_grep "reference does not exist" stdout
+			test_grep "cannot lock ref ${SQ}refs/heads/symbolic${SQ}: unable to resolve reference ${SQ}refs/heads/non-existent${SQ}" stdout
 		)
 	'
 
@@ -2374,7 +2374,7 @@ do
 
 			format_command $type "delete refs/heads/new-branch" "$head" >stdin &&
 			git update-ref $type --stdin --batch-updates <stdin >stdout &&
-			test_grep "incorrect old value provided" stdout
+			test_grep "cannot lock ref ${SQ}refs/heads/new-branch${SQ}: is at $(git rev-parse new-branch) but expected $head" stdout
 		)
 	'
 
@@ -2388,7 +2388,7 @@ do
 
 			format_command $type "delete refs/heads/non-existent" "$head" >stdin &&
 			git update-ref $type --stdin --batch-updates <stdin >stdout &&
-			test_grep "reference does not exist" stdout
+			test_grep "cannot lock ref ${SQ}refs/heads/non-existent${SQ}: unable to resolve reference ${SQ}refs/heads/non-existent${SQ}" stdout
 		)
 	'
 done

-- 
2.51.2

Re: [PATCH 4/6] update-ref: utilize rejected error details if available

[Junio C Hamano]

Karthik Nayak <karthik.188@gmail.com> writes:

> @@ -573,16 +573,18 @@ static void print_rejected_refs(const char *refname,
>  				const char *old_target,
>  				const char *new_target,
>  				enum ref_transaction_error err,
> -				const char *details UNUSED,
> +				const char *details,
>  				void *cb_data UNUSED)
>  {
>  	struct strbuf sb = STRBUF_INIT;
> -	const char *reason = ref_transaction_error_msg(err);
>  
> -	strbuf_addf(&sb, "rejected %s %s %s %s\n", refname,
> -		    new_oid ? oid_to_hex(new_oid) : new_target,
> -		    old_oid ? oid_to_hex(old_oid) : old_target,
> -		    reason);
> +	if (details)
> +		strbuf_addf(&sb, "%s\n", details);
> +	else
> +		strbuf_addf(&sb, "rejected %s %s %s %s\n", refname,
> +			    new_oid ? oid_to_hex(new_oid) : new_target,
> +			    old_oid ? oid_to_hex(old_oid) : old_target,
> +			    ref_transaction_error_msg(err));

Could "details" reported from the lower layer be less detailed than
what we are formulating here, like updating the value of what ref
from what old object to what new object, or what the err code tells
the end-user?

Re: [PATCH 4/6] update-ref: utilize rejected error details if available

[Jeff King]

On Wed, Jan 14, 2026 at 09:27:28AM -0800, Junio C Hamano wrote:

> Karthik Nayak <karthik.188@gmail.com> writes:
> 
> > @@ -573,16 +573,18 @@ static void print_rejected_refs(const char *refname,
> >  				const char *old_target,
> >  				const char *new_target,
> >  				enum ref_transaction_error err,
> > -				const char *details UNUSED,
> > +				const char *details,
> >  				void *cb_data UNUSED)
> >  {
> >  	struct strbuf sb = STRBUF_INIT;
> > -	const char *reason = ref_transaction_error_msg(err);
> >  
> > -	strbuf_addf(&sb, "rejected %s %s %s %s\n", refname,
> > -		    new_oid ? oid_to_hex(new_oid) : new_target,
> > -		    old_oid ? oid_to_hex(old_oid) : old_target,
> > -		    reason);
> > +	if (details)
> > +		strbuf_addf(&sb, "%s\n", details);
> > +	else
> > +		strbuf_addf(&sb, "rejected %s %s %s %s\n", refname,
> > +			    new_oid ? oid_to_hex(new_oid) : new_target,
> > +			    old_oid ? oid_to_hex(old_oid) : old_target,
> > +			    ref_transaction_error_msg(err));
> 
> Could "details" reported from the lower layer be less detailed than
> what we are formulating here, like updating the value of what ref
> from what old object to what new object, or what the err code tells
> the end-user?

I wondered that, too, but also: is this supposed to be machine-readable?
The "rejected ..." output looks like something that could be parsed,
and it seems to be documented in git-update-ref(1).

  Side note: if this is meant to be a stable format, surely there should
  be some coverage in the test suite? There doesn't seem to be.

So should we just be replacing the ref_transaction_error_msg() part? I
_think_ the low-level details will usually be more informative there,
but not necessarily. So possibly we'd even want to show both, though I
suspect just concatenating them would be messy.

Plus the "details" one has a lot of redundant information in it (it
mentions "refname", even though it is already on the "rejected" line).

In the short-term, I wonder if we just want:

  if (details && *details)
	error("%s", details);

That gets us back to the status quo, where the details are at least
available via stderr. And then we can consider how to combine them into
the machine-readable format separately.

-Peff

Re: [PATCH 4/6] update-ref: utilize rejected error details if available

[Karthik Nayak]

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Jeff King <peff@peff.net> writes:

> On Wed, Jan 14, 2026 at 09:27:28AM -0800, Junio C Hamano wrote:
>
>> Karthik Nayak <karthik.188@gmail.com> writes:
>>
>> > @@ -573,16 +573,18 @@ static void print_rejected_refs(const char *refname,
>> >  				const char *old_target,
>> >  				const char *new_target,
>> >  				enum ref_transaction_error err,
>> > -				const char *details UNUSED,
>> > +				const char *details,
>> >  				void *cb_data UNUSED)
>> >  {
>> >  	struct strbuf sb = STRBUF_INIT;
>> > -	const char *reason = ref_transaction_error_msg(err);
>> >
>> > -	strbuf_addf(&sb, "rejected %s %s %s %s\n", refname,
>> > -		    new_oid ? oid_to_hex(new_oid) : new_target,
>> > -		    old_oid ? oid_to_hex(old_oid) : old_target,
>> > -		    reason);
>> > +	if (details)
>> > +		strbuf_addf(&sb, "%s\n", details);
>> > +	else
>> > +		strbuf_addf(&sb, "rejected %s %s %s %s\n", refname,
>> > +			    new_oid ? oid_to_hex(new_oid) : new_target,
>> > +			    old_oid ? oid_to_hex(old_oid) : old_target,
>> > +			    ref_transaction_error_msg(err));
>>
>> Could "details" reported from the lower layer be less detailed than
>> what we are formulating here, like updating the value of what ref
>> from what old object to what new object, or what the err code tells
>> the end-user?
>
> I wondered that, too, but also: is this supposed to be machine-readable?
> The "rejected ..." output looks like something that could be parsed,
> and it seems to be documented in git-update-ref(1).
>
>   Side note: if this is meant to be a stable format, surely there should
>   be some coverage in the test suite? There doesn't seem to be.
>

Good catch, the documentation does indeed promise this format, so it
wouldn't be appropriate to step away from it. Ideally, we should only
replace the last field, but that would be a lot of redundant
information.

Overall, we could also drop this patch too, since the flag was
introduced with batched updates and we could better justice here once we
cleanup all other error messages.

> So should we just be replacing the ref_transaction_error_msg() part? I
> _think_ the low-level details will usually be more informative there,
> but not necessarily. So possibly we'd even want to show both, though I
> suspect just concatenating them would be messy.
>
> Plus the "details" one has a lot of redundant information in it (it
> mentions "refname", even though it is already on the "rejected" line).

Indeed, I've noted all possibilities in another response [1], but there
is some redundancy there and we could do a nice cleanup.
>
> In the short-term, I wonder if we just want:
>
>   if (details && *details)
> 	error("%s", details);
>
> That gets us back to the status quo, where the details are at least
> available via stderr. And then we can consider how to combine them into
> the machine-readable format separately.
>

That's a good compromise too. I'd say we do this for now and see how we
can take it from here.

> -Peff

[1]: CAOLa=ZS0i+YXfVHHAax699ME48YG7jXNZ3WOBYryS0hypMZO-A@mail.gmail.com

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[PATCH 5/6] fetch: utilize rejected ref error details

[Karthik Nayak]

In 0e358de64a (fetch: use batched reference updates, 2025-05-19),
git-fetch(1) switched to using batched reference updates. This also
introduced a regression wherein instead of providing detailed error
messages for failed referenced updates, the users were provided generic
error messages based on the error type.

Similar to the previous commit, switch to using detailed error messages
if present for failed reference updates to fix this regression.

Reported-by: Elijah Newren <newren@gmail.com>
Co-authored-by: Jeff King <peff@peff.net>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
---
 builtin/fetch.c  | 10 ++++++----
 t/t5510-fetch.sh |  8 ++++----
 2 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/builtin/fetch.c b/builtin/fetch.c
index d427adea61..49495be0b6 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -1649,7 +1649,7 @@ static void ref_transaction_rejection_handler(const char *refname,
 					      const char *old_target UNUSED,
 					      const char *new_target UNUSED,
 					      enum ref_transaction_error err,
-					      const char *details UNUSED,
+					      const char *details,
 					      void *cb_data)
 {
 	struct ref_rejection_data *data = cb_data;
@@ -1674,9 +1674,11 @@ static void ref_transaction_rejection_handler(const char *refname,
 			"branches"), data->remote_name);
 		data->conflict_msg_shown = true;
 	} else {
-		const char *reason = ref_transaction_error_msg(err);
-
-		error(_("fetching ref %s failed: %s"), refname, reason);
+		if (details)
+			error("%s", details);
+		else
+			error(_("fetching ref %s failed: %s"),
+			      refname, ref_transaction_error_msg(err));
 	}
 
 	*data->retcode = 1;
diff --git a/t/t5510-fetch.sh b/t/t5510-fetch.sh
index ce1c23684e..c69afb5a60 100755
--- a/t/t5510-fetch.sh
+++ b/t/t5510-fetch.sh
@@ -1516,7 +1516,7 @@ test_expect_success REFFILES 'existing reference lock in repo' '
 		git remote add origin ../base &&
 		touch refs/heads/foo.lock &&
 		test_must_fail git fetch -f origin "refs/heads/*:refs/heads/*" 2>err &&
-		test_grep "error: fetching ref refs/heads/foo failed: reference already exists" err &&
+		test_grep -e "error: cannot lock ref ${SQ}refs/heads/foo${SQ}: Unable to create" -e "refs/heads/foo.lock${SQ}: File exists." err &&
 		git rev-parse refs/heads/main >expect &&
 		git rev-parse refs/heads/branch >actual &&
 		test_cmp expect actual
@@ -1530,7 +1530,7 @@ test_expect_success CASE_INSENSITIVE_FS,REFFILES 'F/D conflict on case insensiti
 		cd case_insensitive &&
 		git remote add origin -- ../case_sensitive_fd &&
 		test_must_fail git fetch -f origin "refs/heads/*:refs/heads/*" 2>err &&
-		test_grep "failed: refname conflict" err &&
+		test_grep "cannot process ${SQ}refs/remotes/origin/foo${SQ} and ${SQ}refs/remotes/origin/foo/bar${SQ} at the same time" err &&
 		git rev-parse refs/heads/main >expect &&
 		git rev-parse refs/heads/foo/bar >actual &&
 		test_cmp expect actual
@@ -1544,7 +1544,7 @@ test_expect_success CASE_INSENSITIVE_FS,REFFILES 'D/F conflict on case insensiti
 		cd case_insensitive &&
 		git remote add origin -- ../case_sensitive_df &&
 		test_must_fail git fetch -f origin "refs/heads/*:refs/heads/*" 2>err &&
-		test_grep "failed: refname conflict" err &&
+		test_grep "cannot lock ref ${SQ}refs/remotes/origin/foo${SQ}: there is a non-empty directory ${SQ}./refs/remotes/origin/foo${SQ} blocking reference ${SQ}refs/remotes/origin/foo${SQ}" err &&
 		git rev-parse refs/heads/main >expect &&
 		git rev-parse refs/heads/Foo/bar >actual &&
 		test_cmp expect actual
@@ -1658,7 +1658,7 @@ test_expect_success REFFILES "FETCH_HEAD is updated even if ref updates fail" '
 		git remote add origin ../base &&
 		>refs/heads/foo.lock &&
 		test_must_fail git fetch -f origin "refs/heads/*:refs/heads/*" 2>err &&
-		test_grep "error: fetching ref refs/heads/foo failed: reference already exists" err &&
+		test_grep -e "error: cannot lock ref ${SQ}refs/heads/foo${SQ}: Unable to create" -e "refs/heads/foo.lock${SQ}: File exists." err &&
 		test_grep "branch ${SQ}branch${SQ} of ../base" FETCH_HEAD &&
 		test_grep "branch ${SQ}foo${SQ} of ../base" FETCH_HEAD
 	)

-- 
2.51.2

Re: [PATCH 5/6] fetch: utilize rejected ref error details

[Junio C Hamano]

Karthik Nayak <karthik.188@gmail.com> writes:

> In 0e358de64a (fetch: use batched reference updates, 2025-05-19),
> git-fetch(1) switched to using batched reference updates. This also
> introduced a regression wherein instead of providing detailed error
> messages for failed referenced updates, the users were provided generic
> error messages based on the error type.
>
> Similar to the previous commit, switch to using detailed error messages
> if present for failed reference updates to fix this regression.

The same question applkies as the previous step.  That is ...

> @@ -1674,9 +1674,11 @@ static void ref_transaction_rejection_handler(const char *refname,
>  			"branches"), data->remote_name);
>  		data->conflict_msg_shown = true;
>  	} else {
> -		const char *reason = ref_transaction_error_msg(err);
> -
> -		error(_("fetching ref %s failed: %s"), refname, reason);
> +		if (details)
> +			error("%s", details);
> +		else
> +			error(_("fetching ref %s failed: %s"),
> +			      refname, ref_transaction_error_msg(err));

... would "details" always carry enough information to cover
"refname" here, plus what the err code tells us?

I guess ...

> diff --git a/t/t5510-fetch.sh b/t/t5510-fetch.sh
> index ce1c23684e..c69afb5a60 100755
> --- a/t/t5510-fetch.sh
> +++ b/t/t5510-fetch.sh
> @@ -1516,7 +1516,7 @@ test_expect_success REFFILES 'existing reference lock in repo' '
>  		git remote add origin ../base &&
>  		touch refs/heads/foo.lock &&
>  		test_must_fail git fetch -f origin "refs/heads/*:refs/heads/*" 2>err &&
> -		test_grep "error: fetching ref refs/heads/foo failed: reference already exists" err &&
> +		test_grep -e "error: cannot lock ref ${SQ}refs/heads/foo${SQ}: Unable to create" -e "refs/heads/foo.lock${SQ}: File exists." err &&

... the error only talks about our local name, and when the command
is "git fetch origin refs/heads/foo:refs/remotes/origin/bar", we
only complain about refs/remotes/origin/bar without ever mentioning
refs/heads/foo on the remote side, so I think "details" has enough
information to replace the existing message here in this case.

Thanks.

Re: [PATCH 5/6] fetch: utilize rejected ref error details

[Karthik Nayak]

[-- Attachment #1: Type: text/plain, Size: 5105 bytes --]

Junio C Hamano <gitster@pobox.com> writes:

> Karthik Nayak <karthik.188@gmail.com> writes:
>
>> In 0e358de64a (fetch: use batched reference updates, 2025-05-19),
>> git-fetch(1) switched to using batched reference updates. This also
>> introduced a regression wherein instead of providing detailed error
>> messages for failed referenced updates, the users were provided generic
>> error messages based on the error type.
>>
>> Similar to the previous commit, switch to using detailed error messages
>> if present for failed reference updates to fix this regression.
>
> The same question applkies as the previous step.  That is ...
>
>> @@ -1674,9 +1674,11 @@ static void ref_transaction_rejection_handler(const char *refname,
>>  			"branches"), data->remote_name);
>>  		data->conflict_msg_shown = true;
>>  	} else {
>> -		const char *reason = ref_transaction_error_msg(err);
>> -
>> -		error(_("fetching ref %s failed: %s"), refname, reason);
>> +		if (details)
>> +			error("%s", details);
>> +		else
>> +			error(_("fetching ref %s failed: %s"),
>> +			      refname, ref_transaction_error_msg(err));
>
> ... would "details" always carry enough information to cover
> "refname" here, plus what the err code tells us?
>
> I guess ...
>

In general, yes. Here's the final detailed error we'd show:

generic availability checks (files + reftable backend):
- '%s' exists; cannot create '%s'
- cannot process '%s' and '%s' at the same time

packed-backend:
- cannot update ref '%s': reference already exists
- cannot update ref '%s': is at %s but expected %s
- cannot update ref '%s': reference is missing but expected %s

files-backend:
- cannot lock ref '%s': '%s' exists; cannot create '%s'
- cannot lock ref '%s': cannot process '%s' and '%s' at the same time
- cannot lock ref '%s': unable to resolve reference '%s'
- multiple updates for 'HEAD' (including one via its referent '%s')
are not allowed
- cannot lock ref '%s': Unable to create '%s.lock': %s.\n\n
  Another git process seems to be running in this repository, e.g.\n an
  editor opened by 'git commit'. Please make sure all processes\n are
  terminated then try again. If it still fails, a git process\n may have
  crashed in this repository earlier:\n remove the file manually to
  continue.
- cannot lock ref '%s': Unable to create '%s.lock': %s
- cannot lock ref '%s': dangling symref already exists
- cannot lock ref '%s': expected symref with target '%s': but is a regular ref
- cannot lock ref '%s': is at %s but expected %s
- cannot lock ref '%s': reference already exists
- cannot lock ref '%s': reference is missing but expected %s
- cannot lock ref '%s': there is a non-empty directory '%s' blocking
reference '%s'
- cannot lock ref '%s': unable to resolve reference '%s'
- cannot update ref '%s': trying to write non-commit object %s to branch '%s'
- cannot update ref '%s': trying to write ref '%s' with nonexistent object %s
- multiple updates for '%s' (including one via symref '%s') are not allowed
- verifying symref target: '%s': is at %s but expected %s
- verifying symref target: '%s': reference is missing but expected %s

reftable-backend:
- cannot lock ref '%s': dangling symref already exists
- cannot lock ref '%s': expected symref with target '%s': but is a
regular ref
- cannot lock ref '%s': is at %s but expected %s
- cannot lock ref '%s': reference already exists
- cannot lock ref '%s': reference is missing but expected %s
- cannot lock ref '%s': unable to resolve reference '%s'
- multiple updates for '%s' (including one via symref '%s') are not allowed
- multiple updates for 'HEAD' (including one via its referent '%s')
are not allowed
- trying to write non-commit object %s to branch '%s'
- trying to write ref '%s' with nonexistent object %s
- verifying symref target: '%s': is at %s but expected %s
- verifying symref target: '%s': reference is missing but expected %s


>> diff --git a/t/t5510-fetch.sh b/t/t5510-fetch.sh
>> index ce1c23684e..c69afb5a60 100755
>> --- a/t/t5510-fetch.sh
>> +++ b/t/t5510-fetch.sh
>> @@ -1516,7 +1516,7 @@ test_expect_success REFFILES 'existing reference lock in repo' '
>>  		git remote add origin ../base &&
>>  		touch refs/heads/foo.lock &&
>>  		test_must_fail git fetch -f origin "refs/heads/*:refs/heads/*" 2>err &&
>> -		test_grep "error: fetching ref refs/heads/foo failed: reference already exists" err &&
>> +		test_grep -e "error: cannot lock ref ${SQ}refs/heads/foo${SQ}: Unable to create" -e "refs/heads/foo.lock${SQ}: File exists." err &&
>
> ... the error only talks about our local name, and when the command
> is "git fetch origin refs/heads/foo:refs/remotes/origin/bar", we
> only complain about refs/remotes/origin/bar without ever mentioning
> refs/heads/foo on the remote side, so I think "details" has enough
> information to replace the existing message here in this case.
>
> Thanks.
>

Yup. I do think there is a good cleanup we could potentially do here,
with some of the error messages and perhaps following a better pattern
in general, perhaps a more structured error message. But I didn't want
to tackle that in this series.

Karthik

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Re: [PATCH 5/6] fetch: utilize rejected ref error details

[Jeff King]

On Wed, Jan 14, 2026 at 04:40:46PM +0100, Karthik Nayak wrote:

> @@ -1674,9 +1674,11 @@ static void ref_transaction_rejection_handler(const char *refname,
>  			"branches"), data->remote_name);
>  		data->conflict_msg_shown = true;
>  	} else {
> -		const char *reason = ref_transaction_error_msg(err);
> -
> -		error(_("fetching ref %s failed: %s"), refname, reason);
> +		if (details)
> +			error("%s", details);
> +		else
> +			error(_("fetching ref %s failed: %s"),
> +			      refname, ref_transaction_error_msg(err));
>  	}

OK, so here we're writing to stderr anyway, and now we'll just give the
more detailed data. Makes sense (though like Junio, I do wonder if the
existing message might provide more details in some cases).

BTW, I think there is still a related fallout for git-fetch. Even with
your patch, doing this:

  $ git fetch . v1.0.0:refs/heads/foo
  From .
   * [new tag]               v1.0.0     -> foo
  error: cannot update ref 'refs/heads/foo': trying to write non-commit object f665776185ad074b236c00751d666da7d1977dbe to branch 'refs/heads/foo'

will not put anything in the status table. Whereas in v2.50.0 and
earlier, we get:

  $ git.v2.50.0 fetch . v1.0.0:refs/heads/foo
  error: cannot update ref 'refs/heads/foo': trying to write non-commit object f665776185ad074b236c00751d666da7d1977dbe to branch 'refs/heads/foo'
  From .
   ! [new tag]               v1.0.0     -> foo  (unable to update local ref)

Note the "!" and the "unable to update local ref" message in the status
table.

-Peff

Re: [PATCH 5/6] fetch: utilize rejected ref error details

[Karthik Nayak]

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Jeff King <peff@peff.net> writes:

> On Wed, Jan 14, 2026 at 04:40:46PM +0100, Karthik Nayak wrote:
>
>> @@ -1674,9 +1674,11 @@ static void ref_transaction_rejection_handler(const char *refname,
>>  			"branches"), data->remote_name);
>>  		data->conflict_msg_shown = true;
>>  	} else {
>> -		const char *reason = ref_transaction_error_msg(err);
>> -
>> -		error(_("fetching ref %s failed: %s"), refname, reason);
>> +		if (details)
>> +			error("%s", details);
>> +		else
>> +			error(_("fetching ref %s failed: %s"),
>> +			      refname, ref_transaction_error_msg(err));
>>  	}
>
> OK, so here we're writing to stderr anyway, and now we'll just give the
> more detailed data. Makes sense (though like Junio, I do wonder if the
> existing message might provide more details in some cases).
>
> BTW, I think there is still a related fallout for git-fetch. Even with
> your patch, doing this:
>
>   $ git fetch . v1.0.0:refs/heads/foo
>   From .
>    * [new tag]               v1.0.0     -> foo
>   error: cannot update ref 'refs/heads/foo': trying to write non-commit object f665776185ad074b236c00751d666da7d1977dbe to branch 'refs/heads/foo'
>
> will not put anything in the status table. Whereas in v2.50.0 and
> earlier, we get:
>
>   $ git.v2.50.0 fetch . v1.0.0:refs/heads/foo
>   error: cannot update ref 'refs/heads/foo': trying to write non-commit object f665776185ad074b236c00751d666da7d1977dbe to branch 'refs/heads/foo'
>   From .
>    ! [new tag]               v1.0.0     -> foo  (unable to update local ref)
>
> Note the "!" and the "unable to update local ref" message in the status
> table.
>
> -Peff

This one is a bit harder to crack, earlier we were getting reference
update results right as we added individual updates. Now that
information is only received at the end when it is committed, we just
don't have that information.

One way is to delay this output until we commit everything. But we don't
want to iterate over refs unnecessarily, so probably store these in a
list, and then iterate over them.

I'll try and add a patch for this too. Thanks for reporting.

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[PATCH 6/6] receive-pack: utilize rejected ref error details

[Karthik Nayak]

In 9d2962a7c4 (receive-pack: use batched reference updates, 2025-05-19),
git-receive-pack(1) switched to using batched reference updates. This also
introduced a regression wherein instead of providing detailed error
messages for failed referenced updates, the users were provided generic
error messages based on the error type.

Similar to the previous commit, switch to using detailed error messages
if present for failed reference updates to fix this regression.

One downside of this is that the messages can be very verbose, for e.g.
in the files backend, when trying to write a non-commit object to a
branch, you would see:

   ! [remote rejected] 3eaec9ccf3a53f168362a6b3fdeb73426fb9813d ->
   branch (cannot update ref 'refs/heads/branch': trying to write
   non-commit object 3eaec9ccf3a53f168362a6b3fdeb73426fb9813d to branch
   'refs/heads/branch')

Here the refname is repeated multiple times due to how error messages
are propagated and filled over the code stack. This potentially can be
cleaned up in a future commit.

Reported-by: Elijah Newren <newren@gmail.com>
Co-authored-by: Jeff King <peff@peff.net>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
---
 builtin/receive-pack.c | 10 +++++++---
 t/t5516-fetch-push.sh  | 15 +++++++++++++++
 2 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index 94d3e73cee..969d59ae3e 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -1813,12 +1813,15 @@ static void ref_transaction_rejection_handler(const char *refname,
 					      const char *old_target UNUSED,
 					      const char *new_target UNUSED,
 					      enum ref_transaction_error err,
-					      const char *details UNUSED,
+					      const char *details,
 					      void *cb_data)
 {
 	struct strmap *failed_refs = cb_data;
 
-	strmap_put(failed_refs, refname, (char *)ref_transaction_error_msg(err));
+	if (!details)
+		details = ref_transaction_error_msg(err);
+
+	strmap_put(failed_refs, refname, (char *)details);
 }
 
 static void execute_commands_non_atomic(struct command *commands,
@@ -1884,6 +1887,7 @@ static void execute_commands_non_atomic(struct command *commands,
 		}
 
 		ref_transaction_for_each_rejected_update(transaction,
+
 							 ref_transaction_rejection_handler,
 							 &failed_refs);
 
@@ -1895,7 +1899,7 @@ static void execute_commands_non_atomic(struct command *commands,
 			if (reported_error)
 				cmd->error_string = reported_error;
 			else if (strmap_contains(&failed_refs, cmd->ref_name))
-				cmd->error_string = strmap_get(&failed_refs, cmd->ref_name);
+				cmd->error_string = cmd->error_string_owned = xstrdup(strmap_get(&failed_refs, cmd->ref_name));
 		}
 
 	cleanup:
diff --git a/t/t5516-fetch-push.sh b/t/t5516-fetch-push.sh
index 46926e7bbd..45595991c8 100755
--- a/t/t5516-fetch-push.sh
+++ b/t/t5516-fetch-push.sh
@@ -1882,4 +1882,19 @@ test_expect_success 'push with F/D conflict with deletion and creation' '
 	git push testrepo :refs/heads/branch/conflict refs/heads/branch
 '
 
+test_expect_success 'pushing non-commit objects should report error' '
+	test_when_finished "rm -rf dest repo" &&
+	git init dest &&
+	git init repo &&
+
+	(
+		cd repo &&
+		test_commit --annotate test &&
+
+		tagsha=$(git rev-parse test^{tag}) &&
+		test_must_fail git push ../dest "$tagsha:refs/heads/branch" 2>err &&
+		test_grep "trying to write non-commit object $tagsha to branch ${SQ}refs/heads/branch${SQ}" err
+	)
+'
+
 test_done

-- 
2.51.2

Re: [PATCH 6/6] receive-pack: utilize rejected ref error details

[Jeff King]

On Wed, Jan 14, 2026 at 04:40:47PM +0100, Karthik Nayak wrote:

> In 9d2962a7c4 (receive-pack: use batched reference updates, 2025-05-19),
> git-receive-pack(1) switched to using batched reference updates. This also
> introduced a regression wherein instead of providing detailed error
> messages for failed referenced updates, the users were provided generic
> error messages based on the error type.
> 
> Similar to the previous commit, switch to using detailed error messages
> if present for failed reference updates to fix this regression.
> 
> One downside of this is that the messages can be very verbose, for e.g.
> in the files backend, when trying to write a non-commit object to a
> branch, you would see:
> 
>    ! [remote rejected] 3eaec9ccf3a53f168362a6b3fdeb73426fb9813d ->
>    branch (cannot update ref 'refs/heads/branch': trying to write
>    non-commit object 3eaec9ccf3a53f168362a6b3fdeb73426fb9813d to branch
>    'refs/heads/branch')
> 
> Here the refname is repeated multiple times due to how error messages
> are propagated and filled over the code stack. This potentially can be
> cleaned up in a future commit.

If we are going to have a "potentially cleaned up in the future" state,
I think I would prefer to see just:

  if (details)
	rp_error("%s", details);

here. And then it comes over the stderr sideband, but the actual
status-table gets the same non-verbose message. That's what happened
in v2.50.0 and earlier. Later if we want to try to cram more details
into the machine-readable message we can.

-Peff

Re: [PATCH 6/6] receive-pack: utilize rejected ref error details

[Karthik Nayak]

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Jeff King <peff@peff.net> writes:

> On Wed, Jan 14, 2026 at 04:40:47PM +0100, Karthik Nayak wrote:
>
>> In 9d2962a7c4 (receive-pack: use batched reference updates, 2025-05-19),
>> git-receive-pack(1) switched to using batched reference updates. This also
>> introduced a regression wherein instead of providing detailed error
>> messages for failed referenced updates, the users were provided generic
>> error messages based on the error type.
>>
>> Similar to the previous commit, switch to using detailed error messages
>> if present for failed reference updates to fix this regression.
>>
>> One downside of this is that the messages can be very verbose, for e.g.
>> in the files backend, when trying to write a non-commit object to a
>> branch, you would see:
>>
>>    ! [remote rejected] 3eaec9ccf3a53f168362a6b3fdeb73426fb9813d ->
>>    branch (cannot update ref 'refs/heads/branch': trying to write
>>    non-commit object 3eaec9ccf3a53f168362a6b3fdeb73426fb9813d to branch
>>    'refs/heads/branch')
>>
>> Here the refname is repeated multiple times due to how error messages
>> are propagated and filled over the code stack. This potentially can be
>> cleaned up in a future commit.
>
> If we are going to have a "potentially cleaned up in the future" state,
> I think I would prefer to see just:
>
>   if (details)
> 	rp_error("%s", details);
>
> here. And then it comes over the stderr sideband, but the actual
> status-table gets the same non-verbose message. That's what happened
> in v2.50.0 and earlier. Later if we want to try to cram more details
> into the machine-readable message we can.
>
> -Peff

Fair enough, I think that would be a better approach for now, will
change.

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Re: [PATCH 0/6] refs: provide detailed error messages when using batched update

[Junio C Hamano]

Karthik Nayak <karthik.188@gmail.com> writes:

> The refs namespace uses an error buffer to capture details about failed
> reference updates. However when we added batched update support to
> reference transactions, these messages were never propagated, instead
> only an error code pertaining to the type of failure was propagated.
>
> Currently, there are three regions which utilize batched updates:
>
>   - git update-ref --batch-updates
>   - git fetch
>   - git receive-pack
>
> While 'git update-ref --batch-updates' was a newly introduced flag, both
> 'git fetch' and 'git receive-pack' were pre-existing. Before using
> batched updates, they provided more detailed error messages to the user,
> but this changed with the introduction of batched updates. This is a
> regression in their workings.
>
> This patch series fixes this, by passing the detailed error message and
> utilizing it whenever available. The regression was reported by Elijah
> Newren [1] and based on the patch submitted by Jeff King [2].
>
> [1]: https://lore.kernel.org/all/CABPp-BGL2tJR4dPidQuFcp-X0_VkVTknCY-0Zgo=jHVGv_P=wA@mail.gmail.com/
> [2]: https://lore.kernel.org/all/20251224081214.GA1879908@coredump.intra.peff.net/

Thanks, all.  It is very nice to see such a collaboration going ;-)

Will queue.


> ---
>  builtin/fetch.c         |  9 +++++---
>  builtin/receive-pack.c  |  9 ++++++--
>  builtin/update-ref.c    | 13 +++++++-----
>  refs.c                  | 56 ++++++++++++++++++++++++++++++-------------------
>  refs.h                  |  1 +
>  refs/files-backend.c    |  3 ++-
>  refs/packed-backend.c   |  9 +++++---
>  refs/refs-internal.h    |  4 +++-
>  refs/reftable-backend.c |  3 ++-
>  t/t1400-update-ref.sh   | 26 +++++++++++------------
>  t/t5510-fetch.sh        |  8 +++----
>  t/t5516-fetch-push.sh   | 15 +++++++++++++
>  12 files changed, 102 insertions(+), 54 deletions(-)
>
> Karthik Nayak (6):
>       refs: remove unused header
>       refs: attach rejection details to updates
>       refs: add rejection detail to the callback function
>       update-ref: utilize rejected error details if available
>       fetch: utilize rejected ref error details
>       receive-pack: utilize rejected ref error details
>
>
>
> base-commit: 8745eae506f700657882b9e32b2aa00f234a6fb6
> change-id: 20260113-633-regression-lost-diagnostic-message-when-pushing-non-commit-objects-to-refs-heads-17786b20894a
>
> Thanks
> - Karthik

[PATCH v2 0/7] refs: provide detailed error messages when using batched update

[Karthik Nayak]

The refs namespace uses an error buffer to capture details about failed
reference updates. However when we added batched update support to
reference transactions, these messages were never propagated, instead
only an error code pertaining to the type of failure was propagated.

Currently, there are three regions which utilize batched updates:

  - git update-ref --batch-updates
  - git fetch
  - git receive-pack

While 'git update-ref --batch-updates' was a newly introduced flag, both
'git fetch' and 'git receive-pack' were pre-existing. Before using
batched updates, they provided more detailed error messages to the user,
but this changed with the introduction of batched updates. This is a
regression in their workings.

This patch series fixes this, by passing the detailed error message and
utilizing it whenever available. The regression was reported by Elijah
Newren [1] and based on the patch submitted by Jeff King [2].

[1]: https://lore.kernel.org/all/CABPp-BGL2tJR4dPidQuFcp-X0_VkVTknCY-0Zgo=jHVGv_P=wA@mail.gmail.com/
[2]: https://lore.kernel.org/all/20251224081214.GA1879908@coredump.intra.peff.net/

---
Changes in v2:
- Updates to the commit messages to be more descriptive.
- Instead of passing the char pointer for the error description, pass
  the 'strbuf' itself. This makes the API a lot cleaner to deal with.
  Also avoids having to remember to reset the strbuf after usage.
- Chalk out a separate commit for using a 'goto next_ref' in
  `refs_verify_refnames_available()`. This makes the intention much
  clearer.
- For git-update-ref(1), keep the existing implementation as is and only
  output the detailed error message to stderr.
- For git-receive-pack(1), use 'rp_error()' for detailed error message
  while keeping the current implementation as is.
- Added a separate patch to handle missing information in git-fetch(1)'s
  status table. This involves delaying updates to the end, where update
  success/failure information is available. I'm not too confident about
  this approach though, we could also drop it from the series and I
  could pick that up independently. This is still 1.19 ± 0.02 times
  faster than non-batched version (v2.50.0) in the files backend.
- Link to v1: https://patch.msgid.link/20260114-633-regression-lost-diagnostic-message-when-pushing-non-commit-objects-to-refs-heads-v1-0-f5f8b173c501@gmail.com

---
 builtin/fetch.c         | 188 ++++++++++++++++++++++++++++++++++++++++--------
 builtin/receive-pack.c  |   7 +-
 builtin/update-ref.c    |   7 +-
 refs.c                  |  48 +++++++------
 refs.h                  |   1 +
 refs/files-backend.c    |   5 +-
 refs/packed-backend.c   |  12 ++--
 refs/refs-internal.h    |   4 +-
 refs/reftable-backend.c |   5 +-
 t/t1400-update-ref.sh   |  71 ++++++++++--------
 t/t5510-fetch.sh        |   8 +--
 t/t5516-fetch-push.sh   |  16 +++++
 t/t5574-fetch-output.sh |  16 ++---
 13 files changed, 280 insertions(+), 108 deletions(-)

Karthik Nayak (7):
      refs: drop unnecessary header includes
      refs: skip to next ref when current ref is rejected
      refs: add rejection detail to the callback function
      update-ref: utilize rejected error details if available
      fetch: utilize rejected ref error details
      receive-pack: utilize rejected ref error details
      fetch: delay user information post committing of transaction

Range-diff versus v1:

1:  806ec3de6e ! 1:  75b7b2f83d refs: remove unused header
    @@ Metadata
     Author: Karthik Nayak <karthik.188@gmail.com>
     
      ## Commit message ##
    -    refs: remove unused header
    +    refs: drop unnecessary header includes
     
    -    Some of the headers in 'refs.c' are no longer required, let's remove
    -    them.
    +    The 'sigchain.h' header isn't being used and can be removed.
    +
    +    Similarly, 'run-command.h' serves no direct purpose here. While it gets pulled in transitively through 'hook.h', we can still drop the explicit include for clarity.
     
         Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
     
2:  6ba3b9da56 ! 2:  507906091c refs: attach rejection details to updates
    @@ Metadata
     Author: Karthik Nayak <karthik.188@gmail.com>
     
      ## Commit message ##
    -    refs: attach rejection details to updates
    +    refs: skip to next ref when current ref is rejected
     
    -    The implementation of batched updates in 23fc8e4f61 (refs: implement
    -    batch reference update support, 2025-04-08) added rejection error codes
    -    to each reference update. This allowed batching of updates, however
    -    while each rejection is linked to a rejection code, the already present
    -    user readable error message is simply dropped.
    +    In `refs_verify_refnames_available()` we have two nested loops: the
    +    outer loop iterates over all references to check, while the inner loop
    +    checks for filesystem conflicts for a given ref by breaking down its
    +    path.
     
    -    Make necessary changes to ensure that the rejection detail is also added
    -    to the reference update. In upcoming commits, we'll utilize this field
    -    to provide better error message to users, namely in:
    +    With batched updates, when we detect a filesystem conflict, we mark the
    +    update as rejected and execute 'continue'. However, this only skips to
    +    the next iteration of the inner loop, not the outer loop as intended.
    +    This causes the same reference to be repeatedly rejected. Fix this by
    +    using a goto statement to skip to the next reference in the outer loop.
     
    -      - git update-ref --batch-updates
    -      - git fetch
    -      - git receive-pack
    -
    -    We move the error message creation right above
    -    `ref_transaction_maybe_set_rejected()`, so that the error message is
    -    available and also reset the error message if utilized to avoid
    -    un-expected concatination.
    -
    -    Co-authored-by: Jeff King <peff@peff.net>
         Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
     
      ## refs.c ##
    @@ refs.c: void ref_transaction_free(struct ref_transaction *transaction)
      				       size_t update_idx,
     -				       enum ref_transaction_error err)
     +				       enum ref_transaction_error err,
    -+				       const char *details)
    ++				       struct strbuf *details)
      {
      	if (update_idx >= transaction->nr)
      		BUG("trying to set rejection on invalid update index");
    @@ refs.c: int ref_transaction_maybe_set_rejected(struct ref_transaction *transacti
      			   transaction->updates[update_idx]->refname, 0);
      
      	transaction->updates[update_idx]->rejection_err = err;
    -+	if (details)
    -+		transaction->updates[update_idx]->rejection_details = xstrdup(details);
    ++	transaction->updates[update_idx]->rejection_details = strbuf_detach(details, NULL);
      	ALLOC_GROW(transaction->rejections->update_indices,
      		   transaction->rejections->nr + 1,
      		   transaction->rejections->alloc);
    @@ refs.c: enum ref_transaction_error refs_verify_refnames_available(struct ref_sto
      				if (transaction && ref_transaction_maybe_set_rejected(
      					    transaction, *update_idx,
     -					    REF_TRANSACTION_ERROR_NAME_CONFLICT)) {
    -+					    REF_TRANSACTION_ERROR_NAME_CONFLICT, err->buf)) {
    ++					    REF_TRANSACTION_ERROR_NAME_CONFLICT, err)) {
      					strset_remove(&dirnames, dirname.buf);
      					strset_add(&conflicting_dirnames, dirname.buf);
     -					continue;
    -+					strbuf_reset(err);
    -+					goto next;
    ++					goto next_ref;
      				}
      
     -				strbuf_addf(err, _("'%s' exists; cannot create '%s'"),
    @@ refs.c: enum ref_transaction_error refs_verify_refnames_available(struct ref_sto
      				if (transaction && ref_transaction_maybe_set_rejected(
      					    transaction, *update_idx,
     -					    REF_TRANSACTION_ERROR_NAME_CONFLICT)) {
    -+					    REF_TRANSACTION_ERROR_NAME_CONFLICT, err->buf)) {
    ++					    REF_TRANSACTION_ERROR_NAME_CONFLICT, err)) {
      					strset_remove(&dirnames, dirname.buf);
     -					continue;
    -+					strbuf_reset(err);
    -+					goto next;
    ++					goto next_ref;
      				}
      
     -				strbuf_addf(err, _("cannot process '%s' and '%s' at the same time"),
    @@ refs.c: enum ref_transaction_error refs_verify_refnames_available(struct ref_sto
      			}
      		}
     @@ refs.c: enum ref_transaction_error refs_verify_refnames_available(struct ref_store *refs
    + 				if (skip &&
      				    string_list_has_string(skip, iter->ref.name))
      					continue;
    - 
     +				strbuf_addf(err, _("'%s' exists; cannot create '%s'"),
     +					    iter->ref.name, refname);
    -+
    + 
      				if (transaction && ref_transaction_maybe_set_rejected(
      					    transaction, *update_idx,
     -					    REF_TRANSACTION_ERROR_NAME_CONFLICT))
     -					continue;
    -+					    REF_TRANSACTION_ERROR_NAME_CONFLICT, err->buf)) {
    -+					strbuf_reset(err);
    -+					goto next;
    -+				}
    ++					    REF_TRANSACTION_ERROR_NAME_CONFLICT, err))
    ++					goto next_ref;
      
     -				strbuf_addf(err, _("'%s' exists; cannot create '%s'"),
     -					    iter->ref.name, refname);
    @@ refs.c: enum ref_transaction_error refs_verify_refnames_available(struct ref_sto
      				    transaction, *update_idx,
     -				    REF_TRANSACTION_ERROR_NAME_CONFLICT))
     -				continue;
    -+				    REF_TRANSACTION_ERROR_NAME_CONFLICT, err->buf)) {
    -+				strbuf_reset(err);
    -+				goto next;
    -+			}
    ++				    REF_TRANSACTION_ERROR_NAME_CONFLICT, err))
    ++				goto next_ref;
      
     -			strbuf_addf(err, _("cannot process '%s' and '%s' at the same time"),
     -				    refname, extra_refname);
      			goto cleanup;
      		}
    -+next:;
    ++next_ref:;
      	}
      
      	ret = 0;
    @@ refs/files-backend.c: static int files_transaction_prepare(struct ref_store *ref
      					  err);
      		if (ret) {
     -			if (ref_transaction_maybe_set_rejected(transaction, i, ret)) {
    +-				strbuf_reset(err);
     +			if (ref_transaction_maybe_set_rejected(transaction, i,
    -+							       ret, err->buf)) {
    - 				strbuf_reset(err);
    ++							       ret, err)) {
      				ret = 0;
    - 
    +-
    + 				continue;
    + 			}
    + 			goto cleanup;
     
      ## refs/packed-backend.c ##
     @@ refs/packed-backend.c: static enum ref_transaction_error write_with_updates(struct packed_ref_store *re
    @@ refs/packed-backend.c: static enum ref_transaction_error write_with_updates(stru
      					ret = REF_TRANSACTION_ERROR_CREATE_EXISTS;
      
     -					if (ref_transaction_maybe_set_rejected(transaction, i, ret)) {
    +-						strbuf_reset(err);
     +					if (ref_transaction_maybe_set_rejected(transaction, i,
    -+									       ret, err->buf)) {
    - 						strbuf_reset(err);
    ++									       ret, err)) {
      						ret = 0;
      						continue;
    + 					}
     @@ refs/packed-backend.c: static enum ref_transaction_error write_with_updates(struct packed_ref_store *re
      						    oid_to_hex(&update->old_oid));
      					ret = REF_TRANSACTION_ERROR_INCORRECT_OLD_VALUE;
      
     -					if (ref_transaction_maybe_set_rejected(transaction, i, ret)) {
    +-						strbuf_reset(err);
     +					if (ref_transaction_maybe_set_rejected(transaction, i,
    -+									       ret, err->buf)) {
    - 						strbuf_reset(err);
    ++									       ret, err)) {
      						ret = 0;
      						continue;
    + 					}
     @@ refs/packed-backend.c: static enum ref_transaction_error write_with_updates(struct packed_ref_store *re
      					    oid_to_hex(&update->old_oid));
      				ret = REF_TRANSACTION_ERROR_NONEXISTENT_REF;
      
     -				if (ref_transaction_maybe_set_rejected(transaction, i, ret)) {
    +-					strbuf_reset(err);
     +				if (ref_transaction_maybe_set_rejected(transaction, i,
    -+								       ret, err->buf)) {
    - 					strbuf_reset(err);
    ++								       ret, err)) {
      					ret = 0;
      					continue;
    + 				}
     
      ## refs/refs-internal.h ##
     @@ refs/refs-internal.h: struct ref_update {
    @@ refs/refs-internal.h: int refs_read_raw_ref(struct ref_store *ref_store, const c
      				       size_t update_idx,
     -				       enum ref_transaction_error err);
     +				       enum ref_transaction_error err,
    -+				       const char *details);
    ++				       struct strbuf *details);
      
      /*
       * Add a ref_update with the specified properties to transaction, and
    @@ refs/reftable-backend.c: static int reftable_be_transaction_prepare(struct ref_s
      					    &head_referent, &referent, err);
      		if (ret) {
     -			if (ref_transaction_maybe_set_rejected(transaction, i, ret)) {
    +-				strbuf_reset(err);
     +			if (ref_transaction_maybe_set_rejected(transaction, i,
    -+							       ret, err->buf)) {
    - 				strbuf_reset(err);
    ++							       ret, err)) {
      				ret = 0;
    - 
    +-
    + 				continue;
    + 			}
    + 			goto done;
3:  76f199b434 ! 3:  78d6220027 refs: add rejection detail to the callback function
    @@ Commit message
         field is unused, but will be integrated in the upcoming commits.
     
         Co-authored-by: Jeff King <peff@peff.net>
    +    Signed-off-by: Jeff King <peff@peff.net>
         Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
     
      ## builtin/fetch.c ##
4:  c05216bf9c < -:  ---------- update-ref: utilize rejected error details if available
-:  ---------- > 4:  6ca8a03f74 update-ref: utilize rejected error details if available
5:  bdfef1b20f = 5:  289282031d fetch: utilize rejected ref error details
6:  08b74e8077 ! 6:  d555777da0 receive-pack: utilize rejected ref error details
    @@ Commit message
         messages for failed referenced updates, the users were provided generic
         error messages based on the error type.
     
    -    Similar to the previous commit, switch to using detailed error messages
    -    if present for failed reference updates to fix this regression.
    -
    -    One downside of this is that the messages can be very verbose, for e.g.
    -    in the files backend, when trying to write a non-commit object to a
    -    branch, you would see:
    +    Now that the updates also contain detailed error message, propagate
    +    those to the client via 'rp_error'. The detailed error messages can be
    +    very verbose, for e.g. in the files backend, when trying to write a
    +    non-commit object to a branch, you would see:
     
            ! [remote rejected] 3eaec9ccf3a53f168362a6b3fdeb73426fb9813d ->
            branch (cannot update ref 'refs/heads/branch': trying to write
    @@ Commit message
     
         Reported-by: Elijah Newren <newren@gmail.com>
         Co-authored-by: Jeff King <peff@peff.net>
    +    Signed-off-by: Jeff King <peff@peff.net>
         Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
     
      ## builtin/receive-pack.c ##
    @@ builtin/receive-pack.c: static void ref_transaction_rejection_handler(const char
      {
      	struct strmap *failed_refs = cb_data;
      
    --	strmap_put(failed_refs, refname, (char *)ref_transaction_error_msg(err));
    -+	if (!details)
    -+		details = ref_transaction_error_msg(err);
    ++	if (details)
    ++		rp_error("%s", details);
     +
    -+	strmap_put(failed_refs, refname, (char *)details);
    + 	strmap_put(failed_refs, refname, (char *)ref_transaction_error_msg(err));
      }
      
    - static void execute_commands_non_atomic(struct command *commands,
     @@ builtin/receive-pack.c: static void execute_commands_non_atomic(struct command *commands,
      		}
      
-:  ---------- > 7:  640d09d408 fetch: delay user information post committing of transaction


base-commit: 8745eae506f700657882b9e32b2aa00f234a6fb6
change-id: 20260113-633-regression-lost-diagnostic-message-when-pushing-non-commit-objects-to-refs-heads-17786b20894a

Thanks
- Karthik

[PATCH v2 1/7] refs: drop unnecessary header includes

[Karthik Nayak]

The 'sigchain.h' header isn't being used and can be removed.

Similarly, 'run-command.h' serves no direct purpose here. While it gets pulled in transitively through 'hook.h', we can still drop the explicit include for clarity.

Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
---
 refs.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/refs.c b/refs.c
index e06e0cb072..965b232a06 100644
--- a/refs.c
+++ b/refs.c
@@ -15,7 +15,6 @@
 #include "iterator.h"
 #include "refs.h"
 #include "refs/refs-internal.h"
-#include "run-command.h"
 #include "hook.h"
 #include "object-name.h"
 #include "odb.h"
@@ -26,7 +25,6 @@
 #include "strvec.h"
 #include "repo-settings.h"
 #include "setup.h"
-#include "sigchain.h"
 #include "date.h"
 #include "commit.h"
 #include "wildmatch.h"

-- 
2.51.2

Re: [PATCH v2 1/7] refs: drop unnecessary header includes

[SZEDER Gábor]

On Fri, Jan 16, 2026 at 10:27:06PM +0100, Karthik Nayak wrote:
> The 'sigchain.h' header isn't being used and can be removed.
> 
> Similarly, 'run-command.h' serves no direct purpose here. While it gets pulled in transitively through 'hook.h', we can still drop the explicit include for clarity.

The need for these #includes went away fairly recently, I think in
26238496a7 (hook: provide stdin via callback, 2025-12-26) and
7a7717427e (reference-transaction: use hook API instead of
run-command, 2025-12-26), which were merged in f406b89552 (Merge
branch 'ar/run-command-hook', 2026-01-06).  Unfortunately, that topic
had some regressions and therefore was reverted in a3d1f391d3 (Revert
"Merge branch 'ar/run-command-hook'", 2026-01-15), and as a result
merging this topic into seen resulted in a merge commit 180b93f7ba
(Merge branch 'kn/ref-batch-output-error-reporting-fix' into jch,
2026-01-16) that can't be built.

I think this patch should be dropped from this series, and these
#includes should be removed in that other topic.

https://public-inbox.org/git/20251226122334.16687-1-adrian.ratiu@collabora.com/T/#u

> Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
> ---
>  refs.c | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/refs.c b/refs.c
> index e06e0cb072..965b232a06 100644
> --- a/refs.c
> +++ b/refs.c
> @@ -15,7 +15,6 @@
>  #include "iterator.h"
>  #include "refs.h"
>  #include "refs/refs-internal.h"
> -#include "run-command.h"
>  #include "hook.h"
>  #include "object-name.h"
>  #include "odb.h"
> @@ -26,7 +25,6 @@
>  #include "strvec.h"
>  #include "repo-settings.h"
>  #include "setup.h"
> -#include "sigchain.h"
>  #include "date.h"
>  #include "commit.h"
>  #include "wildmatch.h"
> 
> -- 
> 2.51.2
> 

Re: [PATCH v2 1/7] refs: drop unnecessary header includes

[Karthik Nayak]

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SZEDER Gábor <szeder.dev@gmail.com> writes:

> On Fri, Jan 16, 2026 at 10:27:06PM +0100, Karthik Nayak wrote:
>> The 'sigchain.h' header isn't being used and can be removed.
>>
>> Similarly, 'run-command.h' serves no direct purpose here. While it gets pulled in transitively through 'hook.h', we can still drop the explicit include for clarity.
>
> The need for these #includes went away fairly recently, I think in
> 26238496a7 (hook: provide stdin via callback, 2025-12-26) and
> 7a7717427e (reference-transaction: use hook API instead of
> run-command, 2025-12-26), which were merged in f406b89552 (Merge
> branch 'ar/run-command-hook', 2026-01-06).  Unfortunately, that topic
> had some regressions and therefore was reverted in a3d1f391d3 (Revert
> "Merge branch 'ar/run-command-hook'", 2026-01-15), and as a result
> merging this topic into seen resulted in a merge commit 180b93f7ba
> (Merge branch 'kn/ref-batch-output-error-reporting-fix' into jch,
> 2026-01-16) that can't be built.
>
> I think this patch should be dropped from this series, and these
> #includes should be removed in that other topic.
>
> https://public-inbox.org/git/20251226122334.16687-1-adrian.ratiu@collabora.com/T/#u
>

Sounds good, thanks for letting me know. I'll drop it from the next
version!

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[PATCH v2 2/7] refs: skip to next ref when current ref is rejected

[Karthik Nayak]

In `refs_verify_refnames_available()` we have two nested loops: the
outer loop iterates over all references to check, while the inner loop
checks for filesystem conflicts for a given ref by breaking down its
path.

With batched updates, when we detect a filesystem conflict, we mark the
update as rejected and execute 'continue'. However, this only skips to
the next iteration of the inner loop, not the outer loop as intended.
This causes the same reference to be repeatedly rejected. Fix this by
using a goto statement to skip to the next reference in the outer loop.

Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
---
 refs.c                  | 44 ++++++++++++++++++++++++++------------------
 refs/files-backend.c    |  5 ++---
 refs/packed-backend.c   | 12 ++++++------
 refs/refs-internal.h    |  4 +++-
 refs/reftable-backend.c |  5 ++---
 5 files changed, 39 insertions(+), 31 deletions(-)

diff --git a/refs.c b/refs.c
index 965b232a06..3459d0e4e5 100644
--- a/refs.c
+++ b/refs.c
@@ -1222,6 +1222,7 @@ void ref_transaction_free(struct ref_transaction *transaction)
 		free(transaction->updates[i]->committer_info);
 		free((char *)transaction->updates[i]->new_target);
 		free((char *)transaction->updates[i]->old_target);
+		free((char *)transaction->updates[i]->rejection_details);
 		free(transaction->updates[i]);
 	}
 
@@ -1236,7 +1237,8 @@ void ref_transaction_free(struct ref_transaction *transaction)
 
 int ref_transaction_maybe_set_rejected(struct ref_transaction *transaction,
 				       size_t update_idx,
-				       enum ref_transaction_error err)
+				       enum ref_transaction_error err,
+				       struct strbuf *details)
 {
 	if (update_idx >= transaction->nr)
 		BUG("trying to set rejection on invalid update index");
@@ -1262,6 +1264,7 @@ int ref_transaction_maybe_set_rejected(struct ref_transaction *transaction,
 			   transaction->updates[update_idx]->refname, 0);
 
 	transaction->updates[update_idx]->rejection_err = err;
+	transaction->updates[update_idx]->rejection_details = strbuf_detach(details, NULL);
 	ALLOC_GROW(transaction->rejections->update_indices,
 		   transaction->rejections->nr + 1,
 		   transaction->rejections->alloc);
@@ -2657,30 +2660,33 @@ enum ref_transaction_error refs_verify_refnames_available(struct ref_store *refs
 			if (!initial_transaction &&
 			    (strset_contains(&conflicting_dirnames, dirname.buf) ||
 			     !refs_read_raw_ref(refs, dirname.buf, &oid, &referent,
-						       &type, &ignore_errno))) {
+						&type, &ignore_errno))) {
+
+				strbuf_addf(err, _("'%s' exists; cannot create '%s'"),
+					    dirname.buf, refname);
+
 				if (transaction && ref_transaction_maybe_set_rejected(
 					    transaction, *update_idx,
-					    REF_TRANSACTION_ERROR_NAME_CONFLICT)) {
+					    REF_TRANSACTION_ERROR_NAME_CONFLICT, err)) {
 					strset_remove(&dirnames, dirname.buf);
 					strset_add(&conflicting_dirnames, dirname.buf);
-					continue;
+					goto next_ref;
 				}
 
-				strbuf_addf(err, _("'%s' exists; cannot create '%s'"),
-					    dirname.buf, refname);
 				goto cleanup;
 			}
 
 			if (extras && string_list_has_string(extras, dirname.buf)) {
+				strbuf_addf(err, _("cannot process '%s' and '%s' at the same time"),
+					    refname, dirname.buf);
+
 				if (transaction && ref_transaction_maybe_set_rejected(
 					    transaction, *update_idx,
-					    REF_TRANSACTION_ERROR_NAME_CONFLICT)) {
+					    REF_TRANSACTION_ERROR_NAME_CONFLICT, err)) {
 					strset_remove(&dirnames, dirname.buf);
-					continue;
+					goto next_ref;
 				}
 
-				strbuf_addf(err, _("cannot process '%s' and '%s' at the same time"),
-					    refname, dirname.buf);
 				goto cleanup;
 			}
 		}
@@ -2710,14 +2716,14 @@ enum ref_transaction_error refs_verify_refnames_available(struct ref_store *refs
 				if (skip &&
 				    string_list_has_string(skip, iter->ref.name))
 					continue;
+				strbuf_addf(err, _("'%s' exists; cannot create '%s'"),
+					    iter->ref.name, refname);
 
 				if (transaction && ref_transaction_maybe_set_rejected(
 					    transaction, *update_idx,
-					    REF_TRANSACTION_ERROR_NAME_CONFLICT))
-					continue;
+					    REF_TRANSACTION_ERROR_NAME_CONFLICT, err))
+					goto next_ref;
 
-				strbuf_addf(err, _("'%s' exists; cannot create '%s'"),
-					    iter->ref.name, refname);
 				goto cleanup;
 			}
 
@@ -2727,15 +2733,17 @@ enum ref_transaction_error refs_verify_refnames_available(struct ref_store *refs
 
 		extra_refname = find_descendant_ref(dirname.buf, extras, skip);
 		if (extra_refname) {
+			strbuf_addf(err, _("cannot process '%s' and '%s' at the same time"),
+				    refname, extra_refname);
+
 			if (transaction && ref_transaction_maybe_set_rejected(
 				    transaction, *update_idx,
-				    REF_TRANSACTION_ERROR_NAME_CONFLICT))
-				continue;
+				    REF_TRANSACTION_ERROR_NAME_CONFLICT, err))
+				goto next_ref;
 
-			strbuf_addf(err, _("cannot process '%s' and '%s' at the same time"),
-				    refname, extra_refname);
 			goto cleanup;
 		}
+next_ref:;
 	}
 
 	ret = 0;
diff --git a/refs/files-backend.c b/refs/files-backend.c
index 6f6f76a8d8..6790d8bf53 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -2983,10 +2983,9 @@ static int files_transaction_prepare(struct ref_store *ref_store,
 					  head_ref, &refnames_to_check,
 					  err);
 		if (ret) {
-			if (ref_transaction_maybe_set_rejected(transaction, i, ret)) {
-				strbuf_reset(err);
+			if (ref_transaction_maybe_set_rejected(transaction, i,
+							       ret, err)) {
 				ret = 0;
-
 				continue;
 			}
 			goto cleanup;
diff --git a/refs/packed-backend.c b/refs/packed-backend.c
index 4ea0c12299..59b3ecb9d6 100644
--- a/refs/packed-backend.c
+++ b/refs/packed-backend.c
@@ -1437,8 +1437,8 @@ static enum ref_transaction_error write_with_updates(struct packed_ref_store *re
 						    update->refname);
 					ret = REF_TRANSACTION_ERROR_CREATE_EXISTS;
 
-					if (ref_transaction_maybe_set_rejected(transaction, i, ret)) {
-						strbuf_reset(err);
+					if (ref_transaction_maybe_set_rejected(transaction, i,
+									       ret, err)) {
 						ret = 0;
 						continue;
 					}
@@ -1452,8 +1452,8 @@ static enum ref_transaction_error write_with_updates(struct packed_ref_store *re
 						    oid_to_hex(&update->old_oid));
 					ret = REF_TRANSACTION_ERROR_INCORRECT_OLD_VALUE;
 
-					if (ref_transaction_maybe_set_rejected(transaction, i, ret)) {
-						strbuf_reset(err);
+					if (ref_transaction_maybe_set_rejected(transaction, i,
+									       ret, err)) {
 						ret = 0;
 						continue;
 					}
@@ -1496,8 +1496,8 @@ static enum ref_transaction_error write_with_updates(struct packed_ref_store *re
 					    oid_to_hex(&update->old_oid));
 				ret = REF_TRANSACTION_ERROR_NONEXISTENT_REF;
 
-				if (ref_transaction_maybe_set_rejected(transaction, i, ret)) {
-					strbuf_reset(err);
+				if (ref_transaction_maybe_set_rejected(transaction, i,
+								       ret, err)) {
 					ret = 0;
 					continue;
 				}
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index c7d2a6e50b..191a25683f 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -128,6 +128,7 @@ struct ref_update {
 	 * was rejected.
 	 */
 	enum ref_transaction_error rejection_err;
+	const char *rejection_details;
 
 	/*
 	 * If this ref_update was split off of a symref update via
@@ -153,7 +154,8 @@ int refs_read_raw_ref(struct ref_store *ref_store, const char *refname,
  */
 int ref_transaction_maybe_set_rejected(struct ref_transaction *transaction,
 				       size_t update_idx,
-				       enum ref_transaction_error err);
+				       enum ref_transaction_error err,
+				       struct strbuf *details);
 
 /*
  * Add a ref_update with the specified properties to transaction, and
diff --git a/refs/reftable-backend.c b/refs/reftable-backend.c
index 4319a4eacb..0e2648e36c 100644
--- a/refs/reftable-backend.c
+++ b/refs/reftable-backend.c
@@ -1401,10 +1401,9 @@ static int reftable_be_transaction_prepare(struct ref_store *ref_store,
 					    &refnames_to_check, head_type,
 					    &head_referent, &referent, err);
 		if (ret) {
-			if (ref_transaction_maybe_set_rejected(transaction, i, ret)) {
-				strbuf_reset(err);
+			if (ref_transaction_maybe_set_rejected(transaction, i,
+							       ret, err)) {
 				ret = 0;
-
 				continue;
 			}
 			goto done;

-- 
2.51.2

[PATCH v2 3/7] refs: add rejection detail to the callback function

[Karthik Nayak]

The previous commit started storing the rejection details alongside the
error code for rejected updates. Pass this along to the callback
function `ref_transaction_for_each_rejected_update()`. Currently the
field is unused, but will be integrated in the upcoming commits.

Co-authored-by: Jeff King <peff@peff.net>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
---
 builtin/fetch.c        | 1 +
 builtin/receive-pack.c | 1 +
 builtin/update-ref.c   | 1 +
 refs.c                 | 2 +-
 refs.h                 | 1 +
 5 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/builtin/fetch.c b/builtin/fetch.c
index 288d3772ea..d427adea61 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -1649,6 +1649,7 @@ static void ref_transaction_rejection_handler(const char *refname,
 					      const char *old_target UNUSED,
 					      const char *new_target UNUSED,
 					      enum ref_transaction_error err,
+					      const char *details UNUSED,
 					      void *cb_data)
 {
 	struct ref_rejection_data *data = cb_data;
diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index ef1f77be8c..94d3e73cee 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -1813,6 +1813,7 @@ static void ref_transaction_rejection_handler(const char *refname,
 					      const char *old_target UNUSED,
 					      const char *new_target UNUSED,
 					      enum ref_transaction_error err,
+					      const char *details UNUSED,
 					      void *cb_data)
 {
 	struct strmap *failed_refs = cb_data;
diff --git a/builtin/update-ref.c b/builtin/update-ref.c
index 195437e7c6..0046a87c57 100644
--- a/builtin/update-ref.c
+++ b/builtin/update-ref.c
@@ -573,6 +573,7 @@ static void print_rejected_refs(const char *refname,
 				const char *old_target,
 				const char *new_target,
 				enum ref_transaction_error err,
+				const char *details UNUSED,
 				void *cb_data UNUSED)
 {
 	struct strbuf sb = STRBUF_INIT;
diff --git a/refs.c b/refs.c
index 3459d0e4e5..e754159c21 100644
--- a/refs.c
+++ b/refs.c
@@ -2872,7 +2872,7 @@ void ref_transaction_for_each_rejected_update(struct ref_transaction *transactio
 		   (update->flags & REF_HAVE_OLD) ? &update->old_oid : NULL,
 		   (update->flags & REF_HAVE_NEW) ? &update->new_oid : NULL,
 		   update->old_target, update->new_target,
-		   update->rejection_err, cb_data);
+		   update->rejection_err, update->rejection_details, cb_data);
 	}
 }
 
diff --git a/refs.h b/refs.h
index d9051bbb04..4fbe3da924 100644
--- a/refs.h
+++ b/refs.h
@@ -975,6 +975,7 @@ typedef void ref_transaction_for_each_rejected_update_fn(const char *refname,
 							 const char *old_target,
 							 const char *new_target,
 							 enum ref_transaction_error err,
+							 const char *details,
 							 void *cb_data);
 void ref_transaction_for_each_rejected_update(struct ref_transaction *transaction,
 					      ref_transaction_for_each_rejected_update_fn cb,

-- 
2.51.2

[PATCH v2 4/7] update-ref: utilize rejected error details if available

[Karthik Nayak]

When git-update-ref(1) received the '--update-ref' flag, the error
details generated in the refs namespace wasn't propagated with failed
updates. Instead only an error code pertaining to the type of rejection
was noted.

This missed detailed error message which the user can act upon. The
previous commits added the required code to propagate these detailed
error messages from the refs namespace. Now that additional details are
available, let's output this additional details to stderr. This allows
users to have additional information over the already present machine
parsable output.

While we're here, improve the existing tests for the machine parsable
output by checking for the entire output string and not just the
rejection reason.

Reported-by: Elijah Newren <newren@gmail.com>
Co-authored-by: Jeff King <peff@peff.net>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
---
 builtin/update-ref.c  |  8 +++---
 t/t1400-update-ref.sh | 71 ++++++++++++++++++++++++++++++---------------------
 2 files changed, 47 insertions(+), 32 deletions(-)

diff --git a/builtin/update-ref.c b/builtin/update-ref.c
index 0046a87c57..2d68c40ecb 100644
--- a/builtin/update-ref.c
+++ b/builtin/update-ref.c
@@ -573,16 +573,18 @@ static void print_rejected_refs(const char *refname,
 				const char *old_target,
 				const char *new_target,
 				enum ref_transaction_error err,
-				const char *details UNUSED,
+				const char *details,
 				void *cb_data UNUSED)
 {
 	struct strbuf sb = STRBUF_INIT;
-	const char *reason = ref_transaction_error_msg(err);
+
+	if (details && *details)
+		error("%s", details);
 
 	strbuf_addf(&sb, "rejected %s %s %s %s\n", refname,
 		    new_oid ? oid_to_hex(new_oid) : new_target,
 		    old_oid ? oid_to_hex(old_oid) : old_target,
-		    reason);
+		    ref_transaction_error_msg(err));
 
 	fwrite(sb.buf, sb.len, 1, stdout);
 	strbuf_release(&sb);
diff --git a/t/t1400-update-ref.sh b/t/t1400-update-ref.sh
index db7f5444da..db6585b8d8 100755
--- a/t/t1400-update-ref.sh
+++ b/t/t1400-update-ref.sh
@@ -2093,14 +2093,15 @@ do
 
 			format_command $type "update refs/heads/ref1" "$old_head" "$head" >stdin &&
 			format_command $type "update refs/heads/ref2" "$(test_oid 001)" "$head" >>stdin &&
-			git update-ref $type --stdin --batch-updates <stdin >stdout &&
+			git update-ref $type --stdin --batch-updates <stdin >stdout 2>err &&
 			echo $old_head >expect &&
 			git rev-parse refs/heads/ref1 >actual &&
 			test_cmp expect actual &&
 			echo $head >expect &&
 			git rev-parse refs/heads/ref2 >actual &&
 			test_cmp expect actual &&
-			test_grep -q "invalid new value provided" stdout
+			test_grep "rejected refs/heads/ref2 $(test_oid 001) $head invalid new value provided" stdout &&
+			test_grep "trying to write ref ${SQ}refs/heads/ref2${SQ} with nonexistent object" err
 		)
 	'
 
@@ -2119,14 +2120,15 @@ do
 
 			format_command $type "update refs/heads/ref1" "$old_head" "$head" >stdin &&
 			format_command $type "update refs/heads/ref2" "$head_tree" "$head" >>stdin &&
-			git update-ref $type --stdin --batch-updates <stdin >stdout &&
+			git update-ref $type --stdin --batch-updates <stdin >stdout 2>err &&
 			echo $old_head >expect &&
 			git rev-parse refs/heads/ref1 >actual &&
 			test_cmp expect actual &&
 			echo $head >expect &&
 			git rev-parse refs/heads/ref2 >actual &&
 			test_cmp expect actual &&
-			test_grep -q "invalid new value provided" stdout
+			test_grep "rejected refs/heads/ref2 $head_tree $head invalid new value provided" stdout &&
+			test_grep "trying to write non-commit object $head_tree to branch ${SQ}refs/heads/ref2${SQ}" err
 		)
 	'
 
@@ -2143,12 +2145,13 @@ do
 
 			format_command $type "update refs/heads/ref1" "$old_head" "$head" >stdin &&
 			format_command $type "update refs/heads/ref2" "$old_head" "$head" >>stdin &&
-			git update-ref $type --stdin --batch-updates <stdin >stdout &&
+			git update-ref $type --stdin --batch-updates <stdin >stdout 2>err &&
 			echo $old_head >expect &&
 			git rev-parse refs/heads/ref1 >actual &&
 			test_cmp expect actual &&
 			test_must_fail git rev-parse refs/heads/ref2 &&
-			test_grep -q "reference does not exist" stdout
+			test_grep "rejected refs/heads/ref2 $old_head $head reference does not exist" stdout &&
+			test_grep "cannot lock ref ${SQ}refs/heads/ref2${SQ}: unable to resolve reference ${SQ}refs/heads/ref2${SQ}" err
 		)
 	'
 
@@ -2166,13 +2169,14 @@ do
 
 			format_command $type "update refs/heads/ref1" "$old_head" "$head" >stdin &&
 			format_command $type "update refs/heads/ref2" "$old_head" "$head" >>stdin &&
-			git update-ref $type --no-deref --stdin --batch-updates <stdin >stdout &&
+			git update-ref $type --no-deref --stdin --batch-updates <stdin >stdout 2>err &&
 			echo $old_head >expect &&
 			git rev-parse refs/heads/ref1 >actual &&
 			test_cmp expect actual &&
 			echo $head >expect &&
 			test_must_fail git rev-parse refs/heads/ref2 &&
-			test_grep -q "reference does not exist" stdout
+			test_grep "rejected refs/heads/ref2 $old_head $head reference does not exist" stdout &&
+			test_grep "cannot lock ref ${SQ}refs/heads/ref2${SQ}: reference is missing but expected $head" err
 		)
 	'
 
@@ -2190,7 +2194,7 @@ do
 
 			format_command $type "update refs/heads/ref1" "$old_head" "$head" >stdin &&
 			format_command $type "symref-update refs/heads/ref2" "$old_head" "ref" "refs/heads/nonexistent" >>stdin &&
-			git update-ref $type --no-deref --stdin --batch-updates <stdin >stdout &&
+			git update-ref $type --no-deref --stdin --batch-updates <stdin >stdout 2>err &&
 			echo $old_head >expect &&
 			git rev-parse refs/heads/ref1 >actual &&
 			test_cmp expect actual &&
@@ -2198,7 +2202,8 @@ do
 			echo $head >expect &&
 			git rev-parse refs/heads/ref2 >actual &&
 			test_cmp expect actual &&
-			test_grep -q "expected symref but found regular ref" stdout
+			test_grep "rejected refs/heads/ref2 $ZERO_OID $ZERO_OID expected symref but found regular ref" stdout &&
+			test_grep "cannot lock ref ${SQ}refs/heads/ref2${SQ}: expected symref with target ${SQ}refs/heads/nonexistent${SQ}: but is a regular ref" err
 		)
 	'
 
@@ -2216,14 +2221,15 @@ do
 
 			format_command $type "update refs/heads/ref1" "$old_head" "$head" >stdin &&
 			format_command $type "update refs/heads/ref2" "$old_head" "$Z" >>stdin &&
-			git update-ref $type --stdin --batch-updates <stdin >stdout &&
+			git update-ref $type --stdin --batch-updates <stdin >stdout 2>err &&
 			echo $old_head >expect &&
 			git rev-parse refs/heads/ref1 >actual &&
 			test_cmp expect actual &&
 			echo $head >expect &&
 			git rev-parse refs/heads/ref2 >actual &&
 			test_cmp expect actual &&
-			test_grep -q "reference already exists" stdout
+			test_grep "rejected refs/heads/ref2 $old_head $ZERO_OID reference already exists" stdout &&
+			test_grep "cannot lock ref ${SQ}refs/heads/ref2${SQ}: reference already exists" err
 		)
 	'
 
@@ -2241,14 +2247,15 @@ do
 
 			format_command $type "update refs/heads/ref1" "$old_head" "$head" >stdin &&
 			format_command $type "update refs/heads/ref2" "$head" "$old_head" >>stdin &&
-			git update-ref $type --stdin --batch-updates <stdin >stdout &&
+			git update-ref $type --stdin --batch-updates <stdin >stdout 2>err &&
 			echo $old_head >expect &&
 			git rev-parse refs/heads/ref1 >actual &&
 			test_cmp expect actual &&
 			echo $head >expect &&
 			git rev-parse refs/heads/ref2 >actual &&
 			test_cmp expect actual &&
-			test_grep -q "incorrect old value provided" stdout
+			test_grep "rejected refs/heads/ref2 $head $old_head incorrect old value provided" stdout &&
+			test_grep "cannot lock ref ${SQ}refs/heads/ref2${SQ}: is at $head but expected $old_head" err
 		)
 	'
 
@@ -2264,12 +2271,13 @@ do
 			git update-ref refs/heads/ref/foo $head &&
 
 			format_command $type "update refs/heads/ref/foo" "$old_head" "$head" >stdin &&
-			format_command $type "update refs/heads/ref" "$old_head" "" >>stdin &&
-			git update-ref $type --stdin --batch-updates <stdin >stdout &&
+			format_command $type "update refs/heads/ref" "$old_head" "$ZERO_OID" >>stdin &&
+			git update-ref $type --stdin --batch-updates <stdin >stdout 2>err &&
 			echo $old_head >expect &&
 			git rev-parse refs/heads/ref/foo >actual &&
 			test_cmp expect actual &&
-			test_grep -q "refname conflict" stdout
+			test_grep "rejected refs/heads/ref $old_head $ZERO_OID refname conflict" stdout &&
+			test_grep "${SQ}refs/heads/ref/foo${SQ} exists; cannot create ${SQ}refs/heads/ref${SQ}" err
 		)
 	'
 
@@ -2284,13 +2292,14 @@ do
 			head=$(git rev-parse HEAD) &&
 			git update-ref refs/heads/ref/foo $head &&
 
-			format_command $type "update refs/heads/foo" "$old_head" "" >stdin &&
-			format_command $type "update refs/heads/ref" "$old_head" "" >>stdin &&
-			git update-ref $type --stdin --batch-updates <stdin >stdout &&
+			format_command $type "update refs/heads/foo" "$old_head" "$ZERO_OID" >stdin &&
+			format_command $type "update refs/heads/ref" "$old_head" "$ZERO_OID" >>stdin &&
+			git update-ref $type --stdin --batch-updates <stdin >stdout 2>err &&
 			echo $old_head >expect &&
 			git rev-parse refs/heads/foo >actual &&
 			test_cmp expect actual &&
-			test_grep -q "refname conflict" stdout
+			test_grep "rejected refs/heads/ref $old_head $ZERO_OID refname conflict" stdout &&
+			test_grep "${SQ}refs/heads/ref/foo${SQ} exists; cannot create ${SQ}refs/heads/ref${SQ}" err
 		)
 	'
 
@@ -2309,14 +2318,15 @@ do
 				format_command $type "create refs/heads/ref" "$old_head" &&
 				format_command $type "create refs/heads/Foo" "$old_head"
 			} >stdin &&
-			git update-ref $type --stdin --batch-updates <stdin >stdout &&
+			git update-ref $type --stdin --batch-updates <stdin >stdout 2>err &&
 
 			echo $head >expect &&
 			git rev-parse refs/heads/foo >actual &&
 			echo $old_head >expect &&
 			git rev-parse refs/heads/ref >actual &&
 			test_cmp expect actual &&
-			test_grep -q "reference conflict due to case-insensitive filesystem" stdout
+			test_grep "rejected refs/heads/Foo $old_head $ZERO_OID reference conflict due to case-insensitive filesystem" stdout &&
+			test_grep -e "cannot lock ref ${SQ}refs/heads/Foo${SQ}: Unable to create" -e "Foo.lock" err
 		)
 	'
 
@@ -2357,8 +2367,9 @@ do
 			git symbolic-ref refs/heads/symbolic refs/heads/non-existent &&
 
 			format_command $type "delete refs/heads/symbolic" "$head" >stdin &&
-			git update-ref $type --stdin --batch-updates <stdin >stdout &&
-			test_grep "reference does not exist" stdout
+			git update-ref $type --stdin --batch-updates <stdin >stdout 2>err &&
+			test_grep "rejected refs/heads/non-existent $ZERO_OID $head reference does not exist" stdout &&
+			test_grep "cannot lock ref ${SQ}refs/heads/symbolic${SQ}: unable to resolve reference ${SQ}refs/heads/non-existent${SQ}" err
 		)
 	'
 
@@ -2373,8 +2384,9 @@ do
 			head=$(git rev-parse HEAD) &&
 
 			format_command $type "delete refs/heads/new-branch" "$head" >stdin &&
-			git update-ref $type --stdin --batch-updates <stdin >stdout &&
-			test_grep "incorrect old value provided" stdout
+			git update-ref $type --stdin --batch-updates <stdin >stdout 2>err &&
+			test_grep "rejected refs/heads/new-branch $ZERO_OID $head incorrect old value provided" stdout &&
+			test_grep "cannot lock ref ${SQ}refs/heads/new-branch${SQ}: is at $(git rev-parse new-branch) but expected $head" err
 		)
 	'
 
@@ -2387,8 +2399,9 @@ do
 			head=$(git rev-parse HEAD) &&
 
 			format_command $type "delete refs/heads/non-existent" "$head" >stdin &&
-			git update-ref $type --stdin --batch-updates <stdin >stdout &&
-			test_grep "reference does not exist" stdout
+			git update-ref $type --stdin --batch-updates <stdin >stdout 2>err &&
+			test_grep "rejected refs/heads/non-existent $ZERO_OID $head reference does not exist" stdout &&
+			test_grep "cannot lock ref ${SQ}refs/heads/non-existent${SQ}: unable to resolve reference ${SQ}refs/heads/non-existent${SQ}" err
 		)
 	'
 done

-- 
2.51.2

[PATCH v2 5/7] fetch: utilize rejected ref error details

[Karthik Nayak]

In 0e358de64a (fetch: use batched reference updates, 2025-05-19),
git-fetch(1) switched to using batched reference updates. This also
introduced a regression wherein instead of providing detailed error
messages for failed referenced updates, the users were provided generic
error messages based on the error type.

Similar to the previous commit, switch to using detailed error messages
if present for failed reference updates to fix this regression.

Reported-by: Elijah Newren <newren@gmail.com>
Co-authored-by: Jeff King <peff@peff.net>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
---
 builtin/fetch.c  | 10 ++++++----
 t/t5510-fetch.sh |  8 ++++----
 2 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/builtin/fetch.c b/builtin/fetch.c
index d427adea61..49495be0b6 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -1649,7 +1649,7 @@ static void ref_transaction_rejection_handler(const char *refname,
 					      const char *old_target UNUSED,
 					      const char *new_target UNUSED,
 					      enum ref_transaction_error err,
-					      const char *details UNUSED,
+					      const char *details,
 					      void *cb_data)
 {
 	struct ref_rejection_data *data = cb_data;
@@ -1674,9 +1674,11 @@ static void ref_transaction_rejection_handler(const char *refname,
 			"branches"), data->remote_name);
 		data->conflict_msg_shown = true;
 	} else {
-		const char *reason = ref_transaction_error_msg(err);
-
-		error(_("fetching ref %s failed: %s"), refname, reason);
+		if (details)
+			error("%s", details);
+		else
+			error(_("fetching ref %s failed: %s"),
+			      refname, ref_transaction_error_msg(err));
 	}
 
 	*data->retcode = 1;
diff --git a/t/t5510-fetch.sh b/t/t5510-fetch.sh
index ce1c23684e..c69afb5a60 100755
--- a/t/t5510-fetch.sh
+++ b/t/t5510-fetch.sh
@@ -1516,7 +1516,7 @@ test_expect_success REFFILES 'existing reference lock in repo' '
 		git remote add origin ../base &&
 		touch refs/heads/foo.lock &&
 		test_must_fail git fetch -f origin "refs/heads/*:refs/heads/*" 2>err &&
-		test_grep "error: fetching ref refs/heads/foo failed: reference already exists" err &&
+		test_grep -e "error: cannot lock ref ${SQ}refs/heads/foo${SQ}: Unable to create" -e "refs/heads/foo.lock${SQ}: File exists." err &&
 		git rev-parse refs/heads/main >expect &&
 		git rev-parse refs/heads/branch >actual &&
 		test_cmp expect actual
@@ -1530,7 +1530,7 @@ test_expect_success CASE_INSENSITIVE_FS,REFFILES 'F/D conflict on case insensiti
 		cd case_insensitive &&
 		git remote add origin -- ../case_sensitive_fd &&
 		test_must_fail git fetch -f origin "refs/heads/*:refs/heads/*" 2>err &&
-		test_grep "failed: refname conflict" err &&
+		test_grep "cannot process ${SQ}refs/remotes/origin/foo${SQ} and ${SQ}refs/remotes/origin/foo/bar${SQ} at the same time" err &&
 		git rev-parse refs/heads/main >expect &&
 		git rev-parse refs/heads/foo/bar >actual &&
 		test_cmp expect actual
@@ -1544,7 +1544,7 @@ test_expect_success CASE_INSENSITIVE_FS,REFFILES 'D/F conflict on case insensiti
 		cd case_insensitive &&
 		git remote add origin -- ../case_sensitive_df &&
 		test_must_fail git fetch -f origin "refs/heads/*:refs/heads/*" 2>err &&
-		test_grep "failed: refname conflict" err &&
+		test_grep "cannot lock ref ${SQ}refs/remotes/origin/foo${SQ}: there is a non-empty directory ${SQ}./refs/remotes/origin/foo${SQ} blocking reference ${SQ}refs/remotes/origin/foo${SQ}" err &&
 		git rev-parse refs/heads/main >expect &&
 		git rev-parse refs/heads/Foo/bar >actual &&
 		test_cmp expect actual
@@ -1658,7 +1658,7 @@ test_expect_success REFFILES "FETCH_HEAD is updated even if ref updates fail" '
 		git remote add origin ../base &&
 		>refs/heads/foo.lock &&
 		test_must_fail git fetch -f origin "refs/heads/*:refs/heads/*" 2>err &&
-		test_grep "error: fetching ref refs/heads/foo failed: reference already exists" err &&
+		test_grep -e "error: cannot lock ref ${SQ}refs/heads/foo${SQ}: Unable to create" -e "refs/heads/foo.lock${SQ}: File exists." err &&
 		test_grep "branch ${SQ}branch${SQ} of ../base" FETCH_HEAD &&
 		test_grep "branch ${SQ}foo${SQ} of ../base" FETCH_HEAD
 	)

-- 
2.51.2

[PATCH v2 6/7] receive-pack: utilize rejected ref error details

[Karthik Nayak]

In 9d2962a7c4 (receive-pack: use batched reference updates, 2025-05-19),
git-receive-pack(1) switched to using batched reference updates. This also
introduced a regression wherein instead of providing detailed error
messages for failed referenced updates, the users were provided generic
error messages based on the error type.

Now that the updates also contain detailed error message, propagate
those to the client via 'rp_error'. The detailed error messages can be
very verbose, for e.g. in the files backend, when trying to write a
non-commit object to a branch, you would see:

   ! [remote rejected] 3eaec9ccf3a53f168362a6b3fdeb73426fb9813d ->
   branch (cannot update ref 'refs/heads/branch': trying to write
   non-commit object 3eaec9ccf3a53f168362a6b3fdeb73426fb9813d to branch
   'refs/heads/branch')

Here the refname is repeated multiple times due to how error messages
are propagated and filled over the code stack. This potentially can be
cleaned up in a future commit.

Reported-by: Elijah Newren <newren@gmail.com>
Co-authored-by: Jeff King <peff@peff.net>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
---
 builtin/receive-pack.c |  8 ++++++--
 t/t5516-fetch-push.sh  | 15 +++++++++++++++
 2 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index 94d3e73cee..70e04b3efb 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -1813,11 +1813,14 @@ static void ref_transaction_rejection_handler(const char *refname,
 					      const char *old_target UNUSED,
 					      const char *new_target UNUSED,
 					      enum ref_transaction_error err,
-					      const char *details UNUSED,
+					      const char *details,
 					      void *cb_data)
 {
 	struct strmap *failed_refs = cb_data;
 
+	if (details)
+		rp_error("%s", details);
+
 	strmap_put(failed_refs, refname, (char *)ref_transaction_error_msg(err));
 }
 
@@ -1884,6 +1887,7 @@ static void execute_commands_non_atomic(struct command *commands,
 		}
 
 		ref_transaction_for_each_rejected_update(transaction,
+
 							 ref_transaction_rejection_handler,
 							 &failed_refs);
 
@@ -1895,7 +1899,7 @@ static void execute_commands_non_atomic(struct command *commands,
 			if (reported_error)
 				cmd->error_string = reported_error;
 			else if (strmap_contains(&failed_refs, cmd->ref_name))
-				cmd->error_string = strmap_get(&failed_refs, cmd->ref_name);
+				cmd->error_string = cmd->error_string_owned = xstrdup(strmap_get(&failed_refs, cmd->ref_name));
 		}
 
 	cleanup:
diff --git a/t/t5516-fetch-push.sh b/t/t5516-fetch-push.sh
index 46926e7bbd..45595991c8 100755
--- a/t/t5516-fetch-push.sh
+++ b/t/t5516-fetch-push.sh
@@ -1882,4 +1882,19 @@ test_expect_success 'push with F/D conflict with deletion and creation' '
 	git push testrepo :refs/heads/branch/conflict refs/heads/branch
 '
 
+test_expect_success 'pushing non-commit objects should report error' '
+	test_when_finished "rm -rf dest repo" &&
+	git init dest &&
+	git init repo &&
+
+	(
+		cd repo &&
+		test_commit --annotate test &&
+
+		tagsha=$(git rev-parse test^{tag}) &&
+		test_must_fail git push ../dest "$tagsha:refs/heads/branch" 2>err &&
+		test_grep "trying to write non-commit object $tagsha to branch ${SQ}refs/heads/branch${SQ}" err
+	)
+'
+
 test_done

-- 
2.51.2

[PATCH v2 7/7] fetch: delay user information post committing of transaction

[Karthik Nayak]

In Git 2.50 and earlier, we would display failure codes and error
message as part of the status display:

  $ git fetch . v1.0.0:refs/heads/foo
    error: cannot update ref 'refs/heads/foo': trying to write non-commit object f665776185ad074b236c00751d666da7d1977dbe to branch 'refs/heads/foo'
    From .
     ! [new tag]               v1.0.0     -> foo  (unable to update local ref)

With the addition of batched updates, this information is no longer
shown to the user:

  $ git fetch . v1.0.0:refs/heads/foo
    From .
     * [new tag]               v1.0.0     -> foo
    error: cannot update ref 'refs/heads/foo': trying to write non-commit object f665776185ad074b236c00751d666da7d1977dbe to branch 'refs/heads/foo'

Since reference updates are batched and processed together at the end,
information around the outcome is not available during individual
reference parsing.

To overcome this, collate and delay the output to the end. Introduce
`ref_update_display_info` which will hold individual update's
information and also whether the update failed or succeeded. This
finally allows us to iterate over all such updates and print them to the
user. While this brings back the functionality, it does change the order
of the output. Modify the tests to reflect this.

Using an strmap does add some overhead to 'git-fetch(1)', but from
benchmarking this seems to be not too bad:

  Benchmark 1: fetch: many refs (refformat = files, refcount = 1000, revision = master)
    Time (mean ± σ):      51.9 ms ±   2.5 ms    [User: 15.6 ms, System: 36.9 ms]
    Range (min … max):    47.4 ms …  58.3 ms    41 runs

  Benchmark 2: fetch: many refs (refformat = files, refcount = 1000, revision = HEAD)
    Time (mean ± σ):      53.0 ms ±   1.8 ms    [User: 17.6 ms, System: 36.0 ms]
    Range (min … max):    49.4 ms …  57.6 ms    40 runs

  Summary
    fetch: many refs (refformat = files, refcount = 1000, revision = master) ran
      1.02 ± 0.06 times faster than fetch: many refs (refformat = files, refcount = 1000, revision = HEAD)

Another approach would be to move the status printing logic to be
handled post the transaction being committed. That however would require
adding an iterator to the ref transaction that tracks both the outcome
(success/failure) and the original refspec information for each update,
which is more involved infrastructure work compared to the strmap
approach here.

Reported-by: Jeff King <peff@peff.net>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
---
 builtin/fetch.c         | 179 ++++++++++++++++++++++++++++++++++++++++--------
 t/t5516-fetch-push.sh   |   1 +
 t/t5574-fetch-output.sh |  16 ++---
 3 files changed, 161 insertions(+), 35 deletions(-)

diff --git a/builtin/fetch.c b/builtin/fetch.c
index 49495be0b6..afe5d321d1 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -861,12 +861,77 @@ static void display_ref_update(struct display_state *display_state, char code,
 	fputs(display_state->buf.buf, f);
 }
 
+struct ref_update_display_info {
+	bool failed;
+	char success_code;
+	char fail_code;
+	const char *summary;
+	const char *fail_detail;
+	const char *success_detail;
+	const char *remote;
+	const char *local;
+	struct object_id old_oid;
+	struct object_id new_oid;
+};
+
+static struct ref_update_display_info *ref_update_display_info_new(
+						char success_code,
+						char fail_code,
+						const char *summary,
+						const char *success_detail,
+						const char *fail_detail,
+						const char *remote,
+						const struct object_id *old_oid,
+						const struct object_id *new_oid)
+{
+	struct ref_update_display_info *info;
+	CALLOC_ARRAY(info, 1);
+
+	info->success_code = success_code;
+	info->fail_code = fail_code;
+	info->summary = xstrdup(summary);
+	info->success_detail = xstrdup_or_null(success_detail);
+	info->fail_detail = xstrdup_or_null(fail_detail);
+	info->remote = xstrdup(remote);
+
+	oidcpy(&info->old_oid, old_oid);
+	oidcpy(&info->new_oid, new_oid);
+
+	return info;
+}
+
+static void ref_update_display_info_set_failed(struct ref_update_display_info *info)
+{
+	info->failed = true;
+}
+
+static void ref_update_display_info_free(struct ref_update_display_info *info)
+{
+	free((char *)info->summary);
+	free((char *)info->success_detail);
+	free((char *)info->fail_detail);
+	free((char *)info->remote);
+}
+
+static void ref_update_display_info_display(struct ref_update_display_info *info,
+					    struct display_state *display_state,
+					    const char *refname, int summary_width)
+{
+	display_ref_update(display_state,
+			   info->failed ? info->fail_code : info->success_code,
+			   info->summary,
+			   info->failed ? info->fail_detail : info->success_detail,
+			   info->remote, refname, &info->old_oid,
+			   &info->new_oid, summary_width);
+}
+
 static int update_local_ref(struct ref *ref,
 			    struct ref_transaction *transaction,
 			    struct display_state *display_state,
 			    const struct ref *remote_ref,
 			    int summary_width,
-			    const struct fetch_config *config)
+			    const struct fetch_config *config,
+			    struct strmap *delayed_ref_display)
 {
 	struct commit *current = NULL, *updated;
 	int fast_forward = 0;
@@ -900,12 +965,19 @@ static int update_local_ref(struct ref *ref,
 	if (!is_null_oid(&ref->old_oid) &&
 	    starts_with(ref->name, "refs/tags/")) {
 		if (force || ref->force) {
+			struct ref_update_display_info *info;
 			int r;
+
 			r = s_update_ref("updating tag", ref, transaction, 0);
-			display_ref_update(display_state, r ? '!' : 't', _("[tag update]"),
-					   r ? _("unable to update local ref") : NULL,
-					   remote_ref->name, ref->name,
-					   &ref->old_oid, &ref->new_oid, summary_width);
+
+			info = ref_update_display_info_new('t', '!', _("[tag update]"), NULL,
+							   _("unable to update local ref"),
+							   remote_ref->name, &ref->old_oid,
+							   &ref->new_oid);
+			if (r)
+				ref_update_display_info_set_failed(info);
+			strmap_put(delayed_ref_display, ref->name, info);
+
 			return r;
 		} else {
 			display_ref_update(display_state, '!', _("[rejected]"),
@@ -921,6 +993,7 @@ static int update_local_ref(struct ref *ref,
 	updated = lookup_commit_reference_gently(the_repository,
 						 &ref->new_oid, 1);
 	if (!current || !updated) {
+		struct ref_update_display_info *info;
 		const char *msg;
 		const char *what;
 		int r;
@@ -941,10 +1014,15 @@ static int update_local_ref(struct ref *ref,
 		}
 
 		r = s_update_ref(msg, ref, transaction, 0);
-		display_ref_update(display_state, r ? '!' : '*', what,
-				   r ? _("unable to update local ref") : NULL,
-				   remote_ref->name, ref->name,
-				   &ref->old_oid, &ref->new_oid, summary_width);
+
+		info = ref_update_display_info_new('*', '!', what, NULL,
+						   _("unable to update local ref"),
+						   remote_ref->name, &ref->old_oid,
+						   &ref->new_oid);
+		if (r)
+			ref_update_display_info_set_failed(info);
+		strmap_put(delayed_ref_display, ref->name, info);
+
 		return r;
 	}
 
@@ -960,6 +1038,7 @@ static int update_local_ref(struct ref *ref,
 	}
 
 	if (fast_forward) {
+		struct ref_update_display_info *info;
 		struct strbuf quickref = STRBUF_INIT;
 		int r;
 
@@ -967,23 +1046,36 @@ static int update_local_ref(struct ref *ref,
 		strbuf_addstr(&quickref, "..");
 		strbuf_add_unique_abbrev(&quickref, &ref->new_oid, DEFAULT_ABBREV);
 		r = s_update_ref("fast-forward", ref, transaction, 1);
-		display_ref_update(display_state, r ? '!' : ' ', quickref.buf,
-				   r ? _("unable to update local ref") : NULL,
-				   remote_ref->name, ref->name,
-				   &ref->old_oid, &ref->new_oid, summary_width);
+
+		info = ref_update_display_info_new(' ', '!', quickref.buf, NULL,
+						   _("unable to update local ref"),
+						   remote_ref->name, &ref->old_oid,
+						   &ref->new_oid);
+		if (r)
+			ref_update_display_info_set_failed(info);
+		strmap_put(delayed_ref_display, ref->name, info);
+
 		strbuf_release(&quickref);
 		return r;
 	} else if (force || ref->force) {
+		struct ref_update_display_info *info;
 		struct strbuf quickref = STRBUF_INIT;
 		int r;
+
 		strbuf_add_unique_abbrev(&quickref, &current->object.oid, DEFAULT_ABBREV);
 		strbuf_addstr(&quickref, "...");
 		strbuf_add_unique_abbrev(&quickref, &ref->new_oid, DEFAULT_ABBREV);
 		r = s_update_ref("forced-update", ref, transaction, 1);
-		display_ref_update(display_state, r ? '!' : '+', quickref.buf,
-				   r ? _("unable to update local ref") : _("forced update"),
-				   remote_ref->name, ref->name,
-				   &ref->old_oid, &ref->new_oid, summary_width);
+
+		info = ref_update_display_info_new('+', '!', quickref.buf,
+						   _("forced update"),
+						   _("unable to update local ref"),
+						   remote_ref->name, &ref->old_oid,
+						   &ref->new_oid);
+		if (r)
+			ref_update_display_info_set_failed(info);
+		strmap_put(delayed_ref_display, ref->name, info);
+
 		strbuf_release(&quickref);
 		return r;
 	} else {
@@ -1103,7 +1195,8 @@ static int store_updated_refs(struct display_state *display_state,
 			      int connectivity_checked,
 			      struct ref_transaction *transaction, struct ref *ref_map,
 			      struct fetch_head *fetch_head,
-			      const struct fetch_config *config)
+			      const struct fetch_config *config,
+			      struct strmap *delayed_ref_display)
 {
 	int rc = 0;
 	struct strbuf note = STRBUF_INIT;
@@ -1219,7 +1312,8 @@ static int store_updated_refs(struct display_state *display_state,
 
 			if (ref) {
 				rc |= update_local_ref(ref, transaction, display_state,
-						       rm, summary_width, config);
+						       rm, summary_width, config,
+						       delayed_ref_display);
 				free(ref);
 			} else if (write_fetch_head || dry_run) {
 				/*
@@ -1300,7 +1394,8 @@ static int fetch_and_consume_refs(struct display_state *display_state,
 				  struct ref_transaction *transaction,
 				  struct ref *ref_map,
 				  struct fetch_head *fetch_head,
-				  const struct fetch_config *config)
+				  const struct fetch_config *config,
+				  struct strmap *delayed_ref_display)
 {
 	int connectivity_checked = 1;
 	int ret;
@@ -1322,7 +1417,8 @@ static int fetch_and_consume_refs(struct display_state *display_state,
 
 	trace2_region_enter("fetch", "consume_refs", the_repository);
 	ret = store_updated_refs(display_state, connectivity_checked,
-				 transaction, ref_map, fetch_head, config);
+				 transaction, ref_map, fetch_head, config,
+				 delayed_ref_display);
 	trace2_region_leave("fetch", "consume_refs", the_repository);
 
 out:
@@ -1493,7 +1589,8 @@ static int backfill_tags(struct display_state *display_state,
 			 struct ref_transaction *transaction,
 			 struct ref *ref_map,
 			 struct fetch_head *fetch_head,
-			 const struct fetch_config *config)
+			 const struct fetch_config *config,
+			 struct strmap *delayed_ref_display)
 {
 	int retcode, cannot_reuse;
 
@@ -1515,7 +1612,7 @@ static int backfill_tags(struct display_state *display_state,
 	transport_set_option(transport, TRANS_OPT_DEPTH, "0");
 	transport_set_option(transport, TRANS_OPT_DEEPEN_RELATIVE, NULL);
 	retcode = fetch_and_consume_refs(display_state, transport, transaction, ref_map,
-					 fetch_head, config);
+					 fetch_head, config, delayed_ref_display);
 
 	if (gsecondary) {
 		transport_disconnect(gsecondary);
@@ -1641,6 +1738,7 @@ struct ref_rejection_data {
 	bool conflict_msg_shown;
 	bool case_sensitive_msg_shown;
 	const char *remote_name;
+	struct strmap *delayed_ref_display;
 };
 
 static void ref_transaction_rejection_handler(const char *refname,
@@ -1653,6 +1751,7 @@ static void ref_transaction_rejection_handler(const char *refname,
 					      void *cb_data)
 {
 	struct ref_rejection_data *data = cb_data;
+	struct ref_update_display_info *info;
 
 	if (err == REF_TRANSACTION_ERROR_CASE_CONFLICT && ignore_case &&
 	    !data->case_sensitive_msg_shown) {
@@ -1681,6 +1780,10 @@ static void ref_transaction_rejection_handler(const char *refname,
 			      refname, ref_transaction_error_msg(err));
 	}
 
+	info = strmap_get(data->delayed_ref_display, refname);
+	if (info)
+		ref_update_display_info_set_failed(info);
+
 	*data->retcode = 1;
 }
 
@@ -1690,6 +1793,7 @@ static void ref_transaction_rejection_handler(const char *refname,
  */
 static int commit_ref_transaction(struct ref_transaction **transaction,
 				  bool is_atomic, const char *remote_name,
+				  struct strmap *delayed_ref_display,
 				  struct strbuf *err)
 {
 	int retcode = ref_transaction_commit(*transaction, err);
@@ -1701,6 +1805,7 @@ static int commit_ref_transaction(struct ref_transaction **transaction,
 			.conflict_msg_shown = 0,
 			.remote_name = remote_name,
 			.retcode = &retcode,
+			.delayed_ref_display = delayed_ref_display,
 		};
 
 		ref_transaction_for_each_rejected_update(*transaction,
@@ -1729,6 +1834,10 @@ static int do_fetch(struct transport *transport,
 	struct fetch_head fetch_head = { 0 };
 	struct strbuf err = STRBUF_INIT;
 	int do_set_head = 0;
+	struct strmap delayed_ref_display = STRMAP_INIT;
+	int summary_width = 0;
+	struct strmap_entry *e;
+	struct hashmap_iter iter;
 
 	if (tags == TAGS_DEFAULT) {
 		if (transport->remote->fetch_tags == 2)
@@ -1853,7 +1962,7 @@ static int do_fetch(struct transport *transport,
 	}
 
 	if (fetch_and_consume_refs(&display_state, transport, transaction, ref_map,
-				   &fetch_head, config)) {
+				   &fetch_head, config, &delayed_ref_display)) {
 		retcode = 1;
 		goto cleanup;
 	}
@@ -1876,7 +1985,7 @@ static int do_fetch(struct transport *transport,
 			 * the transaction and don't commit anything.
 			 */
 			if (backfill_tags(&display_state, transport, transaction, tags_ref_map,
-					  &fetch_head, config))
+					  &fetch_head, config, &delayed_ref_display))
 				retcode = 1;
 		}
 
@@ -1886,8 +1995,12 @@ static int do_fetch(struct transport *transport,
 	if (retcode)
 		goto cleanup;
 
+	if (verbosity >= 0)
+		summary_width = transport_summary_width(ref_map);
+
 	retcode = commit_ref_transaction(&transaction, atomic_fetch,
-					 transport->remote->name, &err);
+					 transport->remote->name,
+					 &delayed_ref_display, &err);
 	/*
 	 * With '--atomic', bail out if the transaction fails. Without '--atomic',
 	 * continue to fetch head and perform other post-fetch operations.
@@ -1965,7 +2078,17 @@ static int do_fetch(struct transport *transport,
 	 */
 	if (retcode && !atomic_fetch && transaction)
 		commit_ref_transaction(&transaction, false,
-				       transport->remote->name, &err);
+				       transport->remote->name,
+				       &delayed_ref_display, &err);
+
+	/*
+	 * Clear any pending information that needs to be shown to the user.
+	 */
+	strmap_for_each_entry(&delayed_ref_display, &iter, e) {
+		struct ref_update_display_info *info = e->value;
+		ref_update_display_info_display(info, &display_state, e->key, summary_width);
+		ref_update_display_info_free(info);
+	}
 
 	if (retcode) {
 		if (err.len) {
@@ -1980,6 +2103,8 @@ static int do_fetch(struct transport *transport,
 
 	if (transaction)
 		ref_transaction_free(transaction);
+
+	strmap_clear(&delayed_ref_display, 1);
 	display_state_release(&display_state);
 	close_fetch_head(&fetch_head);
 	strbuf_release(&err);
diff --git a/t/t5516-fetch-push.sh b/t/t5516-fetch-push.sh
index 45595991c8..29e2f17608 100755
--- a/t/t5516-fetch-push.sh
+++ b/t/t5516-fetch-push.sh
@@ -1893,6 +1893,7 @@ test_expect_success 'pushing non-commit objects should report error' '
 
 		tagsha=$(git rev-parse test^{tag}) &&
 		test_must_fail git push ../dest "$tagsha:refs/heads/branch" 2>err &&
+		test_grep "! \[remote rejected\] $tagsha -> branch (invalid new value provided)" err &&
 		test_grep "trying to write non-commit object $tagsha to branch ${SQ}refs/heads/branch${SQ}" err
 	)
 '
diff --git a/t/t5574-fetch-output.sh b/t/t5574-fetch-output.sh
index 5883839a04..22bfc0c74d 100755
--- a/t/t5574-fetch-output.sh
+++ b/t/t5574-fetch-output.sh
@@ -40,8 +40,8 @@ test_expect_success 'fetch aligned output' '
 		grep -e "->" actual | cut -c 22- >../actual
 	) &&
 	cat >expect <<-\EOF &&
-	main                 -> origin/main
 	looooooooooooong-tag -> looooooooooooong-tag
+	main                 -> origin/main
 	EOF
 	test_cmp expect actual
 '
@@ -55,8 +55,8 @@ test_expect_success 'fetch compact output' '
 		grep -e "->" actual | cut -c 22- >../actual
 	) &&
 	cat >expect <<-\EOF &&
-	main       -> origin/*
 	extraaa    -> *
+	main       -> origin/*
 	EOF
 	test_cmp expect actual
 '
@@ -103,15 +103,15 @@ do
 		cat >expect <<-EOF &&
 		- $MAIN_OLD $ZERO_OID refs/forced/deleted-branch
 		- $MAIN_OLD $ZERO_OID refs/unforced/deleted-branch
-		  $MAIN_OLD $FAST_FORWARD_NEW refs/unforced/fast-forward
 		! $FORCE_UPDATED_OLD $FORCE_UPDATED_NEW refs/unforced/force-updated
+		* $ZERO_OID $MAIN_OLD refs/forced/new-branch
+		* $ZERO_OID $MAIN_OLD refs/remotes/origin/new-branch
+		+ $FORCE_UPDATED_OLD $FORCE_UPDATED_NEW refs/remotes/origin/force-updated
+		  $MAIN_OLD $FAST_FORWARD_NEW refs/unforced/fast-forward
 		* $ZERO_OID $MAIN_OLD refs/unforced/new-branch
 		  $MAIN_OLD $FAST_FORWARD_NEW refs/forced/fast-forward
-		+ $FORCE_UPDATED_OLD $FORCE_UPDATED_NEW refs/forced/force-updated
-		* $ZERO_OID $MAIN_OLD refs/forced/new-branch
 		  $MAIN_OLD $FAST_FORWARD_NEW refs/remotes/origin/fast-forward
-		+ $FORCE_UPDATED_OLD $FORCE_UPDATED_NEW refs/remotes/origin/force-updated
-		* $ZERO_OID $MAIN_OLD refs/remotes/origin/new-branch
+		+ $FORCE_UPDATED_OLD $FORCE_UPDATED_NEW refs/forced/force-updated
 		EOF
 
 		# Change the URL of the repository to fetch different references.
@@ -179,8 +179,8 @@ test_expect_success 'fetch porcelain overrides fetch.output config' '
 	new_commit=$(git rev-parse HEAD) &&
 
 	cat >expect <<-EOF &&
-	  $old_commit $new_commit refs/remotes/origin/config-override
 	* $ZERO_OID $new_commit refs/tags/new-commit
+	  $old_commit $new_commit refs/remotes/origin/config-override
 	EOF
 
 	git -C porcelain -c fetch.output=compact fetch --porcelain >stdout 2>stderr &&

-- 
2.51.2

Re: [PATCH v2 7/7] fetch: delay user information post committing of transaction

[Phillip Wood]

Hi Karthik

On 16/01/2026 21:27, Karthik Nayak wrote:
> In Git 2.50 and earlier, we would display failure codes and error
> message as part of the status display:
> 
>    $ git fetch . v1.0.0:refs/heads/foo
>      error: cannot update ref 'refs/heads/foo': trying to write non-commit object f665776185ad074b236c00751d666da7d1977dbe to branch 'refs/heads/foo'
>      From .
>       ! [new tag]               v1.0.0     -> foo  (unable to update local ref)
> 
> With the addition of batched updates, this information is no longer
> shown to the user:
> 
>    $ git fetch . v1.0.0:refs/heads/foo
>      From .
>       * [new tag]               v1.0.0     -> foo
>      error: cannot update ref 'refs/heads/foo': trying to write non-commit object f665776185ad074b236c00751d666da7d1977dbe to branch 'refs/heads/foo'
> 
> Since reference updates are batched and processed together at the end,
> information around the outcome is not available during individual
> reference parsing.
> 
> To overcome this, collate and delay the output to the end. Introduce
> `ref_update_display_info` which will hold individual update's
> information and also whether the update failed or succeeded. This
> finally allows us to iterate over all such updates and print them to the
> user. While this brings back the functionality, it does change the order
> of the output. Modify the tests to reflect this.

It is unfortunate that a fix for a regression the the messages changes 
the order of those messages. It is doubly unfortunate that the new order 
depends on the implementation of strmap_for_each() which may change in 
the future. I think you can avoid this by appending each update to an 
array in update_local_ref() and adding the errors to a separate strmap 
in ref_transaction_rejection_handler(). Then when you come to print the 
massages, loop over the array and for each update lookup the ref in the 
strmap to see if it failed before printing the appropriate message.

Thanks

Phillip

> Using an strmap does add some overhead to 'git-fetch(1)', but from
> benchmarking this seems to be not too bad:
> 
>    Benchmark 1: fetch: many refs (refformat = files, refcount = 1000, revision = master)
>      Time (mean ± σ):      51.9 ms ±   2.5 ms    [User: 15.6 ms, System: 36.9 ms]
>      Range (min … max):    47.4 ms …  58.3 ms    41 runs
> 
>    Benchmark 2: fetch: many refs (refformat = files, refcount = 1000, revision = HEAD)
>      Time (mean ± σ):      53.0 ms ±   1.8 ms    [User: 17.6 ms, System: 36.0 ms]
>      Range (min … max):    49.4 ms …  57.6 ms    40 runs
> 
>    Summary
>      fetch: many refs (refformat = files, refcount = 1000, revision = master) ran
>        1.02 ± 0.06 times faster than fetch: many refs (refformat = files, refcount = 1000, revision = HEAD)
> 
> Another approach would be to move the status printing logic to be
> handled post the transaction being committed. That however would require
> adding an iterator to the ref transaction that tracks both the outcome
> (success/failure) and the original refspec information for each update,
> which is more involved infrastructure work compared to the strmap
> approach here.
> 
> Reported-by: Jeff King <peff@peff.net>
> Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
> ---
>   builtin/fetch.c         | 179 ++++++++++++++++++++++++++++++++++++++++--------
>   t/t5516-fetch-push.sh   |   1 +
>   t/t5574-fetch-output.sh |  16 ++---
>   3 files changed, 161 insertions(+), 35 deletions(-)
> 
> diff --git a/builtin/fetch.c b/builtin/fetch.c
> index 49495be0b6..afe5d321d1 100644
> --- a/builtin/fetch.c
> +++ b/builtin/fetch.c
> @@ -861,12 +861,77 @@ static void display_ref_update(struct display_state *display_state, char code,
>   	fputs(display_state->buf.buf, f);
>   }
>   
> +struct ref_update_display_info {
> +	bool failed;
> +	char success_code;
> +	char fail_code;
> +	const char *summary;
> +	const char *fail_detail;
> +	const char *success_detail;
> +	const char *remote;
> +	const char *local;
> +	struct object_id old_oid;
> +	struct object_id new_oid;
> +};
> +
> +static struct ref_update_display_info *ref_update_display_info_new(
> +						char success_code,
> +						char fail_code,
> +						const char *summary,
> +						const char *success_detail,
> +						const char *fail_detail,
> +						const char *remote,
> +						const struct object_id *old_oid,
> +						const struct object_id *new_oid)
> +{
> +	struct ref_update_display_info *info;
> +	CALLOC_ARRAY(info, 1);
> +
> +	info->success_code = success_code;
> +	info->fail_code = fail_code;
> +	info->summary = xstrdup(summary);
> +	info->success_detail = xstrdup_or_null(success_detail);
> +	info->fail_detail = xstrdup_or_null(fail_detail);
> +	info->remote = xstrdup(remote);
> +
> +	oidcpy(&info->old_oid, old_oid);
> +	oidcpy(&info->new_oid, new_oid);
> +
> +	return info;
> +}
> +
> +static void ref_update_display_info_set_failed(struct ref_update_display_info *info)
> +{
> +	info->failed = true;
> +}
> +
> +static void ref_update_display_info_free(struct ref_update_display_info *info)
> +{
> +	free((char *)info->summary);
> +	free((char *)info->success_detail);
> +	free((char *)info->fail_detail);
> +	free((char *)info->remote);
> +}
> +
> +static void ref_update_display_info_display(struct ref_update_display_info *info,
> +					    struct display_state *display_state,
> +					    const char *refname, int summary_width)
> +{
> +	display_ref_update(display_state,
> +			   info->failed ? info->fail_code : info->success_code,
> +			   info->summary,
> +			   info->failed ? info->fail_detail : info->success_detail,
> +			   info->remote, refname, &info->old_oid,
> +			   &info->new_oid, summary_width);
> +}
> +
>   static int update_local_ref(struct ref *ref,
>   			    struct ref_transaction *transaction,
>   			    struct display_state *display_state,
>   			    const struct ref *remote_ref,
>   			    int summary_width,
> -			    const struct fetch_config *config)
> +			    const struct fetch_config *config,
> +			    struct strmap *delayed_ref_display)
>   {
>   	struct commit *current = NULL, *updated;
>   	int fast_forward = 0;
> @@ -900,12 +965,19 @@ static int update_local_ref(struct ref *ref,
>   	if (!is_null_oid(&ref->old_oid) &&
>   	    starts_with(ref->name, "refs/tags/")) {
>   		if (force || ref->force) {
> +			struct ref_update_display_info *info;
>   			int r;
> +
>   			r = s_update_ref("updating tag", ref, transaction, 0);
> -			display_ref_update(display_state, r ? '!' : 't', _("[tag update]"),
> -					   r ? _("unable to update local ref") : NULL,
> -					   remote_ref->name, ref->name,
> -					   &ref->old_oid, &ref->new_oid, summary_width);
> +
> +			info = ref_update_display_info_new('t', '!', _("[tag update]"), NULL,
> +							   _("unable to update local ref"),
> +							   remote_ref->name, &ref->old_oid,
> +							   &ref->new_oid);
> +			if (r)
> +				ref_update_display_info_set_failed(info);
> +			strmap_put(delayed_ref_display, ref->name, info);
> +
>   			return r;
>   		} else {
>   			display_ref_update(display_state, '!', _("[rejected]"),
> @@ -921,6 +993,7 @@ static int update_local_ref(struct ref *ref,
>   	updated = lookup_commit_reference_gently(the_repository,
>   						 &ref->new_oid, 1);
>   	if (!current || !updated) {
> +		struct ref_update_display_info *info;
>   		const char *msg;
>   		const char *what;
>   		int r;
> @@ -941,10 +1014,15 @@ static int update_local_ref(struct ref *ref,
>   		}
>   
>   		r = s_update_ref(msg, ref, transaction, 0);
> -		display_ref_update(display_state, r ? '!' : '*', what,
> -				   r ? _("unable to update local ref") : NULL,
> -				   remote_ref->name, ref->name,
> -				   &ref->old_oid, &ref->new_oid, summary_width);
> +
> +		info = ref_update_display_info_new('*', '!', what, NULL,
> +						   _("unable to update local ref"),
> +						   remote_ref->name, &ref->old_oid,
> +						   &ref->new_oid);
> +		if (r)
> +			ref_update_display_info_set_failed(info);
> +		strmap_put(delayed_ref_display, ref->name, info);
> +
>   		return r;
>   	}
>   
> @@ -960,6 +1038,7 @@ static int update_local_ref(struct ref *ref,
>   	}
>   
>   	if (fast_forward) {
> +		struct ref_update_display_info *info;
>   		struct strbuf quickref = STRBUF_INIT;
>   		int r;
>   
> @@ -967,23 +1046,36 @@ static int update_local_ref(struct ref *ref,
>   		strbuf_addstr(&quickref, "..");
>   		strbuf_add_unique_abbrev(&quickref, &ref->new_oid, DEFAULT_ABBREV);
>   		r = s_update_ref("fast-forward", ref, transaction, 1);
> -		display_ref_update(display_state, r ? '!' : ' ', quickref.buf,
> -				   r ? _("unable to update local ref") : NULL,
> -				   remote_ref->name, ref->name,
> -				   &ref->old_oid, &ref->new_oid, summary_width);
> +
> +		info = ref_update_display_info_new(' ', '!', quickref.buf, NULL,
> +						   _("unable to update local ref"),
> +						   remote_ref->name, &ref->old_oid,
> +						   &ref->new_oid);
> +		if (r)
> +			ref_update_display_info_set_failed(info);
> +		strmap_put(delayed_ref_display, ref->name, info);
> +
>   		strbuf_release(&quickref);
>   		return r;
>   	} else if (force || ref->force) {
> +		struct ref_update_display_info *info;
>   		struct strbuf quickref = STRBUF_INIT;
>   		int r;
> +
>   		strbuf_add_unique_abbrev(&quickref, &current->object.oid, DEFAULT_ABBREV);
>   		strbuf_addstr(&quickref, "...");
>   		strbuf_add_unique_abbrev(&quickref, &ref->new_oid, DEFAULT_ABBREV);
>   		r = s_update_ref("forced-update", ref, transaction, 1);
> -		display_ref_update(display_state, r ? '!' : '+', quickref.buf,
> -				   r ? _("unable to update local ref") : _("forced update"),
> -				   remote_ref->name, ref->name,
> -				   &ref->old_oid, &ref->new_oid, summary_width);
> +
> +		info = ref_update_display_info_new('+', '!', quickref.buf,
> +						   _("forced update"),
> +						   _("unable to update local ref"),
> +						   remote_ref->name, &ref->old_oid,
> +						   &ref->new_oid);
> +		if (r)
> +			ref_update_display_info_set_failed(info);
> +		strmap_put(delayed_ref_display, ref->name, info);
> +
>   		strbuf_release(&quickref);
>   		return r;
>   	} else {
> @@ -1103,7 +1195,8 @@ static int store_updated_refs(struct display_state *display_state,
>   			      int connectivity_checked,
>   			      struct ref_transaction *transaction, struct ref *ref_map,
>   			      struct fetch_head *fetch_head,
> -			      const struct fetch_config *config)
> +			      const struct fetch_config *config,
> +			      struct strmap *delayed_ref_display)
>   {
>   	int rc = 0;
>   	struct strbuf note = STRBUF_INIT;
> @@ -1219,7 +1312,8 @@ static int store_updated_refs(struct display_state *display_state,
>   
>   			if (ref) {
>   				rc |= update_local_ref(ref, transaction, display_state,
> -						       rm, summary_width, config);
> +						       rm, summary_width, config,
> +						       delayed_ref_display);
>   				free(ref);
>   			} else if (write_fetch_head || dry_run) {
>   				/*
> @@ -1300,7 +1394,8 @@ static int fetch_and_consume_refs(struct display_state *display_state,
>   				  struct ref_transaction *transaction,
>   				  struct ref *ref_map,
>   				  struct fetch_head *fetch_head,
> -				  const struct fetch_config *config)
> +				  const struct fetch_config *config,
> +				  struct strmap *delayed_ref_display)
>   {
>   	int connectivity_checked = 1;
>   	int ret;
> @@ -1322,7 +1417,8 @@ static int fetch_and_consume_refs(struct display_state *display_state,
>   
>   	trace2_region_enter("fetch", "consume_refs", the_repository);
>   	ret = store_updated_refs(display_state, connectivity_checked,
> -				 transaction, ref_map, fetch_head, config);
> +				 transaction, ref_map, fetch_head, config,
> +				 delayed_ref_display);
>   	trace2_region_leave("fetch", "consume_refs", the_repository);
>   
>   out:
> @@ -1493,7 +1589,8 @@ static int backfill_tags(struct display_state *display_state,
>   			 struct ref_transaction *transaction,
>   			 struct ref *ref_map,
>   			 struct fetch_head *fetch_head,
> -			 const struct fetch_config *config)
> +			 const struct fetch_config *config,
> +			 struct strmap *delayed_ref_display)
>   {
>   	int retcode, cannot_reuse;
>   
> @@ -1515,7 +1612,7 @@ static int backfill_tags(struct display_state *display_state,
>   	transport_set_option(transport, TRANS_OPT_DEPTH, "0");
>   	transport_set_option(transport, TRANS_OPT_DEEPEN_RELATIVE, NULL);
>   	retcode = fetch_and_consume_refs(display_state, transport, transaction, ref_map,
> -					 fetch_head, config);
> +					 fetch_head, config, delayed_ref_display);
>   
>   	if (gsecondary) {
>   		transport_disconnect(gsecondary);
> @@ -1641,6 +1738,7 @@ struct ref_rejection_data {
>   	bool conflict_msg_shown;
>   	bool case_sensitive_msg_shown;
>   	const char *remote_name;
> +	struct strmap *delayed_ref_display;
>   };
>   
>   static void ref_transaction_rejection_handler(const char *refname,
> @@ -1653,6 +1751,7 @@ static void ref_transaction_rejection_handler(const char *refname,
>   					      void *cb_data)
>   {
>   	struct ref_rejection_data *data = cb_data;
> +	struct ref_update_display_info *info;
>   
>   	if (err == REF_TRANSACTION_ERROR_CASE_CONFLICT && ignore_case &&
>   	    !data->case_sensitive_msg_shown) {
> @@ -1681,6 +1780,10 @@ static void ref_transaction_rejection_handler(const char *refname,
>   			      refname, ref_transaction_error_msg(err));
>   	}
>   
> +	info = strmap_get(data->delayed_ref_display, refname);
> +	if (info)
> +		ref_update_display_info_set_failed(info);
> +
>   	*data->retcode = 1;
>   }
>   
> @@ -1690,6 +1793,7 @@ static void ref_transaction_rejection_handler(const char *refname,
>    */
>   static int commit_ref_transaction(struct ref_transaction **transaction,
>   				  bool is_atomic, const char *remote_name,
> +				  struct strmap *delayed_ref_display,
>   				  struct strbuf *err)
>   {
>   	int retcode = ref_transaction_commit(*transaction, err);
> @@ -1701,6 +1805,7 @@ static int commit_ref_transaction(struct ref_transaction **transaction,
>   			.conflict_msg_shown = 0,
>   			.remote_name = remote_name,
>   			.retcode = &retcode,
> +			.delayed_ref_display = delayed_ref_display,
>   		};
>   
>   		ref_transaction_for_each_rejected_update(*transaction,
> @@ -1729,6 +1834,10 @@ static int do_fetch(struct transport *transport,
>   	struct fetch_head fetch_head = { 0 };
>   	struct strbuf err = STRBUF_INIT;
>   	int do_set_head = 0;
> +	struct strmap delayed_ref_display = STRMAP_INIT;
> +	int summary_width = 0;
> +	struct strmap_entry *e;
> +	struct hashmap_iter iter;
>   
>   	if (tags == TAGS_DEFAULT) {
>   		if (transport->remote->fetch_tags == 2)
> @@ -1853,7 +1962,7 @@ static int do_fetch(struct transport *transport,
>   	}
>   
>   	if (fetch_and_consume_refs(&display_state, transport, transaction, ref_map,
> -				   &fetch_head, config)) {
> +				   &fetch_head, config, &delayed_ref_display)) {
>   		retcode = 1;
>   		goto cleanup;
>   	}
> @@ -1876,7 +1985,7 @@ static int do_fetch(struct transport *transport,
>   			 * the transaction and don't commit anything.
>   			 */
>   			if (backfill_tags(&display_state, transport, transaction, tags_ref_map,
> -					  &fetch_head, config))
> +					  &fetch_head, config, &delayed_ref_display))
>   				retcode = 1;
>   		}
>   
> @@ -1886,8 +1995,12 @@ static int do_fetch(struct transport *transport,
>   	if (retcode)
>   		goto cleanup;
>   
> +	if (verbosity >= 0)
> +		summary_width = transport_summary_width(ref_map);
> +
>   	retcode = commit_ref_transaction(&transaction, atomic_fetch,
> -					 transport->remote->name, &err);
> +					 transport->remote->name,
> +					 &delayed_ref_display, &err);
>   	/*
>   	 * With '--atomic', bail out if the transaction fails. Without '--atomic',
>   	 * continue to fetch head and perform other post-fetch operations.
> @@ -1965,7 +2078,17 @@ static int do_fetch(struct transport *transport,
>   	 */
>   	if (retcode && !atomic_fetch && transaction)
>   		commit_ref_transaction(&transaction, false,
> -				       transport->remote->name, &err);
> +				       transport->remote->name,
> +				       &delayed_ref_display, &err);
> +
> +	/*
> +	 * Clear any pending information that needs to be shown to the user.
> +	 */
> +	strmap_for_each_entry(&delayed_ref_display, &iter, e) {
> +		struct ref_update_display_info *info = e->value;
> +		ref_update_display_info_display(info, &display_state, e->key, summary_width);
> +		ref_update_display_info_free(info);
> +	}
>   
>   	if (retcode) {
>   		if (err.len) {
> @@ -1980,6 +2103,8 @@ static int do_fetch(struct transport *transport,
>   
>   	if (transaction)
>   		ref_transaction_free(transaction);
> +
> +	strmap_clear(&delayed_ref_display, 1);
>   	display_state_release(&display_state);
>   	close_fetch_head(&fetch_head);
>   	strbuf_release(&err);
> diff --git a/t/t5516-fetch-push.sh b/t/t5516-fetch-push.sh
> index 45595991c8..29e2f17608 100755
> --- a/t/t5516-fetch-push.sh
> +++ b/t/t5516-fetch-push.sh
> @@ -1893,6 +1893,7 @@ test_expect_success 'pushing non-commit objects should report error' '
>   
>   		tagsha=$(git rev-parse test^{tag}) &&
>   		test_must_fail git push ../dest "$tagsha:refs/heads/branch" 2>err &&
> +		test_grep "! \[remote rejected\] $tagsha -> branch (invalid new value provided)" err &&
>   		test_grep "trying to write non-commit object $tagsha to branch ${SQ}refs/heads/branch${SQ}" err
>   	)
>   '
> diff --git a/t/t5574-fetch-output.sh b/t/t5574-fetch-output.sh
> index 5883839a04..22bfc0c74d 100755
> --- a/t/t5574-fetch-output.sh
> +++ b/t/t5574-fetch-output.sh
> @@ -40,8 +40,8 @@ test_expect_success 'fetch aligned output' '
>   		grep -e "->" actual | cut -c 22- >../actual
>   	) &&
>   	cat >expect <<-\EOF &&
> -	main                 -> origin/main
>   	looooooooooooong-tag -> looooooooooooong-tag
> +	main                 -> origin/main
>   	EOF
>   	test_cmp expect actual
>   '
> @@ -55,8 +55,8 @@ test_expect_success 'fetch compact output' '
>   		grep -e "->" actual | cut -c 22- >../actual
>   	) &&
>   	cat >expect <<-\EOF &&
> -	main       -> origin/*
>   	extraaa    -> *
> +	main       -> origin/*
>   	EOF
>   	test_cmp expect actual
>   '
> @@ -103,15 +103,15 @@ do
>   		cat >expect <<-EOF &&
>   		- $MAIN_OLD $ZERO_OID refs/forced/deleted-branch
>   		- $MAIN_OLD $ZERO_OID refs/unforced/deleted-branch
> -		  $MAIN_OLD $FAST_FORWARD_NEW refs/unforced/fast-forward
>   		! $FORCE_UPDATED_OLD $FORCE_UPDATED_NEW refs/unforced/force-updated
> +		* $ZERO_OID $MAIN_OLD refs/forced/new-branch
> +		* $ZERO_OID $MAIN_OLD refs/remotes/origin/new-branch
> +		+ $FORCE_UPDATED_OLD $FORCE_UPDATED_NEW refs/remotes/origin/force-updated
> +		  $MAIN_OLD $FAST_FORWARD_NEW refs/unforced/fast-forward
>   		* $ZERO_OID $MAIN_OLD refs/unforced/new-branch
>   		  $MAIN_OLD $FAST_FORWARD_NEW refs/forced/fast-forward
> -		+ $FORCE_UPDATED_OLD $FORCE_UPDATED_NEW refs/forced/force-updated
> -		* $ZERO_OID $MAIN_OLD refs/forced/new-branch
>   		  $MAIN_OLD $FAST_FORWARD_NEW refs/remotes/origin/fast-forward
> -		+ $FORCE_UPDATED_OLD $FORCE_UPDATED_NEW refs/remotes/origin/force-updated
> -		* $ZERO_OID $MAIN_OLD refs/remotes/origin/new-branch
> +		+ $FORCE_UPDATED_OLD $FORCE_UPDATED_NEW refs/forced/force-updated
>   		EOF
>   
>   		# Change the URL of the repository to fetch different references.
> @@ -179,8 +179,8 @@ test_expect_success 'fetch porcelain overrides fetch.output config' '
>   	new_commit=$(git rev-parse HEAD) &&
>   
>   	cat >expect <<-EOF &&
> -	  $old_commit $new_commit refs/remotes/origin/config-override
>   	* $ZERO_OID $new_commit refs/tags/new-commit
> +	  $old_commit $new_commit refs/remotes/origin/config-override
>   	EOF
>   
>   	git -C porcelain -c fetch.output=compact fetch --porcelain >stdout 2>stderr &&
> 

Re: [PATCH v2 7/7] fetch: delay user information post committing of transaction

[Karthik Nayak]

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Phillip Wood <phillip.wood123@gmail.com> writes:

> Hi Karthik
>
> On 16/01/2026 21:27, Karthik Nayak wrote:
>> In Git 2.50 and earlier, we would display failure codes and error
>> message as part of the status display:
>>
>>    $ git fetch . v1.0.0:refs/heads/foo
>>      error: cannot update ref 'refs/heads/foo': trying to write non-commit object f665776185ad074b236c00751d666da7d1977dbe to branch 'refs/heads/foo'
>>      From .
>>       ! [new tag]               v1.0.0     -> foo  (unable to update local ref)
>>
>> With the addition of batched updates, this information is no longer
>> shown to the user:
>>
>>    $ git fetch . v1.0.0:refs/heads/foo
>>      From .
>>       * [new tag]               v1.0.0     -> foo
>>      error: cannot update ref 'refs/heads/foo': trying to write non-commit object f665776185ad074b236c00751d666da7d1977dbe to branch 'refs/heads/foo'
>>
>> Since reference updates are batched and processed together at the end,
>> information around the outcome is not available during individual
>> reference parsing.
>>
>> To overcome this, collate and delay the output to the end. Introduce
>> `ref_update_display_info` which will hold individual update's
>> information and also whether the update failed or succeeded. This
>> finally allows us to iterate over all such updates and print them to the
>> user. While this brings back the functionality, it does change the order
>> of the output. Modify the tests to reflect this.
>
> It is unfortunate that a fix for a regression the the messages changes
> the order of those messages. It is doubly unfortunate that the new order
> depends on the implementation of strmap_for_each() which may change in
> the future. I think you can avoid this by appending each update to an
> array in update_local_ref() and adding the errors to a separate strmap
> in ref_transaction_rejection_handler(). Then when you come to print the
> massages, loop over the array and for each update lookup the ref in the
> strmap to see if it failed before printing the appropriate message.
>
> Thanks
>
> Phillip
>

Yes, I think there is merit in the approach you suggested, it ensures
that all messages are delayed (avoiding the split between displaying a
few at the beginning vs some at the end) and that they retain the order.
I have a version cooking locally which does this and works correctly.
I'll send it in with my next version.

Thanks,
Karthik

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[PATCH v3 0/6] refs: provide detailed error messages when using batched update

[Karthik Nayak]

The refs namespace uses an error buffer to capture details about failed
reference updates. However when we added batched update support to
reference transactions, these messages were never propagated, instead
only an error code pertaining to the type of failure was propagated.

Currently, there are three regions which utilize batched updates:

  - git update-ref --batch-updates
  - git fetch
  - git receive-pack

While 'git update-ref --batch-updates' was a newly introduced flag, both
'git fetch' and 'git receive-pack' were pre-existing. Before using
batched updates, they provided more detailed error messages to the user,
but this changed with the introduction of batched updates. This is a
regression in their workings.

This patch series fixes this, by passing the detailed error message and
utilizing it whenever available. The regression was reported by Elijah
Newren [1] and based on the patch submitted by Jeff King [2].

[1]: https://lore.kernel.org/all/CABPp-BGL2tJR4dPidQuFcp-X0_VkVTknCY-0Zgo=jHVGv_P=wA@mail.gmail.com/
[2]: https://lore.kernel.org/all/20251224081214.GA1879908@coredump.intra.peff.net/

---
Changes in v3:
- Drop the first commit.
- For the last commit, where we delay 'git fetch' status information,
  delay all information to the end. Also use a list to compliment the
  existing strmap, this ensures that the order is maintained.
- Link to v2: https://patch.msgid.link/20260116-633-regression-lost-diagnostic-message-when-pushing-non-commit-objects-to-refs-heads-v2-0-925a0e9c7f32@gmail.com

Changes in v2:
- Updates to the commit messages to be more descriptive.
- Instead of passing the char pointer for the error description, pass
  the 'strbuf' itself. This makes the API a lot cleaner to deal with.
  Also avoids having to remember to reset the strbuf after usage.
- Chalk out a separate commit for using a 'goto next_ref' in
  `refs_verify_refnames_available()`. This makes the intention much
  clearer.
- For git-update-ref(1), keep the existing implementation as is and only
  output the detailed error message to stderr.
- For git-receive-pack(1), use 'rp_error()' for detailed error message
  while keeping the current implementation as is.
- Added a separate patch to handle missing information in git-fetch(1)'s
  status table. This involves delaying updates to the end, where update
  success/failure information is available. I'm not too confident about
  this approach though, we could also drop it from the series and I
  could pick that up independently. This is still 1.19 ± 0.02 times
  faster than non-batched version (v2.50.0) in the files backend.
- Link to v1: https://patch.msgid.link/20260114-633-regression-lost-diagnostic-message-when-pushing-non-commit-objects-to-refs-heads-v1-0-f5f8b173c501@gmail.com

---
 builtin/fetch.c         | 259 +++++++++++++++++++++++++++++++++++++-----------
 builtin/receive-pack.c  |   7 +-
 builtin/update-ref.c    |   7 +-
 refs.c                  |  46 +++++----
 refs.h                  |   1 +
 refs/files-backend.c    |   5 +-
 refs/packed-backend.c   |  12 +--
 refs/refs-internal.h    |   4 +-
 refs/reftable-backend.c |   5 +-
 t/t1400-update-ref.sh   |  71 +++++++------
 t/t5510-fetch.sh        |   8 +-
 t/t5516-fetch-push.sh   |  16 +++
 12 files changed, 316 insertions(+), 125 deletions(-)

Karthik Nayak (6):
      refs: skip to next ref when current ref is rejected
      refs: add rejection detail to the callback function
      update-ref: utilize rejected error details if available
      fetch: utilize rejected ref error details
      receive-pack: utilize rejected ref error details
      fetch: delay user information post committing of transaction

Range-diff versus v2:

1:  7592b0a9aa < -:  ---------- refs: drop unnecessary header includes
2:  97095095bc = 1:  dbabb9a172 refs: skip to next ref when current ref is rejected
3:  2dadab77a2 = 2:  b0ab39a262 refs: add rejection detail to the callback function
4:  007c6d58c1 = 3:  2b323bddbc update-ref: utilize rejected error details if available
5:  0d0b8b75c8 = 4:  8bf3d986f4 fetch: utilize rejected ref error details
6:  b9348b5ae3 = 5:  5dab402570 receive-pack: utilize rejected ref error details
7:  d90420903f ! 6:  596762e6b5 fetch: delay user information post committing of transaction
    @@ Commit message
         `ref_update_display_info` which will hold individual update's
         information and also whether the update failed or succeeded. This
         finally allows us to iterate over all such updates and print them to the
    -    user. While this brings back the functionality, it does change the order
    -    of the output. Modify the tests to reflect this.
    +    user.
     
    -    Using an strmap does add some overhead to 'git-fetch(1)', but from
    -    benchmarking this seems to be not too bad:
    +    Using an dynamic array and strmap does add some overhead to
    +    'git-fetch(1)', but from benchmarking this seems to be not too bad:
     
           Benchmark 1: fetch: many refs (refformat = files, refcount = 1000, revision = master)
    -        Time (mean ± σ):      51.9 ms ±   2.5 ms    [User: 15.6 ms, System: 36.9 ms]
    -        Range (min … max):    47.4 ms …  58.3 ms    41 runs
    +        Time (mean ± σ):      42.6 ms ±   1.2 ms    [User: 13.1 ms, System: 29.8 ms]
    +        Range (min … max):    40.1 ms …  45.8 ms    47 runs
     
           Benchmark 2: fetch: many refs (refformat = files, refcount = 1000, revision = HEAD)
    -        Time (mean ± σ):      53.0 ms ±   1.8 ms    [User: 17.6 ms, System: 36.0 ms]
    -        Range (min … max):    49.4 ms …  57.6 ms    40 runs
    +        Time (mean ± σ):      43.1 ms ±   1.2 ms    [User: 12.7 ms, System: 30.7 ms]
    +        Range (min … max):    40.5 ms …  45.8 ms    48 runs
     
           Summary
             fetch: many refs (refformat = files, refcount = 1000, revision = master) ran
    -          1.02 ± 0.06 times faster than fetch: many refs (refformat = files, refcount = 1000, revision = HEAD)
    +          1.01 ± 0.04 times faster than fetch: many refs (refformat = files, refcount = 1000, revision = HEAD)
     
         Another approach would be to move the status printing logic to be
         handled post the transaction being committed. That however would require
    @@ Commit message
         which is more involved infrastructure work compared to the strmap
         approach here.
     
    +    Helped-by: Phillip Wood <phillip.wood123@gmail.com>
         Reported-by: Jeff King <peff@peff.net>
         Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
     
    @@ builtin/fetch.c: static void display_ref_update(struct display_state *display_st
     +	const char *summary;
     +	const char *fail_detail;
     +	const char *success_detail;
    ++	const char *ref;
     +	const char *remote;
    -+	const char *local;
     +	struct object_id old_oid;
     +	struct object_id new_oid;
     +};
     +
    -+static struct ref_update_display_info *ref_update_display_info_new(
    -+						char success_code,
    -+						char fail_code,
    -+						const char *summary,
    -+						const char *success_detail,
    -+						const char *fail_detail,
    -+						const char *remote,
    -+						const struct object_id *old_oid,
    -+						const struct object_id *new_oid)
    ++static struct ref_update_display_info *ref_update_display_info_append(
    ++					   struct ref_update_display_info **list,
    ++					   size_t *count,
    ++					   char success_code,
    ++					   char fail_code,
    ++					   const char *summary,
    ++					   const char *success_detail,
    ++					   const char *fail_detail,
    ++					   const char *ref,
    ++					   const char *remote,
    ++					   const struct object_id *old_oid,
    ++					   const struct object_id *new_oid)
     +{
     +	struct ref_update_display_info *info;
    -+	CALLOC_ARRAY(info, 1);
    ++	size_t index = *count;
     +
    ++	(*count)++;
    ++	REALLOC_ARRAY(*list, *count);
    ++
    ++	info = &(*list)[index];
    ++
    ++	info->failed = false;
     +	info->success_code = success_code;
     +	info->fail_code = fail_code;
     +	info->summary = xstrdup(summary);
     +	info->success_detail = xstrdup_or_null(success_detail);
     +	info->fail_detail = xstrdup_or_null(fail_detail);
     +	info->remote = xstrdup(remote);
    ++	info->ref = xstrdup(ref);
     +
     +	oidcpy(&info->old_oid, old_oid);
     +	oidcpy(&info->new_oid, new_oid);
    @@ builtin/fetch.c: static void display_ref_update(struct display_state *display_st
     +	free((char *)info->success_detail);
     +	free((char *)info->fail_detail);
     +	free((char *)info->remote);
    ++	free((char *)info->ref);
     +}
     +
     +static void ref_update_display_info_display(struct ref_update_display_info *info,
     +					    struct display_state *display_state,
    -+					    const char *refname, int summary_width)
    ++					    int summary_width)
     +{
     +	display_ref_update(display_state,
     +			   info->failed ? info->fail_code : info->success_code,
     +			   info->summary,
     +			   info->failed ? info->fail_detail : info->success_detail,
    -+			   info->remote, refname, &info->old_oid,
    ++			   info->remote, info->ref, &info->old_oid,
     +			   &info->new_oid, summary_width);
     +}
     +
      static int update_local_ref(struct ref *ref,
      			    struct ref_transaction *transaction,
    - 			    struct display_state *display_state,
    +-			    struct display_state *display_state,
      			    const struct ref *remote_ref,
    - 			    int summary_width,
    +-			    int summary_width,
     -			    const struct fetch_config *config)
     +			    const struct fetch_config *config,
    -+			    struct strmap *delayed_ref_display)
    ++			    struct ref_update_display_info **display_list,
    ++			    size_t *display_count)
      {
      	struct commit *current = NULL, *updated;
      	int fast_forward = 0;
     @@ builtin/fetch.c: static int update_local_ref(struct ref *ref,
    + 
    + 	if (oideq(&ref->old_oid, &ref->new_oid)) {
    + 		if (verbosity > 0)
    +-			display_ref_update(display_state, '=', _("[up to date]"), NULL,
    +-					   remote_ref->name, ref->name,
    +-					   &ref->old_oid, &ref->new_oid, summary_width);
    ++			ref_update_display_info_append(display_list, display_count,
    ++						       '=', '=', _("[up to date]"),
    ++						       NULL, NULL, ref->name,
    ++						       remote_ref->name, &ref->old_oid,
    ++						       &ref->new_oid);
    + 		return 0;
    + 	}
    + 
    + 	if (!update_head_ok &&
    + 	    !is_null_oid(&ref->old_oid) &&
    + 	    branch_checked_out(ref->name)) {
    ++		struct ref_update_display_info *info;
    + 		/*
    + 		 * If this is the head, and it's not okay to update
    + 		 * the head, and the old value of the head isn't empty...
    + 		 */
    +-		display_ref_update(display_state, '!', _("[rejected]"),
    +-				   _("can't fetch into checked-out branch"),
    +-				   remote_ref->name, ref->name,
    +-				   &ref->old_oid, &ref->new_oid, summary_width);
    ++		info = ref_update_display_info_append(display_list, display_count,
    ++						      '!', '!', _("[rejected]"),
    ++						      NULL, _("can't fetch into checked-out branch"),
    ++						      ref->name, remote_ref->name,
    ++						      &ref->old_oid, &ref->new_oid);
    ++		ref_update_display_info_set_failed(info);
    + 		return 1;
    + 	}
    + 
      	if (!is_null_oid(&ref->old_oid) &&
      	    starts_with(ref->name, "refs/tags/")) {
    ++		struct ref_update_display_info *info;
    ++
      		if (force || ref->force) {
    -+			struct ref_update_display_info *info;
      			int r;
     +
      			r = s_update_ref("updating tag", ref, transaction, 0);
    @@ builtin/fetch.c: static int update_local_ref(struct ref *ref,
     -					   remote_ref->name, ref->name,
     -					   &ref->old_oid, &ref->new_oid, summary_width);
     +
    -+			info = ref_update_display_info_new('t', '!', _("[tag update]"), NULL,
    -+							   _("unable to update local ref"),
    -+							   remote_ref->name, &ref->old_oid,
    -+							   &ref->new_oid);
    ++			info = ref_update_display_info_append(display_list, display_count,
    ++							      't', '!', _("[tag update]"), NULL,
    ++							      _("unable to update local ref"),
    ++							      ref->name, remote_ref->name,
    ++							      &ref->old_oid, &ref->new_oid);
     +			if (r)
     +				ref_update_display_info_set_failed(info);
    -+			strmap_put(delayed_ref_display, ref->name, info);
     +
      			return r;
      		} else {
    - 			display_ref_update(display_state, '!', _("[rejected]"),
    +-			display_ref_update(display_state, '!', _("[rejected]"),
    +-					   _("would clobber existing tag"),
    +-					   remote_ref->name, ref->name,
    +-					   &ref->old_oid, &ref->new_oid, summary_width);
    ++			info = ref_update_display_info_append(display_list, display_count,
    ++							      '!', '!', _("[rejected]"), NULL,
    ++							      _("would clobber existing tag"),
    ++							      ref->name, remote_ref->name,
    ++							      &ref->old_oid, &ref->new_oid);
    ++			ref_update_display_info_set_failed(info);
    + 			return 1;
    + 		}
    + 	}
     @@ builtin/fetch.c: static int update_local_ref(struct ref *ref,
      	updated = lookup_commit_reference_gently(the_repository,
      						 &ref->new_oid, 1);
    @@ builtin/fetch.c: static int update_local_ref(struct ref *ref,
     -				   remote_ref->name, ref->name,
     -				   &ref->old_oid, &ref->new_oid, summary_width);
     +
    -+		info = ref_update_display_info_new('*', '!', what, NULL,
    -+						   _("unable to update local ref"),
    -+						   remote_ref->name, &ref->old_oid,
    -+						   &ref->new_oid);
    ++		info = ref_update_display_info_append(display_list, display_count,
    ++						      '*', '!', what, NULL,
    ++						      _("unable to update local ref"),
    ++						      ref->name, remote_ref->name,
    ++						      &ref->old_oid, &ref->new_oid);
     +		if (r)
     +			ref_update_display_info_set_failed(info);
    -+		strmap_put(delayed_ref_display, ref->name, info);
     +
      		return r;
      	}
    @@ builtin/fetch.c: static int update_local_ref(struct ref *ref,
     -				   remote_ref->name, ref->name,
     -				   &ref->old_oid, &ref->new_oid, summary_width);
     +
    -+		info = ref_update_display_info_new(' ', '!', quickref.buf, NULL,
    -+						   _("unable to update local ref"),
    -+						   remote_ref->name, &ref->old_oid,
    -+						   &ref->new_oid);
    ++		info = ref_update_display_info_append(display_list, display_count,
    ++						      ' ', '!', quickref.buf, NULL,
    ++						      _("unable to update local ref"),
    ++						      ref->name, remote_ref->name,
    ++						      &ref->old_oid, &ref->new_oid);
     +		if (r)
     +			ref_update_display_info_set_failed(info);
    -+		strmap_put(delayed_ref_display, ref->name, info);
     +
      		strbuf_release(&quickref);
      		return r;
    @@ builtin/fetch.c: static int update_local_ref(struct ref *ref,
     -				   remote_ref->name, ref->name,
     -				   &ref->old_oid, &ref->new_oid, summary_width);
     +
    -+		info = ref_update_display_info_new('+', '!', quickref.buf,
    -+						   _("forced update"),
    -+						   _("unable to update local ref"),
    -+						   remote_ref->name, &ref->old_oid,
    -+						   &ref->new_oid);
    ++		info = ref_update_display_info_append(display_list, display_count,
    ++						      '+', '!', quickref.buf, _("forced update"),
    ++						      _("unable to update local ref"),
    ++						      ref->name, remote_ref->name,
    ++						      &ref->old_oid, &ref->new_oid);
    ++
     +		if (r)
     +			ref_update_display_info_set_failed(info);
    -+		strmap_put(delayed_ref_display, ref->name, info);
     +
      		strbuf_release(&quickref);
      		return r;
      	} else {
    +-		display_ref_update(display_state, '!', _("[rejected]"), _("non-fast-forward"),
    +-				   remote_ref->name, ref->name,
    +-				   &ref->old_oid, &ref->new_oid, summary_width);
    ++		struct ref_update_display_info *info;
    ++		info = ref_update_display_info_append(display_list, display_count,
    ++						      '!', '!', _("[rejected]"), NULL,
    ++						      _("non-fast-forward"),
    ++						      ref->name, remote_ref->name,
    ++						      &ref->old_oid, &ref->new_oid);
    ++		ref_update_display_info_set_failed(info);
    + 		return 1;
    + 	}
    + }
     @@ builtin/fetch.c: static int store_updated_refs(struct display_state *display_state,
      			      int connectivity_checked,
      			      struct ref_transaction *transaction, struct ref *ref_map,
      			      struct fetch_head *fetch_head,
     -			      const struct fetch_config *config)
     +			      const struct fetch_config *config,
    -+			      struct strmap *delayed_ref_display)
    ++			      struct ref_update_display_info **display_list,
    ++			      size_t *display_count)
      {
      	int rc = 0;
      	struct strbuf note = STRBUF_INIT;
    + 	const char *what, *kind;
    + 	struct ref *rm;
    + 	int want_status;
    +-	int summary_width = 0;
    +-
    +-	if (verbosity >= 0)
    +-		summary_width = transport_summary_width(ref_map);
    + 
    + 	if (!connectivity_checked) {
    + 		struct check_connected_options opt = CHECK_CONNECTED_INIT;
     @@ builtin/fetch.c: static int store_updated_refs(struct display_state *display_state,
    + 					  display_state->url_len);
      
      			if (ref) {
    - 				rc |= update_local_ref(ref, transaction, display_state,
    +-				rc |= update_local_ref(ref, transaction, display_state,
     -						       rm, summary_width, config);
    -+						       rm, summary_width, config,
    -+						       delayed_ref_display);
    ++				rc |= update_local_ref(ref, transaction, rm,
    ++						       config, display_list,
    ++						       display_count);
      				free(ref);
      			} else if (write_fetch_head || dry_run) {
      				/*
    +@@ builtin/fetch.c: static int store_updated_refs(struct display_state *display_state,
    + 				 * would be written to FETCH_HEAD, if --dry-run
    + 				 * is set).
    + 				 */
    +-				display_ref_update(display_state, '*',
    +-						   *kind ? kind : "branch", NULL,
    +-						   rm->name,
    +-						   "FETCH_HEAD",
    +-						   &rm->new_oid, &rm->old_oid,
    +-						   summary_width);
    ++
    ++				ref_update_display_info_append(display_list, display_count,
    ++							       '*', '*', *kind ? kind : "branch",
    ++							       NULL, NULL, "FETCH_HEAD", rm->name,
    ++							       &rm->new_oid, &rm->old_oid);
    + 			}
    + 		}
    + 	}
     @@ builtin/fetch.c: static int fetch_and_consume_refs(struct display_state *display_state,
      				  struct ref_transaction *transaction,
      				  struct ref *ref_map,
      				  struct fetch_head *fetch_head,
     -				  const struct fetch_config *config)
     +				  const struct fetch_config *config,
    -+				  struct strmap *delayed_ref_display)
    ++				  struct ref_update_display_info **display_list,
    ++				  size_t *display_count)
      {
      	int connectivity_checked = 1;
      	int ret;
    @@ builtin/fetch.c: static int fetch_and_consume_refs(struct display_state *display
      	ret = store_updated_refs(display_state, connectivity_checked,
     -				 transaction, ref_map, fetch_head, config);
     +				 transaction, ref_map, fetch_head, config,
    -+				 delayed_ref_display);
    ++				 display_list, display_count);
      	trace2_region_leave("fetch", "consume_refs", the_repository);
      
      out:
    @@ builtin/fetch.c: static int backfill_tags(struct display_state *display_state,
      			 struct fetch_head *fetch_head,
     -			 const struct fetch_config *config)
     +			 const struct fetch_config *config,
    -+			 struct strmap *delayed_ref_display)
    ++			 struct ref_update_display_info **display_list,
    ++			 size_t *display_count)
      {
      	int retcode, cannot_reuse;
      
    @@ builtin/fetch.c: static int backfill_tags(struct display_state *display_state,
      	transport_set_option(transport, TRANS_OPT_DEEPEN_RELATIVE, NULL);
      	retcode = fetch_and_consume_refs(display_state, transport, transaction, ref_map,
     -					 fetch_head, config);
    -+					 fetch_head, config, delayed_ref_display);
    ++					 fetch_head, config, display_list, display_count);
      
      	if (gsecondary) {
      		transport_disconnect(gsecondary);
    @@ builtin/fetch.c: struct ref_rejection_data {
      	bool conflict_msg_shown;
      	bool case_sensitive_msg_shown;
      	const char *remote_name;
    -+	struct strmap *delayed_ref_display;
    ++	struct strmap *rejected_refs;
      };
      
      static void ref_transaction_rejection_handler(const char *refname,
    -@@ builtin/fetch.c: static void ref_transaction_rejection_handler(const char *refname,
    - 					      void *cb_data)
    - {
    - 	struct ref_rejection_data *data = cb_data;
    -+	struct ref_update_display_info *info;
    - 
    - 	if (err == REF_TRANSACTION_ERROR_CASE_CONFLICT && ignore_case &&
    - 	    !data->case_sensitive_msg_shown) {
     @@ builtin/fetch.c: static void ref_transaction_rejection_handler(const char *refname,
      			      refname, ref_transaction_error_msg(err));
      	}
      
    -+	info = strmap_get(data->delayed_ref_display, refname);
    -+	if (info)
    -+		ref_update_display_info_set_failed(info);
    -+
    ++	strmap_put(data->rejected_refs, refname, NULL);
      	*data->retcode = 1;
      }
      
    @@ builtin/fetch.c: static void ref_transaction_rejection_handler(const char *refna
       */
      static int commit_ref_transaction(struct ref_transaction **transaction,
      				  bool is_atomic, const char *remote_name,
    -+				  struct strmap *delayed_ref_display,
    ++				  struct strmap *rejected_refs,
      				  struct strbuf *err)
      {
      	int retcode = ref_transaction_commit(*transaction, err);
    @@ builtin/fetch.c: static int commit_ref_transaction(struct ref_transaction **tran
      			.conflict_msg_shown = 0,
      			.remote_name = remote_name,
      			.retcode = &retcode,
    -+			.delayed_ref_display = delayed_ref_display,
    ++			.rejected_refs = rejected_refs,
      		};
      
      		ref_transaction_for_each_rejected_update(*transaction,
    @@ builtin/fetch.c: static int do_fetch(struct transport *transport,
      	struct fetch_head fetch_head = { 0 };
      	struct strbuf err = STRBUF_INIT;
      	int do_set_head = 0;
    -+	struct strmap delayed_ref_display = STRMAP_INIT;
    ++	struct ref_update_display_info *display_list = NULL;
    ++	struct strmap rejected_refs = STRMAP_INIT;
    ++	size_t display_count = 0;
     +	int summary_width = 0;
    -+	struct strmap_entry *e;
    -+	struct hashmap_iter iter;
      
      	if (tags == TAGS_DEFAULT) {
      		if (transport->remote->fetch_tags == 2)
    @@ builtin/fetch.c: static int do_fetch(struct transport *transport,
      
      	if (fetch_and_consume_refs(&display_state, transport, transaction, ref_map,
     -				   &fetch_head, config)) {
    -+				   &fetch_head, config, &delayed_ref_display)) {
    ++				   &fetch_head, config, &display_list, &display_count)) {
      		retcode = 1;
      		goto cleanup;
      	}
    @@ builtin/fetch.c: static int do_fetch(struct transport *transport,
      			 */
      			if (backfill_tags(&display_state, transport, transaction, tags_ref_map,
     -					  &fetch_head, config))
    -+					  &fetch_head, config, &delayed_ref_display))
    ++					  &fetch_head, config, &display_list, &display_count))
      				retcode = 1;
      		}
      
    @@ builtin/fetch.c: static int do_fetch(struct transport *transport,
      	retcode = commit_ref_transaction(&transaction, atomic_fetch,
     -					 transport->remote->name, &err);
     +					 transport->remote->name,
    -+					 &delayed_ref_display, &err);
    ++					 &rejected_refs, &err);
      	/*
      	 * With '--atomic', bail out if the transaction fails. Without '--atomic',
      	 * continue to fetch head and perform other post-fetch operations.
    @@ builtin/fetch.c: static int do_fetch(struct transport *transport,
      		commit_ref_transaction(&transaction, false,
     -				       transport->remote->name, &err);
     +				       transport->remote->name,
    -+				       &delayed_ref_display, &err);
    ++				       &rejected_refs, &err);
     +
    -+	/*
    -+	 * Clear any pending information that needs to be shown to the user.
    -+	 */
    -+	strmap_for_each_entry(&delayed_ref_display, &iter, e) {
    -+		struct ref_update_display_info *info = e->value;
    -+		ref_update_display_info_display(info, &display_state, e->key, summary_width);
    ++	for (size_t i = 0; i < display_count; i++) {
    ++		struct ref_update_display_info *info = &display_list[i];
    ++
    ++		if (!info->failed && strmap_contains(&rejected_refs, info->ref))
    ++			ref_update_display_info_set_failed(info);
    ++		ref_update_display_info_display(info, &display_state, summary_width);
     +		ref_update_display_info_free(info);
     +	}
      
    @@ builtin/fetch.c: static int do_fetch(struct transport *transport,
      	if (transaction)
      		ref_transaction_free(transaction);
     +
    -+	strmap_clear(&delayed_ref_display, 1);
    ++	free(display_list);
    ++	strmap_clear(&rejected_refs, 0);
      	display_state_release(&display_state);
      	close_fetch_head(&fetch_head);
      	strbuf_release(&err);
    @@ t/t5516-fetch-push.sh: test_expect_success 'pushing non-commit objects should re
      		test_grep "trying to write non-commit object $tagsha to branch ${SQ}refs/heads/branch${SQ}" err
      	)
      '
    -
    - ## t/t5574-fetch-output.sh ##
    -@@ t/t5574-fetch-output.sh: test_expect_success 'fetch aligned output' '
    - 		grep -e "->" actual | cut -c 22- >../actual
    - 	) &&
    - 	cat >expect <<-\EOF &&
    --	main                 -> origin/main
    - 	looooooooooooong-tag -> looooooooooooong-tag
    -+	main                 -> origin/main
    - 	EOF
    - 	test_cmp expect actual
    - '
    -@@ t/t5574-fetch-output.sh: test_expect_success 'fetch compact output' '
    - 		grep -e "->" actual | cut -c 22- >../actual
    - 	) &&
    - 	cat >expect <<-\EOF &&
    --	main       -> origin/*
    - 	extraaa    -> *
    -+	main       -> origin/*
    - 	EOF
    - 	test_cmp expect actual
    - '
    -@@ t/t5574-fetch-output.sh: do
    - 		cat >expect <<-EOF &&
    - 		- $MAIN_OLD $ZERO_OID refs/forced/deleted-branch
    - 		- $MAIN_OLD $ZERO_OID refs/unforced/deleted-branch
    --		  $MAIN_OLD $FAST_FORWARD_NEW refs/unforced/fast-forward
    - 		! $FORCE_UPDATED_OLD $FORCE_UPDATED_NEW refs/unforced/force-updated
    -+		* $ZERO_OID $MAIN_OLD refs/forced/new-branch
    -+		* $ZERO_OID $MAIN_OLD refs/remotes/origin/new-branch
    -+		+ $FORCE_UPDATED_OLD $FORCE_UPDATED_NEW refs/remotes/origin/force-updated
    -+		  $MAIN_OLD $FAST_FORWARD_NEW refs/unforced/fast-forward
    - 		* $ZERO_OID $MAIN_OLD refs/unforced/new-branch
    - 		  $MAIN_OLD $FAST_FORWARD_NEW refs/forced/fast-forward
    --		+ $FORCE_UPDATED_OLD $FORCE_UPDATED_NEW refs/forced/force-updated
    --		* $ZERO_OID $MAIN_OLD refs/forced/new-branch
    - 		  $MAIN_OLD $FAST_FORWARD_NEW refs/remotes/origin/fast-forward
    --		+ $FORCE_UPDATED_OLD $FORCE_UPDATED_NEW refs/remotes/origin/force-updated
    --		* $ZERO_OID $MAIN_OLD refs/remotes/origin/new-branch
    -+		+ $FORCE_UPDATED_OLD $FORCE_UPDATED_NEW refs/forced/force-updated
    - 		EOF
    - 
    - 		# Change the URL of the repository to fetch different references.
    -@@ t/t5574-fetch-output.sh: test_expect_success 'fetch porcelain overrides fetch.output config' '
    - 	new_commit=$(git rev-parse HEAD) &&
    - 
    - 	cat >expect <<-EOF &&
    --	  $old_commit $new_commit refs/remotes/origin/config-override
    - 	* $ZERO_OID $new_commit refs/tags/new-commit
    -+	  $old_commit $new_commit refs/remotes/origin/config-override
    - 	EOF
    - 
    - 	git -C porcelain -c fetch.output=compact fetch --porcelain >stdout 2>stderr &&


base-commit: 8745eae506f700657882b9e32b2aa00f234a6fb6
change-id: 20260113-633-regression-lost-diagnostic-message-when-pushing-non-commit-objects-to-refs-heads-17786b20894a

Thanks
- Karthik

[PATCH v3 1/6] refs: skip to next ref when current ref is rejected

[Karthik Nayak]

In `refs_verify_refnames_available()` we have two nested loops: the
outer loop iterates over all references to check, while the inner loop
checks for filesystem conflicts for a given ref by breaking down its
path.

With batched updates, when we detect a filesystem conflict, we mark the
update as rejected and execute 'continue'. However, this only skips to
the next iteration of the inner loop, not the outer loop as intended.
This causes the same reference to be repeatedly rejected. Fix this by
using a goto statement to skip to the next reference in the outer loop.

Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
---
 refs.c                  | 44 ++++++++++++++++++++++++++------------------
 refs/files-backend.c    |  5 ++---
 refs/packed-backend.c   | 12 ++++++------
 refs/refs-internal.h    |  4 +++-
 refs/reftable-backend.c |  5 ++---
 5 files changed, 39 insertions(+), 31 deletions(-)

diff --git a/refs.c b/refs.c
index e06e0cb072..53919c3d22 100644
--- a/refs.c
+++ b/refs.c
@@ -1224,6 +1224,7 @@ void ref_transaction_free(struct ref_transaction *transaction)
 		free(transaction->updates[i]->committer_info);
 		free((char *)transaction->updates[i]->new_target);
 		free((char *)transaction->updates[i]->old_target);
+		free((char *)transaction->updates[i]->rejection_details);
 		free(transaction->updates[i]);
 	}
 
@@ -1238,7 +1239,8 @@ void ref_transaction_free(struct ref_transaction *transaction)
 
 int ref_transaction_maybe_set_rejected(struct ref_transaction *transaction,
 				       size_t update_idx,
-				       enum ref_transaction_error err)
+				       enum ref_transaction_error err,
+				       struct strbuf *details)
 {
 	if (update_idx >= transaction->nr)
 		BUG("trying to set rejection on invalid update index");
@@ -1264,6 +1266,7 @@ int ref_transaction_maybe_set_rejected(struct ref_transaction *transaction,
 			   transaction->updates[update_idx]->refname, 0);
 
 	transaction->updates[update_idx]->rejection_err = err;
+	transaction->updates[update_idx]->rejection_details = strbuf_detach(details, NULL);
 	ALLOC_GROW(transaction->rejections->update_indices,
 		   transaction->rejections->nr + 1,
 		   transaction->rejections->alloc);
@@ -2659,30 +2662,33 @@ enum ref_transaction_error refs_verify_refnames_available(struct ref_store *refs
 			if (!initial_transaction &&
 			    (strset_contains(&conflicting_dirnames, dirname.buf) ||
 			     !refs_read_raw_ref(refs, dirname.buf, &oid, &referent,
-						       &type, &ignore_errno))) {
+						&type, &ignore_errno))) {
+
+				strbuf_addf(err, _("'%s' exists; cannot create '%s'"),
+					    dirname.buf, refname);
+
 				if (transaction && ref_transaction_maybe_set_rejected(
 					    transaction, *update_idx,
-					    REF_TRANSACTION_ERROR_NAME_CONFLICT)) {
+					    REF_TRANSACTION_ERROR_NAME_CONFLICT, err)) {
 					strset_remove(&dirnames, dirname.buf);
 					strset_add(&conflicting_dirnames, dirname.buf);
-					continue;
+					goto next_ref;
 				}
 
-				strbuf_addf(err, _("'%s' exists; cannot create '%s'"),
-					    dirname.buf, refname);
 				goto cleanup;
 			}
 
 			if (extras && string_list_has_string(extras, dirname.buf)) {
+				strbuf_addf(err, _("cannot process '%s' and '%s' at the same time"),
+					    refname, dirname.buf);
+
 				if (transaction && ref_transaction_maybe_set_rejected(
 					    transaction, *update_idx,
-					    REF_TRANSACTION_ERROR_NAME_CONFLICT)) {
+					    REF_TRANSACTION_ERROR_NAME_CONFLICT, err)) {
 					strset_remove(&dirnames, dirname.buf);
-					continue;
+					goto next_ref;
 				}
 
-				strbuf_addf(err, _("cannot process '%s' and '%s' at the same time"),
-					    refname, dirname.buf);
 				goto cleanup;
 			}
 		}
@@ -2712,14 +2718,14 @@ enum ref_transaction_error refs_verify_refnames_available(struct ref_store *refs
 				if (skip &&
 				    string_list_has_string(skip, iter->ref.name))
 					continue;
+				strbuf_addf(err, _("'%s' exists; cannot create '%s'"),
+					    iter->ref.name, refname);
 
 				if (transaction && ref_transaction_maybe_set_rejected(
 					    transaction, *update_idx,
-					    REF_TRANSACTION_ERROR_NAME_CONFLICT))
-					continue;
+					    REF_TRANSACTION_ERROR_NAME_CONFLICT, err))
+					goto next_ref;
 
-				strbuf_addf(err, _("'%s' exists; cannot create '%s'"),
-					    iter->ref.name, refname);
 				goto cleanup;
 			}
 
@@ -2729,15 +2735,17 @@ enum ref_transaction_error refs_verify_refnames_available(struct ref_store *refs
 
 		extra_refname = find_descendant_ref(dirname.buf, extras, skip);
 		if (extra_refname) {
+			strbuf_addf(err, _("cannot process '%s' and '%s' at the same time"),
+				    refname, extra_refname);
+
 			if (transaction && ref_transaction_maybe_set_rejected(
 				    transaction, *update_idx,
-				    REF_TRANSACTION_ERROR_NAME_CONFLICT))
-				continue;
+				    REF_TRANSACTION_ERROR_NAME_CONFLICT, err))
+				goto next_ref;
 
-			strbuf_addf(err, _("cannot process '%s' and '%s' at the same time"),
-				    refname, extra_refname);
 			goto cleanup;
 		}
+next_ref:;
 	}
 
 	ret = 0;
diff --git a/refs/files-backend.c b/refs/files-backend.c
index 6f6f76a8d8..6790d8bf53 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -2983,10 +2983,9 @@ static int files_transaction_prepare(struct ref_store *ref_store,
 					  head_ref, &refnames_to_check,
 					  err);
 		if (ret) {
-			if (ref_transaction_maybe_set_rejected(transaction, i, ret)) {
-				strbuf_reset(err);
+			if (ref_transaction_maybe_set_rejected(transaction, i,
+							       ret, err)) {
 				ret = 0;
-
 				continue;
 			}
 			goto cleanup;
diff --git a/refs/packed-backend.c b/refs/packed-backend.c
index 4ea0c12299..59b3ecb9d6 100644
--- a/refs/packed-backend.c
+++ b/refs/packed-backend.c
@@ -1437,8 +1437,8 @@ static enum ref_transaction_error write_with_updates(struct packed_ref_store *re
 						    update->refname);
 					ret = REF_TRANSACTION_ERROR_CREATE_EXISTS;
 
-					if (ref_transaction_maybe_set_rejected(transaction, i, ret)) {
-						strbuf_reset(err);
+					if (ref_transaction_maybe_set_rejected(transaction, i,
+									       ret, err)) {
 						ret = 0;
 						continue;
 					}
@@ -1452,8 +1452,8 @@ static enum ref_transaction_error write_with_updates(struct packed_ref_store *re
 						    oid_to_hex(&update->old_oid));
 					ret = REF_TRANSACTION_ERROR_INCORRECT_OLD_VALUE;
 
-					if (ref_transaction_maybe_set_rejected(transaction, i, ret)) {
-						strbuf_reset(err);
+					if (ref_transaction_maybe_set_rejected(transaction, i,
+									       ret, err)) {
 						ret = 0;
 						continue;
 					}
@@ -1496,8 +1496,8 @@ static enum ref_transaction_error write_with_updates(struct packed_ref_store *re
 					    oid_to_hex(&update->old_oid));
 				ret = REF_TRANSACTION_ERROR_NONEXISTENT_REF;
 
-				if (ref_transaction_maybe_set_rejected(transaction, i, ret)) {
-					strbuf_reset(err);
+				if (ref_transaction_maybe_set_rejected(transaction, i,
+								       ret, err)) {
 					ret = 0;
 					continue;
 				}
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index c7d2a6e50b..191a25683f 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -128,6 +128,7 @@ struct ref_update {
 	 * was rejected.
 	 */
 	enum ref_transaction_error rejection_err;
+	const char *rejection_details;
 
 	/*
 	 * If this ref_update was split off of a symref update via
@@ -153,7 +154,8 @@ int refs_read_raw_ref(struct ref_store *ref_store, const char *refname,
  */
 int ref_transaction_maybe_set_rejected(struct ref_transaction *transaction,
 				       size_t update_idx,
-				       enum ref_transaction_error err);
+				       enum ref_transaction_error err,
+				       struct strbuf *details);
 
 /*
  * Add a ref_update with the specified properties to transaction, and
diff --git a/refs/reftable-backend.c b/refs/reftable-backend.c
index 4319a4eacb..0e2648e36c 100644
--- a/refs/reftable-backend.c
+++ b/refs/reftable-backend.c
@@ -1401,10 +1401,9 @@ static int reftable_be_transaction_prepare(struct ref_store *ref_store,
 					    &refnames_to_check, head_type,
 					    &head_referent, &referent, err);
 		if (ret) {
-			if (ref_transaction_maybe_set_rejected(transaction, i, ret)) {
-				strbuf_reset(err);
+			if (ref_transaction_maybe_set_rejected(transaction, i,
+							       ret, err)) {
 				ret = 0;
-
 				continue;
 			}
 			goto done;

-- 
2.51.2

[PATCH v3 2/6] refs: add rejection detail to the callback function

[Karthik Nayak]

The previous commit started storing the rejection details alongside the
error code for rejected updates. Pass this along to the callback
function `ref_transaction_for_each_rejected_update()`. Currently the
field is unused, but will be integrated in the upcoming commits.

Co-authored-by: Jeff King <peff@peff.net>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
---
 builtin/fetch.c        | 1 +
 builtin/receive-pack.c | 1 +
 builtin/update-ref.c   | 1 +
 refs.c                 | 2 +-
 refs.h                 | 1 +
 5 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/builtin/fetch.c b/builtin/fetch.c
index 288d3772ea..d427adea61 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -1649,6 +1649,7 @@ static void ref_transaction_rejection_handler(const char *refname,
 					      const char *old_target UNUSED,
 					      const char *new_target UNUSED,
 					      enum ref_transaction_error err,
+					      const char *details UNUSED,
 					      void *cb_data)
 {
 	struct ref_rejection_data *data = cb_data;
diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index ef1f77be8c..94d3e73cee 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -1813,6 +1813,7 @@ static void ref_transaction_rejection_handler(const char *refname,
 					      const char *old_target UNUSED,
 					      const char *new_target UNUSED,
 					      enum ref_transaction_error err,
+					      const char *details UNUSED,
 					      void *cb_data)
 {
 	struct strmap *failed_refs = cb_data;
diff --git a/builtin/update-ref.c b/builtin/update-ref.c
index 195437e7c6..0046a87c57 100644
--- a/builtin/update-ref.c
+++ b/builtin/update-ref.c
@@ -573,6 +573,7 @@ static void print_rejected_refs(const char *refname,
 				const char *old_target,
 				const char *new_target,
 				enum ref_transaction_error err,
+				const char *details UNUSED,
 				void *cb_data UNUSED)
 {
 	struct strbuf sb = STRBUF_INIT;
diff --git a/refs.c b/refs.c
index 53919c3d22..c85c3d2c8b 100644
--- a/refs.c
+++ b/refs.c
@@ -2874,7 +2874,7 @@ void ref_transaction_for_each_rejected_update(struct ref_transaction *transactio
 		   (update->flags & REF_HAVE_OLD) ? &update->old_oid : NULL,
 		   (update->flags & REF_HAVE_NEW) ? &update->new_oid : NULL,
 		   update->old_target, update->new_target,
-		   update->rejection_err, cb_data);
+		   update->rejection_err, update->rejection_details, cb_data);
 	}
 }
 
diff --git a/refs.h b/refs.h
index d9051bbb04..4fbe3da924 100644
--- a/refs.h
+++ b/refs.h
@@ -975,6 +975,7 @@ typedef void ref_transaction_for_each_rejected_update_fn(const char *refname,
 							 const char *old_target,
 							 const char *new_target,
 							 enum ref_transaction_error err,
+							 const char *details,
 							 void *cb_data);
 void ref_transaction_for_each_rejected_update(struct ref_transaction *transaction,
 					      ref_transaction_for_each_rejected_update_fn cb,

-- 
2.51.2

[PATCH v3 3/6] update-ref: utilize rejected error details if available

[Karthik Nayak]

When git-update-ref(1) received the '--update-ref' flag, the error
details generated in the refs namespace wasn't propagated with failed
updates. Instead only an error code pertaining to the type of rejection
was noted.

This missed detailed error message which the user can act upon. The
previous commits added the required code to propagate these detailed
error messages from the refs namespace. Now that additional details are
available, let's output this additional details to stderr. This allows
users to have additional information over the already present machine
parsable output.

While we're here, improve the existing tests for the machine parsable
output by checking for the entire output string and not just the
rejection reason.

Reported-by: Elijah Newren <newren@gmail.com>
Co-authored-by: Jeff King <peff@peff.net>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
---
 builtin/update-ref.c  |  8 +++---
 t/t1400-update-ref.sh | 71 ++++++++++++++++++++++++++++++---------------------
 2 files changed, 47 insertions(+), 32 deletions(-)

diff --git a/builtin/update-ref.c b/builtin/update-ref.c
index 0046a87c57..2d68c40ecb 100644
--- a/builtin/update-ref.c
+++ b/builtin/update-ref.c
@@ -573,16 +573,18 @@ static void print_rejected_refs(const char *refname,
 				const char *old_target,
 				const char *new_target,
 				enum ref_transaction_error err,
-				const char *details UNUSED,
+				const char *details,
 				void *cb_data UNUSED)
 {
 	struct strbuf sb = STRBUF_INIT;
-	const char *reason = ref_transaction_error_msg(err);
+
+	if (details && *details)
+		error("%s", details);
 
 	strbuf_addf(&sb, "rejected %s %s %s %s\n", refname,
 		    new_oid ? oid_to_hex(new_oid) : new_target,
 		    old_oid ? oid_to_hex(old_oid) : old_target,
-		    reason);
+		    ref_transaction_error_msg(err));
 
 	fwrite(sb.buf, sb.len, 1, stdout);
 	strbuf_release(&sb);
diff --git a/t/t1400-update-ref.sh b/t/t1400-update-ref.sh
index db7f5444da..db6585b8d8 100755
--- a/t/t1400-update-ref.sh
+++ b/t/t1400-update-ref.sh
@@ -2093,14 +2093,15 @@ do
 
 			format_command $type "update refs/heads/ref1" "$old_head" "$head" >stdin &&
 			format_command $type "update refs/heads/ref2" "$(test_oid 001)" "$head" >>stdin &&
-			git update-ref $type --stdin --batch-updates <stdin >stdout &&
+			git update-ref $type --stdin --batch-updates <stdin >stdout 2>err &&
 			echo $old_head >expect &&
 			git rev-parse refs/heads/ref1 >actual &&
 			test_cmp expect actual &&
 			echo $head >expect &&
 			git rev-parse refs/heads/ref2 >actual &&
 			test_cmp expect actual &&
-			test_grep -q "invalid new value provided" stdout
+			test_grep "rejected refs/heads/ref2 $(test_oid 001) $head invalid new value provided" stdout &&
+			test_grep "trying to write ref ${SQ}refs/heads/ref2${SQ} with nonexistent object" err
 		)
 	'
 
@@ -2119,14 +2120,15 @@ do
 
 			format_command $type "update refs/heads/ref1" "$old_head" "$head" >stdin &&
 			format_command $type "update refs/heads/ref2" "$head_tree" "$head" >>stdin &&
-			git update-ref $type --stdin --batch-updates <stdin >stdout &&
+			git update-ref $type --stdin --batch-updates <stdin >stdout 2>err &&
 			echo $old_head >expect &&
 			git rev-parse refs/heads/ref1 >actual &&
 			test_cmp expect actual &&
 			echo $head >expect &&
 			git rev-parse refs/heads/ref2 >actual &&
 			test_cmp expect actual &&
-			test_grep -q "invalid new value provided" stdout
+			test_grep "rejected refs/heads/ref2 $head_tree $head invalid new value provided" stdout &&
+			test_grep "trying to write non-commit object $head_tree to branch ${SQ}refs/heads/ref2${SQ}" err
 		)
 	'
 
@@ -2143,12 +2145,13 @@ do
 
 			format_command $type "update refs/heads/ref1" "$old_head" "$head" >stdin &&
 			format_command $type "update refs/heads/ref2" "$old_head" "$head" >>stdin &&
-			git update-ref $type --stdin --batch-updates <stdin >stdout &&
+			git update-ref $type --stdin --batch-updates <stdin >stdout 2>err &&
 			echo $old_head >expect &&
 			git rev-parse refs/heads/ref1 >actual &&
 			test_cmp expect actual &&
 			test_must_fail git rev-parse refs/heads/ref2 &&
-			test_grep -q "reference does not exist" stdout
+			test_grep "rejected refs/heads/ref2 $old_head $head reference does not exist" stdout &&
+			test_grep "cannot lock ref ${SQ}refs/heads/ref2${SQ}: unable to resolve reference ${SQ}refs/heads/ref2${SQ}" err
 		)
 	'
 
@@ -2166,13 +2169,14 @@ do
 
 			format_command $type "update refs/heads/ref1" "$old_head" "$head" >stdin &&
 			format_command $type "update refs/heads/ref2" "$old_head" "$head" >>stdin &&
-			git update-ref $type --no-deref --stdin --batch-updates <stdin >stdout &&
+			git update-ref $type --no-deref --stdin --batch-updates <stdin >stdout 2>err &&
 			echo $old_head >expect &&
 			git rev-parse refs/heads/ref1 >actual &&
 			test_cmp expect actual &&
 			echo $head >expect &&
 			test_must_fail git rev-parse refs/heads/ref2 &&
-			test_grep -q "reference does not exist" stdout
+			test_grep "rejected refs/heads/ref2 $old_head $head reference does not exist" stdout &&
+			test_grep "cannot lock ref ${SQ}refs/heads/ref2${SQ}: reference is missing but expected $head" err
 		)
 	'
 
@@ -2190,7 +2194,7 @@ do
 
 			format_command $type "update refs/heads/ref1" "$old_head" "$head" >stdin &&
 			format_command $type "symref-update refs/heads/ref2" "$old_head" "ref" "refs/heads/nonexistent" >>stdin &&
-			git update-ref $type --no-deref --stdin --batch-updates <stdin >stdout &&
+			git update-ref $type --no-deref --stdin --batch-updates <stdin >stdout 2>err &&
 			echo $old_head >expect &&
 			git rev-parse refs/heads/ref1 >actual &&
 			test_cmp expect actual &&
@@ -2198,7 +2202,8 @@ do
 			echo $head >expect &&
 			git rev-parse refs/heads/ref2 >actual &&
 			test_cmp expect actual &&
-			test_grep -q "expected symref but found regular ref" stdout
+			test_grep "rejected refs/heads/ref2 $ZERO_OID $ZERO_OID expected symref but found regular ref" stdout &&
+			test_grep "cannot lock ref ${SQ}refs/heads/ref2${SQ}: expected symref with target ${SQ}refs/heads/nonexistent${SQ}: but is a regular ref" err
 		)
 	'
 
@@ -2216,14 +2221,15 @@ do
 
 			format_command $type "update refs/heads/ref1" "$old_head" "$head" >stdin &&
 			format_command $type "update refs/heads/ref2" "$old_head" "$Z" >>stdin &&
-			git update-ref $type --stdin --batch-updates <stdin >stdout &&
+			git update-ref $type --stdin --batch-updates <stdin >stdout 2>err &&
 			echo $old_head >expect &&
 			git rev-parse refs/heads/ref1 >actual &&
 			test_cmp expect actual &&
 			echo $head >expect &&
 			git rev-parse refs/heads/ref2 >actual &&
 			test_cmp expect actual &&
-			test_grep -q "reference already exists" stdout
+			test_grep "rejected refs/heads/ref2 $old_head $ZERO_OID reference already exists" stdout &&
+			test_grep "cannot lock ref ${SQ}refs/heads/ref2${SQ}: reference already exists" err
 		)
 	'
 
@@ -2241,14 +2247,15 @@ do
 
 			format_command $type "update refs/heads/ref1" "$old_head" "$head" >stdin &&
 			format_command $type "update refs/heads/ref2" "$head" "$old_head" >>stdin &&
-			git update-ref $type --stdin --batch-updates <stdin >stdout &&
+			git update-ref $type --stdin --batch-updates <stdin >stdout 2>err &&
 			echo $old_head >expect &&
 			git rev-parse refs/heads/ref1 >actual &&
 			test_cmp expect actual &&
 			echo $head >expect &&
 			git rev-parse refs/heads/ref2 >actual &&
 			test_cmp expect actual &&
-			test_grep -q "incorrect old value provided" stdout
+			test_grep "rejected refs/heads/ref2 $head $old_head incorrect old value provided" stdout &&
+			test_grep "cannot lock ref ${SQ}refs/heads/ref2${SQ}: is at $head but expected $old_head" err
 		)
 	'
 
@@ -2264,12 +2271,13 @@ do
 			git update-ref refs/heads/ref/foo $head &&
 
 			format_command $type "update refs/heads/ref/foo" "$old_head" "$head" >stdin &&
-			format_command $type "update refs/heads/ref" "$old_head" "" >>stdin &&
-			git update-ref $type --stdin --batch-updates <stdin >stdout &&
+			format_command $type "update refs/heads/ref" "$old_head" "$ZERO_OID" >>stdin &&
+			git update-ref $type --stdin --batch-updates <stdin >stdout 2>err &&
 			echo $old_head >expect &&
 			git rev-parse refs/heads/ref/foo >actual &&
 			test_cmp expect actual &&
-			test_grep -q "refname conflict" stdout
+			test_grep "rejected refs/heads/ref $old_head $ZERO_OID refname conflict" stdout &&
+			test_grep "${SQ}refs/heads/ref/foo${SQ} exists; cannot create ${SQ}refs/heads/ref${SQ}" err
 		)
 	'
 
@@ -2284,13 +2292,14 @@ do
 			head=$(git rev-parse HEAD) &&
 			git update-ref refs/heads/ref/foo $head &&
 
-			format_command $type "update refs/heads/foo" "$old_head" "" >stdin &&
-			format_command $type "update refs/heads/ref" "$old_head" "" >>stdin &&
-			git update-ref $type --stdin --batch-updates <stdin >stdout &&
+			format_command $type "update refs/heads/foo" "$old_head" "$ZERO_OID" >stdin &&
+			format_command $type "update refs/heads/ref" "$old_head" "$ZERO_OID" >>stdin &&
+			git update-ref $type --stdin --batch-updates <stdin >stdout 2>err &&
 			echo $old_head >expect &&
 			git rev-parse refs/heads/foo >actual &&
 			test_cmp expect actual &&
-			test_grep -q "refname conflict" stdout
+			test_grep "rejected refs/heads/ref $old_head $ZERO_OID refname conflict" stdout &&
+			test_grep "${SQ}refs/heads/ref/foo${SQ} exists; cannot create ${SQ}refs/heads/ref${SQ}" err
 		)
 	'
 
@@ -2309,14 +2318,15 @@ do
 				format_command $type "create refs/heads/ref" "$old_head" &&
 				format_command $type "create refs/heads/Foo" "$old_head"
 			} >stdin &&
-			git update-ref $type --stdin --batch-updates <stdin >stdout &&
+			git update-ref $type --stdin --batch-updates <stdin >stdout 2>err &&
 
 			echo $head >expect &&
 			git rev-parse refs/heads/foo >actual &&
 			echo $old_head >expect &&
 			git rev-parse refs/heads/ref >actual &&
 			test_cmp expect actual &&
-			test_grep -q "reference conflict due to case-insensitive filesystem" stdout
+			test_grep "rejected refs/heads/Foo $old_head $ZERO_OID reference conflict due to case-insensitive filesystem" stdout &&
+			test_grep -e "cannot lock ref ${SQ}refs/heads/Foo${SQ}: Unable to create" -e "Foo.lock" err
 		)
 	'
 
@@ -2357,8 +2367,9 @@ do
 			git symbolic-ref refs/heads/symbolic refs/heads/non-existent &&
 
 			format_command $type "delete refs/heads/symbolic" "$head" >stdin &&
-			git update-ref $type --stdin --batch-updates <stdin >stdout &&
-			test_grep "reference does not exist" stdout
+			git update-ref $type --stdin --batch-updates <stdin >stdout 2>err &&
+			test_grep "rejected refs/heads/non-existent $ZERO_OID $head reference does not exist" stdout &&
+			test_grep "cannot lock ref ${SQ}refs/heads/symbolic${SQ}: unable to resolve reference ${SQ}refs/heads/non-existent${SQ}" err
 		)
 	'
 
@@ -2373,8 +2384,9 @@ do
 			head=$(git rev-parse HEAD) &&
 
 			format_command $type "delete refs/heads/new-branch" "$head" >stdin &&
-			git update-ref $type --stdin --batch-updates <stdin >stdout &&
-			test_grep "incorrect old value provided" stdout
+			git update-ref $type --stdin --batch-updates <stdin >stdout 2>err &&
+			test_grep "rejected refs/heads/new-branch $ZERO_OID $head incorrect old value provided" stdout &&
+			test_grep "cannot lock ref ${SQ}refs/heads/new-branch${SQ}: is at $(git rev-parse new-branch) but expected $head" err
 		)
 	'
 
@@ -2387,8 +2399,9 @@ do
 			head=$(git rev-parse HEAD) &&
 
 			format_command $type "delete refs/heads/non-existent" "$head" >stdin &&
-			git update-ref $type --stdin --batch-updates <stdin >stdout &&
-			test_grep "reference does not exist" stdout
+			git update-ref $type --stdin --batch-updates <stdin >stdout 2>err &&
+			test_grep "rejected refs/heads/non-existent $ZERO_OID $head reference does not exist" stdout &&
+			test_grep "cannot lock ref ${SQ}refs/heads/non-existent${SQ}: unable to resolve reference ${SQ}refs/heads/non-existent${SQ}" err
 		)
 	'
 done

-- 
2.51.2

[PATCH v3 4/6] fetch: utilize rejected ref error details

[Karthik Nayak]

In 0e358de64a (fetch: use batched reference updates, 2025-05-19),
git-fetch(1) switched to using batched reference updates. This also
introduced a regression wherein instead of providing detailed error
messages for failed referenced updates, the users were provided generic
error messages based on the error type.

Similar to the previous commit, switch to using detailed error messages
if present for failed reference updates to fix this regression.

Reported-by: Elijah Newren <newren@gmail.com>
Co-authored-by: Jeff King <peff@peff.net>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
---
 builtin/fetch.c  | 10 ++++++----
 t/t5510-fetch.sh |  8 ++++----
 2 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/builtin/fetch.c b/builtin/fetch.c
index d427adea61..49495be0b6 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -1649,7 +1649,7 @@ static void ref_transaction_rejection_handler(const char *refname,
 					      const char *old_target UNUSED,
 					      const char *new_target UNUSED,
 					      enum ref_transaction_error err,
-					      const char *details UNUSED,
+					      const char *details,
 					      void *cb_data)
 {
 	struct ref_rejection_data *data = cb_data;
@@ -1674,9 +1674,11 @@ static void ref_transaction_rejection_handler(const char *refname,
 			"branches"), data->remote_name);
 		data->conflict_msg_shown = true;
 	} else {
-		const char *reason = ref_transaction_error_msg(err);
-
-		error(_("fetching ref %s failed: %s"), refname, reason);
+		if (details)
+			error("%s", details);
+		else
+			error(_("fetching ref %s failed: %s"),
+			      refname, ref_transaction_error_msg(err));
 	}
 
 	*data->retcode = 1;
diff --git a/t/t5510-fetch.sh b/t/t5510-fetch.sh
index ce1c23684e..c69afb5a60 100755
--- a/t/t5510-fetch.sh
+++ b/t/t5510-fetch.sh
@@ -1516,7 +1516,7 @@ test_expect_success REFFILES 'existing reference lock in repo' '
 		git remote add origin ../base &&
 		touch refs/heads/foo.lock &&
 		test_must_fail git fetch -f origin "refs/heads/*:refs/heads/*" 2>err &&
-		test_grep "error: fetching ref refs/heads/foo failed: reference already exists" err &&
+		test_grep -e "error: cannot lock ref ${SQ}refs/heads/foo${SQ}: Unable to create" -e "refs/heads/foo.lock${SQ}: File exists." err &&
 		git rev-parse refs/heads/main >expect &&
 		git rev-parse refs/heads/branch >actual &&
 		test_cmp expect actual
@@ -1530,7 +1530,7 @@ test_expect_success CASE_INSENSITIVE_FS,REFFILES 'F/D conflict on case insensiti
 		cd case_insensitive &&
 		git remote add origin -- ../case_sensitive_fd &&
 		test_must_fail git fetch -f origin "refs/heads/*:refs/heads/*" 2>err &&
-		test_grep "failed: refname conflict" err &&
+		test_grep "cannot process ${SQ}refs/remotes/origin/foo${SQ} and ${SQ}refs/remotes/origin/foo/bar${SQ} at the same time" err &&
 		git rev-parse refs/heads/main >expect &&
 		git rev-parse refs/heads/foo/bar >actual &&
 		test_cmp expect actual
@@ -1544,7 +1544,7 @@ test_expect_success CASE_INSENSITIVE_FS,REFFILES 'D/F conflict on case insensiti
 		cd case_insensitive &&
 		git remote add origin -- ../case_sensitive_df &&
 		test_must_fail git fetch -f origin "refs/heads/*:refs/heads/*" 2>err &&
-		test_grep "failed: refname conflict" err &&
+		test_grep "cannot lock ref ${SQ}refs/remotes/origin/foo${SQ}: there is a non-empty directory ${SQ}./refs/remotes/origin/foo${SQ} blocking reference ${SQ}refs/remotes/origin/foo${SQ}" err &&
 		git rev-parse refs/heads/main >expect &&
 		git rev-parse refs/heads/Foo/bar >actual &&
 		test_cmp expect actual
@@ -1658,7 +1658,7 @@ test_expect_success REFFILES "FETCH_HEAD is updated even if ref updates fail" '
 		git remote add origin ../base &&
 		>refs/heads/foo.lock &&
 		test_must_fail git fetch -f origin "refs/heads/*:refs/heads/*" 2>err &&
-		test_grep "error: fetching ref refs/heads/foo failed: reference already exists" err &&
+		test_grep -e "error: cannot lock ref ${SQ}refs/heads/foo${SQ}: Unable to create" -e "refs/heads/foo.lock${SQ}: File exists." err &&
 		test_grep "branch ${SQ}branch${SQ} of ../base" FETCH_HEAD &&
 		test_grep "branch ${SQ}foo${SQ} of ../base" FETCH_HEAD
 	)

-- 
2.51.2

[PATCH v3 5/6] receive-pack: utilize rejected ref error details

[Karthik Nayak]

In 9d2962a7c4 (receive-pack: use batched reference updates, 2025-05-19),
git-receive-pack(1) switched to using batched reference updates. This also
introduced a regression wherein instead of providing detailed error
messages for failed referenced updates, the users were provided generic
error messages based on the error type.

Now that the updates also contain detailed error message, propagate
those to the client via 'rp_error'. The detailed error messages can be
very verbose, for e.g. in the files backend, when trying to write a
non-commit object to a branch, you would see:

   ! [remote rejected] 3eaec9ccf3a53f168362a6b3fdeb73426fb9813d ->
   branch (cannot update ref 'refs/heads/branch': trying to write
   non-commit object 3eaec9ccf3a53f168362a6b3fdeb73426fb9813d to branch
   'refs/heads/branch')

Here the refname is repeated multiple times due to how error messages
are propagated and filled over the code stack. This potentially can be
cleaned up in a future commit.

Reported-by: Elijah Newren <newren@gmail.com>
Co-authored-by: Jeff King <peff@peff.net>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
---
 builtin/receive-pack.c |  8 ++++++--
 t/t5516-fetch-push.sh  | 15 +++++++++++++++
 2 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index 94d3e73cee..70e04b3efb 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -1813,11 +1813,14 @@ static void ref_transaction_rejection_handler(const char *refname,
 					      const char *old_target UNUSED,
 					      const char *new_target UNUSED,
 					      enum ref_transaction_error err,
-					      const char *details UNUSED,
+					      const char *details,
 					      void *cb_data)
 {
 	struct strmap *failed_refs = cb_data;
 
+	if (details)
+		rp_error("%s", details);
+
 	strmap_put(failed_refs, refname, (char *)ref_transaction_error_msg(err));
 }
 
@@ -1884,6 +1887,7 @@ static void execute_commands_non_atomic(struct command *commands,
 		}
 
 		ref_transaction_for_each_rejected_update(transaction,
+
 							 ref_transaction_rejection_handler,
 							 &failed_refs);
 
@@ -1895,7 +1899,7 @@ static void execute_commands_non_atomic(struct command *commands,
 			if (reported_error)
 				cmd->error_string = reported_error;
 			else if (strmap_contains(&failed_refs, cmd->ref_name))
-				cmd->error_string = strmap_get(&failed_refs, cmd->ref_name);
+				cmd->error_string = cmd->error_string_owned = xstrdup(strmap_get(&failed_refs, cmd->ref_name));
 		}
 
 	cleanup:
diff --git a/t/t5516-fetch-push.sh b/t/t5516-fetch-push.sh
index 46926e7bbd..45595991c8 100755
--- a/t/t5516-fetch-push.sh
+++ b/t/t5516-fetch-push.sh
@@ -1882,4 +1882,19 @@ test_expect_success 'push with F/D conflict with deletion and creation' '
 	git push testrepo :refs/heads/branch/conflict refs/heads/branch
 '
 
+test_expect_success 'pushing non-commit objects should report error' '
+	test_when_finished "rm -rf dest repo" &&
+	git init dest &&
+	git init repo &&
+
+	(
+		cd repo &&
+		test_commit --annotate test &&
+
+		tagsha=$(git rev-parse test^{tag}) &&
+		test_must_fail git push ../dest "$tagsha:refs/heads/branch" 2>err &&
+		test_grep "trying to write non-commit object $tagsha to branch ${SQ}refs/heads/branch${SQ}" err
+	)
+'
+
 test_done

-- 
2.51.2

[PATCH v3 6/6] fetch: delay user information post committing of transaction

[Karthik Nayak]

In Git 2.50 and earlier, we would display failure codes and error
message as part of the status display:

  $ git fetch . v1.0.0:refs/heads/foo
    error: cannot update ref 'refs/heads/foo': trying to write non-commit object f665776185ad074b236c00751d666da7d1977dbe to branch 'refs/heads/foo'
    From .
     ! [new tag]               v1.0.0     -> foo  (unable to update local ref)

With the addition of batched updates, this information is no longer
shown to the user:

  $ git fetch . v1.0.0:refs/heads/foo
    From .
     * [new tag]               v1.0.0     -> foo
    error: cannot update ref 'refs/heads/foo': trying to write non-commit object f665776185ad074b236c00751d666da7d1977dbe to branch 'refs/heads/foo'

Since reference updates are batched and processed together at the end,
information around the outcome is not available during individual
reference parsing.

To overcome this, collate and delay the output to the end. Introduce
`ref_update_display_info` which will hold individual update's
information and also whether the update failed or succeeded. This
finally allows us to iterate over all such updates and print them to the
user.

Using an dynamic array and strmap does add some overhead to
'git-fetch(1)', but from benchmarking this seems to be not too bad:

  Benchmark 1: fetch: many refs (refformat = files, refcount = 1000, revision = master)
    Time (mean ± σ):      42.6 ms ±   1.2 ms    [User: 13.1 ms, System: 29.8 ms]
    Range (min … max):    40.1 ms …  45.8 ms    47 runs

  Benchmark 2: fetch: many refs (refformat = files, refcount = 1000, revision = HEAD)
    Time (mean ± σ):      43.1 ms ±   1.2 ms    [User: 12.7 ms, System: 30.7 ms]
    Range (min … max):    40.5 ms …  45.8 ms    48 runs

  Summary
    fetch: many refs (refformat = files, refcount = 1000, revision = master) ran
      1.01 ± 0.04 times faster than fetch: many refs (refformat = files, refcount = 1000, revision = HEAD)

Another approach would be to move the status printing logic to be
handled post the transaction being committed. That however would require
adding an iterator to the ref transaction that tracks both the outcome
(success/failure) and the original refspec information for each update,
which is more involved infrastructure work compared to the strmap
approach here.

Helped-by: Phillip Wood <phillip.wood123@gmail.com>
Reported-by: Jeff King <peff@peff.net>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
---
 builtin/fetch.c       | 250 +++++++++++++++++++++++++++++++++++++++-----------
 t/t5516-fetch-push.sh |   1 +
 2 files changed, 197 insertions(+), 54 deletions(-)

diff --git a/builtin/fetch.c b/builtin/fetch.c
index 49495be0b6..3a3f1d8914 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -861,12 +861,87 @@ static void display_ref_update(struct display_state *display_state, char code,
 	fputs(display_state->buf.buf, f);
 }
 
+struct ref_update_display_info {
+	bool failed;
+	char success_code;
+	char fail_code;
+	const char *summary;
+	const char *fail_detail;
+	const char *success_detail;
+	const char *ref;
+	const char *remote;
+	struct object_id old_oid;
+	struct object_id new_oid;
+};
+
+static struct ref_update_display_info *ref_update_display_info_append(
+					   struct ref_update_display_info **list,
+					   size_t *count,
+					   char success_code,
+					   char fail_code,
+					   const char *summary,
+					   const char *success_detail,
+					   const char *fail_detail,
+					   const char *ref,
+					   const char *remote,
+					   const struct object_id *old_oid,
+					   const struct object_id *new_oid)
+{
+	struct ref_update_display_info *info;
+	size_t index = *count;
+
+	(*count)++;
+	REALLOC_ARRAY(*list, *count);
+
+	info = &(*list)[index];
+
+	info->failed = false;
+	info->success_code = success_code;
+	info->fail_code = fail_code;
+	info->summary = xstrdup(summary);
+	info->success_detail = xstrdup_or_null(success_detail);
+	info->fail_detail = xstrdup_or_null(fail_detail);
+	info->remote = xstrdup(remote);
+	info->ref = xstrdup(ref);
+
+	oidcpy(&info->old_oid, old_oid);
+	oidcpy(&info->new_oid, new_oid);
+
+	return info;
+}
+
+static void ref_update_display_info_set_failed(struct ref_update_display_info *info)
+{
+	info->failed = true;
+}
+
+static void ref_update_display_info_free(struct ref_update_display_info *info)
+{
+	free((char *)info->summary);
+	free((char *)info->success_detail);
+	free((char *)info->fail_detail);
+	free((char *)info->remote);
+	free((char *)info->ref);
+}
+
+static void ref_update_display_info_display(struct ref_update_display_info *info,
+					    struct display_state *display_state,
+					    int summary_width)
+{
+	display_ref_update(display_state,
+			   info->failed ? info->fail_code : info->success_code,
+			   info->summary,
+			   info->failed ? info->fail_detail : info->success_detail,
+			   info->remote, info->ref, &info->old_oid,
+			   &info->new_oid, summary_width);
+}
+
 static int update_local_ref(struct ref *ref,
 			    struct ref_transaction *transaction,
-			    struct display_state *display_state,
 			    const struct ref *remote_ref,
-			    int summary_width,
-			    const struct fetch_config *config)
+			    const struct fetch_config *config,
+			    struct ref_update_display_info **display_list,
+			    size_t *display_count)
 {
 	struct commit *current = NULL, *updated;
 	int fast_forward = 0;
@@ -877,41 +952,56 @@ static int update_local_ref(struct ref *ref,
 
 	if (oideq(&ref->old_oid, &ref->new_oid)) {
 		if (verbosity > 0)
-			display_ref_update(display_state, '=', _("[up to date]"), NULL,
-					   remote_ref->name, ref->name,
-					   &ref->old_oid, &ref->new_oid, summary_width);
+			ref_update_display_info_append(display_list, display_count,
+						       '=', '=', _("[up to date]"),
+						       NULL, NULL, ref->name,
+						       remote_ref->name, &ref->old_oid,
+						       &ref->new_oid);
 		return 0;
 	}
 
 	if (!update_head_ok &&
 	    !is_null_oid(&ref->old_oid) &&
 	    branch_checked_out(ref->name)) {
+		struct ref_update_display_info *info;
 		/*
 		 * If this is the head, and it's not okay to update
 		 * the head, and the old value of the head isn't empty...
 		 */
-		display_ref_update(display_state, '!', _("[rejected]"),
-				   _("can't fetch into checked-out branch"),
-				   remote_ref->name, ref->name,
-				   &ref->old_oid, &ref->new_oid, summary_width);
+		info = ref_update_display_info_append(display_list, display_count,
+						      '!', '!', _("[rejected]"),
+						      NULL, _("can't fetch into checked-out branch"),
+						      ref->name, remote_ref->name,
+						      &ref->old_oid, &ref->new_oid);
+		ref_update_display_info_set_failed(info);
 		return 1;
 	}
 
 	if (!is_null_oid(&ref->old_oid) &&
 	    starts_with(ref->name, "refs/tags/")) {
+		struct ref_update_display_info *info;
+
 		if (force || ref->force) {
 			int r;
+
 			r = s_update_ref("updating tag", ref, transaction, 0);
-			display_ref_update(display_state, r ? '!' : 't', _("[tag update]"),
-					   r ? _("unable to update local ref") : NULL,
-					   remote_ref->name, ref->name,
-					   &ref->old_oid, &ref->new_oid, summary_width);
+
+			info = ref_update_display_info_append(display_list, display_count,
+							      't', '!', _("[tag update]"), NULL,
+							      _("unable to update local ref"),
+							      ref->name, remote_ref->name,
+							      &ref->old_oid, &ref->new_oid);
+			if (r)
+				ref_update_display_info_set_failed(info);
+
 			return r;
 		} else {
-			display_ref_update(display_state, '!', _("[rejected]"),
-					   _("would clobber existing tag"),
-					   remote_ref->name, ref->name,
-					   &ref->old_oid, &ref->new_oid, summary_width);
+			info = ref_update_display_info_append(display_list, display_count,
+							      '!', '!', _("[rejected]"), NULL,
+							      _("would clobber existing tag"),
+							      ref->name, remote_ref->name,
+							      &ref->old_oid, &ref->new_oid);
+			ref_update_display_info_set_failed(info);
 			return 1;
 		}
 	}
@@ -921,6 +1011,7 @@ static int update_local_ref(struct ref *ref,
 	updated = lookup_commit_reference_gently(the_repository,
 						 &ref->new_oid, 1);
 	if (!current || !updated) {
+		struct ref_update_display_info *info;
 		const char *msg;
 		const char *what;
 		int r;
@@ -941,10 +1032,15 @@ static int update_local_ref(struct ref *ref,
 		}
 
 		r = s_update_ref(msg, ref, transaction, 0);
-		display_ref_update(display_state, r ? '!' : '*', what,
-				   r ? _("unable to update local ref") : NULL,
-				   remote_ref->name, ref->name,
-				   &ref->old_oid, &ref->new_oid, summary_width);
+
+		info = ref_update_display_info_append(display_list, display_count,
+						      '*', '!', what, NULL,
+						      _("unable to update local ref"),
+						      ref->name, remote_ref->name,
+						      &ref->old_oid, &ref->new_oid);
+		if (r)
+			ref_update_display_info_set_failed(info);
+
 		return r;
 	}
 
@@ -960,6 +1056,7 @@ static int update_local_ref(struct ref *ref,
 	}
 
 	if (fast_forward) {
+		struct ref_update_display_info *info;
 		struct strbuf quickref = STRBUF_INIT;
 		int r;
 
@@ -967,29 +1064,46 @@ static int update_local_ref(struct ref *ref,
 		strbuf_addstr(&quickref, "..");
 		strbuf_add_unique_abbrev(&quickref, &ref->new_oid, DEFAULT_ABBREV);
 		r = s_update_ref("fast-forward", ref, transaction, 1);
-		display_ref_update(display_state, r ? '!' : ' ', quickref.buf,
-				   r ? _("unable to update local ref") : NULL,
-				   remote_ref->name, ref->name,
-				   &ref->old_oid, &ref->new_oid, summary_width);
+
+		info = ref_update_display_info_append(display_list, display_count,
+						      ' ', '!', quickref.buf, NULL,
+						      _("unable to update local ref"),
+						      ref->name, remote_ref->name,
+						      &ref->old_oid, &ref->new_oid);
+		if (r)
+			ref_update_display_info_set_failed(info);
+
 		strbuf_release(&quickref);
 		return r;
 	} else if (force || ref->force) {
+		struct ref_update_display_info *info;
 		struct strbuf quickref = STRBUF_INIT;
 		int r;
+
 		strbuf_add_unique_abbrev(&quickref, &current->object.oid, DEFAULT_ABBREV);
 		strbuf_addstr(&quickref, "...");
 		strbuf_add_unique_abbrev(&quickref, &ref->new_oid, DEFAULT_ABBREV);
 		r = s_update_ref("forced-update", ref, transaction, 1);
-		display_ref_update(display_state, r ? '!' : '+', quickref.buf,
-				   r ? _("unable to update local ref") : _("forced update"),
-				   remote_ref->name, ref->name,
-				   &ref->old_oid, &ref->new_oid, summary_width);
+
+		info = ref_update_display_info_append(display_list, display_count,
+						      '+', '!', quickref.buf, _("forced update"),
+						      _("unable to update local ref"),
+						      ref->name, remote_ref->name,
+						      &ref->old_oid, &ref->new_oid);
+
+		if (r)
+			ref_update_display_info_set_failed(info);
+
 		strbuf_release(&quickref);
 		return r;
 	} else {
-		display_ref_update(display_state, '!', _("[rejected]"), _("non-fast-forward"),
-				   remote_ref->name, ref->name,
-				   &ref->old_oid, &ref->new_oid, summary_width);
+		struct ref_update_display_info *info;
+		info = ref_update_display_info_append(display_list, display_count,
+						      '!', '!', _("[rejected]"), NULL,
+						      _("non-fast-forward"),
+						      ref->name, remote_ref->name,
+						      &ref->old_oid, &ref->new_oid);
+		ref_update_display_info_set_failed(info);
 		return 1;
 	}
 }
@@ -1103,17 +1217,15 @@ static int store_updated_refs(struct display_state *display_state,
 			      int connectivity_checked,
 			      struct ref_transaction *transaction, struct ref *ref_map,
 			      struct fetch_head *fetch_head,
-			      const struct fetch_config *config)
+			      const struct fetch_config *config,
+			      struct ref_update_display_info **display_list,
+			      size_t *display_count)
 {
 	int rc = 0;
 	struct strbuf note = STRBUF_INIT;
 	const char *what, *kind;
 	struct ref *rm;
 	int want_status;
-	int summary_width = 0;
-
-	if (verbosity >= 0)
-		summary_width = transport_summary_width(ref_map);
 
 	if (!connectivity_checked) {
 		struct check_connected_options opt = CHECK_CONNECTED_INIT;
@@ -1218,8 +1330,9 @@ static int store_updated_refs(struct display_state *display_state,
 					  display_state->url_len);
 
 			if (ref) {
-				rc |= update_local_ref(ref, transaction, display_state,
-						       rm, summary_width, config);
+				rc |= update_local_ref(ref, transaction, rm,
+						       config, display_list,
+						       display_count);
 				free(ref);
 			} else if (write_fetch_head || dry_run) {
 				/*
@@ -1227,12 +1340,11 @@ static int store_updated_refs(struct display_state *display_state,
 				 * would be written to FETCH_HEAD, if --dry-run
 				 * is set).
 				 */
-				display_ref_update(display_state, '*',
-						   *kind ? kind : "branch", NULL,
-						   rm->name,
-						   "FETCH_HEAD",
-						   &rm->new_oid, &rm->old_oid,
-						   summary_width);
+
+				ref_update_display_info_append(display_list, display_count,
+							       '*', '*', *kind ? kind : "branch",
+							       NULL, NULL, "FETCH_HEAD", rm->name,
+							       &rm->new_oid, &rm->old_oid);
 			}
 		}
 	}
@@ -1300,7 +1412,9 @@ static int fetch_and_consume_refs(struct display_state *display_state,
 				  struct ref_transaction *transaction,
 				  struct ref *ref_map,
 				  struct fetch_head *fetch_head,
-				  const struct fetch_config *config)
+				  const struct fetch_config *config,
+				  struct ref_update_display_info **display_list,
+				  size_t *display_count)
 {
 	int connectivity_checked = 1;
 	int ret;
@@ -1322,7 +1436,8 @@ static int fetch_and_consume_refs(struct display_state *display_state,
 
 	trace2_region_enter("fetch", "consume_refs", the_repository);
 	ret = store_updated_refs(display_state, connectivity_checked,
-				 transaction, ref_map, fetch_head, config);
+				 transaction, ref_map, fetch_head, config,
+				 display_list, display_count);
 	trace2_region_leave("fetch", "consume_refs", the_repository);
 
 out:
@@ -1493,7 +1608,9 @@ static int backfill_tags(struct display_state *display_state,
 			 struct ref_transaction *transaction,
 			 struct ref *ref_map,
 			 struct fetch_head *fetch_head,
-			 const struct fetch_config *config)
+			 const struct fetch_config *config,
+			 struct ref_update_display_info **display_list,
+			 size_t *display_count)
 {
 	int retcode, cannot_reuse;
 
@@ -1515,7 +1632,7 @@ static int backfill_tags(struct display_state *display_state,
 	transport_set_option(transport, TRANS_OPT_DEPTH, "0");
 	transport_set_option(transport, TRANS_OPT_DEEPEN_RELATIVE, NULL);
 	retcode = fetch_and_consume_refs(display_state, transport, transaction, ref_map,
-					 fetch_head, config);
+					 fetch_head, config, display_list, display_count);
 
 	if (gsecondary) {
 		transport_disconnect(gsecondary);
@@ -1641,6 +1758,7 @@ struct ref_rejection_data {
 	bool conflict_msg_shown;
 	bool case_sensitive_msg_shown;
 	const char *remote_name;
+	struct strmap *rejected_refs;
 };
 
 static void ref_transaction_rejection_handler(const char *refname,
@@ -1681,6 +1799,7 @@ static void ref_transaction_rejection_handler(const char *refname,
 			      refname, ref_transaction_error_msg(err));
 	}
 
+	strmap_put(data->rejected_refs, refname, NULL);
 	*data->retcode = 1;
 }
 
@@ -1690,6 +1809,7 @@ static void ref_transaction_rejection_handler(const char *refname,
  */
 static int commit_ref_transaction(struct ref_transaction **transaction,
 				  bool is_atomic, const char *remote_name,
+				  struct strmap *rejected_refs,
 				  struct strbuf *err)
 {
 	int retcode = ref_transaction_commit(*transaction, err);
@@ -1701,6 +1821,7 @@ static int commit_ref_transaction(struct ref_transaction **transaction,
 			.conflict_msg_shown = 0,
 			.remote_name = remote_name,
 			.retcode = &retcode,
+			.rejected_refs = rejected_refs,
 		};
 
 		ref_transaction_for_each_rejected_update(*transaction,
@@ -1729,6 +1850,10 @@ static int do_fetch(struct transport *transport,
 	struct fetch_head fetch_head = { 0 };
 	struct strbuf err = STRBUF_INIT;
 	int do_set_head = 0;
+	struct ref_update_display_info *display_list = NULL;
+	struct strmap rejected_refs = STRMAP_INIT;
+	size_t display_count = 0;
+	int summary_width = 0;
 
 	if (tags == TAGS_DEFAULT) {
 		if (transport->remote->fetch_tags == 2)
@@ -1853,7 +1978,7 @@ static int do_fetch(struct transport *transport,
 	}
 
 	if (fetch_and_consume_refs(&display_state, transport, transaction, ref_map,
-				   &fetch_head, config)) {
+				   &fetch_head, config, &display_list, &display_count)) {
 		retcode = 1;
 		goto cleanup;
 	}
@@ -1876,7 +2001,7 @@ static int do_fetch(struct transport *transport,
 			 * the transaction and don't commit anything.
 			 */
 			if (backfill_tags(&display_state, transport, transaction, tags_ref_map,
-					  &fetch_head, config))
+					  &fetch_head, config, &display_list, &display_count))
 				retcode = 1;
 		}
 
@@ -1886,8 +2011,12 @@ static int do_fetch(struct transport *transport,
 	if (retcode)
 		goto cleanup;
 
+	if (verbosity >= 0)
+		summary_width = transport_summary_width(ref_map);
+
 	retcode = commit_ref_transaction(&transaction, atomic_fetch,
-					 transport->remote->name, &err);
+					 transport->remote->name,
+					 &rejected_refs, &err);
 	/*
 	 * With '--atomic', bail out if the transaction fails. Without '--atomic',
 	 * continue to fetch head and perform other post-fetch operations.
@@ -1965,7 +2094,17 @@ static int do_fetch(struct transport *transport,
 	 */
 	if (retcode && !atomic_fetch && transaction)
 		commit_ref_transaction(&transaction, false,
-				       transport->remote->name, &err);
+				       transport->remote->name,
+				       &rejected_refs, &err);
+
+	for (size_t i = 0; i < display_count; i++) {
+		struct ref_update_display_info *info = &display_list[i];
+
+		if (!info->failed && strmap_contains(&rejected_refs, info->ref))
+			ref_update_display_info_set_failed(info);
+		ref_update_display_info_display(info, &display_state, summary_width);
+		ref_update_display_info_free(info);
+	}
 
 	if (retcode) {
 		if (err.len) {
@@ -1980,6 +2119,9 @@ static int do_fetch(struct transport *transport,
 
 	if (transaction)
 		ref_transaction_free(transaction);
+
+	free(display_list);
+	strmap_clear(&rejected_refs, 0);
 	display_state_release(&display_state);
 	close_fetch_head(&fetch_head);
 	strbuf_release(&err);
diff --git a/t/t5516-fetch-push.sh b/t/t5516-fetch-push.sh
index 45595991c8..29e2f17608 100755
--- a/t/t5516-fetch-push.sh
+++ b/t/t5516-fetch-push.sh
@@ -1893,6 +1893,7 @@ test_expect_success 'pushing non-commit objects should report error' '
 
 		tagsha=$(git rev-parse test^{tag}) &&
 		test_must_fail git push ../dest "$tagsha:refs/heads/branch" 2>err &&
+		test_grep "! \[remote rejected\] $tagsha -> branch (invalid new value provided)" err &&
 		test_grep "trying to write non-commit object $tagsha to branch ${SQ}refs/heads/branch${SQ}" err
 	)
 '

-- 
2.51.2

Re: [PATCH v3 6/6] fetch: delay user information post committing of transaction

[Phillip Wood]

Hi Karthik

On 20/01/2026 09:59, Karthik Nayak wrote:

> +struct ref_update_display_info {
> +	bool failed;
> +	char success_code;
> +	char fail_code;
> +	const char *summary;
> +	const char *fail_detail;
> +	const char *success_detail;
> +	const char *ref;
> +	const char *remote;
> +	struct object_id old_oid;
> +	struct object_id new_oid;
> +};

I was expecting that we'd pass around a struct like

struct ref_update_display_info_array {
	size_t alloc, nr;
	ref_update_display_info *info;
};

rather than passing a pointer, count pair as separate parameters. That 
would also allow us to use ALLOC_GROW() rather than reallocating the 
array each time we append to it which is rather inefficient.

Thanks

Phillip

> +static struct ref_update_display_info *ref_update_display_info_append(
> +					   struct ref_update_display_info **list,
> +					   size_t *count,
> +					   char success_code,
> +					   char fail_code,
> +					   const char *summary,
> +					   const char *success_detail,
> +					   const char *fail_detail,
> +					   const char *ref,
> +					   const char *remote,
> +					   const struct object_id *old_oid,
> +					   const struct object_id *new_oid)
> +{
> +	struct ref_update_display_info *info;
> +	size_t index = *count;
> +
> +	(*count)++;
> +	REALLOC_ARRAY(*list, *count);
> +
> +	info = &(*list)[index];
> +
> +	info->failed = false;
> +	info->success_code = success_code;
> +	info->fail_code = fail_code;
> +	info->summary = xstrdup(summary);
> +	info->success_detail = xstrdup_or_null(success_detail);
> +	info->fail_detail = xstrdup_or_null(fail_detail);
> +	info->remote = xstrdup(remote);
> +	info->ref = xstrdup(ref);
> +
> +	oidcpy(&info->old_oid, old_oid);
> +	oidcpy(&info->new_oid, new_oid);
> +
> +	return info;
> +}
> +
> +static void ref_update_display_info_set_failed(struct ref_update_display_info *info)
> +{
> +	info->failed = true;
> +}
> +
> +static void ref_update_display_info_free(struct ref_update_display_info *info)
> +{
> +	free((char *)info->summary);
> +	free((char *)info->success_detail);
> +	free((char *)info->fail_detail);
> +	free((char *)info->remote);
> +	free((char *)info->ref);
> +}
> +
> +static void ref_update_display_info_display(struct ref_update_display_info *info,
> +					    struct display_state *display_state,
> +					    int summary_width)
> +{
> +	display_ref_update(display_state,
> +			   info->failed ? info->fail_code : info->success_code,
> +			   info->summary,
> +			   info->failed ? info->fail_detail : info->success_detail,
> +			   info->remote, info->ref, &info->old_oid,
> +			   &info->new_oid, summary_width);
> +}
> +
>   static int update_local_ref(struct ref *ref,
>   			    struct ref_transaction *transaction,
> -			    struct display_state *display_state,
>   			    const struct ref *remote_ref,
> -			    int summary_width,
> -			    const struct fetch_config *config)
> +			    const struct fetch_config *config,
> +			    struct ref_update_display_info **display_list,
> +			    size_t *display_count)
>   {
>   	struct commit *current = NULL, *updated;
>   	int fast_forward = 0;
> @@ -877,41 +952,56 @@ static int update_local_ref(struct ref *ref,
>   
>   	if (oideq(&ref->old_oid, &ref->new_oid)) {
>   		if (verbosity > 0)
> -			display_ref_update(display_state, '=', _("[up to date]"), NULL,
> -					   remote_ref->name, ref->name,
> -					   &ref->old_oid, &ref->new_oid, summary_width);
> +			ref_update_display_info_append(display_list, display_count,
> +						       '=', '=', _("[up to date]"),
> +						       NULL, NULL, ref->name,
> +						       remote_ref->name, &ref->old_oid,
> +						       &ref->new_oid);
>   		return 0;
>   	}
>   
>   	if (!update_head_ok &&
>   	    !is_null_oid(&ref->old_oid) &&
>   	    branch_checked_out(ref->name)) {
> +		struct ref_update_display_info *info;
>   		/*
>   		 * If this is the head, and it's not okay to update
>   		 * the head, and the old value of the head isn't empty...
>   		 */
> -		display_ref_update(display_state, '!', _("[rejected]"),
> -				   _("can't fetch into checked-out branch"),
> -				   remote_ref->name, ref->name,
> -				   &ref->old_oid, &ref->new_oid, summary_width);
> +		info = ref_update_display_info_append(display_list, display_count,
> +						      '!', '!', _("[rejected]"),
> +						      NULL, _("can't fetch into checked-out branch"),
> +						      ref->name, remote_ref->name,
> +						      &ref->old_oid, &ref->new_oid);
> +		ref_update_display_info_set_failed(info);
>   		return 1;
>   	}
>   
>   	if (!is_null_oid(&ref->old_oid) &&
>   	    starts_with(ref->name, "refs/tags/")) {
> +		struct ref_update_display_info *info;
> +
>   		if (force || ref->force) {
>   			int r;
> +
>   			r = s_update_ref("updating tag", ref, transaction, 0);
> -			display_ref_update(display_state, r ? '!' : 't', _("[tag update]"),
> -					   r ? _("unable to update local ref") : NULL,
> -					   remote_ref->name, ref->name,
> -					   &ref->old_oid, &ref->new_oid, summary_width);
> +
> +			info = ref_update_display_info_append(display_list, display_count,
> +							      't', '!', _("[tag update]"), NULL,
> +							      _("unable to update local ref"),
> +							      ref->name, remote_ref->name,
> +							      &ref->old_oid, &ref->new_oid);
> +			if (r)
> +				ref_update_display_info_set_failed(info);
> +
>   			return r;
>   		} else {
> -			display_ref_update(display_state, '!', _("[rejected]"),
> -					   _("would clobber existing tag"),
> -					   remote_ref->name, ref->name,
> -					   &ref->old_oid, &ref->new_oid, summary_width);
> +			info = ref_update_display_info_append(display_list, display_count,
> +							      '!', '!', _("[rejected]"), NULL,
> +							      _("would clobber existing tag"),
> +							      ref->name, remote_ref->name,
> +							      &ref->old_oid, &ref->new_oid);
> +			ref_update_display_info_set_failed(info);
>   			return 1;
>   		}
>   	}
> @@ -921,6 +1011,7 @@ static int update_local_ref(struct ref *ref,
>   	updated = lookup_commit_reference_gently(the_repository,
>   						 &ref->new_oid, 1);
>   	if (!current || !updated) {
> +		struct ref_update_display_info *info;
>   		const char *msg;
>   		const char *what;
>   		int r;
> @@ -941,10 +1032,15 @@ static int update_local_ref(struct ref *ref,
>   		}
>   
>   		r = s_update_ref(msg, ref, transaction, 0);
> -		display_ref_update(display_state, r ? '!' : '*', what,
> -				   r ? _("unable to update local ref") : NULL,
> -				   remote_ref->name, ref->name,
> -				   &ref->old_oid, &ref->new_oid, summary_width);
> +
> +		info = ref_update_display_info_append(display_list, display_count,
> +						      '*', '!', what, NULL,
> +						      _("unable to update local ref"),
> +						      ref->name, remote_ref->name,
> +						      &ref->old_oid, &ref->new_oid);
> +		if (r)
> +			ref_update_display_info_set_failed(info);
> +
>   		return r;
>   	}
>   
> @@ -960,6 +1056,7 @@ static int update_local_ref(struct ref *ref,
>   	}
>   
>   	if (fast_forward) {
> +		struct ref_update_display_info *info;
>   		struct strbuf quickref = STRBUF_INIT;
>   		int r;
>   
> @@ -967,29 +1064,46 @@ static int update_local_ref(struct ref *ref,
>   		strbuf_addstr(&quickref, "..");
>   		strbuf_add_unique_abbrev(&quickref, &ref->new_oid, DEFAULT_ABBREV);
>   		r = s_update_ref("fast-forward", ref, transaction, 1);
> -		display_ref_update(display_state, r ? '!' : ' ', quickref.buf,
> -				   r ? _("unable to update local ref") : NULL,
> -				   remote_ref->name, ref->name,
> -				   &ref->old_oid, &ref->new_oid, summary_width);
> +
> +		info = ref_update_display_info_append(display_list, display_count,
> +						      ' ', '!', quickref.buf, NULL,
> +						      _("unable to update local ref"),
> +						      ref->name, remote_ref->name,
> +						      &ref->old_oid, &ref->new_oid);
> +		if (r)
> +			ref_update_display_info_set_failed(info);
> +
>   		strbuf_release(&quickref);
>   		return r;
>   	} else if (force || ref->force) {
> +		struct ref_update_display_info *info;
>   		struct strbuf quickref = STRBUF_INIT;
>   		int r;
> +
>   		strbuf_add_unique_abbrev(&quickref, &current->object.oid, DEFAULT_ABBREV);
>   		strbuf_addstr(&quickref, "...");
>   		strbuf_add_unique_abbrev(&quickref, &ref->new_oid, DEFAULT_ABBREV);
>   		r = s_update_ref("forced-update", ref, transaction, 1);
> -		display_ref_update(display_state, r ? '!' : '+', quickref.buf,
> -				   r ? _("unable to update local ref") : _("forced update"),
> -				   remote_ref->name, ref->name,
> -				   &ref->old_oid, &ref->new_oid, summary_width);
> +
> +		info = ref_update_display_info_append(display_list, display_count,
> +						      '+', '!', quickref.buf, _("forced update"),
> +						      _("unable to update local ref"),
> +						      ref->name, remote_ref->name,
> +						      &ref->old_oid, &ref->new_oid);
> +
> +		if (r)
> +			ref_update_display_info_set_failed(info);
> +
>   		strbuf_release(&quickref);
>   		return r;
>   	} else {
> -		display_ref_update(display_state, '!', _("[rejected]"), _("non-fast-forward"),
> -				   remote_ref->name, ref->name,
> -				   &ref->old_oid, &ref->new_oid, summary_width);
> +		struct ref_update_display_info *info;
> +		info = ref_update_display_info_append(display_list, display_count,
> +						      '!', '!', _("[rejected]"), NULL,
> +						      _("non-fast-forward"),
> +						      ref->name, remote_ref->name,
> +						      &ref->old_oid, &ref->new_oid);
> +		ref_update_display_info_set_failed(info);
>   		return 1;
>   	}
>   }
> @@ -1103,17 +1217,15 @@ static int store_updated_refs(struct display_state *display_state,
>   			      int connectivity_checked,
>   			      struct ref_transaction *transaction, struct ref *ref_map,
>   			      struct fetch_head *fetch_head,
> -			      const struct fetch_config *config)
> +			      const struct fetch_config *config,
> +			      struct ref_update_display_info **display_list,
> +			      size_t *display_count)
>   {
>   	int rc = 0;
>   	struct strbuf note = STRBUF_INIT;
>   	const char *what, *kind;
>   	struct ref *rm;
>   	int want_status;
> -	int summary_width = 0;
> -
> -	if (verbosity >= 0)
> -		summary_width = transport_summary_width(ref_map);
>   
>   	if (!connectivity_checked) {
>   		struct check_connected_options opt = CHECK_CONNECTED_INIT;
> @@ -1218,8 +1330,9 @@ static int store_updated_refs(struct display_state *display_state,
>   					  display_state->url_len);
>   
>   			if (ref) {
> -				rc |= update_local_ref(ref, transaction, display_state,
> -						       rm, summary_width, config);
> +				rc |= update_local_ref(ref, transaction, rm,
> +						       config, display_list,
> +						       display_count);
>   				free(ref);
>   			} else if (write_fetch_head || dry_run) {
>   				/*
> @@ -1227,12 +1340,11 @@ static int store_updated_refs(struct display_state *display_state,
>   				 * would be written to FETCH_HEAD, if --dry-run
>   				 * is set).
>   				 */
> -				display_ref_update(display_state, '*',
> -						   *kind ? kind : "branch", NULL,
> -						   rm->name,
> -						   "FETCH_HEAD",
> -						   &rm->new_oid, &rm->old_oid,
> -						   summary_width);
> +
> +				ref_update_display_info_append(display_list, display_count,
> +							       '*', '*', *kind ? kind : "branch",
> +							       NULL, NULL, "FETCH_HEAD", rm->name,
> +							       &rm->new_oid, &rm->old_oid);
>   			}
>   		}
>   	}
> @@ -1300,7 +1412,9 @@ static int fetch_and_consume_refs(struct display_state *display_state,
>   				  struct ref_transaction *transaction,
>   				  struct ref *ref_map,
>   				  struct fetch_head *fetch_head,
> -				  const struct fetch_config *config)
> +				  const struct fetch_config *config,
> +				  struct ref_update_display_info **display_list,
> +				  size_t *display_count)
>   {
>   	int connectivity_checked = 1;
>   	int ret;
> @@ -1322,7 +1436,8 @@ static int fetch_and_consume_refs(struct display_state *display_state,
>   
>   	trace2_region_enter("fetch", "consume_refs", the_repository);
>   	ret = store_updated_refs(display_state, connectivity_checked,
> -				 transaction, ref_map, fetch_head, config);
> +				 transaction, ref_map, fetch_head, config,
> +				 display_list, display_count);
>   	trace2_region_leave("fetch", "consume_refs", the_repository);
>   
>   out:
> @@ -1493,7 +1608,9 @@ static int backfill_tags(struct display_state *display_state,
>   			 struct ref_transaction *transaction,
>   			 struct ref *ref_map,
>   			 struct fetch_head *fetch_head,
> -			 const struct fetch_config *config)
> +			 const struct fetch_config *config,
> +			 struct ref_update_display_info **display_list,
> +			 size_t *display_count)
>   {
>   	int retcode, cannot_reuse;
>   
> @@ -1515,7 +1632,7 @@ static int backfill_tags(struct display_state *display_state,
>   	transport_set_option(transport, TRANS_OPT_DEPTH, "0");
>   	transport_set_option(transport, TRANS_OPT_DEEPEN_RELATIVE, NULL);
>   	retcode = fetch_and_consume_refs(display_state, transport, transaction, ref_map,
> -					 fetch_head, config);
> +					 fetch_head, config, display_list, display_count);
>   
>   	if (gsecondary) {
>   		transport_disconnect(gsecondary);
> @@ -1641,6 +1758,7 @@ struct ref_rejection_data {
>   	bool conflict_msg_shown;
>   	bool case_sensitive_msg_shown;
>   	const char *remote_name;
> +	struct strmap *rejected_refs;
>   };
>   
>   static void ref_transaction_rejection_handler(const char *refname,
> @@ -1681,6 +1799,7 @@ static void ref_transaction_rejection_handler(const char *refname,
>   			      refname, ref_transaction_error_msg(err));
>   	}
>   
> +	strmap_put(data->rejected_refs, refname, NULL);
>   	*data->retcode = 1;
>   }
>   
> @@ -1690,6 +1809,7 @@ static void ref_transaction_rejection_handler(const char *refname,
>    */
>   static int commit_ref_transaction(struct ref_transaction **transaction,
>   				  bool is_atomic, const char *remote_name,
> +				  struct strmap *rejected_refs,
>   				  struct strbuf *err)
>   {
>   	int retcode = ref_transaction_commit(*transaction, err);
> @@ -1701,6 +1821,7 @@ static int commit_ref_transaction(struct ref_transaction **transaction,
>   			.conflict_msg_shown = 0,
>   			.remote_name = remote_name,
>   			.retcode = &retcode,
> +			.rejected_refs = rejected_refs,
>   		};
>   
>   		ref_transaction_for_each_rejected_update(*transaction,
> @@ -1729,6 +1850,10 @@ static int do_fetch(struct transport *transport,
>   	struct fetch_head fetch_head = { 0 };
>   	struct strbuf err = STRBUF_INIT;
>   	int do_set_head = 0;
> +	struct ref_update_display_info *display_list = NULL;
> +	struct strmap rejected_refs = STRMAP_INIT;
> +	size_t display_count = 0;
> +	int summary_width = 0;
>   
>   	if (tags == TAGS_DEFAULT) {
>   		if (transport->remote->fetch_tags == 2)
> @@ -1853,7 +1978,7 @@ static int do_fetch(struct transport *transport,
>   	}
>   
>   	if (fetch_and_consume_refs(&display_state, transport, transaction, ref_map,
> -				   &fetch_head, config)) {
> +				   &fetch_head, config, &display_list, &display_count)) {
>   		retcode = 1;
>   		goto cleanup;
>   	}
> @@ -1876,7 +2001,7 @@ static int do_fetch(struct transport *transport,
>   			 * the transaction and don't commit anything.
>   			 */
>   			if (backfill_tags(&display_state, transport, transaction, tags_ref_map,
> -					  &fetch_head, config))
> +					  &fetch_head, config, &display_list, &display_count))
>   				retcode = 1;
>   		}
>   
> @@ -1886,8 +2011,12 @@ static int do_fetch(struct transport *transport,
>   	if (retcode)
>   		goto cleanup;
>   
> +	if (verbosity >= 0)
> +		summary_width = transport_summary_width(ref_map);
> +
>   	retcode = commit_ref_transaction(&transaction, atomic_fetch,
> -					 transport->remote->name, &err);
> +					 transport->remote->name,
> +					 &rejected_refs, &err);
>   	/*
>   	 * With '--atomic', bail out if the transaction fails. Without '--atomic',
>   	 * continue to fetch head and perform other post-fetch operations.
> @@ -1965,7 +2094,17 @@ static int do_fetch(struct transport *transport,
>   	 */
>   	if (retcode && !atomic_fetch && transaction)
>   		commit_ref_transaction(&transaction, false,
> -				       transport->remote->name, &err);
> +				       transport->remote->name,
> +				       &rejected_refs, &err);
> +
> +	for (size_t i = 0; i < display_count; i++) {
> +		struct ref_update_display_info *info = &display_list[i];
> +
> +		if (!info->failed && strmap_contains(&rejected_refs, info->ref))
> +			ref_update_display_info_set_failed(info);
> +		ref_update_display_info_display(info, &display_state, summary_width);
> +		ref_update_display_info_free(info);
> +	}
>   
>   	if (retcode) {
>   		if (err.len) {
> @@ -1980,6 +2119,9 @@ static int do_fetch(struct transport *transport,
>   
>   	if (transaction)
>   		ref_transaction_free(transaction);
> +
> +	free(display_list);
> +	strmap_clear(&rejected_refs, 0);
>   	display_state_release(&display_state);
>   	close_fetch_head(&fetch_head);
>   	strbuf_release(&err);
> diff --git a/t/t5516-fetch-push.sh b/t/t5516-fetch-push.sh
> index 45595991c8..29e2f17608 100755
> --- a/t/t5516-fetch-push.sh
> +++ b/t/t5516-fetch-push.sh
> @@ -1893,6 +1893,7 @@ test_expect_success 'pushing non-commit objects should report error' '
>   
>   		tagsha=$(git rev-parse test^{tag}) &&
>   		test_must_fail git push ../dest "$tagsha:refs/heads/branch" 2>err &&
> +		test_grep "! \[remote rejected\] $tagsha -> branch (invalid new value provided)" err &&
>   		test_grep "trying to write non-commit object $tagsha to branch ${SQ}refs/heads/branch${SQ}" err
>   	)
>   '
> 

Re: [PATCH v3 6/6] fetch: delay user information post committing of transaction

[Junio C Hamano]

Phillip Wood <phillip.wood123@gmail.com> writes:

>> +struct ref_update_display_info {
>> +	bool failed;
>> +	char success_code;
>> +	char fail_code;
>> +	const char *summary;
>> +	const char *fail_detail;
>> +	const char *success_detail;
>> +	const char *ref;
>> +	const char *remote;
>> +	struct object_id old_oid;
>> +	struct object_id new_oid;
>> +};
>
> I was expecting that we'd pass around a struct like
>
> struct ref_update_display_info_array {
> 	size_t alloc, nr;
> 	ref_update_display_info *info;
> };
>
> rather than passing a pointer, count pair as separate parameters. That 
> would also allow us to use ALLOC_GROW() rather than reallocating the 
> array each time we append to it which is rather inefficient.
>
> Thanks

Indeed.  That sounds like a sensible way to keep track of them.

>
> Phillip
>
>> +static struct ref_update_display_info *ref_update_display_info_append(
>> +					   struct ref_update_display_info **list,
>> +					   size_t *count,
>> +					   char success_code,
>> +					   char fail_code,
>> +					   const char *summary,
>> +					   const char *success_detail,
>> +					   const char *fail_detail,
>> +					   const char *ref,
>> +					   const char *remote,
>> +					   const struct object_id *old_oid,
>> +					   const struct object_id *new_oid)
>> +{
>> +	struct ref_update_display_info *info;
>> +	size_t index = *count;
>> +
>> +	(*count)++;
>> +	REALLOC_ARRAY(*list, *count);
>> +
>> +	info = &(*list)[index];
>> +
>> +	info->failed = false;
>> +	info->success_code = success_code;
>> +	info->fail_code = fail_code;
>> +	info->summary = xstrdup(summary);
>> +	info->success_detail = xstrdup_or_null(success_detail);
>> +	info->fail_detail = xstrdup_or_null(fail_detail);
>> +	info->remote = xstrdup(remote);
>> +	info->ref = xstrdup(ref);
>> +
>> +	oidcpy(&info->old_oid, old_oid);
>> +	oidcpy(&info->new_oid, new_oid);
>> +
>> +	return info;
>> +}
>> +
>> +static void ref_update_display_info_set_failed(struct ref_update_display_info *info)
>> +{
>> +	info->failed = true;
>> +}
>> +
>> +static void ref_update_display_info_free(struct ref_update_display_info *info)
>> +{
>> +	free((char *)info->summary);
>> +	free((char *)info->success_detail);
>> +	free((char *)info->fail_detail);
>> +	free((char *)info->remote);
>> +	free((char *)info->ref);
>> +}
>> +
>> +static void ref_update_display_info_display(struct ref_update_display_info *info,
>> +					    struct display_state *display_state,
>> +					    int summary_width)
>> +{
>> +	display_ref_update(display_state,
>> +			   info->failed ? info->fail_code : info->success_code,
>> +			   info->summary,
>> +			   info->failed ? info->fail_detail : info->success_detail,
>> +			   info->remote, info->ref, &info->old_oid,
>> +			   &info->new_oid, summary_width);
>> +}
>> +
>>   static int update_local_ref(struct ref *ref,
>>   			    struct ref_transaction *transaction,
>> -			    struct display_state *display_state,
>>   			    const struct ref *remote_ref,
>> -			    int summary_width,
>> -			    const struct fetch_config *config)
>> +			    const struct fetch_config *config,
>> +			    struct ref_update_display_info **display_list,
>> +			    size_t *display_count)
>>   {
>>   	struct commit *current = NULL, *updated;
>>   	int fast_forward = 0;
>> @@ -877,41 +952,56 @@ static int update_local_ref(struct ref *ref,
>>   
>>   	if (oideq(&ref->old_oid, &ref->new_oid)) {
>>   		if (verbosity > 0)
>> -			display_ref_update(display_state, '=', _("[up to date]"), NULL,
>> -					   remote_ref->name, ref->name,
>> -					   &ref->old_oid, &ref->new_oid, summary_width);
>> +			ref_update_display_info_append(display_list, display_count,
>> +						       '=', '=', _("[up to date]"),
>> +						       NULL, NULL, ref->name,
>> +						       remote_ref->name, &ref->old_oid,
>> +						       &ref->new_oid);
>>   		return 0;
>>   	}
>>   
>>   	if (!update_head_ok &&
>>   	    !is_null_oid(&ref->old_oid) &&
>>   	    branch_checked_out(ref->name)) {
>> +		struct ref_update_display_info *info;
>>   		/*
>>   		 * If this is the head, and it's not okay to update
>>   		 * the head, and the old value of the head isn't empty...
>>   		 */
>> -		display_ref_update(display_state, '!', _("[rejected]"),
>> -				   _("can't fetch into checked-out branch"),
>> -				   remote_ref->name, ref->name,
>> -				   &ref->old_oid, &ref->new_oid, summary_width);
>> +		info = ref_update_display_info_append(display_list, display_count,
>> +						      '!', '!', _("[rejected]"),
>> +						      NULL, _("can't fetch into checked-out branch"),
>> +						      ref->name, remote_ref->name,
>> +						      &ref->old_oid, &ref->new_oid);
>> +		ref_update_display_info_set_failed(info);
>>   		return 1;
>>   	}
>>   
>>   	if (!is_null_oid(&ref->old_oid) &&
>>   	    starts_with(ref->name, "refs/tags/")) {
>> +		struct ref_update_display_info *info;
>> +
>>   		if (force || ref->force) {
>>   			int r;
>> +
>>   			r = s_update_ref("updating tag", ref, transaction, 0);
>> -			display_ref_update(display_state, r ? '!' : 't', _("[tag update]"),
>> -					   r ? _("unable to update local ref") : NULL,
>> -					   remote_ref->name, ref->name,
>> -					   &ref->old_oid, &ref->new_oid, summary_width);
>> +
>> +			info = ref_update_display_info_append(display_list, display_count,
>> +							      't', '!', _("[tag update]"), NULL,
>> +							      _("unable to update local ref"),
>> +							      ref->name, remote_ref->name,
>> +							      &ref->old_oid, &ref->new_oid);
>> +			if (r)
>> +				ref_update_display_info_set_failed(info);
>> +
>>   			return r;
>>   		} else {
>> -			display_ref_update(display_state, '!', _("[rejected]"),
>> -					   _("would clobber existing tag"),
>> -					   remote_ref->name, ref->name,
>> -					   &ref->old_oid, &ref->new_oid, summary_width);
>> +			info = ref_update_display_info_append(display_list, display_count,
>> +							      '!', '!', _("[rejected]"), NULL,
>> +							      _("would clobber existing tag"),
>> +							      ref->name, remote_ref->name,
>> +							      &ref->old_oid, &ref->new_oid);
>> +			ref_update_display_info_set_failed(info);
>>   			return 1;
>>   		}
>>   	}
>> @@ -921,6 +1011,7 @@ static int update_local_ref(struct ref *ref,
>>   	updated = lookup_commit_reference_gently(the_repository,
>>   						 &ref->new_oid, 1);
>>   	if (!current || !updated) {
>> +		struct ref_update_display_info *info;
>>   		const char *msg;
>>   		const char *what;
>>   		int r;
>> @@ -941,10 +1032,15 @@ static int update_local_ref(struct ref *ref,
>>   		}
>>   
>>   		r = s_update_ref(msg, ref, transaction, 0);
>> -		display_ref_update(display_state, r ? '!' : '*', what,
>> -				   r ? _("unable to update local ref") : NULL,
>> -				   remote_ref->name, ref->name,
>> -				   &ref->old_oid, &ref->new_oid, summary_width);
>> +
>> +		info = ref_update_display_info_append(display_list, display_count,
>> +						      '*', '!', what, NULL,
>> +						      _("unable to update local ref"),
>> +						      ref->name, remote_ref->name,
>> +						      &ref->old_oid, &ref->new_oid);
>> +		if (r)
>> +			ref_update_display_info_set_failed(info);
>> +
>>   		return r;
>>   	}
>>   
>> @@ -960,6 +1056,7 @@ static int update_local_ref(struct ref *ref,
>>   	}
>>   
>>   	if (fast_forward) {
>> +		struct ref_update_display_info *info;
>>   		struct strbuf quickref = STRBUF_INIT;
>>   		int r;
>>   
>> @@ -967,29 +1064,46 @@ static int update_local_ref(struct ref *ref,
>>   		strbuf_addstr(&quickref, "..");
>>   		strbuf_add_unique_abbrev(&quickref, &ref->new_oid, DEFAULT_ABBREV);
>>   		r = s_update_ref("fast-forward", ref, transaction, 1);
>> -		display_ref_update(display_state, r ? '!' : ' ', quickref.buf,
>> -				   r ? _("unable to update local ref") : NULL,
>> -				   remote_ref->name, ref->name,
>> -				   &ref->old_oid, &ref->new_oid, summary_width);
>> +
>> +		info = ref_update_display_info_append(display_list, display_count,
>> +						      ' ', '!', quickref.buf, NULL,
>> +						      _("unable to update local ref"),
>> +						      ref->name, remote_ref->name,
>> +						      &ref->old_oid, &ref->new_oid);
>> +		if (r)
>> +			ref_update_display_info_set_failed(info);
>> +
>>   		strbuf_release(&quickref);
>>   		return r;
>>   	} else if (force || ref->force) {
>> +		struct ref_update_display_info *info;
>>   		struct strbuf quickref = STRBUF_INIT;
>>   		int r;
>> +
>>   		strbuf_add_unique_abbrev(&quickref, &current->object.oid, DEFAULT_ABBREV);
>>   		strbuf_addstr(&quickref, "...");
>>   		strbuf_add_unique_abbrev(&quickref, &ref->new_oid, DEFAULT_ABBREV);
>>   		r = s_update_ref("forced-update", ref, transaction, 1);
>> -		display_ref_update(display_state, r ? '!' : '+', quickref.buf,
>> -				   r ? _("unable to update local ref") : _("forced update"),
>> -				   remote_ref->name, ref->name,
>> -				   &ref->old_oid, &ref->new_oid, summary_width);
>> +
>> +		info = ref_update_display_info_append(display_list, display_count,
>> +						      '+', '!', quickref.buf, _("forced update"),
>> +						      _("unable to update local ref"),
>> +						      ref->name, remote_ref->name,
>> +						      &ref->old_oid, &ref->new_oid);
>> +
>> +		if (r)
>> +			ref_update_display_info_set_failed(info);
>> +
>>   		strbuf_release(&quickref);
>>   		return r;
>>   	} else {
>> -		display_ref_update(display_state, '!', _("[rejected]"), _("non-fast-forward"),
>> -				   remote_ref->name, ref->name,
>> -				   &ref->old_oid, &ref->new_oid, summary_width);
>> +		struct ref_update_display_info *info;
>> +		info = ref_update_display_info_append(display_list, display_count,
>> +						      '!', '!', _("[rejected]"), NULL,
>> +						      _("non-fast-forward"),
>> +						      ref->name, remote_ref->name,
>> +						      &ref->old_oid, &ref->new_oid);
>> +		ref_update_display_info_set_failed(info);
>>   		return 1;
>>   	}
>>   }
>> @@ -1103,17 +1217,15 @@ static int store_updated_refs(struct display_state *display_state,
>>   			      int connectivity_checked,
>>   			      struct ref_transaction *transaction, struct ref *ref_map,
>>   			      struct fetch_head *fetch_head,
>> -			      const struct fetch_config *config)
>> +			      const struct fetch_config *config,
>> +			      struct ref_update_display_info **display_list,
>> +			      size_t *display_count)
>>   {
>>   	int rc = 0;
>>   	struct strbuf note = STRBUF_INIT;
>>   	const char *what, *kind;
>>   	struct ref *rm;
>>   	int want_status;
>> -	int summary_width = 0;
>> -
>> -	if (verbosity >= 0)
>> -		summary_width = transport_summary_width(ref_map);
>>   
>>   	if (!connectivity_checked) {
>>   		struct check_connected_options opt = CHECK_CONNECTED_INIT;
>> @@ -1218,8 +1330,9 @@ static int store_updated_refs(struct display_state *display_state,
>>   					  display_state->url_len);
>>   
>>   			if (ref) {
>> -				rc |= update_local_ref(ref, transaction, display_state,
>> -						       rm, summary_width, config);
>> +				rc |= update_local_ref(ref, transaction, rm,
>> +						       config, display_list,
>> +						       display_count);
>>   				free(ref);
>>   			} else if (write_fetch_head || dry_run) {
>>   				/*
>> @@ -1227,12 +1340,11 @@ static int store_updated_refs(struct display_state *display_state,
>>   				 * would be written to FETCH_HEAD, if --dry-run
>>   				 * is set).
>>   				 */
>> -				display_ref_update(display_state, '*',
>> -						   *kind ? kind : "branch", NULL,
>> -						   rm->name,
>> -						   "FETCH_HEAD",
>> -						   &rm->new_oid, &rm->old_oid,
>> -						   summary_width);
>> +
>> +				ref_update_display_info_append(display_list, display_count,
>> +							       '*', '*', *kind ? kind : "branch",
>> +							       NULL, NULL, "FETCH_HEAD", rm->name,
>> +							       &rm->new_oid, &rm->old_oid);
>>   			}
>>   		}
>>   	}
>> @@ -1300,7 +1412,9 @@ static int fetch_and_consume_refs(struct display_state *display_state,
>>   				  struct ref_transaction *transaction,
>>   				  struct ref *ref_map,
>>   				  struct fetch_head *fetch_head,
>> -				  const struct fetch_config *config)
>> +				  const struct fetch_config *config,
>> +				  struct ref_update_display_info **display_list,
>> +				  size_t *display_count)
>>   {
>>   	int connectivity_checked = 1;
>>   	int ret;
>> @@ -1322,7 +1436,8 @@ static int fetch_and_consume_refs(struct display_state *display_state,
>>   
>>   	trace2_region_enter("fetch", "consume_refs", the_repository);
>>   	ret = store_updated_refs(display_state, connectivity_checked,
>> -				 transaction, ref_map, fetch_head, config);
>> +				 transaction, ref_map, fetch_head, config,
>> +				 display_list, display_count);
>>   	trace2_region_leave("fetch", "consume_refs", the_repository);
>>   
>>   out:
>> @@ -1493,7 +1608,9 @@ static int backfill_tags(struct display_state *display_state,
>>   			 struct ref_transaction *transaction,
>>   			 struct ref *ref_map,
>>   			 struct fetch_head *fetch_head,
>> -			 const struct fetch_config *config)
>> +			 const struct fetch_config *config,
>> +			 struct ref_update_display_info **display_list,
>> +			 size_t *display_count)
>>   {
>>   	int retcode, cannot_reuse;
>>   
>> @@ -1515,7 +1632,7 @@ static int backfill_tags(struct display_state *display_state,
>>   	transport_set_option(transport, TRANS_OPT_DEPTH, "0");
>>   	transport_set_option(transport, TRANS_OPT_DEEPEN_RELATIVE, NULL);
>>   	retcode = fetch_and_consume_refs(display_state, transport, transaction, ref_map,
>> -					 fetch_head, config);
>> +					 fetch_head, config, display_list, display_count);
>>   
>>   	if (gsecondary) {
>>   		transport_disconnect(gsecondary);
>> @@ -1641,6 +1758,7 @@ struct ref_rejection_data {
>>   	bool conflict_msg_shown;
>>   	bool case_sensitive_msg_shown;
>>   	const char *remote_name;
>> +	struct strmap *rejected_refs;
>>   };
>>   
>>   static void ref_transaction_rejection_handler(const char *refname,
>> @@ -1681,6 +1799,7 @@ static void ref_transaction_rejection_handler(const char *refname,
>>   			      refname, ref_transaction_error_msg(err));
>>   	}
>>   
>> +	strmap_put(data->rejected_refs, refname, NULL);
>>   	*data->retcode = 1;
>>   }
>>   
>> @@ -1690,6 +1809,7 @@ static void ref_transaction_rejection_handler(const char *refname,
>>    */
>>   static int commit_ref_transaction(struct ref_transaction **transaction,
>>   				  bool is_atomic, const char *remote_name,
>> +				  struct strmap *rejected_refs,
>>   				  struct strbuf *err)
>>   {
>>   	int retcode = ref_transaction_commit(*transaction, err);
>> @@ -1701,6 +1821,7 @@ static int commit_ref_transaction(struct ref_transaction **transaction,
>>   			.conflict_msg_shown = 0,
>>   			.remote_name = remote_name,
>>   			.retcode = &retcode,
>> +			.rejected_refs = rejected_refs,
>>   		};
>>   
>>   		ref_transaction_for_each_rejected_update(*transaction,
>> @@ -1729,6 +1850,10 @@ static int do_fetch(struct transport *transport,
>>   	struct fetch_head fetch_head = { 0 };
>>   	struct strbuf err = STRBUF_INIT;
>>   	int do_set_head = 0;
>> +	struct ref_update_display_info *display_list = NULL;
>> +	struct strmap rejected_refs = STRMAP_INIT;
>> +	size_t display_count = 0;
>> +	int summary_width = 0;
>>   
>>   	if (tags == TAGS_DEFAULT) {
>>   		if (transport->remote->fetch_tags == 2)
>> @@ -1853,7 +1978,7 @@ static int do_fetch(struct transport *transport,
>>   	}
>>   
>>   	if (fetch_and_consume_refs(&display_state, transport, transaction, ref_map,
>> -				   &fetch_head, config)) {
>> +				   &fetch_head, config, &display_list, &display_count)) {
>>   		retcode = 1;
>>   		goto cleanup;
>>   	}
>> @@ -1876,7 +2001,7 @@ static int do_fetch(struct transport *transport,
>>   			 * the transaction and don't commit anything.
>>   			 */
>>   			if (backfill_tags(&display_state, transport, transaction, tags_ref_map,
>> -					  &fetch_head, config))
>> +					  &fetch_head, config, &display_list, &display_count))
>>   				retcode = 1;
>>   		}
>>   
>> @@ -1886,8 +2011,12 @@ static int do_fetch(struct transport *transport,
>>   	if (retcode)
>>   		goto cleanup;
>>   
>> +	if (verbosity >= 0)
>> +		summary_width = transport_summary_width(ref_map);
>> +
>>   	retcode = commit_ref_transaction(&transaction, atomic_fetch,
>> -					 transport->remote->name, &err);
>> +					 transport->remote->name,
>> +					 &rejected_refs, &err);
>>   	/*
>>   	 * With '--atomic', bail out if the transaction fails. Without '--atomic',
>>   	 * continue to fetch head and perform other post-fetch operations.
>> @@ -1965,7 +2094,17 @@ static int do_fetch(struct transport *transport,
>>   	 */
>>   	if (retcode && !atomic_fetch && transaction)
>>   		commit_ref_transaction(&transaction, false,
>> -				       transport->remote->name, &err);
>> +				       transport->remote->name,
>> +				       &rejected_refs, &err);
>> +
>> +	for (size_t i = 0; i < display_count; i++) {
>> +		struct ref_update_display_info *info = &display_list[i];
>> +
>> +		if (!info->failed && strmap_contains(&rejected_refs, info->ref))
>> +			ref_update_display_info_set_failed(info);
>> +		ref_update_display_info_display(info, &display_state, summary_width);
>> +		ref_update_display_info_free(info);
>> +	}
>>   
>>   	if (retcode) {
>>   		if (err.len) {
>> @@ -1980,6 +2119,9 @@ static int do_fetch(struct transport *transport,
>>   
>>   	if (transaction)
>>   		ref_transaction_free(transaction);
>> +
>> +	free(display_list);
>> +	strmap_clear(&rejected_refs, 0);
>>   	display_state_release(&display_state);
>>   	close_fetch_head(&fetch_head);
>>   	strbuf_release(&err);
>> diff --git a/t/t5516-fetch-push.sh b/t/t5516-fetch-push.sh
>> index 45595991c8..29e2f17608 100755
>> --- a/t/t5516-fetch-push.sh
>> +++ b/t/t5516-fetch-push.sh
>> @@ -1893,6 +1893,7 @@ test_expect_success 'pushing non-commit objects should report error' '
>>   
>>   		tagsha=$(git rev-parse test^{tag}) &&
>>   		test_must_fail git push ../dest "$tagsha:refs/heads/branch" 2>err &&
>> +		test_grep "! \[remote rejected\] $tagsha -> branch (invalid new value provided)" err &&
>>   		test_grep "trying to write non-commit object $tagsha to branch ${SQ}refs/heads/branch${SQ}" err
>>   	)
>>   '
>> 

Re: [PATCH v3 6/6] fetch: delay user information post committing of transaction

[Karthik Nayak]

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Phillip Wood <phillip.wood123@gmail.com> writes:

> Hi Karthik
>
> On 20/01/2026 09:59, Karthik Nayak wrote:
>
>> +struct ref_update_display_info {
>> +	bool failed;
>> +	char success_code;
>> +	char fail_code;
>> +	const char *summary;
>> +	const char *fail_detail;
>> +	const char *success_detail;
>> +	const char *ref;
>> +	const char *remote;
>> +	struct object_id old_oid;
>> +	struct object_id new_oid;
>> +};
>
> I was expecting that we'd pass around a struct like
>
> struct ref_update_display_info_array {
> 	size_t alloc, nr;
> 	ref_update_display_info *info;
> };
>
> rather than passing a pointer, count pair as separate parameters. That
> would also allow us to use ALLOC_GROW() rather than reallocating the
> array each time we append to it which is rather inefficient.
>
> Thanks
>
> Phillip
>

That's fair, I was considering an array and didn't see the need, but
using 'ALLOC_GROW()' does make it simpler, plus we'd totally remove the
need for the double pointer. Will change. Thanks!

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Re: [PATCH v3 0/6] refs: provide detailed error messages when using batched update

[Junio C Hamano]

Karthik Nayak <karthik.188@gmail.com> writes:

> The refs namespace uses an error buffer to capture details about failed
> reference updates. However when we added batched update support to
> reference transactions, these messages were never propagated, instead
> only an error code pertaining to the type of failure was propagated.
>
> Currently, there are three regions which utilize batched updates:
>
>   - git update-ref --batch-updates
>   - git fetch
>   - git receive-pack
>
> While 'git update-ref --batch-updates' was a newly introduced flag, both
> 'git fetch' and 'git receive-pack' were pre-existing. Before using
> batched updates, they provided more detailed error messages to the user,
> but this changed with the introduction of batched updates. This is a
> regression in their workings.
>
> This patch series fixes this, by passing the detailed error message and
> utilizing it whenever available. The regression was reported by Elijah
> Newren [1] and based on the patch submitted by Jeff King [2].
>
> [1]: https://lore.kernel.org/all/CABPp-BGL2tJR4dPidQuFcp-X0_VkVTknCY-0Zgo=jHVGv_P=wA@mail.gmail.com/
> [2]: https://lore.kernel.org/all/20251224081214.GA1879908@coredump.intra.peff.net/
>
> ---
> Changes in v3:
> - Drop the first commit.
> - For the last commit, where we delay 'git fetch' status information,
>   delay all information to the end. Also use a list to compliment the
>   existing strmap, this ensures that the order is maintained.
> - Link to v2: https://patch.msgid.link/20260116-633-regression-lost-diagnostic-message-when-pushing-non-commit-objects-to-refs-heads-v2-0-925a0e9c7f32@gmail.com

Thanks.  These look good.

[PATCH v4 0/6] refs: provide detailed error messages when using batched update

[Karthik Nayak]

The refs namespace uses an error buffer to capture details about failed
reference updates. However when we added batched update support to
reference transactions, these messages were never propagated, instead
only an error code pertaining to the type of failure was propagated.

Currently, there are three regions which utilize batched updates:

  - git update-ref --batch-updates
  - git fetch
  - git receive-pack

While 'git update-ref --batch-updates' was a newly introduced flag, both
'git fetch' and 'git receive-pack' were pre-existing. Before using
batched updates, they provided more detailed error messages to the user,
but this changed with the introduction of batched updates. This is a
regression in their workings.

This patch series fixes this, by passing the detailed error message and
utilizing it whenever available. The regression was reported by Elijah
Newren [1] and based on the patch submitted by Jeff King [2].

[1]: https://lore.kernel.org/all/CABPp-BGL2tJR4dPidQuFcp-X0_VkVTknCY-0Zgo=jHVGv_P=wA@mail.gmail.com/
[2]: https://lore.kernel.org/all/20251224081214.GA1879908@coredump.intra.peff.net/

---
Changes in v4:
- In the last commit, instead of propagating {*list, count}, propagate
  an array with {*list, nr, count} and use ALLOC_GROW. This simplifies
  the variables passed and cleanups the code.
- Link to v3: https://patch.msgid.link/20260120-633-regression-lost-diagnostic-message-when-pushing-non-commit-objects-to-refs-heads-v3-0-e0edb29acbef@gmail.com

Changes in v3:
- Drop the first commit.
- For the last commit, where we delay 'git fetch' status information,
  delay all information to the end. Also use a list to compliment the
  existing strmap, this ensures that the order is maintained.
- Link to v2: https://patch.msgid.link/20260116-633-regression-lost-diagnostic-message-when-pushing-non-commit-objects-to-refs-heads-v2-0-925a0e9c7f32@gmail.com

Changes in v2:
- Updates to the commit messages to be more descriptive.
- Instead of passing the char pointer for the error description, pass
  the 'strbuf' itself. This makes the API a lot cleaner to deal with.
  Also avoids having to remember to reset the strbuf after usage.
- Chalk out a separate commit for using a 'goto next_ref' in
  `refs_verify_refnames_available()`. This makes the intention much
  clearer.
- For git-update-ref(1), keep the existing implementation as is and only
  output the detailed error message to stderr.
- For git-receive-pack(1), use 'rp_error()' for detailed error message
  while keeping the current implementation as is.
- Added a separate patch to handle missing information in git-fetch(1)'s
  status table. This involves delaying updates to the end, where update
  success/failure information is available. I'm not too confident about
  this approach though, we could also drop it from the series and I
  could pick that up independently. This is still 1.19 ± 0.02 times
  faster than non-batched version (v2.50.0) in the files backend.
- Link to v1: https://patch.msgid.link/20260114-633-regression-lost-diagnostic-message-when-pushing-non-commit-objects-to-refs-heads-v1-0-f5f8b173c501@gmail.com

---
 builtin/fetch.c         | 255 +++++++++++++++++++++++++++++++++++++-----------
 builtin/receive-pack.c  |   7 +-
 builtin/update-ref.c    |   7 +-
 refs.c                  |  46 +++++----
 refs.h                  |   1 +
 refs/files-backend.c    |   5 +-
 refs/packed-backend.c   |  12 +--
 refs/refs-internal.h    |   4 +-
 refs/reftable-backend.c |   5 +-
 t/t1400-update-ref.sh   |  71 ++++++++------
 t/t5510-fetch.sh        |   8 +-
 t/t5516-fetch-push.sh   |  16 +++
 12 files changed, 312 insertions(+), 125 deletions(-)

Karthik Nayak (6):
      refs: skip to next ref when current ref is rejected
      refs: add rejection detail to the callback function
      update-ref: utilize rejected error details if available
      fetch: utilize rejected ref error details
      receive-pack: utilize rejected ref error details
      fetch: delay user information post committing of transaction

Range-diff versus v3:

1:  f5fa12101b = 1:  f89b8a3526 refs: skip to next ref when current ref is rejected
2:  6911cab2c7 = 2:  c988070f5f refs: add rejection detail to the callback function
3:  c20fc32d3e = 3:  f419704bca update-ref: utilize rejected error details if available
4:  8b5ce22c65 = 4:  0c50af08f3 fetch: utilize rejected ref error details
5:  73a43ddeeb = 5:  758a265930 receive-pack: utilize rejected ref error details
6:  f9b76d57f8 ! 6:  c22d759ae8 fetch: delay user information post committing of transaction
    @@ builtin/fetch.c: static void display_ref_update(struct display_state *display_st
     +	struct object_id new_oid;
     +};
     +
    ++struct ref_update_display_info_array {
    ++	struct ref_update_display_info *info;
    ++	size_t alloc, nr;
    ++};
    ++
     +static struct ref_update_display_info *ref_update_display_info_append(
    -+					   struct ref_update_display_info **list,
    -+					   size_t *count,
    ++					   struct ref_update_display_info_array *array,
     +					   char success_code,
     +					   char fail_code,
     +					   const char *summary,
    @@ builtin/fetch.c: static void display_ref_update(struct display_state *display_st
     +					   const struct object_id *new_oid)
     +{
     +	struct ref_update_display_info *info;
    -+	size_t index = *count;
    -+
    -+	(*count)++;
    -+	REALLOC_ARRAY(*list, *count);
     +
    -+	info = &(*list)[index];
    ++	ALLOC_GROW(array->info, array->nr + 1, array->alloc);
    ++	info = &array->info[array->nr++];
     +
     +	info->failed = false;
     +	info->success_code = success_code;
    @@ builtin/fetch.c: static void display_ref_update(struct display_state *display_st
     -			    int summary_width,
     -			    const struct fetch_config *config)
     +			    const struct fetch_config *config,
    -+			    struct ref_update_display_info **display_list,
    -+			    size_t *display_count)
    ++			    struct ref_update_display_info_array *display_array)
      {
      	struct commit *current = NULL, *updated;
      	int fast_forward = 0;
    @@ builtin/fetch.c: static int update_local_ref(struct ref *ref,
     -			display_ref_update(display_state, '=', _("[up to date]"), NULL,
     -					   remote_ref->name, ref->name,
     -					   &ref->old_oid, &ref->new_oid, summary_width);
    -+			ref_update_display_info_append(display_list, display_count,
    -+						       '=', '=', _("[up to date]"),
    -+						       NULL, NULL, ref->name,
    ++			ref_update_display_info_append(display_array, '=', '=',
    ++						       _("[up to date]"), NULL,
    ++						       NULL, ref->name,
     +						       remote_ref->name, &ref->old_oid,
     +						       &ref->new_oid);
      		return 0;
    @@ builtin/fetch.c: static int update_local_ref(struct ref *ref,
     -				   _("can't fetch into checked-out branch"),
     -				   remote_ref->name, ref->name,
     -				   &ref->old_oid, &ref->new_oid, summary_width);
    -+		info = ref_update_display_info_append(display_list, display_count,
    -+						      '!', '!', _("[rejected]"),
    -+						      NULL, _("can't fetch into checked-out branch"),
    ++		info = ref_update_display_info_append(display_array, '!', '!',
    ++						      _("[rejected]"), NULL,
    ++						      _("can't fetch into checked-out branch"),
     +						      ref->name, remote_ref->name,
     +						      &ref->old_oid, &ref->new_oid);
     +		ref_update_display_info_set_failed(info);
    @@ builtin/fetch.c: static int update_local_ref(struct ref *ref,
     -					   remote_ref->name, ref->name,
     -					   &ref->old_oid, &ref->new_oid, summary_width);
     +
    -+			info = ref_update_display_info_append(display_list, display_count,
    -+							      't', '!', _("[tag update]"), NULL,
    ++			info = ref_update_display_info_append(display_array, 't', '!',
    ++							      _("[tag update]"), NULL,
     +							      _("unable to update local ref"),
     +							      ref->name, remote_ref->name,
     +							      &ref->old_oid, &ref->new_oid);
    @@ builtin/fetch.c: static int update_local_ref(struct ref *ref,
     -					   _("would clobber existing tag"),
     -					   remote_ref->name, ref->name,
     -					   &ref->old_oid, &ref->new_oid, summary_width);
    -+			info = ref_update_display_info_append(display_list, display_count,
    -+							      '!', '!', _("[rejected]"), NULL,
    ++			info = ref_update_display_info_append(display_array, '!', '!',
    ++							      _("[rejected]"), NULL,
     +							      _("would clobber existing tag"),
     +							      ref->name, remote_ref->name,
     +							      &ref->old_oid, &ref->new_oid);
    @@ builtin/fetch.c: static int update_local_ref(struct ref *ref,
     -				   remote_ref->name, ref->name,
     -				   &ref->old_oid, &ref->new_oid, summary_width);
     +
    -+		info = ref_update_display_info_append(display_list, display_count,
    -+						      '*', '!', what, NULL,
    ++		info = ref_update_display_info_append(display_array, '*', '!',
    ++						      what, NULL,
     +						      _("unable to update local ref"),
     +						      ref->name, remote_ref->name,
     +						      &ref->old_oid, &ref->new_oid);
    @@ builtin/fetch.c: static int update_local_ref(struct ref *ref,
     -				   remote_ref->name, ref->name,
     -				   &ref->old_oid, &ref->new_oid, summary_width);
     +
    -+		info = ref_update_display_info_append(display_list, display_count,
    -+						      ' ', '!', quickref.buf, NULL,
    ++		info = ref_update_display_info_append(display_array, ' ', '!',
    ++						      quickref.buf, NULL,
     +						      _("unable to update local ref"),
     +						      ref->name, remote_ref->name,
     +						      &ref->old_oid, &ref->new_oid);
    @@ builtin/fetch.c: static int update_local_ref(struct ref *ref,
     -				   remote_ref->name, ref->name,
     -				   &ref->old_oid, &ref->new_oid, summary_width);
     +
    -+		info = ref_update_display_info_append(display_list, display_count,
    -+						      '+', '!', quickref.buf, _("forced update"),
    ++		info = ref_update_display_info_append(display_array, '+', '!',
    ++						      quickref.buf, _("forced update"),
     +						      _("unable to update local ref"),
     +						      ref->name, remote_ref->name,
     +						      &ref->old_oid, &ref->new_oid);
    @@ builtin/fetch.c: static int update_local_ref(struct ref *ref,
     -				   remote_ref->name, ref->name,
     -				   &ref->old_oid, &ref->new_oid, summary_width);
     +		struct ref_update_display_info *info;
    -+		info = ref_update_display_info_append(display_list, display_count,
    -+						      '!', '!', _("[rejected]"), NULL,
    ++		info = ref_update_display_info_append(display_array, '!', '!',
    ++						      _("[rejected]"), NULL,
     +						      _("non-fast-forward"),
     +						      ref->name, remote_ref->name,
     +						      &ref->old_oid, &ref->new_oid);
    @@ builtin/fetch.c: static int store_updated_refs(struct display_state *display_sta
      			      struct fetch_head *fetch_head,
     -			      const struct fetch_config *config)
     +			      const struct fetch_config *config,
    -+			      struct ref_update_display_info **display_list,
    -+			      size_t *display_count)
    ++			      struct ref_update_display_info_array *display_array)
      {
      	int rc = 0;
      	struct strbuf note = STRBUF_INIT;
    @@ builtin/fetch.c: static int store_updated_refs(struct display_state *display_sta
     -				rc |= update_local_ref(ref, transaction, display_state,
     -						       rm, summary_width, config);
     +				rc |= update_local_ref(ref, transaction, rm,
    -+						       config, display_list,
    -+						       display_count);
    ++						       config, display_array);
      				free(ref);
      			} else if (write_fetch_head || dry_run) {
      				/*
    @@ builtin/fetch.c: static int store_updated_refs(struct display_state *display_sta
     -						   &rm->new_oid, &rm->old_oid,
     -						   summary_width);
     +
    -+				ref_update_display_info_append(display_list, display_count,
    -+							       '*', '*', *kind ? kind : "branch",
    -+							       NULL, NULL, "FETCH_HEAD", rm->name,
    -+							       &rm->new_oid, &rm->old_oid);
    ++				ref_update_display_info_append(display_array, '*', '*',
    ++							       *kind ? kind : "branch",
    ++							       NULL, NULL, "FETCH_HEAD",
    ++							       rm->name, &rm->new_oid,
    ++							       &rm->old_oid);
      			}
      		}
      	}
    @@ builtin/fetch.c: static int fetch_and_consume_refs(struct display_state *display
      				  struct fetch_head *fetch_head,
     -				  const struct fetch_config *config)
     +				  const struct fetch_config *config,
    -+				  struct ref_update_display_info **display_list,
    -+				  size_t *display_count)
    ++				  struct ref_update_display_info_array *display_array)
      {
      	int connectivity_checked = 1;
      	int ret;
    @@ builtin/fetch.c: static int fetch_and_consume_refs(struct display_state *display
      	ret = store_updated_refs(display_state, connectivity_checked,
     -				 transaction, ref_map, fetch_head, config);
     +				 transaction, ref_map, fetch_head, config,
    -+				 display_list, display_count);
    ++				 display_array);
      	trace2_region_leave("fetch", "consume_refs", the_repository);
      
      out:
    @@ builtin/fetch.c: static int backfill_tags(struct display_state *display_state,
      			 struct fetch_head *fetch_head,
     -			 const struct fetch_config *config)
     +			 const struct fetch_config *config,
    -+			 struct ref_update_display_info **display_list,
    -+			 size_t *display_count)
    ++			 struct ref_update_display_info_array *display_array)
      {
      	int retcode, cannot_reuse;
      
    @@ builtin/fetch.c: static int backfill_tags(struct display_state *display_state,
      	transport_set_option(transport, TRANS_OPT_DEEPEN_RELATIVE, NULL);
      	retcode = fetch_and_consume_refs(display_state, transport, transaction, ref_map,
     -					 fetch_head, config);
    -+					 fetch_head, config, display_list, display_count);
    ++					 fetch_head, config, display_array);
      
      	if (gsecondary) {
      		transport_disconnect(gsecondary);
    @@ builtin/fetch.c: static int do_fetch(struct transport *transport,
      	struct fetch_head fetch_head = { 0 };
      	struct strbuf err = STRBUF_INIT;
      	int do_set_head = 0;
    -+	struct ref_update_display_info *display_list = NULL;
    ++	struct ref_update_display_info_array display_array = { 0 };
     +	struct strmap rejected_refs = STRMAP_INIT;
    -+	size_t display_count = 0;
     +	int summary_width = 0;
      
      	if (tags == TAGS_DEFAULT) {
    @@ builtin/fetch.c: static int do_fetch(struct transport *transport,
      
      	if (fetch_and_consume_refs(&display_state, transport, transaction, ref_map,
     -				   &fetch_head, config)) {
    -+				   &fetch_head, config, &display_list, &display_count)) {
    ++				   &fetch_head, config, &display_array)) {
      		retcode = 1;
      		goto cleanup;
      	}
    @@ builtin/fetch.c: static int do_fetch(struct transport *transport,
      			 */
      			if (backfill_tags(&display_state, transport, transaction, tags_ref_map,
     -					  &fetch_head, config))
    -+					  &fetch_head, config, &display_list, &display_count))
    ++					  &fetch_head, config, &display_array))
      				retcode = 1;
      		}
      
    @@ builtin/fetch.c: static int do_fetch(struct transport *transport,
     +				       transport->remote->name,
     +				       &rejected_refs, &err);
     +
    -+	for (size_t i = 0; i < display_count; i++) {
    -+		struct ref_update_display_info *info = &display_list[i];
    ++	for (size_t i = 0; i < display_array.nr; i++) {
    ++		struct ref_update_display_info *info = &display_array.info[i];
     +
     +		if (!info->failed && strmap_contains(&rejected_refs, info->ref))
     +			ref_update_display_info_set_failed(info);
    @@ builtin/fetch.c: static int do_fetch(struct transport *transport,
      	if (transaction)
      		ref_transaction_free(transaction);
     +
    -+	free(display_list);
    ++	free(display_array.info);
     +	strmap_clear(&rejected_refs, 0);
      	display_state_release(&display_state);
      	close_fetch_head(&fetch_head);


base-commit: 8745eae506f700657882b9e32b2aa00f234a6fb6
change-id: 20260113-633-regression-lost-diagnostic-message-when-pushing-non-commit-objects-to-refs-heads-17786b20894a

Thanks
- Karthik

[PATCH v4 1/6] refs: skip to next ref when current ref is rejected

[Karthik Nayak]

In `refs_verify_refnames_available()` we have two nested loops: the
outer loop iterates over all references to check, while the inner loop
checks for filesystem conflicts for a given ref by breaking down its
path.

With batched updates, when we detect a filesystem conflict, we mark the
update as rejected and execute 'continue'. However, this only skips to
the next iteration of the inner loop, not the outer loop as intended.
This causes the same reference to be repeatedly rejected. Fix this by
using a goto statement to skip to the next reference in the outer loop.

Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
---
 refs.c                  | 44 ++++++++++++++++++++++++++------------------
 refs/files-backend.c    |  5 ++---
 refs/packed-backend.c   | 12 ++++++------
 refs/refs-internal.h    |  4 +++-
 refs/reftable-backend.c |  5 ++---
 5 files changed, 39 insertions(+), 31 deletions(-)

diff --git a/refs.c b/refs.c
index e06e0cb072..53919c3d22 100644
--- a/refs.c
+++ b/refs.c
@@ -1224,6 +1224,7 @@ void ref_transaction_free(struct ref_transaction *transaction)
 		free(transaction->updates[i]->committer_info);
 		free((char *)transaction->updates[i]->new_target);
 		free((char *)transaction->updates[i]->old_target);
+		free((char *)transaction->updates[i]->rejection_details);
 		free(transaction->updates[i]);
 	}
 
@@ -1238,7 +1239,8 @@ void ref_transaction_free(struct ref_transaction *transaction)
 
 int ref_transaction_maybe_set_rejected(struct ref_transaction *transaction,
 				       size_t update_idx,
-				       enum ref_transaction_error err)
+				       enum ref_transaction_error err,
+				       struct strbuf *details)
 {
 	if (update_idx >= transaction->nr)
 		BUG("trying to set rejection on invalid update index");
@@ -1264,6 +1266,7 @@ int ref_transaction_maybe_set_rejected(struct ref_transaction *transaction,
 			   transaction->updates[update_idx]->refname, 0);
 
 	transaction->updates[update_idx]->rejection_err = err;
+	transaction->updates[update_idx]->rejection_details = strbuf_detach(details, NULL);
 	ALLOC_GROW(transaction->rejections->update_indices,
 		   transaction->rejections->nr + 1,
 		   transaction->rejections->alloc);
@@ -2659,30 +2662,33 @@ enum ref_transaction_error refs_verify_refnames_available(struct ref_store *refs
 			if (!initial_transaction &&
 			    (strset_contains(&conflicting_dirnames, dirname.buf) ||
 			     !refs_read_raw_ref(refs, dirname.buf, &oid, &referent,
-						       &type, &ignore_errno))) {
+						&type, &ignore_errno))) {
+
+				strbuf_addf(err, _("'%s' exists; cannot create '%s'"),
+					    dirname.buf, refname);
+
 				if (transaction && ref_transaction_maybe_set_rejected(
 					    transaction, *update_idx,
-					    REF_TRANSACTION_ERROR_NAME_CONFLICT)) {
+					    REF_TRANSACTION_ERROR_NAME_CONFLICT, err)) {
 					strset_remove(&dirnames, dirname.buf);
 					strset_add(&conflicting_dirnames, dirname.buf);
-					continue;
+					goto next_ref;
 				}
 
-				strbuf_addf(err, _("'%s' exists; cannot create '%s'"),
-					    dirname.buf, refname);
 				goto cleanup;
 			}
 
 			if (extras && string_list_has_string(extras, dirname.buf)) {
+				strbuf_addf(err, _("cannot process '%s' and '%s' at the same time"),
+					    refname, dirname.buf);
+
 				if (transaction && ref_transaction_maybe_set_rejected(
 					    transaction, *update_idx,
-					    REF_TRANSACTION_ERROR_NAME_CONFLICT)) {
+					    REF_TRANSACTION_ERROR_NAME_CONFLICT, err)) {
 					strset_remove(&dirnames, dirname.buf);
-					continue;
+					goto next_ref;
 				}
 
-				strbuf_addf(err, _("cannot process '%s' and '%s' at the same time"),
-					    refname, dirname.buf);
 				goto cleanup;
 			}
 		}
@@ -2712,14 +2718,14 @@ enum ref_transaction_error refs_verify_refnames_available(struct ref_store *refs
 				if (skip &&
 				    string_list_has_string(skip, iter->ref.name))
 					continue;
+				strbuf_addf(err, _("'%s' exists; cannot create '%s'"),
+					    iter->ref.name, refname);
 
 				if (transaction && ref_transaction_maybe_set_rejected(
 					    transaction, *update_idx,
-					    REF_TRANSACTION_ERROR_NAME_CONFLICT))
-					continue;
+					    REF_TRANSACTION_ERROR_NAME_CONFLICT, err))
+					goto next_ref;
 
-				strbuf_addf(err, _("'%s' exists; cannot create '%s'"),
-					    iter->ref.name, refname);
 				goto cleanup;
 			}
 
@@ -2729,15 +2735,17 @@ enum ref_transaction_error refs_verify_refnames_available(struct ref_store *refs
 
 		extra_refname = find_descendant_ref(dirname.buf, extras, skip);
 		if (extra_refname) {
+			strbuf_addf(err, _("cannot process '%s' and '%s' at the same time"),
+				    refname, extra_refname);
+
 			if (transaction && ref_transaction_maybe_set_rejected(
 				    transaction, *update_idx,
-				    REF_TRANSACTION_ERROR_NAME_CONFLICT))
-				continue;
+				    REF_TRANSACTION_ERROR_NAME_CONFLICT, err))
+				goto next_ref;
 
-			strbuf_addf(err, _("cannot process '%s' and '%s' at the same time"),
-				    refname, extra_refname);
 			goto cleanup;
 		}
+next_ref:;
 	}
 
 	ret = 0;
diff --git a/refs/files-backend.c b/refs/files-backend.c
index 6f6f76a8d8..6790d8bf53 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -2983,10 +2983,9 @@ static int files_transaction_prepare(struct ref_store *ref_store,
 					  head_ref, &refnames_to_check,
 					  err);
 		if (ret) {
-			if (ref_transaction_maybe_set_rejected(transaction, i, ret)) {
-				strbuf_reset(err);
+			if (ref_transaction_maybe_set_rejected(transaction, i,
+							       ret, err)) {
 				ret = 0;
-
 				continue;
 			}
 			goto cleanup;
diff --git a/refs/packed-backend.c b/refs/packed-backend.c
index 4ea0c12299..59b3ecb9d6 100644
--- a/refs/packed-backend.c
+++ b/refs/packed-backend.c
@@ -1437,8 +1437,8 @@ static enum ref_transaction_error write_with_updates(struct packed_ref_store *re
 						    update->refname);
 					ret = REF_TRANSACTION_ERROR_CREATE_EXISTS;
 
-					if (ref_transaction_maybe_set_rejected(transaction, i, ret)) {
-						strbuf_reset(err);
+					if (ref_transaction_maybe_set_rejected(transaction, i,
+									       ret, err)) {
 						ret = 0;
 						continue;
 					}
@@ -1452,8 +1452,8 @@ static enum ref_transaction_error write_with_updates(struct packed_ref_store *re
 						    oid_to_hex(&update->old_oid));
 					ret = REF_TRANSACTION_ERROR_INCORRECT_OLD_VALUE;
 
-					if (ref_transaction_maybe_set_rejected(transaction, i, ret)) {
-						strbuf_reset(err);
+					if (ref_transaction_maybe_set_rejected(transaction, i,
+									       ret, err)) {
 						ret = 0;
 						continue;
 					}
@@ -1496,8 +1496,8 @@ static enum ref_transaction_error write_with_updates(struct packed_ref_store *re
 					    oid_to_hex(&update->old_oid));
 				ret = REF_TRANSACTION_ERROR_NONEXISTENT_REF;
 
-				if (ref_transaction_maybe_set_rejected(transaction, i, ret)) {
-					strbuf_reset(err);
+				if (ref_transaction_maybe_set_rejected(transaction, i,
+								       ret, err)) {
 					ret = 0;
 					continue;
 				}
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index c7d2a6e50b..191a25683f 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -128,6 +128,7 @@ struct ref_update {
 	 * was rejected.
 	 */
 	enum ref_transaction_error rejection_err;
+	const char *rejection_details;
 
 	/*
 	 * If this ref_update was split off of a symref update via
@@ -153,7 +154,8 @@ int refs_read_raw_ref(struct ref_store *ref_store, const char *refname,
  */
 int ref_transaction_maybe_set_rejected(struct ref_transaction *transaction,
 				       size_t update_idx,
-				       enum ref_transaction_error err);
+				       enum ref_transaction_error err,
+				       struct strbuf *details);
 
 /*
  * Add a ref_update with the specified properties to transaction, and
diff --git a/refs/reftable-backend.c b/refs/reftable-backend.c
index 4319a4eacb..0e2648e36c 100644
--- a/refs/reftable-backend.c
+++ b/refs/reftable-backend.c
@@ -1401,10 +1401,9 @@ static int reftable_be_transaction_prepare(struct ref_store *ref_store,
 					    &refnames_to_check, head_type,
 					    &head_referent, &referent, err);
 		if (ret) {
-			if (ref_transaction_maybe_set_rejected(transaction, i, ret)) {
-				strbuf_reset(err);
+			if (ref_transaction_maybe_set_rejected(transaction, i,
+							       ret, err)) {
 				ret = 0;
-
 				continue;
 			}
 			goto done;

-- 
2.52.0

[PATCH v4 2/6] refs: add rejection detail to the callback function

[Karthik Nayak]

The previous commit started storing the rejection details alongside the
error code for rejected updates. Pass this along to the callback
function `ref_transaction_for_each_rejected_update()`. Currently the
field is unused, but will be integrated in the upcoming commits.

Co-authored-by: Jeff King <peff@peff.net>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
---
 builtin/fetch.c        | 1 +
 builtin/receive-pack.c | 1 +
 builtin/update-ref.c   | 1 +
 refs.c                 | 2 +-
 refs.h                 | 1 +
 5 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/builtin/fetch.c b/builtin/fetch.c
index 288d3772ea..d427adea61 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -1649,6 +1649,7 @@ static void ref_transaction_rejection_handler(const char *refname,
 					      const char *old_target UNUSED,
 					      const char *new_target UNUSED,
 					      enum ref_transaction_error err,
+					      const char *details UNUSED,
 					      void *cb_data)
 {
 	struct ref_rejection_data *data = cb_data;
diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index ef1f77be8c..94d3e73cee 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -1813,6 +1813,7 @@ static void ref_transaction_rejection_handler(const char *refname,
 					      const char *old_target UNUSED,
 					      const char *new_target UNUSED,
 					      enum ref_transaction_error err,
+					      const char *details UNUSED,
 					      void *cb_data)
 {
 	struct strmap *failed_refs = cb_data;
diff --git a/builtin/update-ref.c b/builtin/update-ref.c
index 195437e7c6..0046a87c57 100644
--- a/builtin/update-ref.c
+++ b/builtin/update-ref.c
@@ -573,6 +573,7 @@ static void print_rejected_refs(const char *refname,
 				const char *old_target,
 				const char *new_target,
 				enum ref_transaction_error err,
+				const char *details UNUSED,
 				void *cb_data UNUSED)
 {
 	struct strbuf sb = STRBUF_INIT;
diff --git a/refs.c b/refs.c
index 53919c3d22..c85c3d2c8b 100644
--- a/refs.c
+++ b/refs.c
@@ -2874,7 +2874,7 @@ void ref_transaction_for_each_rejected_update(struct ref_transaction *transactio
 		   (update->flags & REF_HAVE_OLD) ? &update->old_oid : NULL,
 		   (update->flags & REF_HAVE_NEW) ? &update->new_oid : NULL,
 		   update->old_target, update->new_target,
-		   update->rejection_err, cb_data);
+		   update->rejection_err, update->rejection_details, cb_data);
 	}
 }
 
diff --git a/refs.h b/refs.h
index d9051bbb04..4fbe3da924 100644
--- a/refs.h
+++ b/refs.h
@@ -975,6 +975,7 @@ typedef void ref_transaction_for_each_rejected_update_fn(const char *refname,
 							 const char *old_target,
 							 const char *new_target,
 							 enum ref_transaction_error err,
+							 const char *details,
 							 void *cb_data);
 void ref_transaction_for_each_rejected_update(struct ref_transaction *transaction,
 					      ref_transaction_for_each_rejected_update_fn cb,

-- 
2.52.0

[PATCH v4 3/6] update-ref: utilize rejected error details if available

[Karthik Nayak]

When git-update-ref(1) received the '--update-ref' flag, the error
details generated in the refs namespace wasn't propagated with failed
updates. Instead only an error code pertaining to the type of rejection
was noted.

This missed detailed error message which the user can act upon. The
previous commits added the required code to propagate these detailed
error messages from the refs namespace. Now that additional details are
available, let's output this additional details to stderr. This allows
users to have additional information over the already present machine
parsable output.

While we're here, improve the existing tests for the machine parsable
output by checking for the entire output string and not just the
rejection reason.

Reported-by: Elijah Newren <newren@gmail.com>
Co-authored-by: Jeff King <peff@peff.net>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
---
 builtin/update-ref.c  |  8 +++---
 t/t1400-update-ref.sh | 71 ++++++++++++++++++++++++++++++---------------------
 2 files changed, 47 insertions(+), 32 deletions(-)

diff --git a/builtin/update-ref.c b/builtin/update-ref.c
index 0046a87c57..2d68c40ecb 100644
--- a/builtin/update-ref.c
+++ b/builtin/update-ref.c
@@ -573,16 +573,18 @@ static void print_rejected_refs(const char *refname,
 				const char *old_target,
 				const char *new_target,
 				enum ref_transaction_error err,
-				const char *details UNUSED,
+				const char *details,
 				void *cb_data UNUSED)
 {
 	struct strbuf sb = STRBUF_INIT;
-	const char *reason = ref_transaction_error_msg(err);
+
+	if (details && *details)
+		error("%s", details);
 
 	strbuf_addf(&sb, "rejected %s %s %s %s\n", refname,
 		    new_oid ? oid_to_hex(new_oid) : new_target,
 		    old_oid ? oid_to_hex(old_oid) : old_target,
-		    reason);
+		    ref_transaction_error_msg(err));
 
 	fwrite(sb.buf, sb.len, 1, stdout);
 	strbuf_release(&sb);
diff --git a/t/t1400-update-ref.sh b/t/t1400-update-ref.sh
index db7f5444da..db6585b8d8 100755
--- a/t/t1400-update-ref.sh
+++ b/t/t1400-update-ref.sh
@@ -2093,14 +2093,15 @@ do
 
 			format_command $type "update refs/heads/ref1" "$old_head" "$head" >stdin &&
 			format_command $type "update refs/heads/ref2" "$(test_oid 001)" "$head" >>stdin &&
-			git update-ref $type --stdin --batch-updates <stdin >stdout &&
+			git update-ref $type --stdin --batch-updates <stdin >stdout 2>err &&
 			echo $old_head >expect &&
 			git rev-parse refs/heads/ref1 >actual &&
 			test_cmp expect actual &&
 			echo $head >expect &&
 			git rev-parse refs/heads/ref2 >actual &&
 			test_cmp expect actual &&
-			test_grep -q "invalid new value provided" stdout
+			test_grep "rejected refs/heads/ref2 $(test_oid 001) $head invalid new value provided" stdout &&
+			test_grep "trying to write ref ${SQ}refs/heads/ref2${SQ} with nonexistent object" err
 		)
 	'
 
@@ -2119,14 +2120,15 @@ do
 
 			format_command $type "update refs/heads/ref1" "$old_head" "$head" >stdin &&
 			format_command $type "update refs/heads/ref2" "$head_tree" "$head" >>stdin &&
-			git update-ref $type --stdin --batch-updates <stdin >stdout &&
+			git update-ref $type --stdin --batch-updates <stdin >stdout 2>err &&
 			echo $old_head >expect &&
 			git rev-parse refs/heads/ref1 >actual &&
 			test_cmp expect actual &&
 			echo $head >expect &&
 			git rev-parse refs/heads/ref2 >actual &&
 			test_cmp expect actual &&
-			test_grep -q "invalid new value provided" stdout
+			test_grep "rejected refs/heads/ref2 $head_tree $head invalid new value provided" stdout &&
+			test_grep "trying to write non-commit object $head_tree to branch ${SQ}refs/heads/ref2${SQ}" err
 		)
 	'
 
@@ -2143,12 +2145,13 @@ do
 
 			format_command $type "update refs/heads/ref1" "$old_head" "$head" >stdin &&
 			format_command $type "update refs/heads/ref2" "$old_head" "$head" >>stdin &&
-			git update-ref $type --stdin --batch-updates <stdin >stdout &&
+			git update-ref $type --stdin --batch-updates <stdin >stdout 2>err &&
 			echo $old_head >expect &&
 			git rev-parse refs/heads/ref1 >actual &&
 			test_cmp expect actual &&
 			test_must_fail git rev-parse refs/heads/ref2 &&
-			test_grep -q "reference does not exist" stdout
+			test_grep "rejected refs/heads/ref2 $old_head $head reference does not exist" stdout &&
+			test_grep "cannot lock ref ${SQ}refs/heads/ref2${SQ}: unable to resolve reference ${SQ}refs/heads/ref2${SQ}" err
 		)
 	'
 
@@ -2166,13 +2169,14 @@ do
 
 			format_command $type "update refs/heads/ref1" "$old_head" "$head" >stdin &&
 			format_command $type "update refs/heads/ref2" "$old_head" "$head" >>stdin &&
-			git update-ref $type --no-deref --stdin --batch-updates <stdin >stdout &&
+			git update-ref $type --no-deref --stdin --batch-updates <stdin >stdout 2>err &&
 			echo $old_head >expect &&
 			git rev-parse refs/heads/ref1 >actual &&
 			test_cmp expect actual &&
 			echo $head >expect &&
 			test_must_fail git rev-parse refs/heads/ref2 &&
-			test_grep -q "reference does not exist" stdout
+			test_grep "rejected refs/heads/ref2 $old_head $head reference does not exist" stdout &&
+			test_grep "cannot lock ref ${SQ}refs/heads/ref2${SQ}: reference is missing but expected $head" err
 		)
 	'
 
@@ -2190,7 +2194,7 @@ do
 
 			format_command $type "update refs/heads/ref1" "$old_head" "$head" >stdin &&
 			format_command $type "symref-update refs/heads/ref2" "$old_head" "ref" "refs/heads/nonexistent" >>stdin &&
-			git update-ref $type --no-deref --stdin --batch-updates <stdin >stdout &&
+			git update-ref $type --no-deref --stdin --batch-updates <stdin >stdout 2>err &&
 			echo $old_head >expect &&
 			git rev-parse refs/heads/ref1 >actual &&
 			test_cmp expect actual &&
@@ -2198,7 +2202,8 @@ do
 			echo $head >expect &&
 			git rev-parse refs/heads/ref2 >actual &&
 			test_cmp expect actual &&
-			test_grep -q "expected symref but found regular ref" stdout
+			test_grep "rejected refs/heads/ref2 $ZERO_OID $ZERO_OID expected symref but found regular ref" stdout &&
+			test_grep "cannot lock ref ${SQ}refs/heads/ref2${SQ}: expected symref with target ${SQ}refs/heads/nonexistent${SQ}: but is a regular ref" err
 		)
 	'
 
@@ -2216,14 +2221,15 @@ do
 
 			format_command $type "update refs/heads/ref1" "$old_head" "$head" >stdin &&
 			format_command $type "update refs/heads/ref2" "$old_head" "$Z" >>stdin &&
-			git update-ref $type --stdin --batch-updates <stdin >stdout &&
+			git update-ref $type --stdin --batch-updates <stdin >stdout 2>err &&
 			echo $old_head >expect &&
 			git rev-parse refs/heads/ref1 >actual &&
 			test_cmp expect actual &&
 			echo $head >expect &&
 			git rev-parse refs/heads/ref2 >actual &&
 			test_cmp expect actual &&
-			test_grep -q "reference already exists" stdout
+			test_grep "rejected refs/heads/ref2 $old_head $ZERO_OID reference already exists" stdout &&
+			test_grep "cannot lock ref ${SQ}refs/heads/ref2${SQ}: reference already exists" err
 		)
 	'
 
@@ -2241,14 +2247,15 @@ do
 
 			format_command $type "update refs/heads/ref1" "$old_head" "$head" >stdin &&
 			format_command $type "update refs/heads/ref2" "$head" "$old_head" >>stdin &&
-			git update-ref $type --stdin --batch-updates <stdin >stdout &&
+			git update-ref $type --stdin --batch-updates <stdin >stdout 2>err &&
 			echo $old_head >expect &&
 			git rev-parse refs/heads/ref1 >actual &&
 			test_cmp expect actual &&
 			echo $head >expect &&
 			git rev-parse refs/heads/ref2 >actual &&
 			test_cmp expect actual &&
-			test_grep -q "incorrect old value provided" stdout
+			test_grep "rejected refs/heads/ref2 $head $old_head incorrect old value provided" stdout &&
+			test_grep "cannot lock ref ${SQ}refs/heads/ref2${SQ}: is at $head but expected $old_head" err
 		)
 	'
 
@@ -2264,12 +2271,13 @@ do
 			git update-ref refs/heads/ref/foo $head &&
 
 			format_command $type "update refs/heads/ref/foo" "$old_head" "$head" >stdin &&
-			format_command $type "update refs/heads/ref" "$old_head" "" >>stdin &&
-			git update-ref $type --stdin --batch-updates <stdin >stdout &&
+			format_command $type "update refs/heads/ref" "$old_head" "$ZERO_OID" >>stdin &&
+			git update-ref $type --stdin --batch-updates <stdin >stdout 2>err &&
 			echo $old_head >expect &&
 			git rev-parse refs/heads/ref/foo >actual &&
 			test_cmp expect actual &&
-			test_grep -q "refname conflict" stdout
+			test_grep "rejected refs/heads/ref $old_head $ZERO_OID refname conflict" stdout &&
+			test_grep "${SQ}refs/heads/ref/foo${SQ} exists; cannot create ${SQ}refs/heads/ref${SQ}" err
 		)
 	'
 
@@ -2284,13 +2292,14 @@ do
 			head=$(git rev-parse HEAD) &&
 			git update-ref refs/heads/ref/foo $head &&
 
-			format_command $type "update refs/heads/foo" "$old_head" "" >stdin &&
-			format_command $type "update refs/heads/ref" "$old_head" "" >>stdin &&
-			git update-ref $type --stdin --batch-updates <stdin >stdout &&
+			format_command $type "update refs/heads/foo" "$old_head" "$ZERO_OID" >stdin &&
+			format_command $type "update refs/heads/ref" "$old_head" "$ZERO_OID" >>stdin &&
+			git update-ref $type --stdin --batch-updates <stdin >stdout 2>err &&
 			echo $old_head >expect &&
 			git rev-parse refs/heads/foo >actual &&
 			test_cmp expect actual &&
-			test_grep -q "refname conflict" stdout
+			test_grep "rejected refs/heads/ref $old_head $ZERO_OID refname conflict" stdout &&
+			test_grep "${SQ}refs/heads/ref/foo${SQ} exists; cannot create ${SQ}refs/heads/ref${SQ}" err
 		)
 	'
 
@@ -2309,14 +2318,15 @@ do
 				format_command $type "create refs/heads/ref" "$old_head" &&
 				format_command $type "create refs/heads/Foo" "$old_head"
 			} >stdin &&
-			git update-ref $type --stdin --batch-updates <stdin >stdout &&
+			git update-ref $type --stdin --batch-updates <stdin >stdout 2>err &&
 
 			echo $head >expect &&
 			git rev-parse refs/heads/foo >actual &&
 			echo $old_head >expect &&
 			git rev-parse refs/heads/ref >actual &&
 			test_cmp expect actual &&
-			test_grep -q "reference conflict due to case-insensitive filesystem" stdout
+			test_grep "rejected refs/heads/Foo $old_head $ZERO_OID reference conflict due to case-insensitive filesystem" stdout &&
+			test_grep -e "cannot lock ref ${SQ}refs/heads/Foo${SQ}: Unable to create" -e "Foo.lock" err
 		)
 	'
 
@@ -2357,8 +2367,9 @@ do
 			git symbolic-ref refs/heads/symbolic refs/heads/non-existent &&
 
 			format_command $type "delete refs/heads/symbolic" "$head" >stdin &&
-			git update-ref $type --stdin --batch-updates <stdin >stdout &&
-			test_grep "reference does not exist" stdout
+			git update-ref $type --stdin --batch-updates <stdin >stdout 2>err &&
+			test_grep "rejected refs/heads/non-existent $ZERO_OID $head reference does not exist" stdout &&
+			test_grep "cannot lock ref ${SQ}refs/heads/symbolic${SQ}: unable to resolve reference ${SQ}refs/heads/non-existent${SQ}" err
 		)
 	'
 
@@ -2373,8 +2384,9 @@ do
 			head=$(git rev-parse HEAD) &&
 
 			format_command $type "delete refs/heads/new-branch" "$head" >stdin &&
-			git update-ref $type --stdin --batch-updates <stdin >stdout &&
-			test_grep "incorrect old value provided" stdout
+			git update-ref $type --stdin --batch-updates <stdin >stdout 2>err &&
+			test_grep "rejected refs/heads/new-branch $ZERO_OID $head incorrect old value provided" stdout &&
+			test_grep "cannot lock ref ${SQ}refs/heads/new-branch${SQ}: is at $(git rev-parse new-branch) but expected $head" err
 		)
 	'
 
@@ -2387,8 +2399,9 @@ do
 			head=$(git rev-parse HEAD) &&
 
 			format_command $type "delete refs/heads/non-existent" "$head" >stdin &&
-			git update-ref $type --stdin --batch-updates <stdin >stdout &&
-			test_grep "reference does not exist" stdout
+			git update-ref $type --stdin --batch-updates <stdin >stdout 2>err &&
+			test_grep "rejected refs/heads/non-existent $ZERO_OID $head reference does not exist" stdout &&
+			test_grep "cannot lock ref ${SQ}refs/heads/non-existent${SQ}: unable to resolve reference ${SQ}refs/heads/non-existent${SQ}" err
 		)
 	'
 done

-- 
2.52.0

[PATCH v4 4/6] fetch: utilize rejected ref error details

[Karthik Nayak]

In 0e358de64a (fetch: use batched reference updates, 2025-05-19),
git-fetch(1) switched to using batched reference updates. This also
introduced a regression wherein instead of providing detailed error
messages for failed referenced updates, the users were provided generic
error messages based on the error type.

Similar to the previous commit, switch to using detailed error messages
if present for failed reference updates to fix this regression.

Reported-by: Elijah Newren <newren@gmail.com>
Co-authored-by: Jeff King <peff@peff.net>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
---
 builtin/fetch.c  | 10 ++++++----
 t/t5510-fetch.sh |  8 ++++----
 2 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/builtin/fetch.c b/builtin/fetch.c
index d427adea61..49495be0b6 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -1649,7 +1649,7 @@ static void ref_transaction_rejection_handler(const char *refname,
 					      const char *old_target UNUSED,
 					      const char *new_target UNUSED,
 					      enum ref_transaction_error err,
-					      const char *details UNUSED,
+					      const char *details,
 					      void *cb_data)
 {
 	struct ref_rejection_data *data = cb_data;
@@ -1674,9 +1674,11 @@ static void ref_transaction_rejection_handler(const char *refname,
 			"branches"), data->remote_name);
 		data->conflict_msg_shown = true;
 	} else {
-		const char *reason = ref_transaction_error_msg(err);
-
-		error(_("fetching ref %s failed: %s"), refname, reason);
+		if (details)
+			error("%s", details);
+		else
+			error(_("fetching ref %s failed: %s"),
+			      refname, ref_transaction_error_msg(err));
 	}
 
 	*data->retcode = 1;
diff --git a/t/t5510-fetch.sh b/t/t5510-fetch.sh
index ce1c23684e..c69afb5a60 100755
--- a/t/t5510-fetch.sh
+++ b/t/t5510-fetch.sh
@@ -1516,7 +1516,7 @@ test_expect_success REFFILES 'existing reference lock in repo' '
 		git remote add origin ../base &&
 		touch refs/heads/foo.lock &&
 		test_must_fail git fetch -f origin "refs/heads/*:refs/heads/*" 2>err &&
-		test_grep "error: fetching ref refs/heads/foo failed: reference already exists" err &&
+		test_grep -e "error: cannot lock ref ${SQ}refs/heads/foo${SQ}: Unable to create" -e "refs/heads/foo.lock${SQ}: File exists." err &&
 		git rev-parse refs/heads/main >expect &&
 		git rev-parse refs/heads/branch >actual &&
 		test_cmp expect actual
@@ -1530,7 +1530,7 @@ test_expect_success CASE_INSENSITIVE_FS,REFFILES 'F/D conflict on case insensiti
 		cd case_insensitive &&
 		git remote add origin -- ../case_sensitive_fd &&
 		test_must_fail git fetch -f origin "refs/heads/*:refs/heads/*" 2>err &&
-		test_grep "failed: refname conflict" err &&
+		test_grep "cannot process ${SQ}refs/remotes/origin/foo${SQ} and ${SQ}refs/remotes/origin/foo/bar${SQ} at the same time" err &&
 		git rev-parse refs/heads/main >expect &&
 		git rev-parse refs/heads/foo/bar >actual &&
 		test_cmp expect actual
@@ -1544,7 +1544,7 @@ test_expect_success CASE_INSENSITIVE_FS,REFFILES 'D/F conflict on case insensiti
 		cd case_insensitive &&
 		git remote add origin -- ../case_sensitive_df &&
 		test_must_fail git fetch -f origin "refs/heads/*:refs/heads/*" 2>err &&
-		test_grep "failed: refname conflict" err &&
+		test_grep "cannot lock ref ${SQ}refs/remotes/origin/foo${SQ}: there is a non-empty directory ${SQ}./refs/remotes/origin/foo${SQ} blocking reference ${SQ}refs/remotes/origin/foo${SQ}" err &&
 		git rev-parse refs/heads/main >expect &&
 		git rev-parse refs/heads/Foo/bar >actual &&
 		test_cmp expect actual
@@ -1658,7 +1658,7 @@ test_expect_success REFFILES "FETCH_HEAD is updated even if ref updates fail" '
 		git remote add origin ../base &&
 		>refs/heads/foo.lock &&
 		test_must_fail git fetch -f origin "refs/heads/*:refs/heads/*" 2>err &&
-		test_grep "error: fetching ref refs/heads/foo failed: reference already exists" err &&
+		test_grep -e "error: cannot lock ref ${SQ}refs/heads/foo${SQ}: Unable to create" -e "refs/heads/foo.lock${SQ}: File exists." err &&
 		test_grep "branch ${SQ}branch${SQ} of ../base" FETCH_HEAD &&
 		test_grep "branch ${SQ}foo${SQ} of ../base" FETCH_HEAD
 	)

-- 
2.52.0

[PATCH v4 5/6] receive-pack: utilize rejected ref error details

[Karthik Nayak]

In 9d2962a7c4 (receive-pack: use batched reference updates, 2025-05-19),
git-receive-pack(1) switched to using batched reference updates. This also
introduced a regression wherein instead of providing detailed error
messages for failed referenced updates, the users were provided generic
error messages based on the error type.

Now that the updates also contain detailed error message, propagate
those to the client via 'rp_error'. The detailed error messages can be
very verbose, for e.g. in the files backend, when trying to write a
non-commit object to a branch, you would see:

   ! [remote rejected] 3eaec9ccf3a53f168362a6b3fdeb73426fb9813d ->
   branch (cannot update ref 'refs/heads/branch': trying to write
   non-commit object 3eaec9ccf3a53f168362a6b3fdeb73426fb9813d to branch
   'refs/heads/branch')

Here the refname is repeated multiple times due to how error messages
are propagated and filled over the code stack. This potentially can be
cleaned up in a future commit.

Reported-by: Elijah Newren <newren@gmail.com>
Co-authored-by: Jeff King <peff@peff.net>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
---
 builtin/receive-pack.c |  8 ++++++--
 t/t5516-fetch-push.sh  | 15 +++++++++++++++
 2 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index 94d3e73cee..70e04b3efb 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -1813,11 +1813,14 @@ static void ref_transaction_rejection_handler(const char *refname,
 					      const char *old_target UNUSED,
 					      const char *new_target UNUSED,
 					      enum ref_transaction_error err,
-					      const char *details UNUSED,
+					      const char *details,
 					      void *cb_data)
 {
 	struct strmap *failed_refs = cb_data;
 
+	if (details)
+		rp_error("%s", details);
+
 	strmap_put(failed_refs, refname, (char *)ref_transaction_error_msg(err));
 }
 
@@ -1884,6 +1887,7 @@ static void execute_commands_non_atomic(struct command *commands,
 		}
 
 		ref_transaction_for_each_rejected_update(transaction,
+
 							 ref_transaction_rejection_handler,
 							 &failed_refs);
 
@@ -1895,7 +1899,7 @@ static void execute_commands_non_atomic(struct command *commands,
 			if (reported_error)
 				cmd->error_string = reported_error;
 			else if (strmap_contains(&failed_refs, cmd->ref_name))
-				cmd->error_string = strmap_get(&failed_refs, cmd->ref_name);
+				cmd->error_string = cmd->error_string_owned = xstrdup(strmap_get(&failed_refs, cmd->ref_name));
 		}
 
 	cleanup:
diff --git a/t/t5516-fetch-push.sh b/t/t5516-fetch-push.sh
index 46926e7bbd..45595991c8 100755
--- a/t/t5516-fetch-push.sh
+++ b/t/t5516-fetch-push.sh
@@ -1882,4 +1882,19 @@ test_expect_success 'push with F/D conflict with deletion and creation' '
 	git push testrepo :refs/heads/branch/conflict refs/heads/branch
 '
 
+test_expect_success 'pushing non-commit objects should report error' '
+	test_when_finished "rm -rf dest repo" &&
+	git init dest &&
+	git init repo &&
+
+	(
+		cd repo &&
+		test_commit --annotate test &&
+
+		tagsha=$(git rev-parse test^{tag}) &&
+		test_must_fail git push ../dest "$tagsha:refs/heads/branch" 2>err &&
+		test_grep "trying to write non-commit object $tagsha to branch ${SQ}refs/heads/branch${SQ}" err
+	)
+'
+
 test_done

-- 
2.52.0

[PATCH v4 6/6] fetch: delay user information post committing of transaction

[Karthik Nayak]

In Git 2.50 and earlier, we would display failure codes and error
message as part of the status display:

  $ git fetch . v1.0.0:refs/heads/foo
    error: cannot update ref 'refs/heads/foo': trying to write non-commit object f665776185ad074b236c00751d666da7d1977dbe to branch 'refs/heads/foo'
    From .
     ! [new tag]               v1.0.0     -> foo  (unable to update local ref)

With the addition of batched updates, this information is no longer
shown to the user:

  $ git fetch . v1.0.0:refs/heads/foo
    From .
     * [new tag]               v1.0.0     -> foo
    error: cannot update ref 'refs/heads/foo': trying to write non-commit object f665776185ad074b236c00751d666da7d1977dbe to branch 'refs/heads/foo'

Since reference updates are batched and processed together at the end,
information around the outcome is not available during individual
reference parsing.

To overcome this, collate and delay the output to the end. Introduce
`ref_update_display_info` which will hold individual update's
information and also whether the update failed or succeeded. This
finally allows us to iterate over all such updates and print them to the
user.

Using an dynamic array and strmap does add some overhead to
'git-fetch(1)', but from benchmarking this seems to be not too bad:

  Benchmark 1: fetch: many refs (refformat = files, refcount = 1000, revision = master)
    Time (mean ± σ):      42.6 ms ±   1.2 ms    [User: 13.1 ms, System: 29.8 ms]
    Range (min … max):    40.1 ms …  45.8 ms    47 runs

  Benchmark 2: fetch: many refs (refformat = files, refcount = 1000, revision = HEAD)
    Time (mean ± σ):      43.1 ms ±   1.2 ms    [User: 12.7 ms, System: 30.7 ms]
    Range (min … max):    40.5 ms …  45.8 ms    48 runs

  Summary
    fetch: many refs (refformat = files, refcount = 1000, revision = master) ran
      1.01 ± 0.04 times faster than fetch: many refs (refformat = files, refcount = 1000, revision = HEAD)

Another approach would be to move the status printing logic to be
handled post the transaction being committed. That however would require
adding an iterator to the ref transaction that tracks both the outcome
(success/failure) and the original refspec information for each update,
which is more involved infrastructure work compared to the strmap
approach here.

Helped-by: Phillip Wood <phillip.wood123@gmail.com>
Reported-by: Jeff King <peff@peff.net>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
---
 builtin/fetch.c       | 246 +++++++++++++++++++++++++++++++++++++++-----------
 t/t5516-fetch-push.sh |   1 +
 2 files changed, 193 insertions(+), 54 deletions(-)

diff --git a/builtin/fetch.c b/builtin/fetch.c
index 49495be0b6..5f6486a1ce 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -861,12 +861,87 @@ static void display_ref_update(struct display_state *display_state, char code,
 	fputs(display_state->buf.buf, f);
 }
 
+struct ref_update_display_info {
+	bool failed;
+	char success_code;
+	char fail_code;
+	const char *summary;
+	const char *fail_detail;
+	const char *success_detail;
+	const char *ref;
+	const char *remote;
+	struct object_id old_oid;
+	struct object_id new_oid;
+};
+
+struct ref_update_display_info_array {
+	struct ref_update_display_info *info;
+	size_t alloc, nr;
+};
+
+static struct ref_update_display_info *ref_update_display_info_append(
+					   struct ref_update_display_info_array *array,
+					   char success_code,
+					   char fail_code,
+					   const char *summary,
+					   const char *success_detail,
+					   const char *fail_detail,
+					   const char *ref,
+					   const char *remote,
+					   const struct object_id *old_oid,
+					   const struct object_id *new_oid)
+{
+	struct ref_update_display_info *info;
+
+	ALLOC_GROW(array->info, array->nr + 1, array->alloc);
+	info = &array->info[array->nr++];
+
+	info->failed = false;
+	info->success_code = success_code;
+	info->fail_code = fail_code;
+	info->summary = xstrdup(summary);
+	info->success_detail = xstrdup_or_null(success_detail);
+	info->fail_detail = xstrdup_or_null(fail_detail);
+	info->remote = xstrdup(remote);
+	info->ref = xstrdup(ref);
+
+	oidcpy(&info->old_oid, old_oid);
+	oidcpy(&info->new_oid, new_oid);
+
+	return info;
+}
+
+static void ref_update_display_info_set_failed(struct ref_update_display_info *info)
+{
+	info->failed = true;
+}
+
+static void ref_update_display_info_free(struct ref_update_display_info *info)
+{
+	free((char *)info->summary);
+	free((char *)info->success_detail);
+	free((char *)info->fail_detail);
+	free((char *)info->remote);
+	free((char *)info->ref);
+}
+
+static void ref_update_display_info_display(struct ref_update_display_info *info,
+					    struct display_state *display_state,
+					    int summary_width)
+{
+	display_ref_update(display_state,
+			   info->failed ? info->fail_code : info->success_code,
+			   info->summary,
+			   info->failed ? info->fail_detail : info->success_detail,
+			   info->remote, info->ref, &info->old_oid,
+			   &info->new_oid, summary_width);
+}
+
 static int update_local_ref(struct ref *ref,
 			    struct ref_transaction *transaction,
-			    struct display_state *display_state,
 			    const struct ref *remote_ref,
-			    int summary_width,
-			    const struct fetch_config *config)
+			    const struct fetch_config *config,
+			    struct ref_update_display_info_array *display_array)
 {
 	struct commit *current = NULL, *updated;
 	int fast_forward = 0;
@@ -877,41 +952,56 @@ static int update_local_ref(struct ref *ref,
 
 	if (oideq(&ref->old_oid, &ref->new_oid)) {
 		if (verbosity > 0)
-			display_ref_update(display_state, '=', _("[up to date]"), NULL,
-					   remote_ref->name, ref->name,
-					   &ref->old_oid, &ref->new_oid, summary_width);
+			ref_update_display_info_append(display_array, '=', '=',
+						       _("[up to date]"), NULL,
+						       NULL, ref->name,
+						       remote_ref->name, &ref->old_oid,
+						       &ref->new_oid);
 		return 0;
 	}
 
 	if (!update_head_ok &&
 	    !is_null_oid(&ref->old_oid) &&
 	    branch_checked_out(ref->name)) {
+		struct ref_update_display_info *info;
 		/*
 		 * If this is the head, and it's not okay to update
 		 * the head, and the old value of the head isn't empty...
 		 */
-		display_ref_update(display_state, '!', _("[rejected]"),
-				   _("can't fetch into checked-out branch"),
-				   remote_ref->name, ref->name,
-				   &ref->old_oid, &ref->new_oid, summary_width);
+		info = ref_update_display_info_append(display_array, '!', '!',
+						      _("[rejected]"), NULL,
+						      _("can't fetch into checked-out branch"),
+						      ref->name, remote_ref->name,
+						      &ref->old_oid, &ref->new_oid);
+		ref_update_display_info_set_failed(info);
 		return 1;
 	}
 
 	if (!is_null_oid(&ref->old_oid) &&
 	    starts_with(ref->name, "refs/tags/")) {
+		struct ref_update_display_info *info;
+
 		if (force || ref->force) {
 			int r;
+
 			r = s_update_ref("updating tag", ref, transaction, 0);
-			display_ref_update(display_state, r ? '!' : 't', _("[tag update]"),
-					   r ? _("unable to update local ref") : NULL,
-					   remote_ref->name, ref->name,
-					   &ref->old_oid, &ref->new_oid, summary_width);
+
+			info = ref_update_display_info_append(display_array, 't', '!',
+							      _("[tag update]"), NULL,
+							      _("unable to update local ref"),
+							      ref->name, remote_ref->name,
+							      &ref->old_oid, &ref->new_oid);
+			if (r)
+				ref_update_display_info_set_failed(info);
+
 			return r;
 		} else {
-			display_ref_update(display_state, '!', _("[rejected]"),
-					   _("would clobber existing tag"),
-					   remote_ref->name, ref->name,
-					   &ref->old_oid, &ref->new_oid, summary_width);
+			info = ref_update_display_info_append(display_array, '!', '!',
+							      _("[rejected]"), NULL,
+							      _("would clobber existing tag"),
+							      ref->name, remote_ref->name,
+							      &ref->old_oid, &ref->new_oid);
+			ref_update_display_info_set_failed(info);
 			return 1;
 		}
 	}
@@ -921,6 +1011,7 @@ static int update_local_ref(struct ref *ref,
 	updated = lookup_commit_reference_gently(the_repository,
 						 &ref->new_oid, 1);
 	if (!current || !updated) {
+		struct ref_update_display_info *info;
 		const char *msg;
 		const char *what;
 		int r;
@@ -941,10 +1032,15 @@ static int update_local_ref(struct ref *ref,
 		}
 
 		r = s_update_ref(msg, ref, transaction, 0);
-		display_ref_update(display_state, r ? '!' : '*', what,
-				   r ? _("unable to update local ref") : NULL,
-				   remote_ref->name, ref->name,
-				   &ref->old_oid, &ref->new_oid, summary_width);
+
+		info = ref_update_display_info_append(display_array, '*', '!',
+						      what, NULL,
+						      _("unable to update local ref"),
+						      ref->name, remote_ref->name,
+						      &ref->old_oid, &ref->new_oid);
+		if (r)
+			ref_update_display_info_set_failed(info);
+
 		return r;
 	}
 
@@ -960,6 +1056,7 @@ static int update_local_ref(struct ref *ref,
 	}
 
 	if (fast_forward) {
+		struct ref_update_display_info *info;
 		struct strbuf quickref = STRBUF_INIT;
 		int r;
 
@@ -967,29 +1064,46 @@ static int update_local_ref(struct ref *ref,
 		strbuf_addstr(&quickref, "..");
 		strbuf_add_unique_abbrev(&quickref, &ref->new_oid, DEFAULT_ABBREV);
 		r = s_update_ref("fast-forward", ref, transaction, 1);
-		display_ref_update(display_state, r ? '!' : ' ', quickref.buf,
-				   r ? _("unable to update local ref") : NULL,
-				   remote_ref->name, ref->name,
-				   &ref->old_oid, &ref->new_oid, summary_width);
+
+		info = ref_update_display_info_append(display_array, ' ', '!',
+						      quickref.buf, NULL,
+						      _("unable to update local ref"),
+						      ref->name, remote_ref->name,
+						      &ref->old_oid, &ref->new_oid);
+		if (r)
+			ref_update_display_info_set_failed(info);
+
 		strbuf_release(&quickref);
 		return r;
 	} else if (force || ref->force) {
+		struct ref_update_display_info *info;
 		struct strbuf quickref = STRBUF_INIT;
 		int r;
+
 		strbuf_add_unique_abbrev(&quickref, &current->object.oid, DEFAULT_ABBREV);
 		strbuf_addstr(&quickref, "...");
 		strbuf_add_unique_abbrev(&quickref, &ref->new_oid, DEFAULT_ABBREV);
 		r = s_update_ref("forced-update", ref, transaction, 1);
-		display_ref_update(display_state, r ? '!' : '+', quickref.buf,
-				   r ? _("unable to update local ref") : _("forced update"),
-				   remote_ref->name, ref->name,
-				   &ref->old_oid, &ref->new_oid, summary_width);
+
+		info = ref_update_display_info_append(display_array, '+', '!',
+						      quickref.buf, _("forced update"),
+						      _("unable to update local ref"),
+						      ref->name, remote_ref->name,
+						      &ref->old_oid, &ref->new_oid);
+
+		if (r)
+			ref_update_display_info_set_failed(info);
+
 		strbuf_release(&quickref);
 		return r;
 	} else {
-		display_ref_update(display_state, '!', _("[rejected]"), _("non-fast-forward"),
-				   remote_ref->name, ref->name,
-				   &ref->old_oid, &ref->new_oid, summary_width);
+		struct ref_update_display_info *info;
+		info = ref_update_display_info_append(display_array, '!', '!',
+						      _("[rejected]"), NULL,
+						      _("non-fast-forward"),
+						      ref->name, remote_ref->name,
+						      &ref->old_oid, &ref->new_oid);
+		ref_update_display_info_set_failed(info);
 		return 1;
 	}
 }
@@ -1103,17 +1217,14 @@ static int store_updated_refs(struct display_state *display_state,
 			      int connectivity_checked,
 			      struct ref_transaction *transaction, struct ref *ref_map,
 			      struct fetch_head *fetch_head,
-			      const struct fetch_config *config)
+			      const struct fetch_config *config,
+			      struct ref_update_display_info_array *display_array)
 {
 	int rc = 0;
 	struct strbuf note = STRBUF_INIT;
 	const char *what, *kind;
 	struct ref *rm;
 	int want_status;
-	int summary_width = 0;
-
-	if (verbosity >= 0)
-		summary_width = transport_summary_width(ref_map);
 
 	if (!connectivity_checked) {
 		struct check_connected_options opt = CHECK_CONNECTED_INIT;
@@ -1218,8 +1329,8 @@ static int store_updated_refs(struct display_state *display_state,
 					  display_state->url_len);
 
 			if (ref) {
-				rc |= update_local_ref(ref, transaction, display_state,
-						       rm, summary_width, config);
+				rc |= update_local_ref(ref, transaction, rm,
+						       config, display_array);
 				free(ref);
 			} else if (write_fetch_head || dry_run) {
 				/*
@@ -1227,12 +1338,12 @@ static int store_updated_refs(struct display_state *display_state,
 				 * would be written to FETCH_HEAD, if --dry-run
 				 * is set).
 				 */
-				display_ref_update(display_state, '*',
-						   *kind ? kind : "branch", NULL,
-						   rm->name,
-						   "FETCH_HEAD",
-						   &rm->new_oid, &rm->old_oid,
-						   summary_width);
+
+				ref_update_display_info_append(display_array, '*', '*',
+							       *kind ? kind : "branch",
+							       NULL, NULL, "FETCH_HEAD",
+							       rm->name, &rm->new_oid,
+							       &rm->old_oid);
 			}
 		}
 	}
@@ -1300,7 +1411,8 @@ static int fetch_and_consume_refs(struct display_state *display_state,
 				  struct ref_transaction *transaction,
 				  struct ref *ref_map,
 				  struct fetch_head *fetch_head,
-				  const struct fetch_config *config)
+				  const struct fetch_config *config,
+				  struct ref_update_display_info_array *display_array)
 {
 	int connectivity_checked = 1;
 	int ret;
@@ -1322,7 +1434,8 @@ static int fetch_and_consume_refs(struct display_state *display_state,
 
 	trace2_region_enter("fetch", "consume_refs", the_repository);
 	ret = store_updated_refs(display_state, connectivity_checked,
-				 transaction, ref_map, fetch_head, config);
+				 transaction, ref_map, fetch_head, config,
+				 display_array);
 	trace2_region_leave("fetch", "consume_refs", the_repository);
 
 out:
@@ -1493,7 +1606,8 @@ static int backfill_tags(struct display_state *display_state,
 			 struct ref_transaction *transaction,
 			 struct ref *ref_map,
 			 struct fetch_head *fetch_head,
-			 const struct fetch_config *config)
+			 const struct fetch_config *config,
+			 struct ref_update_display_info_array *display_array)
 {
 	int retcode, cannot_reuse;
 
@@ -1515,7 +1629,7 @@ static int backfill_tags(struct display_state *display_state,
 	transport_set_option(transport, TRANS_OPT_DEPTH, "0");
 	transport_set_option(transport, TRANS_OPT_DEEPEN_RELATIVE, NULL);
 	retcode = fetch_and_consume_refs(display_state, transport, transaction, ref_map,
-					 fetch_head, config);
+					 fetch_head, config, display_array);
 
 	if (gsecondary) {
 		transport_disconnect(gsecondary);
@@ -1641,6 +1755,7 @@ struct ref_rejection_data {
 	bool conflict_msg_shown;
 	bool case_sensitive_msg_shown;
 	const char *remote_name;
+	struct strmap *rejected_refs;
 };
 
 static void ref_transaction_rejection_handler(const char *refname,
@@ -1681,6 +1796,7 @@ static void ref_transaction_rejection_handler(const char *refname,
 			      refname, ref_transaction_error_msg(err));
 	}
 
+	strmap_put(data->rejected_refs, refname, NULL);
 	*data->retcode = 1;
 }
 
@@ -1690,6 +1806,7 @@ static void ref_transaction_rejection_handler(const char *refname,
  */
 static int commit_ref_transaction(struct ref_transaction **transaction,
 				  bool is_atomic, const char *remote_name,
+				  struct strmap *rejected_refs,
 				  struct strbuf *err)
 {
 	int retcode = ref_transaction_commit(*transaction, err);
@@ -1701,6 +1818,7 @@ static int commit_ref_transaction(struct ref_transaction **transaction,
 			.conflict_msg_shown = 0,
 			.remote_name = remote_name,
 			.retcode = &retcode,
+			.rejected_refs = rejected_refs,
 		};
 
 		ref_transaction_for_each_rejected_update(*transaction,
@@ -1729,6 +1847,9 @@ static int do_fetch(struct transport *transport,
 	struct fetch_head fetch_head = { 0 };
 	struct strbuf err = STRBUF_INIT;
 	int do_set_head = 0;
+	struct ref_update_display_info_array display_array = { 0 };
+	struct strmap rejected_refs = STRMAP_INIT;
+	int summary_width = 0;
 
 	if (tags == TAGS_DEFAULT) {
 		if (transport->remote->fetch_tags == 2)
@@ -1853,7 +1974,7 @@ static int do_fetch(struct transport *transport,
 	}
 
 	if (fetch_and_consume_refs(&display_state, transport, transaction, ref_map,
-				   &fetch_head, config)) {
+				   &fetch_head, config, &display_array)) {
 		retcode = 1;
 		goto cleanup;
 	}
@@ -1876,7 +1997,7 @@ static int do_fetch(struct transport *transport,
 			 * the transaction and don't commit anything.
 			 */
 			if (backfill_tags(&display_state, transport, transaction, tags_ref_map,
-					  &fetch_head, config))
+					  &fetch_head, config, &display_array))
 				retcode = 1;
 		}
 
@@ -1886,8 +2007,12 @@ static int do_fetch(struct transport *transport,
 	if (retcode)
 		goto cleanup;
 
+	if (verbosity >= 0)
+		summary_width = transport_summary_width(ref_map);
+
 	retcode = commit_ref_transaction(&transaction, atomic_fetch,
-					 transport->remote->name, &err);
+					 transport->remote->name,
+					 &rejected_refs, &err);
 	/*
 	 * With '--atomic', bail out if the transaction fails. Without '--atomic',
 	 * continue to fetch head and perform other post-fetch operations.
@@ -1965,7 +2090,17 @@ static int do_fetch(struct transport *transport,
 	 */
 	if (retcode && !atomic_fetch && transaction)
 		commit_ref_transaction(&transaction, false,
-				       transport->remote->name, &err);
+				       transport->remote->name,
+				       &rejected_refs, &err);
+
+	for (size_t i = 0; i < display_array.nr; i++) {
+		struct ref_update_display_info *info = &display_array.info[i];
+
+		if (!info->failed && strmap_contains(&rejected_refs, info->ref))
+			ref_update_display_info_set_failed(info);
+		ref_update_display_info_display(info, &display_state, summary_width);
+		ref_update_display_info_free(info);
+	}
 
 	if (retcode) {
 		if (err.len) {
@@ -1980,6 +2115,9 @@ static int do_fetch(struct transport *transport,
 
 	if (transaction)
 		ref_transaction_free(transaction);
+
+	free(display_array.info);
+	strmap_clear(&rejected_refs, 0);
 	display_state_release(&display_state);
 	close_fetch_head(&fetch_head);
 	strbuf_release(&err);
diff --git a/t/t5516-fetch-push.sh b/t/t5516-fetch-push.sh
index 45595991c8..29e2f17608 100755
--- a/t/t5516-fetch-push.sh
+++ b/t/t5516-fetch-push.sh
@@ -1893,6 +1893,7 @@ test_expect_success 'pushing non-commit objects should report error' '
 
 		tagsha=$(git rev-parse test^{tag}) &&
 		test_must_fail git push ../dest "$tagsha:refs/heads/branch" 2>err &&
+		test_grep "! \[remote rejected\] $tagsha -> branch (invalid new value provided)" err &&
 		test_grep "trying to write non-commit object $tagsha to branch ${SQ}refs/heads/branch${SQ}" err
 	)
 '

-- 
2.52.0

Re: [PATCH v4 6/6] fetch: delay user information post committing of transaction

[Junio C Hamano]

Karthik Nayak <karthik.188@gmail.com> writes:

> +struct ref_update_display_info {
> +	bool failed;
> +	char success_code;
> +	char fail_code;
> +	const char *summary;
> +	const char *fail_detail;
> +	const char *success_detail;
> +	const char *ref;
> +	const char *remote;
> +	struct object_id old_oid;
> +	struct object_id new_oid;
> +};
> +
> +struct ref_update_display_info_array {
> +	struct ref_update_display_info *info;
> +	size_t alloc, nr;
> +};

OK.  The ref_update_display_info structure is full of pointers.
They are of "const char *" type, hinting that they are borrowed
pieces of memory, and there is nothing to clean inside, other than
the .info member itself?

> +static struct ref_update_display_info *ref_update_display_info_append(
> +					   struct ref_update_display_info_array *array,
> +					   char success_code,
> +					   char fail_code,
> +					   const char *summary,
> +					   const char *success_detail,
> +					   const char *fail_detail,
> +					   const char *ref,
> +					   const char *remote,
> +					   const struct object_id *old_oid,
> +					   const struct object_id *new_oid)
> +{

This helper that consumes the structure is used throughout the
patch, and relative to the previous round it got easier to read.

> +static void ref_update_display_info_free(struct ref_update_display_info *info)
> +{
> +	free((char *)info->summary);
> +	free((char *)info->success_detail);
> +	free((char *)info->fail_detail);
> +	free((char *)info->remote);
> +	free((char *)info->ref);
> +}

This answers "no" to my previous question.  These are not borrowed,
but are owned by this structure.

> @@ -1965,7 +2090,17 @@ static int do_fetch(struct transport *transport,
>  	 */
>  	if (retcode && !atomic_fetch && transaction)
>  		commit_ref_transaction(&transaction, false,
> -				       transport->remote->name, &err);
> +				       transport->remote->name,
> +				       &rejected_refs, &err);
> +
> +	for (size_t i = 0; i < display_array.nr; i++) {
> +		struct ref_update_display_info *info = &display_array.info[i];
> +
> +		if (!info->failed && strmap_contains(&rejected_refs, info->ref))
> +			ref_update_display_info_set_failed(info);
> +		ref_update_display_info_display(info, &display_state, summary_width);
> +		ref_update_display_info_free(info);
> +	}

And after a fetch finishes and we consume the display_info, we call
_free() to release the resource held there, plus ...

>  	if (retcode) {
>  		if (err.len) {
> @@ -1980,6 +2115,9 @@ static int do_fetch(struct transport *transport,
>  
>  	if (transaction)
>  		ref_transaction_free(transaction);
> +
> +	free(display_array.info);

... of course the array itself, which makes sense.

Re: [PATCH v4 6/6] fetch: delay user information post committing of transaction

[Karthik Nayak]

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Junio C Hamano <gitster@pobox.com> writes:

> Karthik Nayak <karthik.188@gmail.com> writes:
>
>> +struct ref_update_display_info {
>> +	bool failed;
>> +	char success_code;
>> +	char fail_code;
>> +	const char *summary;
>> +	const char *fail_detail;
>> +	const char *success_detail;
>> +	const char *ref;
>> +	const char *remote;
>> +	struct object_id old_oid;
>> +	struct object_id new_oid;
>> +};
>> +
>> +struct ref_update_display_info_array {
>> +	struct ref_update_display_info *info;
>> +	size_t alloc, nr;
>> +};
>
> OK.  The ref_update_display_info structure is full of pointers.
> They are of "const char *" type, hinting that they are borrowed
> pieces of memory, and there is nothing to clean inside, other than
> the .info member itself?
>
>> +static struct ref_update_display_info *ref_update_display_info_append(
>> +					   struct ref_update_display_info_array *array,
>> +					   char success_code,
>> +					   char fail_code,
>> +					   const char *summary,
>> +					   const char *success_detail,
>> +					   const char *fail_detail,
>> +					   const char *ref,
>> +					   const char *remote,
>> +					   const struct object_id *old_oid,
>> +					   const struct object_id *new_oid)
>> +{
>
> This helper that consumes the structure is used throughout the
> patch, and relative to the previous round it got easier to read.
>
>> +static void ref_update_display_info_free(struct ref_update_display_info *info)
>> +{
>> +	free((char *)info->summary);
>> +	free((char *)info->success_detail);
>> +	free((char *)info->fail_detail);
>> +	free((char *)info->remote);
>> +	free((char *)info->ref);
>> +}
>
> This answers "no" to my previous question.  These are not borrowed,
> but are owned by this structure.
>

Yup, cannot be borrowed, since those go out of scope much earlier.

>> @@ -1965,7 +2090,17 @@ static int do_fetch(struct transport *transport,
>>  	 */
>>  	if (retcode && !atomic_fetch && transaction)
>>  		commit_ref_transaction(&transaction, false,
>> -				       transport->remote->name, &err);
>> +				       transport->remote->name,
>> +				       &rejected_refs, &err);
>> +
>> +	for (size_t i = 0; i < display_array.nr; i++) {
>> +		struct ref_update_display_info *info = &display_array.info[i];
>> +
>> +		if (!info->failed && strmap_contains(&rejected_refs, info->ref))
>> +			ref_update_display_info_set_failed(info);
>> +		ref_update_display_info_display(info, &display_state, summary_width);
>> +		ref_update_display_info_free(info);
>> +	}
>
> And after a fetch finishes and we consume the display_info, we call
> _free() to release the resource held there, plus ...
>
>>  	if (retcode) {
>>  		if (err.len) {
>> @@ -1980,6 +2115,9 @@ static int do_fetch(struct transport *transport,
>>
>>  	if (transaction)
>>  		ref_transaction_free(transaction);
>> +
>> +	free(display_array.info);
>
> ... of course the array itself, which makes sense.

Yeah, the CI also didn't show any leaks, so we should be good.

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Re: [PATCH v4 6/6] fetch: delay user information post committing of transaction

[Junio C Hamano]

Karthik Nayak <karthik.188@gmail.com> writes:

>>> +static void ref_update_display_info_free(struct ref_update_display_info *info)
>>> +{
>>> +	free((char *)info->summary);
>>> +	free((char *)info->success_detail);
>>> +	free((char *)info->fail_detail);
>>> +	free((char *)info->remote);
>>> +	free((char *)info->ref);
>>> +}
>>
>> This answers "no" to my previous question.  These are not borrowed,
>> but are owned by this structure.
>>
>
> Yup, cannot be borrowed, since those go out of scope much earlier.

And the reason why they are marked "const char *" which typically
signals that they are borrowed is?  After all, that is where these
casts inside free() comes from.

There are two schools of thought.  One (which I originally was in)
marks resources we own with "const", if these members will not
change once we initialize them and we want to avoid accidentally
muck with the contents of these pieces of memory during the course
of the program.  Those of us in the school often have to cast away
constness in their calls to free() like the above.

But I saw many of our developers squarely fall into the other camp,
where they always use a non-const pointer to point at the resource
the structure owns.

The latter school of thought opens us up to bugs caused by mistaken
code that modifies these memory regions that those of us in the
former school would use "const" to avoid, but it makes it easier to
reason about memory ownership models by signalling if the enclosing
structure owns or borrows the resources.

I'd say the latter school are majority of our developer base, and a
lot of existing structures follow that rule.  I was hinting that we
may want to follow suit in this new structure.

Thanks.

Re: [PATCH v4 6/6] fetch: delay user information post committing of transaction

[Karthik Nayak]

[-- Attachment #1: Type: text/plain, Size: 2242 bytes --]

Junio C Hamano <gitster@pobox.com> writes:

> Karthik Nayak <karthik.188@gmail.com> writes:
>
>>>> +static void ref_update_display_info_free(struct ref_update_display_info *info)
>>>> +{
>>>> +	free((char *)info->summary);
>>>> +	free((char *)info->success_detail);
>>>> +	free((char *)info->fail_detail);
>>>> +	free((char *)info->remote);
>>>> +	free((char *)info->ref);
>>>> +}
>>>
>>> This answers "no" to my previous question.  These are not borrowed,
>>> but are owned by this structure.
>>>
>>
>> Yup, cannot be borrowed, since those go out of scope much earlier.
>
> And the reason why they are marked "const char *" which typically
> signals that they are borrowed is?  After all, that is where these
> casts inside free() comes from.
>
> There are two schools of thought.  One (which I originally was in)
> marks resources we own with "const", if these members will not
> change once we initialize them and we want to avoid accidentally
> muck with the contents of these pieces of memory during the course
> of the program.  Those of us in the school often have to cast away
> constness in their calls to free() like the above.
>

That's my thought process too, to use 'const' to indicate that the value
will not be modified post assignment.

> But I saw many of our developers squarely fall into the other camp,
> where they always use a non-const pointer to point at the resource
> the structure owns.
>
> The latter school of thought opens us up to bugs caused by mistaken
> code that modifies these memory regions that those of us in the
> former school would use "const" to avoid, but it makes it easier to
> reason about memory ownership models by signalling if the enclosing
> structure owns or borrows the resources.
>
> I'd say the latter school are majority of our developer base, and a
> lot of existing structures follow that rule.  I was hinting that we
> may want to follow suit in this new structure.
>
> Thanks.

That was what you were implying. Yeah, I've seen that, but it hasn't
been generally how I used to reason with using 'const'.

It does open up for modification bugs though. It's unfortunate that we
have one axis to denote both Mutability and Ownership. To stay
consistent, I'll make the change,

Karthik

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Re: [PATCH v4 6/6] fetch: delay user information post committing of transaction

[Phillip Wood]

Hi Karthik

I haven't looked in detail at the conversion of the callers from 
display_ref_update() to ref_update_display_info_append() but the array 
handling looks good.

Thanks

Phillip

On 22/01/2026 12:05, Karthik Nayak wrote:
> In Git 2.50 and earlier, we would display failure codes and error
> message as part of the status display:
> 
>    $ git fetch . v1.0.0:refs/heads/foo
>      error: cannot update ref 'refs/heads/foo': trying to write non-commit object f665776185ad074b236c00751d666da7d1977dbe to branch 'refs/heads/foo'
>      From .
>       ! [new tag]               v1.0.0     -> foo  (unable to update local ref)
> 
> With the addition of batched updates, this information is no longer
> shown to the user:
> 
>    $ git fetch . v1.0.0:refs/heads/foo
>      From .
>       * [new tag]               v1.0.0     -> foo
>      error: cannot update ref 'refs/heads/foo': trying to write non-commit object f665776185ad074b236c00751d666da7d1977dbe to branch 'refs/heads/foo'
> 
> Since reference updates are batched and processed together at the end,
> information around the outcome is not available during individual
> reference parsing.
> 
> To overcome this, collate and delay the output to the end. Introduce
> `ref_update_display_info` which will hold individual update's
> information and also whether the update failed or succeeded. This
> finally allows us to iterate over all such updates and print them to the
> user.
> 
> Using an dynamic array and strmap does add some overhead to
> 'git-fetch(1)', but from benchmarking this seems to be not too bad:
> 
>    Benchmark 1: fetch: many refs (refformat = files, refcount = 1000, revision = master)
>      Time (mean ± σ):      42.6 ms ±   1.2 ms    [User: 13.1 ms, System: 29.8 ms]
>      Range (min … max):    40.1 ms …  45.8 ms    47 runs
> 
>    Benchmark 2: fetch: many refs (refformat = files, refcount = 1000, revision = HEAD)
>      Time (mean ± σ):      43.1 ms ±   1.2 ms    [User: 12.7 ms, System: 30.7 ms]
>      Range (min … max):    40.5 ms …  45.8 ms    48 runs
> 
>    Summary
>      fetch: many refs (refformat = files, refcount = 1000, revision = master) ran
>        1.01 ± 0.04 times faster than fetch: many refs (refformat = files, refcount = 1000, revision = HEAD)
> 
> Another approach would be to move the status printing logic to be
> handled post the transaction being committed. That however would require
> adding an iterator to the ref transaction that tracks both the outcome
> (success/failure) and the original refspec information for each update,
> which is more involved infrastructure work compared to the strmap
> approach here.
> 
> Helped-by: Phillip Wood <phillip.wood123@gmail.com>
> Reported-by: Jeff King <peff@peff.net>
> Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
> ---
>   builtin/fetch.c       | 246 +++++++++++++++++++++++++++++++++++++++-----------
>   t/t5516-fetch-push.sh |   1 +
>   2 files changed, 193 insertions(+), 54 deletions(-)
> 
> diff --git a/builtin/fetch.c b/builtin/fetch.c
> index 49495be0b6..5f6486a1ce 100644
> --- a/builtin/fetch.c
> +++ b/builtin/fetch.c
> @@ -861,12 +861,87 @@ static void display_ref_update(struct display_state *display_state, char code,
>   	fputs(display_state->buf.buf, f);
>   }
>   
> +struct ref_update_display_info {
> +	bool failed;
> +	char success_code;
> +	char fail_code;
> +	const char *summary;
> +	const char *fail_detail;
> +	const char *success_detail;
> +	const char *ref;
> +	const char *remote;
> +	struct object_id old_oid;
> +	struct object_id new_oid;
> +};
> +
> +struct ref_update_display_info_array {
> +	struct ref_update_display_info *info;
> +	size_t alloc, nr;
> +};
> +
> +static struct ref_update_display_info *ref_update_display_info_append(
> +					   struct ref_update_display_info_array *array,
> +					   char success_code,
> +					   char fail_code,
> +					   const char *summary,
> +					   const char *success_detail,
> +					   const char *fail_detail,
> +					   const char *ref,
> +					   const char *remote,
> +					   const struct object_id *old_oid,
> +					   const struct object_id *new_oid)
> +{
> +	struct ref_update_display_info *info;
> +
> +	ALLOC_GROW(array->info, array->nr + 1, array->alloc);
> +	info = &array->info[array->nr++];
> +
> +	info->failed = false;
> +	info->success_code = success_code;
> +	info->fail_code = fail_code;
> +	info->summary = xstrdup(summary);
> +	info->success_detail = xstrdup_or_null(success_detail);
> +	info->fail_detail = xstrdup_or_null(fail_detail);
> +	info->remote = xstrdup(remote);
> +	info->ref = xstrdup(ref);
> +
> +	oidcpy(&info->old_oid, old_oid);
> +	oidcpy(&info->new_oid, new_oid);
> +
> +	return info;
> +}
> +
> +static void ref_update_display_info_set_failed(struct ref_update_display_info *info)
> +{
> +	info->failed = true;
> +}
> +
> +static void ref_update_display_info_free(struct ref_update_display_info *info)
> +{
> +	free((char *)info->summary);
> +	free((char *)info->success_detail);
> +	free((char *)info->fail_detail);
> +	free((char *)info->remote);
> +	free((char *)info->ref);
> +}
> +
> +static void ref_update_display_info_display(struct ref_update_display_info *info,
> +					    struct display_state *display_state,
> +					    int summary_width)
> +{
> +	display_ref_update(display_state,
> +			   info->failed ? info->fail_code : info->success_code,
> +			   info->summary,
> +			   info->failed ? info->fail_detail : info->success_detail,
> +			   info->remote, info->ref, &info->old_oid,
> +			   &info->new_oid, summary_width);
> +}
> +
>   static int update_local_ref(struct ref *ref,
>   			    struct ref_transaction *transaction,
> -			    struct display_state *display_state,
>   			    const struct ref *remote_ref,
> -			    int summary_width,
> -			    const struct fetch_config *config)
> +			    const struct fetch_config *config,
> +			    struct ref_update_display_info_array *display_array)
>   {
>   	struct commit *current = NULL, *updated;
>   	int fast_forward = 0;
> @@ -877,41 +952,56 @@ static int update_local_ref(struct ref *ref,
>   
>   	if (oideq(&ref->old_oid, &ref->new_oid)) {
>   		if (verbosity > 0)
> -			display_ref_update(display_state, '=', _("[up to date]"), NULL,
> -					   remote_ref->name, ref->name,
> -					   &ref->old_oid, &ref->new_oid, summary_width);
> +			ref_update_display_info_append(display_array, '=', '=',
> +						       _("[up to date]"), NULL,
> +						       NULL, ref->name,
> +						       remote_ref->name, &ref->old_oid,
> +						       &ref->new_oid);
>   		return 0;
>   	}
>   
>   	if (!update_head_ok &&
>   	    !is_null_oid(&ref->old_oid) &&
>   	    branch_checked_out(ref->name)) {
> +		struct ref_update_display_info *info;
>   		/*
>   		 * If this is the head, and it's not okay to update
>   		 * the head, and the old value of the head isn't empty...
>   		 */
> -		display_ref_update(display_state, '!', _("[rejected]"),
> -				   _("can't fetch into checked-out branch"),
> -				   remote_ref->name, ref->name,
> -				   &ref->old_oid, &ref->new_oid, summary_width);
> +		info = ref_update_display_info_append(display_array, '!', '!',
> +						      _("[rejected]"), NULL,
> +						      _("can't fetch into checked-out branch"),
> +						      ref->name, remote_ref->name,
> +						      &ref->old_oid, &ref->new_oid);
> +		ref_update_display_info_set_failed(info);
>   		return 1;
>   	}
>   
>   	if (!is_null_oid(&ref->old_oid) &&
>   	    starts_with(ref->name, "refs/tags/")) {
> +		struct ref_update_display_info *info;
> +
>   		if (force || ref->force) {
>   			int r;
> +
>   			r = s_update_ref("updating tag", ref, transaction, 0);
> -			display_ref_update(display_state, r ? '!' : 't', _("[tag update]"),
> -					   r ? _("unable to update local ref") : NULL,
> -					   remote_ref->name, ref->name,
> -					   &ref->old_oid, &ref->new_oid, summary_width);
> +
> +			info = ref_update_display_info_append(display_array, 't', '!',
> +							      _("[tag update]"), NULL,
> +							      _("unable to update local ref"),
> +							      ref->name, remote_ref->name,
> +							      &ref->old_oid, &ref->new_oid);
> +			if (r)
> +				ref_update_display_info_set_failed(info);
> +
>   			return r;
>   		} else {
> -			display_ref_update(display_state, '!', _("[rejected]"),
> -					   _("would clobber existing tag"),
> -					   remote_ref->name, ref->name,
> -					   &ref->old_oid, &ref->new_oid, summary_width);
> +			info = ref_update_display_info_append(display_array, '!', '!',
> +							      _("[rejected]"), NULL,
> +							      _("would clobber existing tag"),
> +							      ref->name, remote_ref->name,
> +							      &ref->old_oid, &ref->new_oid);
> +			ref_update_display_info_set_failed(info);
>   			return 1;
>   		}
>   	}
> @@ -921,6 +1011,7 @@ static int update_local_ref(struct ref *ref,
>   	updated = lookup_commit_reference_gently(the_repository,
>   						 &ref->new_oid, 1);
>   	if (!current || !updated) {
> +		struct ref_update_display_info *info;
>   		const char *msg;
>   		const char *what;
>   		int r;
> @@ -941,10 +1032,15 @@ static int update_local_ref(struct ref *ref,
>   		}
>   
>   		r = s_update_ref(msg, ref, transaction, 0);
> -		display_ref_update(display_state, r ? '!' : '*', what,
> -				   r ? _("unable to update local ref") : NULL,
> -				   remote_ref->name, ref->name,
> -				   &ref->old_oid, &ref->new_oid, summary_width);
> +
> +		info = ref_update_display_info_append(display_array, '*', '!',
> +						      what, NULL,
> +						      _("unable to update local ref"),
> +						      ref->name, remote_ref->name,
> +						      &ref->old_oid, &ref->new_oid);
> +		if (r)
> +			ref_update_display_info_set_failed(info);
> +
>   		return r;
>   	}
>   
> @@ -960,6 +1056,7 @@ static int update_local_ref(struct ref *ref,
>   	}
>   
>   	if (fast_forward) {
> +		struct ref_update_display_info *info;
>   		struct strbuf quickref = STRBUF_INIT;
>   		int r;
>   
> @@ -967,29 +1064,46 @@ static int update_local_ref(struct ref *ref,
>   		strbuf_addstr(&quickref, "..");
>   		strbuf_add_unique_abbrev(&quickref, &ref->new_oid, DEFAULT_ABBREV);
>   		r = s_update_ref("fast-forward", ref, transaction, 1);
> -		display_ref_update(display_state, r ? '!' : ' ', quickref.buf,
> -				   r ? _("unable to update local ref") : NULL,
> -				   remote_ref->name, ref->name,
> -				   &ref->old_oid, &ref->new_oid, summary_width);
> +
> +		info = ref_update_display_info_append(display_array, ' ', '!',
> +						      quickref.buf, NULL,
> +						      _("unable to update local ref"),
> +						      ref->name, remote_ref->name,
> +						      &ref->old_oid, &ref->new_oid);
> +		if (r)
> +			ref_update_display_info_set_failed(info);
> +
>   		strbuf_release(&quickref);
>   		return r;
>   	} else if (force || ref->force) {
> +		struct ref_update_display_info *info;
>   		struct strbuf quickref = STRBUF_INIT;
>   		int r;
> +
>   		strbuf_add_unique_abbrev(&quickref, &current->object.oid, DEFAULT_ABBREV);
>   		strbuf_addstr(&quickref, "...");
>   		strbuf_add_unique_abbrev(&quickref, &ref->new_oid, DEFAULT_ABBREV);
>   		r = s_update_ref("forced-update", ref, transaction, 1);
> -		display_ref_update(display_state, r ? '!' : '+', quickref.buf,
> -				   r ? _("unable to update local ref") : _("forced update"),
> -				   remote_ref->name, ref->name,
> -				   &ref->old_oid, &ref->new_oid, summary_width);
> +
> +		info = ref_update_display_info_append(display_array, '+', '!',
> +						      quickref.buf, _("forced update"),
> +						      _("unable to update local ref"),
> +						      ref->name, remote_ref->name,
> +						      &ref->old_oid, &ref->new_oid);
> +
> +		if (r)
> +			ref_update_display_info_set_failed(info);
> +
>   		strbuf_release(&quickref);
>   		return r;
>   	} else {
> -		display_ref_update(display_state, '!', _("[rejected]"), _("non-fast-forward"),
> -				   remote_ref->name, ref->name,
> -				   &ref->old_oid, &ref->new_oid, summary_width);
> +		struct ref_update_display_info *info;
> +		info = ref_update_display_info_append(display_array, '!', '!',
> +						      _("[rejected]"), NULL,
> +						      _("non-fast-forward"),
> +						      ref->name, remote_ref->name,
> +						      &ref->old_oid, &ref->new_oid);
> +		ref_update_display_info_set_failed(info);
>   		return 1;
>   	}
>   }
> @@ -1103,17 +1217,14 @@ static int store_updated_refs(struct display_state *display_state,
>   			      int connectivity_checked,
>   			      struct ref_transaction *transaction, struct ref *ref_map,
>   			      struct fetch_head *fetch_head,
> -			      const struct fetch_config *config)
> +			      const struct fetch_config *config,
> +			      struct ref_update_display_info_array *display_array)
>   {
>   	int rc = 0;
>   	struct strbuf note = STRBUF_INIT;
>   	const char *what, *kind;
>   	struct ref *rm;
>   	int want_status;
> -	int summary_width = 0;
> -
> -	if (verbosity >= 0)
> -		summary_width = transport_summary_width(ref_map);
>   
>   	if (!connectivity_checked) {
>   		struct check_connected_options opt = CHECK_CONNECTED_INIT;
> @@ -1218,8 +1329,8 @@ static int store_updated_refs(struct display_state *display_state,
>   					  display_state->url_len);
>   
>   			if (ref) {
> -				rc |= update_local_ref(ref, transaction, display_state,
> -						       rm, summary_width, config);
> +				rc |= update_local_ref(ref, transaction, rm,
> +						       config, display_array);
>   				free(ref);
>   			} else if (write_fetch_head || dry_run) {
>   				/*
> @@ -1227,12 +1338,12 @@ static int store_updated_refs(struct display_state *display_state,
>   				 * would be written to FETCH_HEAD, if --dry-run
>   				 * is set).
>   				 */
> -				display_ref_update(display_state, '*',
> -						   *kind ? kind : "branch", NULL,
> -						   rm->name,
> -						   "FETCH_HEAD",
> -						   &rm->new_oid, &rm->old_oid,
> -						   summary_width);
> +
> +				ref_update_display_info_append(display_array, '*', '*',
> +							       *kind ? kind : "branch",
> +							       NULL, NULL, "FETCH_HEAD",
> +							       rm->name, &rm->new_oid,
> +							       &rm->old_oid);
>   			}
>   		}
>   	}
> @@ -1300,7 +1411,8 @@ static int fetch_and_consume_refs(struct display_state *display_state,
>   				  struct ref_transaction *transaction,
>   				  struct ref *ref_map,
>   				  struct fetch_head *fetch_head,
> -				  const struct fetch_config *config)
> +				  const struct fetch_config *config,
> +				  struct ref_update_display_info_array *display_array)
>   {
>   	int connectivity_checked = 1;
>   	int ret;
> @@ -1322,7 +1434,8 @@ static int fetch_and_consume_refs(struct display_state *display_state,
>   
>   	trace2_region_enter("fetch", "consume_refs", the_repository);
>   	ret = store_updated_refs(display_state, connectivity_checked,
> -				 transaction, ref_map, fetch_head, config);
> +				 transaction, ref_map, fetch_head, config,
> +				 display_array);
>   	trace2_region_leave("fetch", "consume_refs", the_repository);
>   
>   out:
> @@ -1493,7 +1606,8 @@ static int backfill_tags(struct display_state *display_state,
>   			 struct ref_transaction *transaction,
>   			 struct ref *ref_map,
>   			 struct fetch_head *fetch_head,
> -			 const struct fetch_config *config)
> +			 const struct fetch_config *config,
> +			 struct ref_update_display_info_array *display_array)
>   {
>   	int retcode, cannot_reuse;
>   
> @@ -1515,7 +1629,7 @@ static int backfill_tags(struct display_state *display_state,
>   	transport_set_option(transport, TRANS_OPT_DEPTH, "0");
>   	transport_set_option(transport, TRANS_OPT_DEEPEN_RELATIVE, NULL);
>   	retcode = fetch_and_consume_refs(display_state, transport, transaction, ref_map,
> -					 fetch_head, config);
> +					 fetch_head, config, display_array);
>   
>   	if (gsecondary) {
>   		transport_disconnect(gsecondary);
> @@ -1641,6 +1755,7 @@ struct ref_rejection_data {
>   	bool conflict_msg_shown;
>   	bool case_sensitive_msg_shown;
>   	const char *remote_name;
> +	struct strmap *rejected_refs;
>   };
>   
>   static void ref_transaction_rejection_handler(const char *refname,
> @@ -1681,6 +1796,7 @@ static void ref_transaction_rejection_handler(const char *refname,
>   			      refname, ref_transaction_error_msg(err));
>   	}
>   
> +	strmap_put(data->rejected_refs, refname, NULL);
>   	*data->retcode = 1;
>   }
>   
> @@ -1690,6 +1806,7 @@ static void ref_transaction_rejection_handler(const char *refname,
>    */
>   static int commit_ref_transaction(struct ref_transaction **transaction,
>   				  bool is_atomic, const char *remote_name,
> +				  struct strmap *rejected_refs,
>   				  struct strbuf *err)
>   {
>   	int retcode = ref_transaction_commit(*transaction, err);
> @@ -1701,6 +1818,7 @@ static int commit_ref_transaction(struct ref_transaction **transaction,
>   			.conflict_msg_shown = 0,
>   			.remote_name = remote_name,
>   			.retcode = &retcode,
> +			.rejected_refs = rejected_refs,
>   		};
>   
>   		ref_transaction_for_each_rejected_update(*transaction,
> @@ -1729,6 +1847,9 @@ static int do_fetch(struct transport *transport,
>   	struct fetch_head fetch_head = { 0 };
>   	struct strbuf err = STRBUF_INIT;
>   	int do_set_head = 0;
> +	struct ref_update_display_info_array display_array = { 0 };
> +	struct strmap rejected_refs = STRMAP_INIT;
> +	int summary_width = 0;
>   
>   	if (tags == TAGS_DEFAULT) {
>   		if (transport->remote->fetch_tags == 2)
> @@ -1853,7 +1974,7 @@ static int do_fetch(struct transport *transport,
>   	}
>   
>   	if (fetch_and_consume_refs(&display_state, transport, transaction, ref_map,
> -				   &fetch_head, config)) {
> +				   &fetch_head, config, &display_array)) {
>   		retcode = 1;
>   		goto cleanup;
>   	}
> @@ -1876,7 +1997,7 @@ static int do_fetch(struct transport *transport,
>   			 * the transaction and don't commit anything.
>   			 */
>   			if (backfill_tags(&display_state, transport, transaction, tags_ref_map,
> -					  &fetch_head, config))
> +					  &fetch_head, config, &display_array))
>   				retcode = 1;
>   		}
>   
> @@ -1886,8 +2007,12 @@ static int do_fetch(struct transport *transport,
>   	if (retcode)
>   		goto cleanup;
>   
> +	if (verbosity >= 0)
> +		summary_width = transport_summary_width(ref_map);
> +
>   	retcode = commit_ref_transaction(&transaction, atomic_fetch,
> -					 transport->remote->name, &err);
> +					 transport->remote->name,
> +					 &rejected_refs, &err);
>   	/*
>   	 * With '--atomic', bail out if the transaction fails. Without '--atomic',
>   	 * continue to fetch head and perform other post-fetch operations.
> @@ -1965,7 +2090,17 @@ static int do_fetch(struct transport *transport,
>   	 */
>   	if (retcode && !atomic_fetch && transaction)
>   		commit_ref_transaction(&transaction, false,
> -				       transport->remote->name, &err);
> +				       transport->remote->name,
> +				       &rejected_refs, &err);
> +
> +	for (size_t i = 0; i < display_array.nr; i++) {
> +		struct ref_update_display_info *info = &display_array.info[i];
> +
> +		if (!info->failed && strmap_contains(&rejected_refs, info->ref))
> +			ref_update_display_info_set_failed(info);
> +		ref_update_display_info_display(info, &display_state, summary_width);
> +		ref_update_display_info_free(info);
> +	}
>   
>   	if (retcode) {
>   		if (err.len) {
> @@ -1980,6 +2115,9 @@ static int do_fetch(struct transport *transport,
>   
>   	if (transaction)
>   		ref_transaction_free(transaction);
> +
> +	free(display_array.info);
> +	strmap_clear(&rejected_refs, 0);
>   	display_state_release(&display_state);
>   	close_fetch_head(&fetch_head);
>   	strbuf_release(&err);
> diff --git a/t/t5516-fetch-push.sh b/t/t5516-fetch-push.sh
> index 45595991c8..29e2f17608 100755
> --- a/t/t5516-fetch-push.sh
> +++ b/t/t5516-fetch-push.sh
> @@ -1893,6 +1893,7 @@ test_expect_success 'pushing non-commit objects should report error' '
>   
>   		tagsha=$(git rev-parse test^{tag}) &&
>   		test_must_fail git push ../dest "$tagsha:refs/heads/branch" 2>err &&
> +		test_grep "! \[remote rejected\] $tagsha -> branch (invalid new value provided)" err &&
>   		test_grep "trying to write non-commit object $tagsha to branch ${SQ}refs/heads/branch${SQ}" err
>   	)
>   '
> 

Re: [PATCH v4 6/6] fetch: delay user information post committing of transaction

[Karthik Nayak]

[-- Attachment #1: Type: text/plain, Size: 303 bytes --]

Phillip Wood <phillip.wood123@gmail.com> writes:

> Hi Karthik
>
> I haven't looked in detail at the conversion of the callers from
> display_ref_update() to ref_update_display_info_append() but the array
> handling looks good.
>
> Thanks
>
> Phillip
>

Thanks Phillip for both the review and the help!

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 690 bytes --]

[PATCH v5 0/6] refs: provide detailed error messages when using batched update

[Karthik Nayak]

The refs namespace uses an error buffer to capture details about failed
reference updates. However when we added batched update support to
reference transactions, these messages were never propagated, instead
only an error code pertaining to the type of failure was propagated.

Currently, there are three regions which utilize batched updates:

  - git update-ref --batch-updates
  - git fetch
  - git receive-pack

While 'git update-ref --batch-updates' was a newly introduced flag, both
'git fetch' and 'git receive-pack' were pre-existing. Before using
batched updates, they provided more detailed error messages to the user,
but this changed with the introduction of batched updates. This is a
regression in their workings.

This patch series fixes this, by passing the detailed error message and
utilizing it whenever available. The regression was reported by Elijah
Newren [1] and based on the patch submitted by Jeff King [2].

[1]: https://lore.kernel.org/all/CABPp-BGL2tJR4dPidQuFcp-X0_VkVTknCY-0Zgo=jHVGv_P=wA@mail.gmail.com/
[2]: https://lore.kernel.org/all/20251224081214.GA1879908@coredump.intra.peff.net/

---
Changes in v5:
- In the last commit, drop 'const *' used to indicate immutability of
  fields within the struct. In the project it is more common to use
  'const *' to indicate ownership. Since the memory of the fields are
  owned by the struct, let's drop the 'const *'.
- Link to v4: https://patch.msgid.link/20260122-633-regression-lost-diagnostic-message-when-pushing-non-commit-objects-to-refs-heads-v4-0-2ddba0832440@gmail.com

Changes in v4:
- In the last commit, instead of propagating {*list, count}, propagate
  an array with {*list, nr, count} and use ALLOC_GROW. This simplifies
  the variables passed and cleanups the code.
- Link to v3: https://patch.msgid.link/20260120-633-regression-lost-diagnostic-message-when-pushing-non-commit-objects-to-refs-heads-v3-0-e0edb29acbef@gmail.com

Changes in v3:
- Drop the first commit.
- For the last commit, where we delay 'git fetch' status information,
  delay all information to the end. Also use a list to compliment the
  existing strmap, this ensures that the order is maintained.
- Link to v2: https://patch.msgid.link/20260116-633-regression-lost-diagnostic-message-when-pushing-non-commit-objects-to-refs-heads-v2-0-925a0e9c7f32@gmail.com

Changes in v2:
- Updates to the commit messages to be more descriptive.
- Instead of passing the char pointer for the error description, pass
  the 'strbuf' itself. This makes the API a lot cleaner to deal with.
  Also avoids having to remember to reset the strbuf after usage.
- Chalk out a separate commit for using a 'goto next_ref' in
  `refs_verify_refnames_available()`. This makes the intention much
  clearer.
- For git-update-ref(1), keep the existing implementation as is and only
  output the detailed error message to stderr.
- For git-receive-pack(1), use 'rp_error()' for detailed error message
  while keeping the current implementation as is.
- Added a separate patch to handle missing information in git-fetch(1)'s
  status table. This involves delaying updates to the end, where update
  success/failure information is available. I'm not too confident about
  this approach though, we could also drop it from the series and I
  could pick that up independently. This is still 1.19 ± 0.02 times
  faster than non-batched version (v2.50.0) in the files backend.
- Link to v1: https://patch.msgid.link/20260114-633-regression-lost-diagnostic-message-when-pushing-non-commit-objects-to-refs-heads-v1-0-f5f8b173c501@gmail.com

---
 builtin/fetch.c         | 255 +++++++++++++++++++++++++++++++++++++-----------
 builtin/receive-pack.c  |   7 +-
 builtin/update-ref.c    |   7 +-
 refs.c                  |  46 +++++----
 refs.h                  |   1 +
 refs/files-backend.c    |   5 +-
 refs/packed-backend.c   |  12 +--
 refs/refs-internal.h    |   4 +-
 refs/reftable-backend.c |   5 +-
 t/t1400-update-ref.sh   |  71 ++++++++------
 t/t5510-fetch.sh        |   8 +-
 t/t5516-fetch-push.sh   |  16 +++
 12 files changed, 312 insertions(+), 125 deletions(-)

Karthik Nayak (6):
      refs: skip to next ref when current ref is rejected
      refs: add rejection detail to the callback function
      update-ref: utilize rejected error details if available
      fetch: utilize rejected ref error details
      receive-pack: utilize rejected ref error details
      fetch: delay user information post committing of transaction

Range-diff versus v4:

1:  3264b8c3bf = 1:  661265fb86 refs: skip to next ref when current ref is rejected
2:  3d2af7a15a = 2:  1f0f2b6224 refs: add rejection detail to the callback function
3:  bc7556f4b0 = 3:  8413ca46b5 update-ref: utilize rejected error details if available
4:  d114f13967 = 4:  b0c4441c55 fetch: utilize rejected ref error details
5:  4606c3b991 = 5:  8aa4477f51 receive-pack: utilize rejected ref error details
6:  c75ccc40f3 ! 6:  c9698e06bb fetch: delay user information post committing of transaction
    @@ builtin/fetch.c: static void display_ref_update(struct display_state *display_st
     +	bool failed;
     +	char success_code;
     +	char fail_code;
    -+	const char *summary;
    -+	const char *fail_detail;
    -+	const char *success_detail;
    -+	const char *ref;
    -+	const char *remote;
    ++	char *summary;
    ++	char *fail_detail;
    ++	char *success_detail;
    ++	char *ref;
    ++	char *remote;
     +	struct object_id old_oid;
     +	struct object_id new_oid;
     +};
    @@ builtin/fetch.c: static void display_ref_update(struct display_state *display_st
     +
     +static void ref_update_display_info_free(struct ref_update_display_info *info)
     +{
    -+	free((char *)info->summary);
    -+	free((char *)info->success_detail);
    -+	free((char *)info->fail_detail);
    -+	free((char *)info->remote);
    -+	free((char *)info->ref);
    ++	free(info->summary);
    ++	free(info->success_detail);
    ++	free(info->fail_detail);
    ++	free(info->remote);
    ++	free(info->ref);
     +}
     +
     +static void ref_update_display_info_display(struct ref_update_display_info *info,


base-commit: 8745eae506f700657882b9e32b2aa00f234a6fb6
change-id: 20260113-633-regression-lost-diagnostic-message-when-pushing-non-commit-objects-to-refs-heads-17786b20894a

Thanks
- Karthik

[PATCH v5 1/6] refs: skip to next ref when current ref is rejected

[Karthik Nayak]

In `refs_verify_refnames_available()` we have two nested loops: the
outer loop iterates over all references to check, while the inner loop
checks for filesystem conflicts for a given ref by breaking down its
path.

With batched updates, when we detect a filesystem conflict, we mark the
update as rejected and execute 'continue'. However, this only skips to
the next iteration of the inner loop, not the outer loop as intended.
This causes the same reference to be repeatedly rejected. Fix this by
using a goto statement to skip to the next reference in the outer loop.

Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
---
 refs.c                  | 44 ++++++++++++++++++++++++++------------------
 refs/files-backend.c    |  5 ++---
 refs/packed-backend.c   | 12 ++++++------
 refs/refs-internal.h    |  4 +++-
 refs/reftable-backend.c |  5 ++---
 5 files changed, 39 insertions(+), 31 deletions(-)

diff --git a/refs.c b/refs.c
index e06e0cb072..53919c3d22 100644
--- a/refs.c
+++ b/refs.c
@@ -1224,6 +1224,7 @@ void ref_transaction_free(struct ref_transaction *transaction)
 		free(transaction->updates[i]->committer_info);
 		free((char *)transaction->updates[i]->new_target);
 		free((char *)transaction->updates[i]->old_target);
+		free((char *)transaction->updates[i]->rejection_details);
 		free(transaction->updates[i]);
 	}
 
@@ -1238,7 +1239,8 @@ void ref_transaction_free(struct ref_transaction *transaction)
 
 int ref_transaction_maybe_set_rejected(struct ref_transaction *transaction,
 				       size_t update_idx,
-				       enum ref_transaction_error err)
+				       enum ref_transaction_error err,
+				       struct strbuf *details)
 {
 	if (update_idx >= transaction->nr)
 		BUG("trying to set rejection on invalid update index");
@@ -1264,6 +1266,7 @@ int ref_transaction_maybe_set_rejected(struct ref_transaction *transaction,
 			   transaction->updates[update_idx]->refname, 0);
 
 	transaction->updates[update_idx]->rejection_err = err;
+	transaction->updates[update_idx]->rejection_details = strbuf_detach(details, NULL);
 	ALLOC_GROW(transaction->rejections->update_indices,
 		   transaction->rejections->nr + 1,
 		   transaction->rejections->alloc);
@@ -2659,30 +2662,33 @@ enum ref_transaction_error refs_verify_refnames_available(struct ref_store *refs
 			if (!initial_transaction &&
 			    (strset_contains(&conflicting_dirnames, dirname.buf) ||
 			     !refs_read_raw_ref(refs, dirname.buf, &oid, &referent,
-						       &type, &ignore_errno))) {
+						&type, &ignore_errno))) {
+
+				strbuf_addf(err, _("'%s' exists; cannot create '%s'"),
+					    dirname.buf, refname);
+
 				if (transaction && ref_transaction_maybe_set_rejected(
 					    transaction, *update_idx,
-					    REF_TRANSACTION_ERROR_NAME_CONFLICT)) {
+					    REF_TRANSACTION_ERROR_NAME_CONFLICT, err)) {
 					strset_remove(&dirnames, dirname.buf);
 					strset_add(&conflicting_dirnames, dirname.buf);
-					continue;
+					goto next_ref;
 				}
 
-				strbuf_addf(err, _("'%s' exists; cannot create '%s'"),
-					    dirname.buf, refname);
 				goto cleanup;
 			}
 
 			if (extras && string_list_has_string(extras, dirname.buf)) {
+				strbuf_addf(err, _("cannot process '%s' and '%s' at the same time"),
+					    refname, dirname.buf);
+
 				if (transaction && ref_transaction_maybe_set_rejected(
 					    transaction, *update_idx,
-					    REF_TRANSACTION_ERROR_NAME_CONFLICT)) {
+					    REF_TRANSACTION_ERROR_NAME_CONFLICT, err)) {
 					strset_remove(&dirnames, dirname.buf);
-					continue;
+					goto next_ref;
 				}
 
-				strbuf_addf(err, _("cannot process '%s' and '%s' at the same time"),
-					    refname, dirname.buf);
 				goto cleanup;
 			}
 		}
@@ -2712,14 +2718,14 @@ enum ref_transaction_error refs_verify_refnames_available(struct ref_store *refs
 				if (skip &&
 				    string_list_has_string(skip, iter->ref.name))
 					continue;
+				strbuf_addf(err, _("'%s' exists; cannot create '%s'"),
+					    iter->ref.name, refname);
 
 				if (transaction && ref_transaction_maybe_set_rejected(
 					    transaction, *update_idx,
-					    REF_TRANSACTION_ERROR_NAME_CONFLICT))
-					continue;
+					    REF_TRANSACTION_ERROR_NAME_CONFLICT, err))
+					goto next_ref;
 
-				strbuf_addf(err, _("'%s' exists; cannot create '%s'"),
-					    iter->ref.name, refname);
 				goto cleanup;
 			}
 
@@ -2729,15 +2735,17 @@ enum ref_transaction_error refs_verify_refnames_available(struct ref_store *refs
 
 		extra_refname = find_descendant_ref(dirname.buf, extras, skip);
 		if (extra_refname) {
+			strbuf_addf(err, _("cannot process '%s' and '%s' at the same time"),
+				    refname, extra_refname);
+
 			if (transaction && ref_transaction_maybe_set_rejected(
 				    transaction, *update_idx,
-				    REF_TRANSACTION_ERROR_NAME_CONFLICT))
-				continue;
+				    REF_TRANSACTION_ERROR_NAME_CONFLICT, err))
+				goto next_ref;
 
-			strbuf_addf(err, _("cannot process '%s' and '%s' at the same time"),
-				    refname, extra_refname);
 			goto cleanup;
 		}
+next_ref:;
 	}
 
 	ret = 0;
diff --git a/refs/files-backend.c b/refs/files-backend.c
index 6f6f76a8d8..6790d8bf53 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -2983,10 +2983,9 @@ static int files_transaction_prepare(struct ref_store *ref_store,
 					  head_ref, &refnames_to_check,
 					  err);
 		if (ret) {
-			if (ref_transaction_maybe_set_rejected(transaction, i, ret)) {
-				strbuf_reset(err);
+			if (ref_transaction_maybe_set_rejected(transaction, i,
+							       ret, err)) {
 				ret = 0;
-
 				continue;
 			}
 			goto cleanup;
diff --git a/refs/packed-backend.c b/refs/packed-backend.c
index 4ea0c12299..59b3ecb9d6 100644
--- a/refs/packed-backend.c
+++ b/refs/packed-backend.c
@@ -1437,8 +1437,8 @@ static enum ref_transaction_error write_with_updates(struct packed_ref_store *re
 						    update->refname);
 					ret = REF_TRANSACTION_ERROR_CREATE_EXISTS;
 
-					if (ref_transaction_maybe_set_rejected(transaction, i, ret)) {
-						strbuf_reset(err);
+					if (ref_transaction_maybe_set_rejected(transaction, i,
+									       ret, err)) {
 						ret = 0;
 						continue;
 					}
@@ -1452,8 +1452,8 @@ static enum ref_transaction_error write_with_updates(struct packed_ref_store *re
 						    oid_to_hex(&update->old_oid));
 					ret = REF_TRANSACTION_ERROR_INCORRECT_OLD_VALUE;
 
-					if (ref_transaction_maybe_set_rejected(transaction, i, ret)) {
-						strbuf_reset(err);
+					if (ref_transaction_maybe_set_rejected(transaction, i,
+									       ret, err)) {
 						ret = 0;
 						continue;
 					}
@@ -1496,8 +1496,8 @@ static enum ref_transaction_error write_with_updates(struct packed_ref_store *re
 					    oid_to_hex(&update->old_oid));
 				ret = REF_TRANSACTION_ERROR_NONEXISTENT_REF;
 
-				if (ref_transaction_maybe_set_rejected(transaction, i, ret)) {
-					strbuf_reset(err);
+				if (ref_transaction_maybe_set_rejected(transaction, i,
+								       ret, err)) {
 					ret = 0;
 					continue;
 				}
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index c7d2a6e50b..191a25683f 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -128,6 +128,7 @@ struct ref_update {
 	 * was rejected.
 	 */
 	enum ref_transaction_error rejection_err;
+	const char *rejection_details;
 
 	/*
 	 * If this ref_update was split off of a symref update via
@@ -153,7 +154,8 @@ int refs_read_raw_ref(struct ref_store *ref_store, const char *refname,
  */
 int ref_transaction_maybe_set_rejected(struct ref_transaction *transaction,
 				       size_t update_idx,
-				       enum ref_transaction_error err);
+				       enum ref_transaction_error err,
+				       struct strbuf *details);
 
 /*
  * Add a ref_update with the specified properties to transaction, and
diff --git a/refs/reftable-backend.c b/refs/reftable-backend.c
index 4319a4eacb..0e2648e36c 100644
--- a/refs/reftable-backend.c
+++ b/refs/reftable-backend.c
@@ -1401,10 +1401,9 @@ static int reftable_be_transaction_prepare(struct ref_store *ref_store,
 					    &refnames_to_check, head_type,
 					    &head_referent, &referent, err);
 		if (ret) {
-			if (ref_transaction_maybe_set_rejected(transaction, i, ret)) {
-				strbuf_reset(err);
+			if (ref_transaction_maybe_set_rejected(transaction, i,
+							       ret, err)) {
 				ret = 0;
-
 				continue;
 			}
 			goto done;

-- 
2.52.0

[PATCH v5 2/6] refs: add rejection detail to the callback function

[Karthik Nayak]

The previous commit started storing the rejection details alongside the
error code for rejected updates. Pass this along to the callback
function `ref_transaction_for_each_rejected_update()`. Currently the
field is unused, but will be integrated in the upcoming commits.

Co-authored-by: Jeff King <peff@peff.net>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
---
 builtin/fetch.c        | 1 +
 builtin/receive-pack.c | 1 +
 builtin/update-ref.c   | 1 +
 refs.c                 | 2 +-
 refs.h                 | 1 +
 5 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/builtin/fetch.c b/builtin/fetch.c
index 288d3772ea..d427adea61 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -1649,6 +1649,7 @@ static void ref_transaction_rejection_handler(const char *refname,
 					      const char *old_target UNUSED,
 					      const char *new_target UNUSED,
 					      enum ref_transaction_error err,
+					      const char *details UNUSED,
 					      void *cb_data)
 {
 	struct ref_rejection_data *data = cb_data;
diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index ef1f77be8c..94d3e73cee 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -1813,6 +1813,7 @@ static void ref_transaction_rejection_handler(const char *refname,
 					      const char *old_target UNUSED,
 					      const char *new_target UNUSED,
 					      enum ref_transaction_error err,
+					      const char *details UNUSED,
 					      void *cb_data)
 {
 	struct strmap *failed_refs = cb_data;
diff --git a/builtin/update-ref.c b/builtin/update-ref.c
index 195437e7c6..0046a87c57 100644
--- a/builtin/update-ref.c
+++ b/builtin/update-ref.c
@@ -573,6 +573,7 @@ static void print_rejected_refs(const char *refname,
 				const char *old_target,
 				const char *new_target,
 				enum ref_transaction_error err,
+				const char *details UNUSED,
 				void *cb_data UNUSED)
 {
 	struct strbuf sb = STRBUF_INIT;
diff --git a/refs.c b/refs.c
index 53919c3d22..c85c3d2c8b 100644
--- a/refs.c
+++ b/refs.c
@@ -2874,7 +2874,7 @@ void ref_transaction_for_each_rejected_update(struct ref_transaction *transactio
 		   (update->flags & REF_HAVE_OLD) ? &update->old_oid : NULL,
 		   (update->flags & REF_HAVE_NEW) ? &update->new_oid : NULL,
 		   update->old_target, update->new_target,
-		   update->rejection_err, cb_data);
+		   update->rejection_err, update->rejection_details, cb_data);
 	}
 }
 
diff --git a/refs.h b/refs.h
index d9051bbb04..4fbe3da924 100644
--- a/refs.h
+++ b/refs.h
@@ -975,6 +975,7 @@ typedef void ref_transaction_for_each_rejected_update_fn(const char *refname,
 							 const char *old_target,
 							 const char *new_target,
 							 enum ref_transaction_error err,
+							 const char *details,
 							 void *cb_data);
 void ref_transaction_for_each_rejected_update(struct ref_transaction *transaction,
 					      ref_transaction_for_each_rejected_update_fn cb,

-- 
2.52.0

[PATCH v5 3/6] update-ref: utilize rejected error details if available

[Karthik Nayak]

When git-update-ref(1) received the '--update-ref' flag, the error
details generated in the refs namespace wasn't propagated with failed
updates. Instead only an error code pertaining to the type of rejection
was noted.

This missed detailed error message which the user can act upon. The
previous commits added the required code to propagate these detailed
error messages from the refs namespace. Now that additional details are
available, let's output this additional details to stderr. This allows
users to have additional information over the already present machine
parsable output.

While we're here, improve the existing tests for the machine parsable
output by checking for the entire output string and not just the
rejection reason.

Reported-by: Elijah Newren <newren@gmail.com>
Co-authored-by: Jeff King <peff@peff.net>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
---
 builtin/update-ref.c  |  8 +++---
 t/t1400-update-ref.sh | 71 ++++++++++++++++++++++++++++++---------------------
 2 files changed, 47 insertions(+), 32 deletions(-)

diff --git a/builtin/update-ref.c b/builtin/update-ref.c
index 0046a87c57..2d68c40ecb 100644
--- a/builtin/update-ref.c
+++ b/builtin/update-ref.c
@@ -573,16 +573,18 @@ static void print_rejected_refs(const char *refname,
 				const char *old_target,
 				const char *new_target,
 				enum ref_transaction_error err,
-				const char *details UNUSED,
+				const char *details,
 				void *cb_data UNUSED)
 {
 	struct strbuf sb = STRBUF_INIT;
-	const char *reason = ref_transaction_error_msg(err);
+
+	if (details && *details)
+		error("%s", details);
 
 	strbuf_addf(&sb, "rejected %s %s %s %s\n", refname,
 		    new_oid ? oid_to_hex(new_oid) : new_target,
 		    old_oid ? oid_to_hex(old_oid) : old_target,
-		    reason);
+		    ref_transaction_error_msg(err));
 
 	fwrite(sb.buf, sb.len, 1, stdout);
 	strbuf_release(&sb);
diff --git a/t/t1400-update-ref.sh b/t/t1400-update-ref.sh
index db7f5444da..db6585b8d8 100755
--- a/t/t1400-update-ref.sh
+++ b/t/t1400-update-ref.sh
@@ -2093,14 +2093,15 @@ do
 
 			format_command $type "update refs/heads/ref1" "$old_head" "$head" >stdin &&
 			format_command $type "update refs/heads/ref2" "$(test_oid 001)" "$head" >>stdin &&
-			git update-ref $type --stdin --batch-updates <stdin >stdout &&
+			git update-ref $type --stdin --batch-updates <stdin >stdout 2>err &&
 			echo $old_head >expect &&
 			git rev-parse refs/heads/ref1 >actual &&
 			test_cmp expect actual &&
 			echo $head >expect &&
 			git rev-parse refs/heads/ref2 >actual &&
 			test_cmp expect actual &&
-			test_grep -q "invalid new value provided" stdout
+			test_grep "rejected refs/heads/ref2 $(test_oid 001) $head invalid new value provided" stdout &&
+			test_grep "trying to write ref ${SQ}refs/heads/ref2${SQ} with nonexistent object" err
 		)
 	'
 
@@ -2119,14 +2120,15 @@ do
 
 			format_command $type "update refs/heads/ref1" "$old_head" "$head" >stdin &&
 			format_command $type "update refs/heads/ref2" "$head_tree" "$head" >>stdin &&
-			git update-ref $type --stdin --batch-updates <stdin >stdout &&
+			git update-ref $type --stdin --batch-updates <stdin >stdout 2>err &&
 			echo $old_head >expect &&
 			git rev-parse refs/heads/ref1 >actual &&
 			test_cmp expect actual &&
 			echo $head >expect &&
 			git rev-parse refs/heads/ref2 >actual &&
 			test_cmp expect actual &&
-			test_grep -q "invalid new value provided" stdout
+			test_grep "rejected refs/heads/ref2 $head_tree $head invalid new value provided" stdout &&
+			test_grep "trying to write non-commit object $head_tree to branch ${SQ}refs/heads/ref2${SQ}" err
 		)
 	'
 
@@ -2143,12 +2145,13 @@ do
 
 			format_command $type "update refs/heads/ref1" "$old_head" "$head" >stdin &&
 			format_command $type "update refs/heads/ref2" "$old_head" "$head" >>stdin &&
-			git update-ref $type --stdin --batch-updates <stdin >stdout &&
+			git update-ref $type --stdin --batch-updates <stdin >stdout 2>err &&
 			echo $old_head >expect &&
 			git rev-parse refs/heads/ref1 >actual &&
 			test_cmp expect actual &&
 			test_must_fail git rev-parse refs/heads/ref2 &&
-			test_grep -q "reference does not exist" stdout
+			test_grep "rejected refs/heads/ref2 $old_head $head reference does not exist" stdout &&
+			test_grep "cannot lock ref ${SQ}refs/heads/ref2${SQ}: unable to resolve reference ${SQ}refs/heads/ref2${SQ}" err
 		)
 	'
 
@@ -2166,13 +2169,14 @@ do
 
 			format_command $type "update refs/heads/ref1" "$old_head" "$head" >stdin &&
 			format_command $type "update refs/heads/ref2" "$old_head" "$head" >>stdin &&
-			git update-ref $type --no-deref --stdin --batch-updates <stdin >stdout &&
+			git update-ref $type --no-deref --stdin --batch-updates <stdin >stdout 2>err &&
 			echo $old_head >expect &&
 			git rev-parse refs/heads/ref1 >actual &&
 			test_cmp expect actual &&
 			echo $head >expect &&
 			test_must_fail git rev-parse refs/heads/ref2 &&
-			test_grep -q "reference does not exist" stdout
+			test_grep "rejected refs/heads/ref2 $old_head $head reference does not exist" stdout &&
+			test_grep "cannot lock ref ${SQ}refs/heads/ref2${SQ}: reference is missing but expected $head" err
 		)
 	'
 
@@ -2190,7 +2194,7 @@ do
 
 			format_command $type "update refs/heads/ref1" "$old_head" "$head" >stdin &&
 			format_command $type "symref-update refs/heads/ref2" "$old_head" "ref" "refs/heads/nonexistent" >>stdin &&
-			git update-ref $type --no-deref --stdin --batch-updates <stdin >stdout &&
+			git update-ref $type --no-deref --stdin --batch-updates <stdin >stdout 2>err &&
 			echo $old_head >expect &&
 			git rev-parse refs/heads/ref1 >actual &&
 			test_cmp expect actual &&
@@ -2198,7 +2202,8 @@ do
 			echo $head >expect &&
 			git rev-parse refs/heads/ref2 >actual &&
 			test_cmp expect actual &&
-			test_grep -q "expected symref but found regular ref" stdout
+			test_grep "rejected refs/heads/ref2 $ZERO_OID $ZERO_OID expected symref but found regular ref" stdout &&
+			test_grep "cannot lock ref ${SQ}refs/heads/ref2${SQ}: expected symref with target ${SQ}refs/heads/nonexistent${SQ}: but is a regular ref" err
 		)
 	'
 
@@ -2216,14 +2221,15 @@ do
 
 			format_command $type "update refs/heads/ref1" "$old_head" "$head" >stdin &&
 			format_command $type "update refs/heads/ref2" "$old_head" "$Z" >>stdin &&
-			git update-ref $type --stdin --batch-updates <stdin >stdout &&
+			git update-ref $type --stdin --batch-updates <stdin >stdout 2>err &&
 			echo $old_head >expect &&
 			git rev-parse refs/heads/ref1 >actual &&
 			test_cmp expect actual &&
 			echo $head >expect &&
 			git rev-parse refs/heads/ref2 >actual &&
 			test_cmp expect actual &&
-			test_grep -q "reference already exists" stdout
+			test_grep "rejected refs/heads/ref2 $old_head $ZERO_OID reference already exists" stdout &&
+			test_grep "cannot lock ref ${SQ}refs/heads/ref2${SQ}: reference already exists" err
 		)
 	'
 
@@ -2241,14 +2247,15 @@ do
 
 			format_command $type "update refs/heads/ref1" "$old_head" "$head" >stdin &&
 			format_command $type "update refs/heads/ref2" "$head" "$old_head" >>stdin &&
-			git update-ref $type --stdin --batch-updates <stdin >stdout &&
+			git update-ref $type --stdin --batch-updates <stdin >stdout 2>err &&
 			echo $old_head >expect &&
 			git rev-parse refs/heads/ref1 >actual &&
 			test_cmp expect actual &&
 			echo $head >expect &&
 			git rev-parse refs/heads/ref2 >actual &&
 			test_cmp expect actual &&
-			test_grep -q "incorrect old value provided" stdout
+			test_grep "rejected refs/heads/ref2 $head $old_head incorrect old value provided" stdout &&
+			test_grep "cannot lock ref ${SQ}refs/heads/ref2${SQ}: is at $head but expected $old_head" err
 		)
 	'
 
@@ -2264,12 +2271,13 @@ do
 			git update-ref refs/heads/ref/foo $head &&
 
 			format_command $type "update refs/heads/ref/foo" "$old_head" "$head" >stdin &&
-			format_command $type "update refs/heads/ref" "$old_head" "" >>stdin &&
-			git update-ref $type --stdin --batch-updates <stdin >stdout &&
+			format_command $type "update refs/heads/ref" "$old_head" "$ZERO_OID" >>stdin &&
+			git update-ref $type --stdin --batch-updates <stdin >stdout 2>err &&
 			echo $old_head >expect &&
 			git rev-parse refs/heads/ref/foo >actual &&
 			test_cmp expect actual &&
-			test_grep -q "refname conflict" stdout
+			test_grep "rejected refs/heads/ref $old_head $ZERO_OID refname conflict" stdout &&
+			test_grep "${SQ}refs/heads/ref/foo${SQ} exists; cannot create ${SQ}refs/heads/ref${SQ}" err
 		)
 	'
 
@@ -2284,13 +2292,14 @@ do
 			head=$(git rev-parse HEAD) &&
 			git update-ref refs/heads/ref/foo $head &&
 
-			format_command $type "update refs/heads/foo" "$old_head" "" >stdin &&
-			format_command $type "update refs/heads/ref" "$old_head" "" >>stdin &&
-			git update-ref $type --stdin --batch-updates <stdin >stdout &&
+			format_command $type "update refs/heads/foo" "$old_head" "$ZERO_OID" >stdin &&
+			format_command $type "update refs/heads/ref" "$old_head" "$ZERO_OID" >>stdin &&
+			git update-ref $type --stdin --batch-updates <stdin >stdout 2>err &&
 			echo $old_head >expect &&
 			git rev-parse refs/heads/foo >actual &&
 			test_cmp expect actual &&
-			test_grep -q "refname conflict" stdout
+			test_grep "rejected refs/heads/ref $old_head $ZERO_OID refname conflict" stdout &&
+			test_grep "${SQ}refs/heads/ref/foo${SQ} exists; cannot create ${SQ}refs/heads/ref${SQ}" err
 		)
 	'
 
@@ -2309,14 +2318,15 @@ do
 				format_command $type "create refs/heads/ref" "$old_head" &&
 				format_command $type "create refs/heads/Foo" "$old_head"
 			} >stdin &&
-			git update-ref $type --stdin --batch-updates <stdin >stdout &&
+			git update-ref $type --stdin --batch-updates <stdin >stdout 2>err &&
 
 			echo $head >expect &&
 			git rev-parse refs/heads/foo >actual &&
 			echo $old_head >expect &&
 			git rev-parse refs/heads/ref >actual &&
 			test_cmp expect actual &&
-			test_grep -q "reference conflict due to case-insensitive filesystem" stdout
+			test_grep "rejected refs/heads/Foo $old_head $ZERO_OID reference conflict due to case-insensitive filesystem" stdout &&
+			test_grep -e "cannot lock ref ${SQ}refs/heads/Foo${SQ}: Unable to create" -e "Foo.lock" err
 		)
 	'
 
@@ -2357,8 +2367,9 @@ do
 			git symbolic-ref refs/heads/symbolic refs/heads/non-existent &&
 
 			format_command $type "delete refs/heads/symbolic" "$head" >stdin &&
-			git update-ref $type --stdin --batch-updates <stdin >stdout &&
-			test_grep "reference does not exist" stdout
+			git update-ref $type --stdin --batch-updates <stdin >stdout 2>err &&
+			test_grep "rejected refs/heads/non-existent $ZERO_OID $head reference does not exist" stdout &&
+			test_grep "cannot lock ref ${SQ}refs/heads/symbolic${SQ}: unable to resolve reference ${SQ}refs/heads/non-existent${SQ}" err
 		)
 	'
 
@@ -2373,8 +2384,9 @@ do
 			head=$(git rev-parse HEAD) &&
 
 			format_command $type "delete refs/heads/new-branch" "$head" >stdin &&
-			git update-ref $type --stdin --batch-updates <stdin >stdout &&
-			test_grep "incorrect old value provided" stdout
+			git update-ref $type --stdin --batch-updates <stdin >stdout 2>err &&
+			test_grep "rejected refs/heads/new-branch $ZERO_OID $head incorrect old value provided" stdout &&
+			test_grep "cannot lock ref ${SQ}refs/heads/new-branch${SQ}: is at $(git rev-parse new-branch) but expected $head" err
 		)
 	'
 
@@ -2387,8 +2399,9 @@ do
 			head=$(git rev-parse HEAD) &&
 
 			format_command $type "delete refs/heads/non-existent" "$head" >stdin &&
-			git update-ref $type --stdin --batch-updates <stdin >stdout &&
-			test_grep "reference does not exist" stdout
+			git update-ref $type --stdin --batch-updates <stdin >stdout 2>err &&
+			test_grep "rejected refs/heads/non-existent $ZERO_OID $head reference does not exist" stdout &&
+			test_grep "cannot lock ref ${SQ}refs/heads/non-existent${SQ}: unable to resolve reference ${SQ}refs/heads/non-existent${SQ}" err
 		)
 	'
 done

-- 
2.52.0

[PATCH v5 4/6] fetch: utilize rejected ref error details

[Karthik Nayak]

In 0e358de64a (fetch: use batched reference updates, 2025-05-19),
git-fetch(1) switched to using batched reference updates. This also
introduced a regression wherein instead of providing detailed error
messages for failed referenced updates, the users were provided generic
error messages based on the error type.

Similar to the previous commit, switch to using detailed error messages
if present for failed reference updates to fix this regression.

Reported-by: Elijah Newren <newren@gmail.com>
Co-authored-by: Jeff King <peff@peff.net>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
---
 builtin/fetch.c  | 10 ++++++----
 t/t5510-fetch.sh |  8 ++++----
 2 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/builtin/fetch.c b/builtin/fetch.c
index d427adea61..49495be0b6 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -1649,7 +1649,7 @@ static void ref_transaction_rejection_handler(const char *refname,
 					      const char *old_target UNUSED,
 					      const char *new_target UNUSED,
 					      enum ref_transaction_error err,
-					      const char *details UNUSED,
+					      const char *details,
 					      void *cb_data)
 {
 	struct ref_rejection_data *data = cb_data;
@@ -1674,9 +1674,11 @@ static void ref_transaction_rejection_handler(const char *refname,
 			"branches"), data->remote_name);
 		data->conflict_msg_shown = true;
 	} else {
-		const char *reason = ref_transaction_error_msg(err);
-
-		error(_("fetching ref %s failed: %s"), refname, reason);
+		if (details)
+			error("%s", details);
+		else
+			error(_("fetching ref %s failed: %s"),
+			      refname, ref_transaction_error_msg(err));
 	}
 
 	*data->retcode = 1;
diff --git a/t/t5510-fetch.sh b/t/t5510-fetch.sh
index ce1c23684e..c69afb5a60 100755
--- a/t/t5510-fetch.sh
+++ b/t/t5510-fetch.sh
@@ -1516,7 +1516,7 @@ test_expect_success REFFILES 'existing reference lock in repo' '
 		git remote add origin ../base &&
 		touch refs/heads/foo.lock &&
 		test_must_fail git fetch -f origin "refs/heads/*:refs/heads/*" 2>err &&
-		test_grep "error: fetching ref refs/heads/foo failed: reference already exists" err &&
+		test_grep -e "error: cannot lock ref ${SQ}refs/heads/foo${SQ}: Unable to create" -e "refs/heads/foo.lock${SQ}: File exists." err &&
 		git rev-parse refs/heads/main >expect &&
 		git rev-parse refs/heads/branch >actual &&
 		test_cmp expect actual
@@ -1530,7 +1530,7 @@ test_expect_success CASE_INSENSITIVE_FS,REFFILES 'F/D conflict on case insensiti
 		cd case_insensitive &&
 		git remote add origin -- ../case_sensitive_fd &&
 		test_must_fail git fetch -f origin "refs/heads/*:refs/heads/*" 2>err &&
-		test_grep "failed: refname conflict" err &&
+		test_grep "cannot process ${SQ}refs/remotes/origin/foo${SQ} and ${SQ}refs/remotes/origin/foo/bar${SQ} at the same time" err &&
 		git rev-parse refs/heads/main >expect &&
 		git rev-parse refs/heads/foo/bar >actual &&
 		test_cmp expect actual
@@ -1544,7 +1544,7 @@ test_expect_success CASE_INSENSITIVE_FS,REFFILES 'D/F conflict on case insensiti
 		cd case_insensitive &&
 		git remote add origin -- ../case_sensitive_df &&
 		test_must_fail git fetch -f origin "refs/heads/*:refs/heads/*" 2>err &&
-		test_grep "failed: refname conflict" err &&
+		test_grep "cannot lock ref ${SQ}refs/remotes/origin/foo${SQ}: there is a non-empty directory ${SQ}./refs/remotes/origin/foo${SQ} blocking reference ${SQ}refs/remotes/origin/foo${SQ}" err &&
 		git rev-parse refs/heads/main >expect &&
 		git rev-parse refs/heads/Foo/bar >actual &&
 		test_cmp expect actual
@@ -1658,7 +1658,7 @@ test_expect_success REFFILES "FETCH_HEAD is updated even if ref updates fail" '
 		git remote add origin ../base &&
 		>refs/heads/foo.lock &&
 		test_must_fail git fetch -f origin "refs/heads/*:refs/heads/*" 2>err &&
-		test_grep "error: fetching ref refs/heads/foo failed: reference already exists" err &&
+		test_grep -e "error: cannot lock ref ${SQ}refs/heads/foo${SQ}: Unable to create" -e "refs/heads/foo.lock${SQ}: File exists." err &&
 		test_grep "branch ${SQ}branch${SQ} of ../base" FETCH_HEAD &&
 		test_grep "branch ${SQ}foo${SQ} of ../base" FETCH_HEAD
 	)

-- 
2.52.0

[PATCH v5 5/6] receive-pack: utilize rejected ref error details

[Karthik Nayak]

In 9d2962a7c4 (receive-pack: use batched reference updates, 2025-05-19),
git-receive-pack(1) switched to using batched reference updates. This also
introduced a regression wherein instead of providing detailed error
messages for failed referenced updates, the users were provided generic
error messages based on the error type.

Now that the updates also contain detailed error message, propagate
those to the client via 'rp_error'. The detailed error messages can be
very verbose, for e.g. in the files backend, when trying to write a
non-commit object to a branch, you would see:

   ! [remote rejected] 3eaec9ccf3a53f168362a6b3fdeb73426fb9813d ->
   branch (cannot update ref 'refs/heads/branch': trying to write
   non-commit object 3eaec9ccf3a53f168362a6b3fdeb73426fb9813d to branch
   'refs/heads/branch')

Here the refname is repeated multiple times due to how error messages
are propagated and filled over the code stack. This potentially can be
cleaned up in a future commit.

Reported-by: Elijah Newren <newren@gmail.com>
Co-authored-by: Jeff King <peff@peff.net>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
---
 builtin/receive-pack.c |  8 ++++++--
 t/t5516-fetch-push.sh  | 15 +++++++++++++++
 2 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index 94d3e73cee..70e04b3efb 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -1813,11 +1813,14 @@ static void ref_transaction_rejection_handler(const char *refname,
 					      const char *old_target UNUSED,
 					      const char *new_target UNUSED,
 					      enum ref_transaction_error err,
-					      const char *details UNUSED,
+					      const char *details,
 					      void *cb_data)
 {
 	struct strmap *failed_refs = cb_data;
 
+	if (details)
+		rp_error("%s", details);
+
 	strmap_put(failed_refs, refname, (char *)ref_transaction_error_msg(err));
 }
 
@@ -1884,6 +1887,7 @@ static void execute_commands_non_atomic(struct command *commands,
 		}
 
 		ref_transaction_for_each_rejected_update(transaction,
+
 							 ref_transaction_rejection_handler,
 							 &failed_refs);
 
@@ -1895,7 +1899,7 @@ static void execute_commands_non_atomic(struct command *commands,
 			if (reported_error)
 				cmd->error_string = reported_error;
 			else if (strmap_contains(&failed_refs, cmd->ref_name))
-				cmd->error_string = strmap_get(&failed_refs, cmd->ref_name);
+				cmd->error_string = cmd->error_string_owned = xstrdup(strmap_get(&failed_refs, cmd->ref_name));
 		}
 
 	cleanup:
diff --git a/t/t5516-fetch-push.sh b/t/t5516-fetch-push.sh
index 46926e7bbd..45595991c8 100755
--- a/t/t5516-fetch-push.sh
+++ b/t/t5516-fetch-push.sh
@@ -1882,4 +1882,19 @@ test_expect_success 'push with F/D conflict with deletion and creation' '
 	git push testrepo :refs/heads/branch/conflict refs/heads/branch
 '
 
+test_expect_success 'pushing non-commit objects should report error' '
+	test_when_finished "rm -rf dest repo" &&
+	git init dest &&
+	git init repo &&
+
+	(
+		cd repo &&
+		test_commit --annotate test &&
+
+		tagsha=$(git rev-parse test^{tag}) &&
+		test_must_fail git push ../dest "$tagsha:refs/heads/branch" 2>err &&
+		test_grep "trying to write non-commit object $tagsha to branch ${SQ}refs/heads/branch${SQ}" err
+	)
+'
+
 test_done

-- 
2.52.0

[PATCH v5 6/6] fetch: delay user information post committing of transaction

[Karthik Nayak]

In Git 2.50 and earlier, we would display failure codes and error
message as part of the status display:

  $ git fetch . v1.0.0:refs/heads/foo
    error: cannot update ref 'refs/heads/foo': trying to write non-commit object f665776185ad074b236c00751d666da7d1977dbe to branch 'refs/heads/foo'
    From .
     ! [new tag]               v1.0.0     -> foo  (unable to update local ref)

With the addition of batched updates, this information is no longer
shown to the user:

  $ git fetch . v1.0.0:refs/heads/foo
    From .
     * [new tag]               v1.0.0     -> foo
    error: cannot update ref 'refs/heads/foo': trying to write non-commit object f665776185ad074b236c00751d666da7d1977dbe to branch 'refs/heads/foo'

Since reference updates are batched and processed together at the end,
information around the outcome is not available during individual
reference parsing.

To overcome this, collate and delay the output to the end. Introduce
`ref_update_display_info` which will hold individual update's
information and also whether the update failed or succeeded. This
finally allows us to iterate over all such updates and print them to the
user.

Using an dynamic array and strmap does add some overhead to
'git-fetch(1)', but from benchmarking this seems to be not too bad:

  Benchmark 1: fetch: many refs (refformat = files, refcount = 1000, revision = master)
    Time (mean ± σ):      42.6 ms ±   1.2 ms    [User: 13.1 ms, System: 29.8 ms]
    Range (min … max):    40.1 ms …  45.8 ms    47 runs

  Benchmark 2: fetch: many refs (refformat = files, refcount = 1000, revision = HEAD)
    Time (mean ± σ):      43.1 ms ±   1.2 ms    [User: 12.7 ms, System: 30.7 ms]
    Range (min … max):    40.5 ms …  45.8 ms    48 runs

  Summary
    fetch: many refs (refformat = files, refcount = 1000, revision = master) ran
      1.01 ± 0.04 times faster than fetch: many refs (refformat = files, refcount = 1000, revision = HEAD)

Another approach would be to move the status printing logic to be
handled post the transaction being committed. That however would require
adding an iterator to the ref transaction that tracks both the outcome
(success/failure) and the original refspec information for each update,
which is more involved infrastructure work compared to the strmap
approach here.

Helped-by: Phillip Wood <phillip.wood123@gmail.com>
Reported-by: Jeff King <peff@peff.net>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
---
 builtin/fetch.c       | 246 +++++++++++++++++++++++++++++++++++++++-----------
 t/t5516-fetch-push.sh |   1 +
 2 files changed, 193 insertions(+), 54 deletions(-)

diff --git a/builtin/fetch.c b/builtin/fetch.c
index 49495be0b6..a3bc7e9380 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -861,12 +861,87 @@ static void display_ref_update(struct display_state *display_state, char code,
 	fputs(display_state->buf.buf, f);
 }
 
+struct ref_update_display_info {
+	bool failed;
+	char success_code;
+	char fail_code;
+	char *summary;
+	char *fail_detail;
+	char *success_detail;
+	char *ref;
+	char *remote;
+	struct object_id old_oid;
+	struct object_id new_oid;
+};
+
+struct ref_update_display_info_array {
+	struct ref_update_display_info *info;
+	size_t alloc, nr;
+};
+
+static struct ref_update_display_info *ref_update_display_info_append(
+					   struct ref_update_display_info_array *array,
+					   char success_code,
+					   char fail_code,
+					   const char *summary,
+					   const char *success_detail,
+					   const char *fail_detail,
+					   const char *ref,
+					   const char *remote,
+					   const struct object_id *old_oid,
+					   const struct object_id *new_oid)
+{
+	struct ref_update_display_info *info;
+
+	ALLOC_GROW(array->info, array->nr + 1, array->alloc);
+	info = &array->info[array->nr++];
+
+	info->failed = false;
+	info->success_code = success_code;
+	info->fail_code = fail_code;
+	info->summary = xstrdup(summary);
+	info->success_detail = xstrdup_or_null(success_detail);
+	info->fail_detail = xstrdup_or_null(fail_detail);
+	info->remote = xstrdup(remote);
+	info->ref = xstrdup(ref);
+
+	oidcpy(&info->old_oid, old_oid);
+	oidcpy(&info->new_oid, new_oid);
+
+	return info;
+}
+
+static void ref_update_display_info_set_failed(struct ref_update_display_info *info)
+{
+	info->failed = true;
+}
+
+static void ref_update_display_info_free(struct ref_update_display_info *info)
+{
+	free(info->summary);
+	free(info->success_detail);
+	free(info->fail_detail);
+	free(info->remote);
+	free(info->ref);
+}
+
+static void ref_update_display_info_display(struct ref_update_display_info *info,
+					    struct display_state *display_state,
+					    int summary_width)
+{
+	display_ref_update(display_state,
+			   info->failed ? info->fail_code : info->success_code,
+			   info->summary,
+			   info->failed ? info->fail_detail : info->success_detail,
+			   info->remote, info->ref, &info->old_oid,
+			   &info->new_oid, summary_width);
+}
+
 static int update_local_ref(struct ref *ref,
 			    struct ref_transaction *transaction,
-			    struct display_state *display_state,
 			    const struct ref *remote_ref,
-			    int summary_width,
-			    const struct fetch_config *config)
+			    const struct fetch_config *config,
+			    struct ref_update_display_info_array *display_array)
 {
 	struct commit *current = NULL, *updated;
 	int fast_forward = 0;
@@ -877,41 +952,56 @@ static int update_local_ref(struct ref *ref,
 
 	if (oideq(&ref->old_oid, &ref->new_oid)) {
 		if (verbosity > 0)
-			display_ref_update(display_state, '=', _("[up to date]"), NULL,
-					   remote_ref->name, ref->name,
-					   &ref->old_oid, &ref->new_oid, summary_width);
+			ref_update_display_info_append(display_array, '=', '=',
+						       _("[up to date]"), NULL,
+						       NULL, ref->name,
+						       remote_ref->name, &ref->old_oid,
+						       &ref->new_oid);
 		return 0;
 	}
 
 	if (!update_head_ok &&
 	    !is_null_oid(&ref->old_oid) &&
 	    branch_checked_out(ref->name)) {
+		struct ref_update_display_info *info;
 		/*
 		 * If this is the head, and it's not okay to update
 		 * the head, and the old value of the head isn't empty...
 		 */
-		display_ref_update(display_state, '!', _("[rejected]"),
-				   _("can't fetch into checked-out branch"),
-				   remote_ref->name, ref->name,
-				   &ref->old_oid, &ref->new_oid, summary_width);
+		info = ref_update_display_info_append(display_array, '!', '!',
+						      _("[rejected]"), NULL,
+						      _("can't fetch into checked-out branch"),
+						      ref->name, remote_ref->name,
+						      &ref->old_oid, &ref->new_oid);
+		ref_update_display_info_set_failed(info);
 		return 1;
 	}
 
 	if (!is_null_oid(&ref->old_oid) &&
 	    starts_with(ref->name, "refs/tags/")) {
+		struct ref_update_display_info *info;
+
 		if (force || ref->force) {
 			int r;
+
 			r = s_update_ref("updating tag", ref, transaction, 0);
-			display_ref_update(display_state, r ? '!' : 't', _("[tag update]"),
-					   r ? _("unable to update local ref") : NULL,
-					   remote_ref->name, ref->name,
-					   &ref->old_oid, &ref->new_oid, summary_width);
+
+			info = ref_update_display_info_append(display_array, 't', '!',
+							      _("[tag update]"), NULL,
+							      _("unable to update local ref"),
+							      ref->name, remote_ref->name,
+							      &ref->old_oid, &ref->new_oid);
+			if (r)
+				ref_update_display_info_set_failed(info);
+
 			return r;
 		} else {
-			display_ref_update(display_state, '!', _("[rejected]"),
-					   _("would clobber existing tag"),
-					   remote_ref->name, ref->name,
-					   &ref->old_oid, &ref->new_oid, summary_width);
+			info = ref_update_display_info_append(display_array, '!', '!',
+							      _("[rejected]"), NULL,
+							      _("would clobber existing tag"),
+							      ref->name, remote_ref->name,
+							      &ref->old_oid, &ref->new_oid);
+			ref_update_display_info_set_failed(info);
 			return 1;
 		}
 	}
@@ -921,6 +1011,7 @@ static int update_local_ref(struct ref *ref,
 	updated = lookup_commit_reference_gently(the_repository,
 						 &ref->new_oid, 1);
 	if (!current || !updated) {
+		struct ref_update_display_info *info;
 		const char *msg;
 		const char *what;
 		int r;
@@ -941,10 +1032,15 @@ static int update_local_ref(struct ref *ref,
 		}
 
 		r = s_update_ref(msg, ref, transaction, 0);
-		display_ref_update(display_state, r ? '!' : '*', what,
-				   r ? _("unable to update local ref") : NULL,
-				   remote_ref->name, ref->name,
-				   &ref->old_oid, &ref->new_oid, summary_width);
+
+		info = ref_update_display_info_append(display_array, '*', '!',
+						      what, NULL,
+						      _("unable to update local ref"),
+						      ref->name, remote_ref->name,
+						      &ref->old_oid, &ref->new_oid);
+		if (r)
+			ref_update_display_info_set_failed(info);
+
 		return r;
 	}
 
@@ -960,6 +1056,7 @@ static int update_local_ref(struct ref *ref,
 	}
 
 	if (fast_forward) {
+		struct ref_update_display_info *info;
 		struct strbuf quickref = STRBUF_INIT;
 		int r;
 
@@ -967,29 +1064,46 @@ static int update_local_ref(struct ref *ref,
 		strbuf_addstr(&quickref, "..");
 		strbuf_add_unique_abbrev(&quickref, &ref->new_oid, DEFAULT_ABBREV);
 		r = s_update_ref("fast-forward", ref, transaction, 1);
-		display_ref_update(display_state, r ? '!' : ' ', quickref.buf,
-				   r ? _("unable to update local ref") : NULL,
-				   remote_ref->name, ref->name,
-				   &ref->old_oid, &ref->new_oid, summary_width);
+
+		info = ref_update_display_info_append(display_array, ' ', '!',
+						      quickref.buf, NULL,
+						      _("unable to update local ref"),
+						      ref->name, remote_ref->name,
+						      &ref->old_oid, &ref->new_oid);
+		if (r)
+			ref_update_display_info_set_failed(info);
+
 		strbuf_release(&quickref);
 		return r;
 	} else if (force || ref->force) {
+		struct ref_update_display_info *info;
 		struct strbuf quickref = STRBUF_INIT;
 		int r;
+
 		strbuf_add_unique_abbrev(&quickref, &current->object.oid, DEFAULT_ABBREV);
 		strbuf_addstr(&quickref, "...");
 		strbuf_add_unique_abbrev(&quickref, &ref->new_oid, DEFAULT_ABBREV);
 		r = s_update_ref("forced-update", ref, transaction, 1);
-		display_ref_update(display_state, r ? '!' : '+', quickref.buf,
-				   r ? _("unable to update local ref") : _("forced update"),
-				   remote_ref->name, ref->name,
-				   &ref->old_oid, &ref->new_oid, summary_width);
+
+		info = ref_update_display_info_append(display_array, '+', '!',
+						      quickref.buf, _("forced update"),
+						      _("unable to update local ref"),
+						      ref->name, remote_ref->name,
+						      &ref->old_oid, &ref->new_oid);
+
+		if (r)
+			ref_update_display_info_set_failed(info);
+
 		strbuf_release(&quickref);
 		return r;
 	} else {
-		display_ref_update(display_state, '!', _("[rejected]"), _("non-fast-forward"),
-				   remote_ref->name, ref->name,
-				   &ref->old_oid, &ref->new_oid, summary_width);
+		struct ref_update_display_info *info;
+		info = ref_update_display_info_append(display_array, '!', '!',
+						      _("[rejected]"), NULL,
+						      _("non-fast-forward"),
+						      ref->name, remote_ref->name,
+						      &ref->old_oid, &ref->new_oid);
+		ref_update_display_info_set_failed(info);
 		return 1;
 	}
 }
@@ -1103,17 +1217,14 @@ static int store_updated_refs(struct display_state *display_state,
 			      int connectivity_checked,
 			      struct ref_transaction *transaction, struct ref *ref_map,
 			      struct fetch_head *fetch_head,
-			      const struct fetch_config *config)
+			      const struct fetch_config *config,
+			      struct ref_update_display_info_array *display_array)
 {
 	int rc = 0;
 	struct strbuf note = STRBUF_INIT;
 	const char *what, *kind;
 	struct ref *rm;
 	int want_status;
-	int summary_width = 0;
-
-	if (verbosity >= 0)
-		summary_width = transport_summary_width(ref_map);
 
 	if (!connectivity_checked) {
 		struct check_connected_options opt = CHECK_CONNECTED_INIT;
@@ -1218,8 +1329,8 @@ static int store_updated_refs(struct display_state *display_state,
 					  display_state->url_len);
 
 			if (ref) {
-				rc |= update_local_ref(ref, transaction, display_state,
-						       rm, summary_width, config);
+				rc |= update_local_ref(ref, transaction, rm,
+						       config, display_array);
 				free(ref);
 			} else if (write_fetch_head || dry_run) {
 				/*
@@ -1227,12 +1338,12 @@ static int store_updated_refs(struct display_state *display_state,
 				 * would be written to FETCH_HEAD, if --dry-run
 				 * is set).
 				 */
-				display_ref_update(display_state, '*',
-						   *kind ? kind : "branch", NULL,
-						   rm->name,
-						   "FETCH_HEAD",
-						   &rm->new_oid, &rm->old_oid,
-						   summary_width);
+
+				ref_update_display_info_append(display_array, '*', '*',
+							       *kind ? kind : "branch",
+							       NULL, NULL, "FETCH_HEAD",
+							       rm->name, &rm->new_oid,
+							       &rm->old_oid);
 			}
 		}
 	}
@@ -1300,7 +1411,8 @@ static int fetch_and_consume_refs(struct display_state *display_state,
 				  struct ref_transaction *transaction,
 				  struct ref *ref_map,
 				  struct fetch_head *fetch_head,
-				  const struct fetch_config *config)
+				  const struct fetch_config *config,
+				  struct ref_update_display_info_array *display_array)
 {
 	int connectivity_checked = 1;
 	int ret;
@@ -1322,7 +1434,8 @@ static int fetch_and_consume_refs(struct display_state *display_state,
 
 	trace2_region_enter("fetch", "consume_refs", the_repository);
 	ret = store_updated_refs(display_state, connectivity_checked,
-				 transaction, ref_map, fetch_head, config);
+				 transaction, ref_map, fetch_head, config,
+				 display_array);
 	trace2_region_leave("fetch", "consume_refs", the_repository);
 
 out:
@@ -1493,7 +1606,8 @@ static int backfill_tags(struct display_state *display_state,
 			 struct ref_transaction *transaction,
 			 struct ref *ref_map,
 			 struct fetch_head *fetch_head,
-			 const struct fetch_config *config)
+			 const struct fetch_config *config,
+			 struct ref_update_display_info_array *display_array)
 {
 	int retcode, cannot_reuse;
 
@@ -1515,7 +1629,7 @@ static int backfill_tags(struct display_state *display_state,
 	transport_set_option(transport, TRANS_OPT_DEPTH, "0");
 	transport_set_option(transport, TRANS_OPT_DEEPEN_RELATIVE, NULL);
 	retcode = fetch_and_consume_refs(display_state, transport, transaction, ref_map,
-					 fetch_head, config);
+					 fetch_head, config, display_array);
 
 	if (gsecondary) {
 		transport_disconnect(gsecondary);
@@ -1641,6 +1755,7 @@ struct ref_rejection_data {
 	bool conflict_msg_shown;
 	bool case_sensitive_msg_shown;
 	const char *remote_name;
+	struct strmap *rejected_refs;
 };
 
 static void ref_transaction_rejection_handler(const char *refname,
@@ -1681,6 +1796,7 @@ static void ref_transaction_rejection_handler(const char *refname,
 			      refname, ref_transaction_error_msg(err));
 	}
 
+	strmap_put(data->rejected_refs, refname, NULL);
 	*data->retcode = 1;
 }
 
@@ -1690,6 +1806,7 @@ static void ref_transaction_rejection_handler(const char *refname,
  */
 static int commit_ref_transaction(struct ref_transaction **transaction,
 				  bool is_atomic, const char *remote_name,
+				  struct strmap *rejected_refs,
 				  struct strbuf *err)
 {
 	int retcode = ref_transaction_commit(*transaction, err);
@@ -1701,6 +1818,7 @@ static int commit_ref_transaction(struct ref_transaction **transaction,
 			.conflict_msg_shown = 0,
 			.remote_name = remote_name,
 			.retcode = &retcode,
+			.rejected_refs = rejected_refs,
 		};
 
 		ref_transaction_for_each_rejected_update(*transaction,
@@ -1729,6 +1847,9 @@ static int do_fetch(struct transport *transport,
 	struct fetch_head fetch_head = { 0 };
 	struct strbuf err = STRBUF_INIT;
 	int do_set_head = 0;
+	struct ref_update_display_info_array display_array = { 0 };
+	struct strmap rejected_refs = STRMAP_INIT;
+	int summary_width = 0;
 
 	if (tags == TAGS_DEFAULT) {
 		if (transport->remote->fetch_tags == 2)
@@ -1853,7 +1974,7 @@ static int do_fetch(struct transport *transport,
 	}
 
 	if (fetch_and_consume_refs(&display_state, transport, transaction, ref_map,
-				   &fetch_head, config)) {
+				   &fetch_head, config, &display_array)) {
 		retcode = 1;
 		goto cleanup;
 	}
@@ -1876,7 +1997,7 @@ static int do_fetch(struct transport *transport,
 			 * the transaction and don't commit anything.
 			 */
 			if (backfill_tags(&display_state, transport, transaction, tags_ref_map,
-					  &fetch_head, config))
+					  &fetch_head, config, &display_array))
 				retcode = 1;
 		}
 
@@ -1886,8 +2007,12 @@ static int do_fetch(struct transport *transport,
 	if (retcode)
 		goto cleanup;
 
+	if (verbosity >= 0)
+		summary_width = transport_summary_width(ref_map);
+
 	retcode = commit_ref_transaction(&transaction, atomic_fetch,
-					 transport->remote->name, &err);
+					 transport->remote->name,
+					 &rejected_refs, &err);
 	/*
 	 * With '--atomic', bail out if the transaction fails. Without '--atomic',
 	 * continue to fetch head and perform other post-fetch operations.
@@ -1965,7 +2090,17 @@ static int do_fetch(struct transport *transport,
 	 */
 	if (retcode && !atomic_fetch && transaction)
 		commit_ref_transaction(&transaction, false,
-				       transport->remote->name, &err);
+				       transport->remote->name,
+				       &rejected_refs, &err);
+
+	for (size_t i = 0; i < display_array.nr; i++) {
+		struct ref_update_display_info *info = &display_array.info[i];
+
+		if (!info->failed && strmap_contains(&rejected_refs, info->ref))
+			ref_update_display_info_set_failed(info);
+		ref_update_display_info_display(info, &display_state, summary_width);
+		ref_update_display_info_free(info);
+	}
 
 	if (retcode) {
 		if (err.len) {
@@ -1980,6 +2115,9 @@ static int do_fetch(struct transport *transport,
 
 	if (transaction)
 		ref_transaction_free(transaction);
+
+	free(display_array.info);
+	strmap_clear(&rejected_refs, 0);
 	display_state_release(&display_state);
 	close_fetch_head(&fetch_head);
 	strbuf_release(&err);
diff --git a/t/t5516-fetch-push.sh b/t/t5516-fetch-push.sh
index 45595991c8..29e2f17608 100755
--- a/t/t5516-fetch-push.sh
+++ b/t/t5516-fetch-push.sh
@@ -1893,6 +1893,7 @@ test_expect_success 'pushing non-commit objects should report error' '
 
 		tagsha=$(git rev-parse test^{tag}) &&
 		test_must_fail git push ../dest "$tagsha:refs/heads/branch" 2>err &&
+		test_grep "! \[remote rejected\] $tagsha -> branch (invalid new value provided)" err &&
 		test_grep "trying to write non-commit object $tagsha to branch ${SQ}refs/heads/branch${SQ}" err
 	)
 '

-- 
2.52.0