[PATCH v2 00/23] Change semantics of "fetch --tags"

[PATCH v2 00/23] Change semantics of "fetch --tags"

[Michael Haggerty]

This is v2 of my proposed fix for the "local tag killer" problem that
I reported recently [1].  Thanks a lot to Junio for his feedback on
v1.

Changes since v1:

* Rebase to current upstream master (0d6cf2471f); no conflicts were
  encountered.

* Incorporate feedback from Junio:

  * Improve the documentation as suggested

  * Fix a few typos

* Document get_expanded_map() and fix a minor memory leak that I found
  there.

* get_ref_map(): Do not look for references that can be updated
  opportunistically among the entries added by "--tags".  Preserve the
  order of output list when changing the function to handle the new
  "--tags" semantics.  (I know more about how the output is used and
  am less worried now that the changes will have bad interactions with
  the rest of the system.)

* Improve the description of tag-following in the "git fetch" manpage.

* Moved the changes to ref_remove_duplicates() later in the series, as
  they were not really integral to the rest of the patch series.
  Make the following changes to that function:

  * Add tests of how it handles duplicates.

  * Simplify the loop in a different way than v1, to make it more
    modular.

  * Extract a function to handle duplicates.

  * Improve the error messages emitted if ref_remove_duplicates()
    finds conflicting duplicates, and mark the messages for
    translation.

  * Do not die() if a user-specified refspec conflicts with
    an opportunistic update.

[1] http://article.gmane.org/gmane.comp.version-control.git/234723

Michael Haggerty (23):
  t5510: use the correct tag name in test
  t5510: prepare test refs more straightforwardly
  t5510: check that "git fetch --prune --tags" does not prune branches
  api-remote.txt: correct section "struct refspec"
  get_ref_map(): rename local variables
  builtin/fetch.c: reorder function definitions
  get_expanded_map(): add docstring
  get_expanded_map(): avoid memory leak
  fetch: only opportunistically update references based on command line
  fetch --tags: fetch tags *in addition to* other stuff
  fetch --prune: prune only based on explicit refspecs
  query_refspecs(): move some constants out of the loop
  builtin/remote.c: reorder function definitions
  builtin/remote.c:update(): use struct argv_array
  fetch, remote: properly convey --no-prune options to subprocesses
  fetch-options.txt: simplify ifdef/ifndef/endif usage
  git-fetch.txt: improve description of tag auto-following
  ref_remove_duplicates(): avoid redundant bisection
  t5536: new test of refspec conflicts when fetching
  ref_remove_duplicates(): simplify loop logic
  ref_remote_duplicates(): extract a function handle_duplicate()
  handle_duplicate(): mark error message for translation
  fetch: improve the error messages emitted for conflicting refspecs

 Documentation/config.txt                 |   4 +-
 Documentation/fetch-options.txt          |  26 +--
 Documentation/git-fetch.txt              |  14 +-
 Documentation/technical/api-remote.txt   |  20 +--
 builtin/fetch.c                          | 298 ++++++++++++++++---------------
 builtin/remote.c                         | 196 ++++++++++----------
 git-pull.sh                              |   2 +-
 remote.c                                 |  94 +++++++---
 remote.h                                 |   8 +-
 t/t5510-fetch.sh                         |  36 +++-
 t/t5515/fetch.br-unconfig_--tags_.._.git |   1 +
 t/t5515/fetch.master_--tags_.._.git      |   1 +
 t/t5525-fetch-tagopt.sh                  |  23 ++-
 t/t5536-fetch-conflicts.sh               | 100 +++++++++++
 14 files changed, 503 insertions(+), 320 deletions(-)
 create mode 100755 t/t5536-fetch-conflicts.sh

-- 
1.8.4.1

[PATCH v2 01/23] t5510: use the correct tag name in test

[Michael Haggerty]

Fix an apparent copy-paste error: A few lines earlier, a tag
"refs/tags/sometag" is created.  Check for the (non-)existence of that
tag, not "somebranch", which is otherwise never mentioned in the
script.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
---
 t/t5510-fetch.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/t/t5510-fetch.sh b/t/t5510-fetch.sh
index 1f0f8e6..c5e5dfc 100755
--- a/t/t5510-fetch.sh
+++ b/t/t5510-fetch.sh
@@ -121,7 +121,7 @@ test_expect_success 'fetch --prune --tags does not delete the remote-tracking br
 
 	git fetch --prune --tags origin &&
 	git rev-parse origin/master &&
-	test_must_fail git rev-parse somebranch
+	test_must_fail git rev-parse sometag
 '
 
 test_expect_success 'fetch --prune --tags with branch does not delete other remote-tracking branches' '
-- 
1.8.4.1

[PATCH v2 02/23] t5510: prepare test refs more straightforwardly

[Michael Haggerty]

"git fetch" was being used with contrived refspecs to create tags and
remote-tracking branches in test repositories in preparation for the
actual tests.  This is obscure and also makes one wonder whether this
is indeed just preparation or whether some side-effect of "git fetch"
is being tested.

So use the more straightforward commands "git tag" / "git update-ref"
when preparing branches in test repositories.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
---
 t/t5510-fetch.sh | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/t/t5510-fetch.sh b/t/t5510-fetch.sh
index c5e5dfc..08d8dbb 100755
--- a/t/t5510-fetch.sh
+++ b/t/t5510-fetch.sh
@@ -88,7 +88,7 @@ test_expect_success 'fetch --prune on its own works as expected' '
 	cd "$D" &&
 	git clone . prune &&
 	cd prune &&
-	git fetch origin refs/heads/master:refs/remotes/origin/extrabranch &&
+	git update-ref refs/remotes/origin/extrabranch master &&
 
 	git fetch --prune origin &&
 	test_must_fail git rev-parse origin/extrabranch
@@ -98,7 +98,7 @@ test_expect_success 'fetch --prune with a branch name keeps branches' '
 	cd "$D" &&
 	git clone . prune-branch &&
 	cd prune-branch &&
-	git fetch origin refs/heads/master:refs/remotes/origin/extrabranch &&
+	git update-ref refs/remotes/origin/extrabranch master &&
 
 	git fetch --prune origin master &&
 	git rev-parse origin/extrabranch
@@ -117,7 +117,7 @@ test_expect_success 'fetch --prune --tags does not delete the remote-tracking br
 	cd "$D" &&
 	git clone . prune-tags &&
 	cd prune-tags &&
-	git fetch origin refs/heads/master:refs/tags/sometag &&
+	git tag sometag master &&
 
 	git fetch --prune --tags origin &&
 	git rev-parse origin/master &&
@@ -128,7 +128,7 @@ test_expect_success 'fetch --prune --tags with branch does not delete other remo
 	cd "$D" &&
 	git clone . prune-tags-branch &&
 	cd prune-tags-branch &&
-	git fetch origin refs/heads/master:refs/remotes/origin/extrabranch &&
+	git update-ref refs/remotes/origin/extrabranch master &&
 
 	git fetch --prune --tags origin master &&
 	git rev-parse origin/extrabranch
-- 
1.8.4.1

Re: [PATCH v2 02/23] t5510: prepare test refs more straightforwardly

[Ramkumar Ramachandra]

Michael Haggerty wrote:
> "git fetch" was being used with contrived refspecs to create tags and
> remote-tracking branches in test repositories in preparation for the
> actual tests.  This is obscure and also makes one wonder whether this
> is indeed just preparation or whether some side-effect of "git fetch"
> is being tested.

As the test titles indicate, we are exercising the 'fetch --prune'
functionality. However, I don't see the 'git fetch <remote>
<src>:<dst>' form exercised anywhere else in the file.

Re: [PATCH v2 02/23] t5510: prepare test refs more straightforwardly

[Michael Haggerty]

On 10/30/2013 11:57 AM, Ramkumar Ramachandra wrote:
> Michael Haggerty wrote:
>> "git fetch" was being used with contrived refspecs to create tags and
>> remote-tracking branches in test repositories in preparation for the
>> actual tests.  This is obscure and also makes one wonder whether this
>> is indeed just preparation or whether some side-effect of "git fetch"
>> is being tested.
> 
> As the test titles indicate, we are exercising the 'fetch --prune'
> functionality. However, I don't see the 'git fetch <remote>
> <src>:<dst>' form exercised anywhere else in the file.

I see a couple of examples:

$ grep 'git fetch.*:' t/t5510*.sh
	git fetch --prune origin refs/heads/a/*:refs/remotes/origin/a/* &&
	git fetch --prune --tags origin
refs/heads/foo/*:refs/remotes/origin/foo/* &&
	git fetch .. :track &&
	test_must_fail git fetch .. anno:five
	git fetch .. six:six
	test_must_fail git fetch "$D/bundle1" master:master
	git fetch ../bundle2 master:master &&
	 git fetch "rsync:$(pwd)/../.git" master:refs/heads/master &&
	test_must_fail git fetch . side:master
	git fetch --update-head-ok . side:master

The tests in question didn't really check the results of the fetch
anyway.  I don't think they were intended to test fetch but only to set
up the initial conditions for the real test.

Michael

-- 
Michael Haggerty
mhagger@alum.mit.edu
http://softwareswirl.blogspot.com/

[PATCH v2 03/23] t5510: check that "git fetch --prune --tags" does not prune branches

[Michael Haggerty]

"git fetch --prune --tags" is currently interpreted as follows:

* "--tags" is equivalent to specifying a refspec
  "refs/tags/*:refs/tags/*", and supersedes any default refspecs
  configured via remote.$REMOTE.fetch.

* "--prune" only operates on the refspecs being fetched.

Therefore, "git fetch --prune --tags" prunes tags in refs/tags/* but
does not fetch or prune other references.  The fact that this command
does not prune references outside of refs/tags/* was previously
untested.  So add a test that verifies the status quo.

However, the status quo is surprising, so it will be changed later in
this patch series.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
---
 t/t5510-fetch.sh | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/t/t5510-fetch.sh b/t/t5510-fetch.sh
index 08d8dbb..8328be1 100755
--- a/t/t5510-fetch.sh
+++ b/t/t5510-fetch.sh
@@ -118,9 +118,13 @@ test_expect_success 'fetch --prune --tags does not delete the remote-tracking br
 	git clone . prune-tags &&
 	cd prune-tags &&
 	git tag sometag master &&
+	# Create what looks like a remote-tracking branch from an earlier
+	# fetch that has since been deleted from the remote:
+	git update-ref refs/remotes/origin/fake-remote master &&
 
 	git fetch --prune --tags origin &&
 	git rev-parse origin/master &&
+	git rev-parse origin/fake-remote &&
 	test_must_fail git rev-parse sometag
 '
 
-- 
1.8.4.1

[PATCH v2 04/23] api-remote.txt: correct section "struct refspec"

[Michael Haggerty]

* Replace reference to function parse_ref_spec() with references to
  functions parse_fetch_refspec() and parse_push_refspec().

* Correct description of src and dst: they *do* include the '*'
  characters.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
---
 Documentation/technical/api-remote.txt | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/Documentation/technical/api-remote.txt b/Documentation/technical/api-remote.txt
index 4be8776..5d245aa 100644
--- a/Documentation/technical/api-remote.txt
+++ b/Documentation/technical/api-remote.txt
@@ -58,16 +58,16 @@ default remote, given the current branch and configuration.
 struct refspec
 --------------
 
-A struct refspec holds the parsed interpretation of a refspec. If it
-will force updates (starts with a '+'), force is true. If it is a
-pattern (sides end with '*') pattern is true. src and dest are the two
-sides (if a pattern, only the part outside of the wildcards); if there
-is only one side, it is src, and dst is NULL; if sides exist but are
-empty (i.e., the refspec either starts or ends with ':'), the
-corresponding side is "".
-
-This parsing can be done to an array of strings to give an array of
-struct refpsecs with parse_ref_spec().
+A struct refspec holds the parsed interpretation of a refspec.  If it
+will force updates (starts with a '+'), force is true.  If it is a
+pattern (sides end with '*') pattern is true.  src and dest are the
+two sides (including '*' characters if present); if there is only one
+side, it is src, and dst is NULL; if sides exist but are empty (i.e.,
+the refspec either starts or ends with ':'), the corresponding side is
+"".
+
+An array of strings can be parsed into an array of struct refspecs
+using parse_fetch_refspec() or parse_push_refspec().
 
 remote_find_tracking(), given a remote and a struct refspec with
 either src or dst filled out, will fill out the other such that the
-- 
1.8.4.1

[PATCH v2 05/23] get_ref_map(): rename local variables

[Michael Haggerty]

Rename "refs" -> "refspecs" and "ref_count" -> "refspec_count" to
reduce confusion, because they describe an array of "struct refspec",
as opposed to the "struct ref" objects that are also used in this
function.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
---
 builtin/fetch.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/builtin/fetch.c b/builtin/fetch.c
index bd7a101..2248abf 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -165,8 +165,8 @@ static void find_non_local_tags(struct transport *transport,
 			struct ref ***tail);
 
 static struct ref *get_ref_map(struct transport *transport,
-			       struct refspec *refs, int ref_count, int tags,
-			       int *autotags)
+			       struct refspec *refspecs, int refspec_count,
+			       int tags, int *autotags)
 {
 	int i;
 	struct ref *rm;
@@ -175,12 +175,12 @@ static struct ref *get_ref_map(struct transport *transport,
 
 	const struct ref *remote_refs = transport_get_remote_refs(transport);
 
-	if (ref_count || tags == TAGS_SET) {
+	if (refspec_count || tags == TAGS_SET) {
 		struct ref **old_tail;
 
-		for (i = 0; i < ref_count; i++) {
-			get_fetch_map(remote_refs, &refs[i], &tail, 0);
-			if (refs[i].dst && refs[i].dst[0])
+		for (i = 0; i < refspec_count; i++) {
+			get_fetch_map(remote_refs, &refspecs[i], &tail, 0);
+			if (refspecs[i].dst && refspecs[i].dst[0])
 				*autotags = 1;
 		}
 		/* Merge everything on the command line, but not --tags */
-- 
1.8.4.1

[PATCH v2 06/23] builtin/fetch.c: reorder function definitions

[Michael Haggerty]

Reorder function definitions to avoid the need for a forward
declaration of function find_non_local_tags().

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
---
 builtin/fetch.c | 198 +++++++++++++++++++++++++++-----------------------------
 1 file changed, 97 insertions(+), 101 deletions(-)

diff --git a/builtin/fetch.c b/builtin/fetch.c
index 2248abf..61e8117 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -160,9 +160,105 @@ static void add_merge_config(struct ref **head,
 	}
 }
 
+static int add_existing(const char *refname, const unsigned char *sha1,
+			int flag, void *cbdata)
+{
+	struct string_list *list = (struct string_list *)cbdata;
+	struct string_list_item *item = string_list_insert(list, refname);
+	item->util = xmalloc(20);
+	hashcpy(item->util, sha1);
+	return 0;
+}
+
+static int will_fetch(struct ref **head, const unsigned char *sha1)
+{
+	struct ref *rm = *head;
+	while (rm) {
+		if (!hashcmp(rm->old_sha1, sha1))
+			return 1;
+		rm = rm->next;
+	}
+	return 0;
+}
+
 static void find_non_local_tags(struct transport *transport,
 			struct ref **head,
-			struct ref ***tail);
+			struct ref ***tail)
+{
+	struct string_list existing_refs = STRING_LIST_INIT_DUP;
+	struct string_list remote_refs = STRING_LIST_INIT_NODUP;
+	const struct ref *ref;
+	struct string_list_item *item = NULL;
+
+	for_each_ref(add_existing, &existing_refs);
+	for (ref = transport_get_remote_refs(transport); ref; ref = ref->next) {
+		if (prefixcmp(ref->name, "refs/tags/"))
+			continue;
+
+		/*
+		 * The peeled ref always follows the matching base
+		 * ref, so if we see a peeled ref that we don't want
+		 * to fetch then we can mark the ref entry in the list
+		 * as one to ignore by setting util to NULL.
+		 */
+		if (!suffixcmp(ref->name, "^{}")) {
+			if (item && !has_sha1_file(ref->old_sha1) &&
+			    !will_fetch(head, ref->old_sha1) &&
+			    !has_sha1_file(item->util) &&
+			    !will_fetch(head, item->util))
+				item->util = NULL;
+			item = NULL;
+			continue;
+		}
+
+		/*
+		 * If item is non-NULL here, then we previously saw a
+		 * ref not followed by a peeled reference, so we need
+		 * to check if it is a lightweight tag that we want to
+		 * fetch.
+		 */
+		if (item && !has_sha1_file(item->util) &&
+		    !will_fetch(head, item->util))
+			item->util = NULL;
+
+		item = NULL;
+
+		/* skip duplicates and refs that we already have */
+		if (string_list_has_string(&remote_refs, ref->name) ||
+		    string_list_has_string(&existing_refs, ref->name))
+			continue;
+
+		item = string_list_insert(&remote_refs, ref->name);
+		item->util = (void *)ref->old_sha1;
+	}
+	string_list_clear(&existing_refs, 1);
+
+	/*
+	 * We may have a final lightweight tag that needs to be
+	 * checked to see if it needs fetching.
+	 */
+	if (item && !has_sha1_file(item->util) &&
+	    !will_fetch(head, item->util))
+		item->util = NULL;
+
+	/*
+	 * For all the tags in the remote_refs string list,
+	 * add them to the list of refs to be fetched
+	 */
+	for_each_string_list_item(item, &remote_refs) {
+		/* Unless we have already decided to ignore this item... */
+		if (item->util)
+		{
+			struct ref *rm = alloc_ref(item->string);
+			rm->peer_ref = alloc_ref(item->string);
+			hashcpy(rm->old_sha1, item->util);
+			**tail = rm;
+			*tail = &rm->next;
+		}
+	}
+
+	string_list_clear(&remote_refs, 0);
+}
 
 static struct ref *get_ref_map(struct transport *transport,
 			       struct refspec *refspecs, int refspec_count,
@@ -612,106 +708,6 @@ static int prune_refs(struct refspec *refs, int ref_count, struct ref *ref_map)
 	return result;
 }
 
-static int add_existing(const char *refname, const unsigned char *sha1,
-			int flag, void *cbdata)
-{
-	struct string_list *list = (struct string_list *)cbdata;
-	struct string_list_item *item = string_list_insert(list, refname);
-	item->util = xmalloc(20);
-	hashcpy(item->util, sha1);
-	return 0;
-}
-
-static int will_fetch(struct ref **head, const unsigned char *sha1)
-{
-	struct ref *rm = *head;
-	while (rm) {
-		if (!hashcmp(rm->old_sha1, sha1))
-			return 1;
-		rm = rm->next;
-	}
-	return 0;
-}
-
-static void find_non_local_tags(struct transport *transport,
-			struct ref **head,
-			struct ref ***tail)
-{
-	struct string_list existing_refs = STRING_LIST_INIT_DUP;
-	struct string_list remote_refs = STRING_LIST_INIT_NODUP;
-	const struct ref *ref;
-	struct string_list_item *item = NULL;
-
-	for_each_ref(add_existing, &existing_refs);
-	for (ref = transport_get_remote_refs(transport); ref; ref = ref->next) {
-		if (prefixcmp(ref->name, "refs/tags/"))
-			continue;
-
-		/*
-		 * The peeled ref always follows the matching base
-		 * ref, so if we see a peeled ref that we don't want
-		 * to fetch then we can mark the ref entry in the list
-		 * as one to ignore by setting util to NULL.
-		 */
-		if (!suffixcmp(ref->name, "^{}")) {
-			if (item && !has_sha1_file(ref->old_sha1) &&
-			    !will_fetch(head, ref->old_sha1) &&
-			    !has_sha1_file(item->util) &&
-			    !will_fetch(head, item->util))
-				item->util = NULL;
-			item = NULL;
-			continue;
-		}
-
-		/*
-		 * If item is non-NULL here, then we previously saw a
-		 * ref not followed by a peeled reference, so we need
-		 * to check if it is a lightweight tag that we want to
-		 * fetch.
-		 */
-		if (item && !has_sha1_file(item->util) &&
-		    !will_fetch(head, item->util))
-			item->util = NULL;
-
-		item = NULL;
-
-		/* skip duplicates and refs that we already have */
-		if (string_list_has_string(&remote_refs, ref->name) ||
-		    string_list_has_string(&existing_refs, ref->name))
-			continue;
-
-		item = string_list_insert(&remote_refs, ref->name);
-		item->util = (void *)ref->old_sha1;
-	}
-	string_list_clear(&existing_refs, 1);
-
-	/*
-	 * We may have a final lightweight tag that needs to be
-	 * checked to see if it needs fetching.
-	 */
-	if (item && !has_sha1_file(item->util) &&
-	    !will_fetch(head, item->util))
-		item->util = NULL;
-
-	/*
-	 * For all the tags in the remote_refs string list,
-	 * add them to the list of refs to be fetched
-	 */
-	for_each_string_list_item(item, &remote_refs) {
-		/* Unless we have already decided to ignore this item... */
-		if (item->util)
-		{
-			struct ref *rm = alloc_ref(item->string);
-			rm->peer_ref = alloc_ref(item->string);
-			hashcpy(rm->old_sha1, item->util);
-			**tail = rm;
-			*tail = &rm->next;
-		}
-	}
-
-	string_list_clear(&remote_refs, 0);
-}
-
 static void check_not_current_branch(struct ref *ref_map)
 {
 	struct branch *current_branch = branch_get(NULL);
-- 
1.8.4.1

[PATCH v2 07/23] get_expanded_map(): add docstring

[Michael Haggerty]

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
---
 remote.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/remote.c b/remote.c
index 9f1a8aa..0d082cd 100644
--- a/remote.c
+++ b/remote.c
@@ -1553,6 +1553,13 @@ static int ignore_symref_update(const char *refname)
 	return (flag & REF_ISSYMREF);
 }
 
+/*
+ * Create and return a list of (struct ref) consisting of copies of
+ * each remote_ref that matches refspec.  refspec must be a pattern.
+ * Fill in the copies' peer_ref to describe the local tracking refs to
+ * which they map.  Omit any references that would map to an existing
+ * local symbolic ref.
+ */
 static struct ref *get_expanded_map(const struct ref *remote_refs,
 				    const struct refspec *refspec)
 {
-- 
1.8.4.1

[PATCH v2 08/23] get_expanded_map(): avoid memory leak

[Michael Haggerty]

The old code could leak *expn_name if match_name_with_pattern()
succeeded but ignore_symref_update() returned true.  So make sure that
*expn_name is freed in any case.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
---
 remote.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/remote.c b/remote.c
index 0d082cd..e42daa8 100644
--- a/remote.c
+++ b/remote.c
@@ -1567,9 +1567,9 @@ static struct ref *get_expanded_map(const struct ref *remote_refs,
 	struct ref *ret = NULL;
 	struct ref **tail = &ret;
 
-	char *expn_name;
-
 	for (ref = remote_refs; ref; ref = ref->next) {
+		char *expn_name = NULL;
+
 		if (strchr(ref->name, '^'))
 			continue; /* a dereference item */
 		if (match_name_with_pattern(refspec->src, ref->name,
@@ -1578,12 +1578,12 @@ static struct ref *get_expanded_map(const struct ref *remote_refs,
 			struct ref *cpy = copy_ref(ref);
 
 			cpy->peer_ref = alloc_ref(expn_name);
-			free(expn_name);
 			if (refspec->force)
 				cpy->peer_ref->force = 1;
 			*tail = cpy;
 			tail = &cpy->next;
 		}
+		free(expn_name);
 	}
 
 	return ret;
-- 
1.8.4.1

[PATCH v2 09/23] fetch: only opportunistically update references based on command line

[Michael Haggerty]

The old code processed (tags == TAGS_SET) before adding the entries
used to opportunistically update references mentioned on the command
line.  The result was that all tags were also considered candidates
for opportunistic updating.

This is harmless for two reasons: (a) because it would only add
entries if there is a configured refspec that covers tags *and* both
--tags and another refspec appear on the command-line; (b) because any
extra entries would be deleted later by the call to
ref_remove_duplicates() anyway.

But, to avoid extra work and extra memory usage, and to make the
implementation better match the intention, change the algorithm
slightly: compute the opportunistic refspecs based only on the
command-line arguments, storing the results into a separate temporary
list.  Then add the tags (which have to come earlier in the list so
that they are not de-duped in favor of an opportunistic entry).  Then
concatenate the temporary list onto the main list.

This change will also make later changes easier.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
---
 builtin/fetch.c | 44 ++++++++++++++++++++++++++++++++------------
 1 file changed, 32 insertions(+), 12 deletions(-)

diff --git a/builtin/fetch.c b/builtin/fetch.c
index 61e8117..0849f09 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -272,32 +272,50 @@ static struct ref *get_ref_map(struct transport *transport,
 	const struct ref *remote_refs = transport_get_remote_refs(transport);
 
 	if (refspec_count || tags == TAGS_SET) {
-		struct ref **old_tail;
+		/* opportunistically-updated references: */
+		struct ref *orefs = NULL, **oref_tail = &orefs;
 
 		for (i = 0; i < refspec_count; i++) {
 			get_fetch_map(remote_refs, &refspecs[i], &tail, 0);
 			if (refspecs[i].dst && refspecs[i].dst[0])
 				*autotags = 1;
 		}
-		/* Merge everything on the command line, but not --tags */
+		/* Merge everything on the command line (but not --tags) */
 		for (rm = ref_map; rm; rm = rm->next)
 			rm->fetch_head_status = FETCH_HEAD_MERGE;
-		if (tags == TAGS_SET)
-			get_fetch_map(remote_refs, tag_refspec, &tail, 0);
 
 		/*
-		 * For any refs that we happen to be fetching via command-line
-		 * arguments, take the opportunity to update their configured
-		 * counterparts. However, we do not want to mention these
-		 * entries in FETCH_HEAD at all, as they would simply be
-		 * duplicates of existing entries.
+		 * For any refs that we happen to be fetching via
+		 * command-line arguments, the destination ref might
+		 * have been missing or have been different than the
+		 * remote-tracking ref that would be derived from the
+		 * configured refspec.  In these cases, we want to
+		 * take the opportunity to update their configured
+		 * remote-tracking reference.  However, we do not want
+		 * to mention these entries in FETCH_HEAD at all, as
+		 * they would simply be duplicates of existing
+		 * entries, so we set them FETCH_HEAD_IGNORE below.
+		 *
+		 * We compute these entries now, based only on the
+		 * refspecs specified on the command line.  But we add
+		 * them to the list following the refspecs resulting
+		 * from the tags option so that one of the latter,
+		 * which has FETCH_HEAD_NOT_FOR_MERGE, is not removed
+		 * by ref_remove_duplicates() in favor of one of these
+		 * opportunistic entries with FETCH_HEAD_IGNORE.
 		 */
-		old_tail = tail;
 		for (i = 0; i < transport->remote->fetch_refspec_nr; i++)
 			get_fetch_map(ref_map, &transport->remote->fetch[i],
-				      &tail, 1);
-		for (rm = *old_tail; rm; rm = rm->next)
+				      &oref_tail, 1);
+
+		if (tags == TAGS_SET)
+			get_fetch_map(remote_refs, tag_refspec, &tail, 0);
+
+		*tail = orefs;
+		for (rm = orefs; rm; rm = rm->next) {
 			rm->fetch_head_status = FETCH_HEAD_IGNORE;
+			tail = &rm->next;
+		}
 	} else {
 		/* Use the defaults */
 		struct remote *remote = transport->remote;
@@ -334,8 +352,10 @@ static struct ref *get_ref_map(struct transport *transport,
 			tail = &ref_map->next;
 		}
 	}
+
 	if (tags == TAGS_DEFAULT && *autotags)
 		find_non_local_tags(transport, &ref_map, &tail);
+
 	ref_remove_duplicates(ref_map);
 
 	return ref_map;
-- 
1.8.4.1

[PATCH v2 10/23] fetch --tags: fetch tags *in addition to* other stuff

[Michael Haggerty]

Previously, fetch's "--tags" option was considered equivalent to
specifying the refspec "refs/tags/*:refs/tags/*" on the command line;
in particular, it caused the remote.<name>.refspec configuration to be
ignored.

But it is not very useful to fetch tags without also fetching other
references, whereas it *is* quite useful to be able to fetch tags *in
addition to* other references.  So change the semantics of this option
to do the latter.

If a user wants to fetch *only* tags, then it is still possible to
specifying an explicit refspec:

    git fetch <remote> 'refs/tags/*:refs/tags/*'

Please note that the documentation prior to 1.8.0.3 was ambiguous
about this aspect of "fetch --tags" behavior.  Commit

    f0cb2f137c 2012-12-14 fetch --tags: clarify documentation

made the documentation match the old behavior.  This commit changes
the documentation to match the new behavior.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
---
 Documentation/fetch-options.txt          |  8 ++---
 builtin/fetch.c                          | 59 +++++++++++++++++++-------------
 git-pull.sh                              |  2 +-
 t/t5510-fetch.sh                         | 22 ++++++++++--
 t/t5515/fetch.br-unconfig_--tags_.._.git |  1 +
 t/t5515/fetch.master_--tags_.._.git      |  1 +
 t/t5525-fetch-tagopt.sh                  | 23 ++++++++++---
 7 files changed, 78 insertions(+), 38 deletions(-)

diff --git a/Documentation/fetch-options.txt b/Documentation/fetch-options.txt
index ba1fe49..921f6be 100644
--- a/Documentation/fetch-options.txt
+++ b/Documentation/fetch-options.txt
@@ -61,11 +61,9 @@ endif::git-pull[]
 ifndef::git-pull[]
 -t::
 --tags::
-	This is a short-hand for giving `refs/tags/*:refs/tags/*`
-	refspec from the command line, to ask all tags to be fetched
-	and stored locally.  Because this acts as an explicit
-	refspec, the default refspecs (configured with the
-	remote.$name.fetch variable) are overridden and not used.
+	Request that all tags be fetched from the remote in addition
+	to whatever else is being fetched.  Its effect is similar to
+	that of the refspec `refs/tags/*:refs/tags/*`.
 
 --recurse-submodules[=yes|on-demand|no]::
 	This option controls if and under what conditions new commits of
diff --git a/builtin/fetch.c b/builtin/fetch.c
index 0849f09..887fa3e 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -269,12 +269,12 @@ static struct ref *get_ref_map(struct transport *transport,
 	struct ref *ref_map = NULL;
 	struct ref **tail = &ref_map;
 
-	const struct ref *remote_refs = transport_get_remote_refs(transport);
+	/* opportunistically-updated references: */
+	struct ref *orefs = NULL, **oref_tail = &orefs;
 
-	if (refspec_count || tags == TAGS_SET) {
-		/* opportunistically-updated references: */
-		struct ref *orefs = NULL, **oref_tail = &orefs;
+	const struct ref *remote_refs = transport_get_remote_refs(transport);
 
+	if (refspec_count) {
 		for (i = 0; i < refspec_count; i++) {
 			get_fetch_map(remote_refs, &refspecs[i], &tail, 0);
 			if (refspecs[i].dst && refspecs[i].dst[0])
@@ -310,12 +310,6 @@ static struct ref *get_ref_map(struct transport *transport,
 
 		if (tags == TAGS_SET)
 			get_fetch_map(remote_refs, tag_refspec, &tail, 0);
-
-		*tail = orefs;
-		for (rm = orefs; rm; rm = rm->next) {
-			rm->fetch_head_status = FETCH_HEAD_IGNORE;
-			tail = &rm->next;
-		}
 	} else {
 		/* Use the defaults */
 		struct remote *remote = transport->remote;
@@ -353,9 +347,19 @@ static struct ref *get_ref_map(struct transport *transport,
 		}
 	}
 
-	if (tags == TAGS_DEFAULT && *autotags)
+	if (tags == TAGS_SET)
+		/* also fetch all tags */
+		get_fetch_map(remote_refs, tag_refspec, &tail, 0);
+	else if (tags == TAGS_DEFAULT && *autotags)
 		find_non_local_tags(transport, &ref_map, &tail);
 
+	/* Now append any refs to be updated opportunistically: */
+	*tail = orefs;
+	for (rm = orefs; rm; rm = rm->next) {
+		rm->fetch_head_status = FETCH_HEAD_IGNORE;
+		tail = &rm->next;
+	}
+
 	ref_remove_duplicates(ref_map);
 
 	return ref_map;
@@ -846,31 +850,38 @@ static int do_fetch(struct transport *transport,
 		goto cleanup;
 	}
 	if (prune) {
-		/*
-		 * If --tags was specified, pretend that the user gave us
-		 * the canonical tags refspec
-		 */
+		struct refspec *prune_refspecs;
+		int prune_refspec_count;
+
+		if (ref_count) {
+			prune_refspecs = refs;
+			prune_refspec_count = ref_count;
+		} else {
+			prune_refspecs = transport->remote->fetch;
+			prune_refspec_count = transport->remote->fetch_refspec_nr;
+		}
+
 		if (tags == TAGS_SET) {
+			/*
+			 * --tags was specified.  Pretend that the user also
+			 * gave us the canonical tags refspec
+			 */
 			const char *tags_str = "refs/tags/*:refs/tags/*";
 			struct refspec *tags_refspec, *refspec;
 
 			/* Copy the refspec and add the tags to it */
-			refspec = xcalloc(ref_count + 1, sizeof(struct refspec));
+			refspec = xcalloc(prune_refspec_count + 1, sizeof(*refspec));
 			tags_refspec = parse_fetch_refspec(1, &tags_str);
-			memcpy(refspec, refs, ref_count * sizeof(struct refspec));
-			memcpy(&refspec[ref_count], tags_refspec, sizeof(struct refspec));
-			ref_count++;
+			memcpy(refspec, prune_refspecs, prune_refspec_count * sizeof(*refspec));
+			memcpy(&refspec[prune_refspec_count], tags_refspec, sizeof(*refspec));
 
-			prune_refs(refspec, ref_count, ref_map);
+			prune_refs(refspec, prune_refspec_count + 1, ref_map);
 
-			ref_count--;
 			/* The rest of the strings belong to fetch_one */
 			free_refspec(1, tags_refspec);
 			free(refspec);
-		} else if (ref_count) {
-			prune_refs(refs, ref_count, ref_map);
 		} else {
-			prune_refs(transport->remote->fetch, transport->remote->fetch_refspec_nr, ref_map);
+			prune_refs(prune_refspecs, prune_refspec_count, ref_map);
 		}
 	}
 	free_refs(ref_map);
diff --git a/git-pull.sh b/git-pull.sh
index b946fd9..97716b8 100755
--- a/git-pull.sh
+++ b/git-pull.sh
@@ -172,7 +172,7 @@ error_on_no_merge_candidates () {
 	do
 		case "$opt" in
 		-t|--t|--ta|--tag|--tags)
-			echo "Fetching tags only, you probably meant:"
+			echo "It doesn't make sense to pull all tags; you probably meant:"
 			echo "  git fetch --tags"
 			exit 1
 		esac
diff --git a/t/t5510-fetch.sh b/t/t5510-fetch.sh
index 8328be1..02e5901 100755
--- a/t/t5510-fetch.sh
+++ b/t/t5510-fetch.sh
@@ -113,7 +113,7 @@ test_expect_success 'fetch --prune with a namespace keeps other namespaces' '
 	git rev-parse origin/master
 '
 
-test_expect_success 'fetch --prune --tags does not delete the remote-tracking branches' '
+test_expect_success 'fetch --prune --tags prunes tags and branches' '
 	cd "$D" &&
 	git clone . prune-tags &&
 	cd prune-tags &&
@@ -124,7 +124,7 @@ test_expect_success 'fetch --prune --tags does not delete the remote-tracking br
 
 	git fetch --prune --tags origin &&
 	git rev-parse origin/master &&
-	git rev-parse origin/fake-remote &&
+	test_must_fail git rev-parse origin/fake-remote &&
 	test_must_fail git rev-parse sometag
 '
 
@@ -132,10 +132,26 @@ test_expect_success 'fetch --prune --tags with branch does not delete other remo
 	cd "$D" &&
 	git clone . prune-tags-branch &&
 	cd prune-tags-branch &&
+	git tag sometag master &&
 	git update-ref refs/remotes/origin/extrabranch master &&
 
 	git fetch --prune --tags origin master &&
-	git rev-parse origin/extrabranch
+	git rev-parse origin/extrabranch &&
+	test_must_fail git rev-parse sometag
+'
+
+test_expect_success 'fetch --prune --tags with refspec prunes based on refspec' '
+	cd "$D" &&
+	git clone . prune-tags-refspec &&
+	cd prune-tags-refspec &&
+	git tag sometag master &&
+	git update-ref refs/remotes/origin/foo/otherbranch master &&
+	git update-ref refs/remotes/origin/extrabranch master &&
+
+	git fetch --prune --tags origin refs/heads/foo/*:refs/remotes/origin/foo/* &&
+	test_must_fail git rev-parse refs/remotes/origin/foo/otherbranch &&
+	git rev-parse origin/extrabranch &&
+	test_must_fail git rev-parse sometag
 '
 
 test_expect_success 'fetch tags when there is no tags' '
diff --git a/t/t5515/fetch.br-unconfig_--tags_.._.git b/t/t5515/fetch.br-unconfig_--tags_.._.git
index 1669cc4..0f70f66 100644
--- a/t/t5515/fetch.br-unconfig_--tags_.._.git
+++ b/t/t5515/fetch.br-unconfig_--tags_.._.git
@@ -1,4 +1,5 @@
 # br-unconfig --tags ../.git
+0567da4d5edd2ff4bb292a465ba9e64dcad9536b		../
 6c9dec2b923228c9ff994c6cfe4ae16c12408dc5	not-for-merge	tag 'tag-master' of ../
 8e32a6d901327a23ef831511badce7bf3bf46689	not-for-merge	tag 'tag-one' of ../
 22feea448b023a2d864ef94b013735af34d238ba	not-for-merge	tag 'tag-one-tree' of ../
diff --git a/t/t5515/fetch.master_--tags_.._.git b/t/t5515/fetch.master_--tags_.._.git
index 8a74935..ab473a6 100644
--- a/t/t5515/fetch.master_--tags_.._.git
+++ b/t/t5515/fetch.master_--tags_.._.git
@@ -1,4 +1,5 @@
 # master --tags ../.git
+0567da4d5edd2ff4bb292a465ba9e64dcad9536b		../
 6c9dec2b923228c9ff994c6cfe4ae16c12408dc5	not-for-merge	tag 'tag-master' of ../
 8e32a6d901327a23ef831511badce7bf3bf46689	not-for-merge	tag 'tag-one' of ../
 22feea448b023a2d864ef94b013735af34d238ba	not-for-merge	tag 'tag-one-tree' of ../
diff --git a/t/t5525-fetch-tagopt.sh b/t/t5525-fetch-tagopt.sh
index 4fbf7a1..45815f7 100755
--- a/t/t5525-fetch-tagopt.sh
+++ b/t/t5525-fetch-tagopt.sh
@@ -8,7 +8,8 @@ setup_clone () {
 	git clone --mirror . $1 &&
 	git remote add remote_$1 $1 &&
 	(cd $1 &&
-	git tag tag_$1)
+	git tag tag_$1 &&
+	git branch branch_$1)
 }
 
 test_expect_success setup '
@@ -21,21 +22,33 @@ test_expect_success setup '
 
 test_expect_success "fetch with tagopt=--no-tags does not get tag" '
 	git fetch remote_one &&
-	test_must_fail git show-ref tag_one
+	test_must_fail git show-ref tag_one &&
+	git show-ref remote_one/branch_one
 	'
 
 test_expect_success "fetch --tags with tagopt=--no-tags gets tag" '
+	(
+		cd one &&
+		git branch second_branch_one
+	) &&
 	git fetch --tags remote_one &&
-	git show-ref tag_one
+	git show-ref tag_one &&
+	git show-ref remote_one/second_branch_one
 	'
 
 test_expect_success "fetch --no-tags with tagopt=--tags does not get tag" '
 	git fetch --no-tags remote_two &&
-	test_must_fail git show-ref tag_two
+	test_must_fail git show-ref tag_two &&
+	git show-ref remote_two/branch_two
 	'
 
 test_expect_success "fetch with tagopt=--tags gets tag" '
+	(
+		cd two &&
+		git branch second_branch_two
+	) &&
 	git fetch remote_two &&
-	git show-ref tag_two
+	git show-ref tag_two &&
+	git show-ref remote_two/second_branch_two
 	'
 test_done
-- 
1.8.4.1

[PATCH v2 11/23] fetch --prune: prune only based on explicit refspecs

[Michael Haggerty]

The old behavior of "fetch --prune" was to prune whatever was being
fetched.  In particular, "fetch --prune --tags" caused tags not only
to be fetched, but also to be pruned.  This is inappropriate because
there is only one tags namespace that is shared among the local
repository and all remotes.  Therefore, if the user defines a local
tag and then runs "git fetch --prune --tags", then the local tag is
deleted.  Moreover, "--prune" and "--tags" can also be configured via
fetch.prune / remote.<name>.prune and remote.<name>.tagopt, making it
even less obvious that an invocation of "git fetch" could result in
tag lossage.

Since the command "git remote update" invokes "git fetch", it had the
same problem.

The command "git remote prune", on the other hand, disregarded the
setting of remote.<name>.tagopt, and so its behavior was inconsistent
with that of the other commands.

So the old behavior made it too easy to lose tags.  To fix this
problem, change "fetch --prune" to prune references based only on
refspecs specified explicitly by the user, either on the command line
or via remote.<name>.fetch.  Thus, tags are no longer made subject to
pruning by the --tags option or the remote.<name>.tagopt setting.

However, tags *are* still subject to pruning if they are fetched as
part of a refspec, and that is good.  For example:

* On the command line,

      git fetch --prune 'refs/tags/*:refs/tags/*'

  causes tags, and only tags, to be fetched and pruned, and is
  therefore a simple way for the user to get the equivalent of the old
  behavior of "--prune --tag".

* For a remote that was configured with the "--mirror" option, the
  configuration is set to include

      [remote "name"]
              fetch = +refs/*:refs/*

  , which causes tags to be subject to pruning along with all other
  references.  This is the behavior that will typically be desired for
  a mirror.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
---
 Documentation/config.txt        |  4 ++--
 Documentation/fetch-options.txt | 19 ++++++++++++++-----
 builtin/fetch.c                 | 39 +++++++++------------------------------
 t/t5510-fetch.sh                | 10 +++++-----
 4 files changed, 30 insertions(+), 42 deletions(-)

diff --git a/Documentation/config.txt b/Documentation/config.txt
index ab26963..a405806 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -2087,8 +2087,8 @@ remote.<name>.vcs::
 
 remote.<name>.prune::
 	When set to true, fetching from this remote by default will also
-	remove any remote-tracking branches which no longer exist on the
-	remote (as if the `--prune` option was give on the command line).
+	remove any remote-tracking references that no longer exist on the
+	remote (as if the `--prune` option was given on the command line).
 	Overrides `fetch.prune` settings, if any.
 
 remotes.<group>::
diff --git a/Documentation/fetch-options.txt b/Documentation/fetch-options.txt
index 921f6be..12b1d92 100644
--- a/Documentation/fetch-options.txt
+++ b/Documentation/fetch-options.txt
@@ -41,8 +41,14 @@ ifndef::git-pull[]
 
 -p::
 --prune::
-	After fetching, remove any remote-tracking branches which
-	no longer exist	on the remote.
+	After fetching, remove any remote-tracking references that no
+	longer exist on the remote.  Tags are not subject to pruning
+	if they are fetched only because of the default tag
+	auto-following or due to a --tags option.  However, if tags
+	are fetched due to an explicit refspec (either on the command
+	line or in the remote configuration, for example if the remote
+	was cloned with the --mirror option), then they are also
+	subject to pruning.
 endif::git-pull[]
 
 ifdef::git-pull[]
@@ -61,9 +67,12 @@ endif::git-pull[]
 ifndef::git-pull[]
 -t::
 --tags::
-	Request that all tags be fetched from the remote in addition
-	to whatever else is being fetched.  Its effect is similar to
-	that of the refspec `refs/tags/*:refs/tags/*`.
+	Fetch all tags from the remote (i.e., fetch remote tags
+	`refs/tags/*` into local tags with the same name), in addition
+	to whatever else would otherwise be fetched.  Using this
+	option alone does not subject tags to pruning, even if --prune
+	is used (though tags may be pruned anyway if they are also the
+	destination of an explicit refspec; see '--prune').
 
 --recurse-submodules[=yes|on-demand|no]::
 	This option controls if and under what conditions new commits of
diff --git a/builtin/fetch.c b/builtin/fetch.c
index 887fa3e..1514b90 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -850,38 +850,17 @@ static int do_fetch(struct transport *transport,
 		goto cleanup;
 	}
 	if (prune) {
-		struct refspec *prune_refspecs;
-		int prune_refspec_count;
-
+		/*
+		 * We only prune based on refspecs specified
+		 * explicitly (via command line or configuration); we
+		 * don't care whether --tags was specified.
+		 */
 		if (ref_count) {
-			prune_refspecs = refs;
-			prune_refspec_count = ref_count;
-		} else {
-			prune_refspecs = transport->remote->fetch;
-			prune_refspec_count = transport->remote->fetch_refspec_nr;
-		}
-
-		if (tags == TAGS_SET) {
-			/*
-			 * --tags was specified.  Pretend that the user also
-			 * gave us the canonical tags refspec
-			 */
-			const char *tags_str = "refs/tags/*:refs/tags/*";
-			struct refspec *tags_refspec, *refspec;
-
-			/* Copy the refspec and add the tags to it */
-			refspec = xcalloc(prune_refspec_count + 1, sizeof(*refspec));
-			tags_refspec = parse_fetch_refspec(1, &tags_str);
-			memcpy(refspec, prune_refspecs, prune_refspec_count * sizeof(*refspec));
-			memcpy(&refspec[prune_refspec_count], tags_refspec, sizeof(*refspec));
-
-			prune_refs(refspec, prune_refspec_count + 1, ref_map);
-
-			/* The rest of the strings belong to fetch_one */
-			free_refspec(1, tags_refspec);
-			free(refspec);
+			prune_refs(refs, ref_count, ref_map);
 		} else {
-			prune_refs(prune_refspecs, prune_refspec_count, ref_map);
+			prune_refs(transport->remote->fetch,
+				   transport->remote->fetch_refspec_nr,
+				   ref_map);
 		}
 	}
 	free_refs(ref_map);
diff --git a/t/t5510-fetch.sh b/t/t5510-fetch.sh
index 02e5901..5d4581d 100755
--- a/t/t5510-fetch.sh
+++ b/t/t5510-fetch.sh
@@ -113,7 +113,7 @@ test_expect_success 'fetch --prune with a namespace keeps other namespaces' '
 	git rev-parse origin/master
 '
 
-test_expect_success 'fetch --prune --tags prunes tags and branches' '
+test_expect_success 'fetch --prune --tags prunes branches but not tags' '
 	cd "$D" &&
 	git clone . prune-tags &&
 	cd prune-tags &&
@@ -125,10 +125,10 @@ test_expect_success 'fetch --prune --tags prunes tags and branches' '
 	git fetch --prune --tags origin &&
 	git rev-parse origin/master &&
 	test_must_fail git rev-parse origin/fake-remote &&
-	test_must_fail git rev-parse sometag
+	git rev-parse sometag
 '
 
-test_expect_success 'fetch --prune --tags with branch does not delete other remote-tracking branches' '
+test_expect_success 'fetch --prune --tags with branch does not prune other things' '
 	cd "$D" &&
 	git clone . prune-tags-branch &&
 	cd prune-tags-branch &&
@@ -137,7 +137,7 @@ test_expect_success 'fetch --prune --tags with branch does not delete other remo
 
 	git fetch --prune --tags origin master &&
 	git rev-parse origin/extrabranch &&
-	test_must_fail git rev-parse sometag
+	git rev-parse sometag
 '
 
 test_expect_success 'fetch --prune --tags with refspec prunes based on refspec' '
@@ -151,7 +151,7 @@ test_expect_success 'fetch --prune --tags with refspec prunes based on refspec'
 	git fetch --prune --tags origin refs/heads/foo/*:refs/remotes/origin/foo/* &&
 	test_must_fail git rev-parse refs/remotes/origin/foo/otherbranch &&
 	git rev-parse origin/extrabranch &&
-	test_must_fail git rev-parse sometag
+	git rev-parse sometag
 '
 
 test_expect_success 'fetch tags when there is no tags' '
-- 
1.8.4.1

[PATCH v2 12/23] query_refspecs(): move some constants out of the loop

[Michael Haggerty]

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
---
 remote.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/remote.c b/remote.c
index e42daa8..a5e6c7f 100644
--- a/remote.c
+++ b/remote.c
@@ -825,6 +825,8 @@ static int query_refspecs(struct refspec *refs, int ref_count, struct refspec *q
 {
 	int i;
 	int find_src = !query->src;
+	const char *needle = find_src ? query->dst : query->src;
+	char **result = find_src ? &query->src : &query->dst;
 
 	if (find_src && !query->dst)
 		return error("query_refspecs: need either src or dst");
@@ -833,8 +835,6 @@ static int query_refspecs(struct refspec *refs, int ref_count, struct refspec *q
 		struct refspec *refspec = &refs[i];
 		const char *key = find_src ? refspec->dst : refspec->src;
 		const char *value = find_src ? refspec->src : refspec->dst;
-		const char *needle = find_src ? query->dst : query->src;
-		char **result = find_src ? &query->src : &query->dst;
 
 		if (!refspec->dst)
 			continue;
-- 
1.8.4.1

Re: [PATCH v2 12/23] query_refspecs(): move some constants out of the loop

[Ramkumar Ramachandra]

Michael Haggerty wrote:
> diff --git a/remote.c b/remote.c
> index e42daa8..a5e6c7f 100644
> --- a/remote.c
> +++ b/remote.c
> @@ -825,6 +825,8 @@ static int query_refspecs(struct refspec *refs, int ref_count, struct refspec *q
>  {
>         int i;
>         int find_src = !query->src;
> +       const char *needle = find_src ? query->dst : query->src;
> +       char **result = find_src ? &query->src : &query->dst;
>
>         if (find_src && !query->dst)
>                 return error("query_refspecs: need either src or dst");
> @@ -833,8 +835,6 @@ static int query_refspecs(struct refspec *refs, int ref_count, struct refspec *q
>                 struct refspec *refspec = &refs[i];
>                 const char *key = find_src ? refspec->dst : refspec->src;
>                 const char *value = find_src ? refspec->src : refspec->dst;
> -               const char *needle = find_src ? query->dst : query->src;
> -               char **result = find_src ? &query->src : &query->dst;
>
>                 if (!refspec->dst)
>                         continue;

Why? Is it used in some later patch?

Re: [PATCH v2 12/23] query_refspecs(): move some constants out of the loop

[Michael Haggerty]

On 10/30/2013 12:05 PM, Ramkumar Ramachandra wrote:
> Michael Haggerty wrote:
>> diff --git a/remote.c b/remote.c
>> index e42daa8..a5e6c7f 100644
>> --- a/remote.c
>> +++ b/remote.c
>> @@ -825,6 +825,8 @@ static int query_refspecs(struct refspec *refs, int ref_count, struct refspec *q
>>  {
>>         int i;
>>         int find_src = !query->src;
>> +       const char *needle = find_src ? query->dst : query->src;
>> +       char **result = find_src ? &query->src : &query->dst;
>>
>>         if (find_src && !query->dst)
>>                 return error("query_refspecs: need either src or dst");
>> @@ -833,8 +835,6 @@ static int query_refspecs(struct refspec *refs, int ref_count, struct refspec *q
>>                 struct refspec *refspec = &refs[i];
>>                 const char *key = find_src ? refspec->dst : refspec->src;
>>                 const char *value = find_src ? refspec->src : refspec->dst;
>> -               const char *needle = find_src ? query->dst : query->src;
>> -               char **result = find_src ? &query->src : &query->dst;
>>
>>                 if (!refspec->dst)
>>                         continue;
> 
> Why? Is it used in some later patch?

It's just improving the code hygiene in a function that I was reading to
understand the other code affected by the patches.  It's unrelated to
the other patches.

Michael

-- 
Michael Haggerty
mhagger@alum.mit.edu
http://softwareswirl.blogspot.com/

[PATCH v2 13/23] builtin/remote.c: reorder function definitions

[Michael Haggerty]

Reorder function definitions to remove the need for forward
declarations.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
---
 builtin/remote.c | 159 +++++++++++++++++++++++++++----------------------------
 1 file changed, 78 insertions(+), 81 deletions(-)

diff --git a/builtin/remote.c b/builtin/remote.c
index 4e14891..ecedd96 100644
--- a/builtin/remote.c
+++ b/builtin/remote.c
@@ -77,9 +77,6 @@ static const char * const builtin_remote_seturl_usage[] = {
 
 static int verbose;
 
-static int show_all(void);
-static int prune_remote(const char *remote, int dry_run);
-
 static inline int postfixcmp(const char *string, const char *postfix)
 {
 	int len1 = strlen(string), len2 = strlen(postfix);
@@ -1084,6 +1081,64 @@ static int show_push_info_item(struct string_list_item *item, void *cb_data)
 	return 0;
 }
 
+static int get_one_entry(struct remote *remote, void *priv)
+{
+	struct string_list *list = priv;
+	struct strbuf url_buf = STRBUF_INIT;
+	const char **url;
+	int i, url_nr;
+
+	if (remote->url_nr > 0) {
+		strbuf_addf(&url_buf, "%s (fetch)", remote->url[0]);
+		string_list_append(list, remote->name)->util =
+				strbuf_detach(&url_buf, NULL);
+	} else
+		string_list_append(list, remote->name)->util = NULL;
+	if (remote->pushurl_nr) {
+		url = remote->pushurl;
+		url_nr = remote->pushurl_nr;
+	} else {
+		url = remote->url;
+		url_nr = remote->url_nr;
+	}
+	for (i = 0; i < url_nr; i++)
+	{
+		strbuf_addf(&url_buf, "%s (push)", url[i]);
+		string_list_append(list, remote->name)->util =
+				strbuf_detach(&url_buf, NULL);
+	}
+
+	return 0;
+}
+
+static int show_all(void)
+{
+	struct string_list list = STRING_LIST_INIT_NODUP;
+	int result;
+
+	list.strdup_strings = 1;
+	result = for_each_remote(get_one_entry, &list);
+
+	if (!result) {
+		int i;
+
+		sort_string_list(&list);
+		for (i = 0; i < list.nr; i++) {
+			struct string_list_item *item = list.items + i;
+			if (verbose)
+				printf("%s\t%s\n", item->string,
+					item->util ? (const char *)item->util : "");
+			else {
+				if (i && !strcmp((item - 1)->string, item->string))
+					continue;
+				printf("%s\n", item->string);
+			}
+		}
+	}
+	string_list_clear(&list, 1);
+	return result;
+}
+
 static int show(int argc, const char **argv)
 {
 	int no_query = 0, result = 0, query_flag = 0;
@@ -1246,26 +1301,6 @@ static int set_head(int argc, const char **argv)
 	return result;
 }
 
-static int prune(int argc, const char **argv)
-{
-	int dry_run = 0, result = 0;
-	struct option options[] = {
-		OPT__DRY_RUN(&dry_run, N_("dry run")),
-		OPT_END()
-	};
-
-	argc = parse_options(argc, argv, NULL, options, builtin_remote_prune_usage,
-			     0);
-
-	if (argc < 1)
-		usage_with_options(builtin_remote_prune_usage, options);
-
-	for (; argc; argc--, argv++)
-		result |= prune_remote(*argv, dry_run);
-
-	return result;
-}
-
 static int prune_remote(const char *remote, int dry_run)
 {
 	int result = 0, i;
@@ -1304,6 +1339,26 @@ static int prune_remote(const char *remote, int dry_run)
 	return result;
 }
 
+static int prune(int argc, const char **argv)
+{
+	int dry_run = 0, result = 0;
+	struct option options[] = {
+		OPT__DRY_RUN(&dry_run, N_("dry run")),
+		OPT_END()
+	};
+
+	argc = parse_options(argc, argv, NULL, options, builtin_remote_prune_usage,
+			     0);
+
+	if (argc < 1)
+		usage_with_options(builtin_remote_prune_usage, options);
+
+	for (; argc; argc--, argv++)
+		result |= prune_remote(*argv, dry_run);
+
+	return result;
+}
+
 static int get_remote_default(const char *key, const char *value, void *priv)
 {
 	if (strcmp(key, "remotes.default") == 0) {
@@ -1505,64 +1560,6 @@ static int set_url(int argc, const char **argv)
 	return 0;
 }
 
-static int get_one_entry(struct remote *remote, void *priv)
-{
-	struct string_list *list = priv;
-	struct strbuf url_buf = STRBUF_INIT;
-	const char **url;
-	int i, url_nr;
-
-	if (remote->url_nr > 0) {
-		strbuf_addf(&url_buf, "%s (fetch)", remote->url[0]);
-		string_list_append(list, remote->name)->util =
-				strbuf_detach(&url_buf, NULL);
-	} else
-		string_list_append(list, remote->name)->util = NULL;
-	if (remote->pushurl_nr) {
-		url = remote->pushurl;
-		url_nr = remote->pushurl_nr;
-	} else {
-		url = remote->url;
-		url_nr = remote->url_nr;
-	}
-	for (i = 0; i < url_nr; i++)
-	{
-		strbuf_addf(&url_buf, "%s (push)", url[i]);
-		string_list_append(list, remote->name)->util =
-				strbuf_detach(&url_buf, NULL);
-	}
-
-	return 0;
-}
-
-static int show_all(void)
-{
-	struct string_list list = STRING_LIST_INIT_NODUP;
-	int result;
-
-	list.strdup_strings = 1;
-	result = for_each_remote(get_one_entry, &list);
-
-	if (!result) {
-		int i;
-
-		sort_string_list(&list);
-		for (i = 0; i < list.nr; i++) {
-			struct string_list_item *item = list.items + i;
-			if (verbose)
-				printf("%s\t%s\n", item->string,
-					item->util ? (const char *)item->util : "");
-			else {
-				if (i && !strcmp((item - 1)->string, item->string))
-					continue;
-				printf("%s\n", item->string);
-			}
-		}
-	}
-	string_list_clear(&list, 1);
-	return result;
-}
-
 int cmd_remote(int argc, const char **argv, const char *prefix)
 {
 	struct option options[] = {
-- 
1.8.4.1

[PATCH v2 14/23] builtin/remote.c:update(): use struct argv_array

[Michael Haggerty]

Use struct argv_array for calling the "git fetch" subprocesses.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
---
 builtin/remote.c | 33 +++++++++++++++++----------------
 1 file changed, 17 insertions(+), 16 deletions(-)

diff --git a/builtin/remote.c b/builtin/remote.c
index ecedd96..bffe2f9 100644
--- a/builtin/remote.c
+++ b/builtin/remote.c
@@ -6,6 +6,7 @@
 #include "strbuf.h"
 #include "run-command.h"
 #include "refs.h"
+#include "argv-array.h"
 
 static const char * const builtin_remote_usage[] = {
 	N_("git remote [-v | --verbose]"),
@@ -1376,36 +1377,36 @@ static int update(int argc, const char **argv)
 			 N_("prune remotes after fetching")),
 		OPT_END()
 	};
-	const char **fetch_argv;
-	int fetch_argc = 0;
+	struct argv_array fetch_argv = ARGV_ARRAY_INIT;
 	int default_defined = 0;
-
-	fetch_argv = xmalloc(sizeof(char *) * (argc+5));
+	int retval;
 
 	argc = parse_options(argc, argv, NULL, options, builtin_remote_update_usage,
 			     PARSE_OPT_KEEP_ARGV0);
 
-	fetch_argv[fetch_argc++] = "fetch";
+	argv_array_push(&fetch_argv, "fetch");
 
 	if (prune)
-		fetch_argv[fetch_argc++] = "--prune";
+		argv_array_push(&fetch_argv, "--prune");
 	if (verbose)
-		fetch_argv[fetch_argc++] = "-v";
-	fetch_argv[fetch_argc++] = "--multiple";
+		argv_array_push(&fetch_argv, "-v");
+	argv_array_push(&fetch_argv, "--multiple");
 	if (argc < 2)
-		fetch_argv[fetch_argc++] = "default";
+		argv_array_push(&fetch_argv, "default");
 	for (i = 1; i < argc; i++)
-		fetch_argv[fetch_argc++] = argv[i];
+		argv_array_push(&fetch_argv, argv[i]);
 
-	if (strcmp(fetch_argv[fetch_argc-1], "default") == 0) {
+	if (strcmp(fetch_argv.argv[fetch_argv.argc-1], "default") == 0) {
 		git_config(get_remote_default, &default_defined);
-		if (!default_defined)
-			fetch_argv[fetch_argc-1] = "--all";
+		if (!default_defined) {
+			argv_array_pop(&fetch_argv);
+			argv_array_push(&fetch_argv, "--all");
+		}
 	}
 
-	fetch_argv[fetch_argc] = NULL;
-
-	return run_command_v_opt(fetch_argv, RUN_GIT_CMD);
+	retval = run_command_v_opt(fetch_argv.argv, RUN_GIT_CMD);
+	argv_array_clear(&fetch_argv);
+	return retval;
 }
 
 static int remove_all_fetch_refspecs(const char *remote, const char *key)
-- 
1.8.4.1

[PATCH v2 15/23] fetch, remote: properly convey --no-prune options to subprocesses

[Michael Haggerty]

If --no-prune is passed to one of the following commands:

    git fetch --all
    git fetch --multiple
    git fetch --recurse-submodules
    git remote update

then it must also be passed to the "fetch" subprocesses that those
commands use to do their work.  Otherwise there might be a fetch.prune
or remote.<name>.prune configuration setting that causes pruning to
occur, contrary to the user's express wish.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
---
 builtin/fetch.c  | 4 ++--
 builtin/remote.c | 6 +++---
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/builtin/fetch.c b/builtin/fetch.c
index 1514b90..5ddb9af 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -936,8 +936,8 @@ static void add_options_to_argv(struct argv_array *argv)
 {
 	if (dry_run)
 		argv_array_push(argv, "--dry-run");
-	if (prune > 0)
-		argv_array_push(argv, "--prune");
+	if (prune != -1)
+		argv_array_push(argv, prune ? "--prune" : "--no-prune");
 	if (update_head_ok)
 		argv_array_push(argv, "--update-head-ok");
 	if (force)
diff --git a/builtin/remote.c b/builtin/remote.c
index bffe2f9..f532f35 100644
--- a/builtin/remote.c
+++ b/builtin/remote.c
@@ -1371,7 +1371,7 @@ static int get_remote_default(const char *key, const char *value, void *priv)
 
 static int update(int argc, const char **argv)
 {
-	int i, prune = 0;
+	int i, prune = -1;
 	struct option options[] = {
 		OPT_BOOL('p', "prune", &prune,
 			 N_("prune remotes after fetching")),
@@ -1386,8 +1386,8 @@ static int update(int argc, const char **argv)
 
 	argv_array_push(&fetch_argv, "fetch");
 
-	if (prune)
-		argv_array_push(&fetch_argv, "--prune");
+	if (prune != -1)
+		argv_array_push(&fetch_argv, prune ? "--prune" : "--no-prune");
 	if (verbose)
 		argv_array_push(&fetch_argv, "-v");
 	argv_array_push(&fetch_argv, "--multiple");
-- 
1.8.4.1

[PATCH v2 16/23] fetch-options.txt: simplify ifdef/ifndef/endif usage

[Michael Haggerty]

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
---
 Documentation/fetch-options.txt | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/Documentation/fetch-options.txt b/Documentation/fetch-options.txt
index 12b1d92..f0ef7d0 100644
--- a/Documentation/fetch-options.txt
+++ b/Documentation/fetch-options.txt
@@ -51,13 +51,10 @@ ifndef::git-pull[]
 	subject to pruning.
 endif::git-pull[]
 
-ifdef::git-pull[]
---no-tags::
-endif::git-pull[]
 ifndef::git-pull[]
 -n::
---no-tags::
 endif::git-pull[]
+--no-tags::
 	By default, tags that point at objects that are downloaded
 	from the remote repository are fetched and stored locally.
 	This option disables this automatic tag following. The default
-- 
1.8.4.1

[PATCH v2 17/23] git-fetch.txt: improve description of tag auto-following

[Michael Haggerty]

Make it clearer that tags are fetched independent of which branches
were fetched from the remote in any particular fetch.  (Tags are even
fetched if they point at objects that are in the current repository
but not reachable, which is probably a bug.)

Put less emphasis on the mechanism and more on the effect of tag
auto-following.  Also mention the options and configuration settings
that can change the tag-fetching behavior.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
---

The "probable bug" mentioned above has been reported to the mailing
list [1] but is not addressed in the current patch series.

[1] http://article.gmane.org/gmane.comp.version-control.git/236829

 Documentation/git-fetch.txt | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/Documentation/git-fetch.txt b/Documentation/git-fetch.txt
index e08a028..1065713 100644
--- a/Documentation/git-fetch.txt
+++ b/Documentation/git-fetch.txt
@@ -24,13 +24,13 @@ The ref names and their object names of fetched refs are stored
 in `.git/FETCH_HEAD`.  This information is left for a later merge
 operation done by 'git merge'.
 
-When <refspec> stores the fetched result in remote-tracking branches,
-the tags that point at these branches are automatically
-followed.  This is done by first fetching from the remote using
-the given <refspec>s, and if the repository has objects that are
-pointed by remote tags that it does not yet have, then fetch
-those missing tags.  If the other end has tags that point at
-branches you are not interested in, you will not get them.
+By default, tags are auto-followed.  This means that when fetching
+from a remote, any tags on the remote that point to objects that exist
+in the local repository are fetched.  The effect is to fetch tags that
+point at branches that you are interested in.  This default behavior
+can be changed by using the --tags or --no-tags options, by
+configuring remote.<name>.tagopt, or by using a refspec that fetches
+tags explicitly.
 
 'git fetch' can fetch from either a single named repository,
 or from several repositories at once if <group> is given and
-- 
1.8.4.1

[PATCH v2 18/23] ref_remove_duplicates(): avoid redundant bisection

[Michael Haggerty]

The old code called string_list_lookup(), and if that failed called
string_list_insert(), thus doing the bisection search through the
string list twice in the latter code path.

Instead, just call string_list_insert() right away.  If an entry for
that peer reference name already existed, then its util pointer is
always non-NULL.

Of course this doesn't change the fact that the repeated
string_list_insert() calls make the function scale like O(N^2) if the
input reference list is not already approximately sorted.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
---
 remote.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/remote.c b/remote.c
index a5e6c7f..15f3dc5 100644
--- a/remote.c
+++ b/remote.c
@@ -750,13 +750,15 @@ void ref_remove_duplicates(struct ref *ref_map)
 	struct string_list refs = STRING_LIST_INIT_NODUP;
 	struct string_list_item *item = NULL;
 	struct ref *prev = NULL, *next = NULL;
+
 	for (; ref_map; prev = ref_map, ref_map = next) {
 		next = ref_map->next;
 		if (!ref_map->peer_ref)
 			continue;
 
-		item = string_list_lookup(&refs, ref_map->peer_ref->name);
-		if (item) {
+		item = string_list_insert(&refs, ref_map->peer_ref->name);
+		if (item->util) {
+			/* Entry already existed */
 			if (strcmp(((struct ref *)item->util)->name,
 				   ref_map->name))
 				die("%s tracks both %s and %s",
@@ -767,11 +769,9 @@ void ref_remove_duplicates(struct ref *ref_map)
 			free(ref_map->peer_ref);
 			free(ref_map);
 			ref_map = prev; /* skip this; we freed it */
-			continue;
+		} else {
+			item->util = ref_map;
 		}
-
-		item = string_list_insert(&refs, ref_map->peer_ref->name);
-		item->util = ref_map;
 	}
 	string_list_clear(&refs, 0);
 }
-- 
1.8.4.1

[PATCH v2 19/23] t5536: new test of refspec conflicts when fetching

[Michael Haggerty]

Add some tests that "git fetch" handles refspec conflicts (i.e., when
the same local reference should be updated from two different remote
references) correctly.

There is a small bug when updating references opportunistically,
namely that an explicit user wish like

    git fetch origin \
        refs/heads/branch1:refs/remotes/origin/branch2 \
        refs/heads/branch2:refs/remotes/origin/branch1

should override a configured refspec like

    +refs/heads/*:refs/remotes/origin/*

The current code incorrectly treats this as a fatal error.

In a few commits we will improve the error messages for refspec
conflicts in general and also turn this buggy fatal error into a
warning.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
---
 t/t5536-fetch-conflicts.sh | 96 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 96 insertions(+)
 create mode 100755 t/t5536-fetch-conflicts.sh

diff --git a/t/t5536-fetch-conflicts.sh b/t/t5536-fetch-conflicts.sh
new file mode 100755
index 0000000..679c53e
--- /dev/null
+++ b/t/t5536-fetch-conflicts.sh
@@ -0,0 +1,96 @@
+#!/bin/sh
+
+test_description='fetch handles conflicting refspecs correctly'
+
+. ./test-lib.sh
+
+D=$(pwd)
+
+setup_repository () {
+	git init "$1" && (
+		cd "$1" &&
+		git config remote.origin.url "$D" &&
+		shift &&
+		for refspec in "$@"
+		do
+			git config --add remote.origin.fetch "$refspec"
+		done
+	)
+}
+
+verify_stderr () {
+	cat >expected &&
+	# We're not interested in the error
+	# "fatal: The remote end hung up unexpectedly":
+	grep -v "hung up" <error >actual &&
+	test_cmp expected actual
+}
+
+test_expect_success 'setup' '
+	git commit --allow-empty -m "Initial" &&
+	git branch branch1 &&
+	git tag tag1 &&
+	git commit --allow-empty -m "First" &&
+	git branch branch2 &&
+	git tag tag2
+'
+
+test_expect_success 'fetch with no conflict' '
+	setup_repository ok "+refs/heads/*:refs/remotes/origin/*" && (
+		cd ok &&
+		git fetch origin
+	)
+'
+
+test_expect_success 'fetch conflict: config vs. config' '
+	setup_repository ccc \
+		"+refs/heads/branch1:refs/remotes/origin/branch1" \
+		"+refs/heads/branch2:refs/remotes/origin/branch1" && (
+		cd ccc &&
+		test_must_fail git fetch origin 2>error &&
+		verify_stderr <<-\EOF
+		fatal: refs/remotes/origin/branch1 tracks both refs/heads/branch1 and refs/heads/branch2
+		EOF
+	)
+'
+
+test_expect_success 'fetch duplicate: config vs. config' '
+	setup_repository dcc \
+		"+refs/heads/*:refs/remotes/origin/*" \
+		"+refs/heads/branch1:refs/remotes/origin/branch1" && (
+		cd dcc &&
+		git fetch origin
+	)
+'
+
+test_expect_success 'fetch conflict: arg overrides config' '
+	setup_repository aoc \
+		"+refs/heads/*:refs/remotes/origin/*" && (
+		cd aoc &&
+		git fetch origin refs/heads/branch2:refs/remotes/origin/branch1
+	)
+'
+
+test_expect_success 'fetch conflict: arg vs. arg' '
+	setup_repository caa && (
+		cd caa &&
+		test_must_fail git fetch origin \
+			refs/heads/*:refs/remotes/origin/* \
+			refs/heads/branch2:refs/remotes/origin/branch1 2>error &&
+		verify_stderr <<-\EOF
+		fatal: refs/remotes/origin/branch1 tracks both refs/heads/branch1 and refs/heads/branch2
+		EOF
+	)
+'
+
+test_expect_failure 'fetch conflict: criss-cross args' '
+	setup_repository xaa \
+		"+refs/heads/*:refs/remotes/origin/*" && (
+		cd xaa &&
+		git fetch origin \
+			refs/heads/branch1:refs/remotes/origin/branch2 \
+			refs/heads/branch2:refs/remotes/origin/branch1
+	)
+'
+
+test_done
-- 
1.8.4.1

[PATCH v2 20/23] ref_remove_duplicates(): simplify loop logic

[Michael Haggerty]

Change the loop body into the more straightforward

* remove item from the front of the old list
* if necessary, add it to the tail of the new list

and return a pointer to the new list (even though it is currently
always the same as the input argument, because the first element in
the list is currently never deleted).

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
---
 builtin/fetch.c |  4 +---
 remote.c        | 52 +++++++++++++++++++++++++++++++---------------------
 remote.h        |  8 ++++++--
 3 files changed, 38 insertions(+), 26 deletions(-)

diff --git a/builtin/fetch.c b/builtin/fetch.c
index 5ddb9af..3d978eb 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -360,9 +360,7 @@ static struct ref *get_ref_map(struct transport *transport,
 		tail = &rm->next;
 	}
 
-	ref_remove_duplicates(ref_map);
-
-	return ref_map;
+	return ref_remove_duplicates(ref_map);
 }
 
 #define STORE_REF_ERROR_OTHER 1
diff --git a/remote.c b/remote.c
index 15f3dc5..c90a2bf 100644
--- a/remote.c
+++ b/remote.c
@@ -745,35 +745,45 @@ int for_each_remote(each_remote_fn fn, void *priv)
 	return result;
 }
 
-void ref_remove_duplicates(struct ref *ref_map)
+struct ref *ref_remove_duplicates(struct ref *ref_map)
 {
 	struct string_list refs = STRING_LIST_INIT_NODUP;
-	struct string_list_item *item = NULL;
-	struct ref *prev = NULL, *next = NULL;
+	struct ref *retval = NULL;
+	struct ref **p = &retval;
 
-	for (; ref_map; prev = ref_map, ref_map = next) {
-		next = ref_map->next;
-		if (!ref_map->peer_ref)
-			continue;
+	while (ref_map) {
+		struct ref *ref = ref_map;
+
+		ref_map = ref_map->next;
+		ref->next = NULL;
 
-		item = string_list_insert(&refs, ref_map->peer_ref->name);
-		if (item->util) {
-			/* Entry already existed */
-			if (strcmp(((struct ref *)item->util)->name,
-				   ref_map->name))
-				die("%s tracks both %s and %s",
-				    ref_map->peer_ref->name,
-				    ((struct ref *)item->util)->name,
-				    ref_map->name);
-			prev->next = ref_map->next;
-			free(ref_map->peer_ref);
-			free(ref_map);
-			ref_map = prev; /* skip this; we freed it */
+		if (!ref->peer_ref) {
+			*p = ref;
+			p = &ref->next;
 		} else {
-			item->util = ref_map;
+			struct string_list_item *item =
+				string_list_insert(&refs, ref->peer_ref->name);
+
+			if (item->util) {
+				/* Entry already existed */
+				if (strcmp(((struct ref *)item->util)->name,
+					   ref->name))
+					die("%s tracks both %s and %s",
+					    ref->peer_ref->name,
+					    ((struct ref *)item->util)->name,
+					    ref->name);
+				free(ref->peer_ref);
+				free(ref);
+			} else {
+				*p = ref;
+				p = &ref->next;
+				item->util = ref;
+			}
 		}
 	}
+
 	string_list_clear(&refs, 0);
+	return retval;
 }
 
 int remote_has_url(struct remote *remote, const char *url)
diff --git a/remote.h b/remote.h
index 131130a..c07eb99 100644
--- a/remote.h
+++ b/remote.h
@@ -149,9 +149,13 @@ int resolve_remote_symref(struct ref *ref, struct ref *list);
 int ref_newer(const unsigned char *new_sha1, const unsigned char *old_sha1);
 
 /*
- * Removes and frees any duplicate refs in the map.
+ * Remove and free all but the first of any entries in the input list
+ * that map the same remote reference to the same local reference.  If
+ * there are two entries that map different remote references to the
+ * same local reference, emit an error message and die.  Return a
+ * pointer to the head of the resulting list.
  */
-void ref_remove_duplicates(struct ref *ref_map);
+struct ref *ref_remove_duplicates(struct ref *ref_map);
 
 int valid_fetch_refspec(const char *refspec);
 struct refspec *parse_fetch_refspec(int nr_refspec, const char **refspec);
-- 
1.8.4.1

[PATCH v2 21/23] ref_remote_duplicates(): extract a function handle_duplicate()

[Michael Haggerty]

It will become more complex in a moment.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
---
 remote.c | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/remote.c b/remote.c
index c90a2bf..2deb2db 100644
--- a/remote.c
+++ b/remote.c
@@ -745,6 +745,15 @@ int for_each_remote(each_remote_fn fn, void *priv)
 	return result;
 }
 
+static void handle_duplicate(struct ref *ref1, struct ref *ref2)
+{
+	if (strcmp(ref1->name, ref2->name))
+		die("%s tracks both %s and %s",
+		    ref2->peer_ref->name, ref1->name, ref2->name);
+	free(ref2->peer_ref);
+	free(ref2);
+}
+
 struct ref *ref_remove_duplicates(struct ref *ref_map)
 {
 	struct string_list refs = STRING_LIST_INIT_NODUP;
@@ -766,14 +775,7 @@ struct ref *ref_remove_duplicates(struct ref *ref_map)
 
 			if (item->util) {
 				/* Entry already existed */
-				if (strcmp(((struct ref *)item->util)->name,
-					   ref->name))
-					die("%s tracks both %s and %s",
-					    ref->peer_ref->name,
-					    ((struct ref *)item->util)->name,
-					    ref->name);
-				free(ref->peer_ref);
-				free(ref);
+				handle_duplicate((struct ref *)item->util, ref);
 			} else {
 				*p = ref;
 				p = &ref->next;
-- 
1.8.4.1

[PATCH v2 22/23] handle_duplicate(): mark error message for translation

[Michael Haggerty]

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
---
 remote.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/remote.c b/remote.c
index 2deb2db..06a0eda 100644
--- a/remote.c
+++ b/remote.c
@@ -748,7 +748,7 @@ int for_each_remote(each_remote_fn fn, void *priv)
 static void handle_duplicate(struct ref *ref1, struct ref *ref2)
 {
 	if (strcmp(ref1->name, ref2->name))
-		die("%s tracks both %s and %s",
+		die(_("%s tracks both %s and %s"),
 		    ref2->peer_ref->name, ref1->name, ref2->name);
 	free(ref2->peer_ref);
 	free(ref2);
-- 
1.8.4.1

[PATCH v2 23/23] fetch: improve the error messages emitted for conflicting refspecs

[Michael Haggerty]

If we find two refspecs that want to update the same local reference,
emit an error message that is more informative based on whether one of
the conflicting refspecs is an opportunistic update during a fetch
with explicit command-line refspecs.  And especially, do not die if an
opportunistic reference update conflicts with an express wish of the
user; rather, just emit a warning and skip the opportunistic reference
update.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
---
 remote.c                   | 25 ++++++++++++++++++++++---
 t/t5536-fetch-conflicts.sh | 14 +++++++++-----
 2 files changed, 31 insertions(+), 8 deletions(-)

diff --git a/remote.c b/remote.c
index 06a0eda..15e6e5e 100644
--- a/remote.c
+++ b/remote.c
@@ -747,9 +747,28 @@ int for_each_remote(each_remote_fn fn, void *priv)
 
 static void handle_duplicate(struct ref *ref1, struct ref *ref2)
 {
-	if (strcmp(ref1->name, ref2->name))
-		die(_("%s tracks both %s and %s"),
-		    ref2->peer_ref->name, ref1->name, ref2->name);
+	if (strcmp(ref1->name, ref2->name)) {
+		if (ref1->fetch_head_status != FETCH_HEAD_IGNORE &&
+		    ref2->fetch_head_status != FETCH_HEAD_IGNORE) {
+			die(_("Cannot fetch both %s and %s to %s"),
+			    ref1->name, ref2->name, ref2->peer_ref->name);
+		} else if (ref1->fetch_head_status != FETCH_HEAD_IGNORE &&
+			   ref2->fetch_head_status == FETCH_HEAD_IGNORE) {
+			warning(_("%s usually tracks %s, not %s"),
+				ref2->peer_ref->name, ref2->name, ref1->name);
+		} else if (ref1->fetch_head_status == FETCH_HEAD_IGNORE &&
+			   ref2->fetch_head_status == FETCH_HEAD_IGNORE) {
+			die(_("%s tracks both %s and %s"),
+			    ref2->peer_ref->name, ref1->name, ref2->name);
+		} else {
+			/*
+			 * This last possibility doesn't occur because
+			 * FETCH_HEAD_IGNORE entries always appear at
+			 * the end of the list.
+			 */
+			die(_("Internal error"));
+		}
+	}
 	free(ref2->peer_ref);
 	free(ref2);
 }
diff --git a/t/t5536-fetch-conflicts.sh b/t/t5536-fetch-conflicts.sh
index 679c53e..6c5d3a4 100755
--- a/t/t5536-fetch-conflicts.sh
+++ b/t/t5536-fetch-conflicts.sh
@@ -22,7 +22,7 @@ verify_stderr () {
 	cat >expected &&
 	# We're not interested in the error
 	# "fatal: The remote end hung up unexpectedly":
-	grep -v "hung up" <error >actual &&
+	grep -E '^(fatal|warning):' <error | grep -v 'hung up' >actual | sort &&
 	test_cmp expected actual
 }
 
@@ -49,7 +49,7 @@ test_expect_success 'fetch conflict: config vs. config' '
 		cd ccc &&
 		test_must_fail git fetch origin 2>error &&
 		verify_stderr <<-\EOF
-		fatal: refs/remotes/origin/branch1 tracks both refs/heads/branch1 and refs/heads/branch2
+		fatal: Cannot fetch both refs/heads/branch1 and refs/heads/branch2 to refs/remotes/origin/branch1
 		EOF
 	)
 '
@@ -78,18 +78,22 @@ test_expect_success 'fetch conflict: arg vs. arg' '
 			refs/heads/*:refs/remotes/origin/* \
 			refs/heads/branch2:refs/remotes/origin/branch1 2>error &&
 		verify_stderr <<-\EOF
-		fatal: refs/remotes/origin/branch1 tracks both refs/heads/branch1 and refs/heads/branch2
+		fatal: Cannot fetch both refs/heads/branch1 and refs/heads/branch2 to refs/remotes/origin/branch1
 		EOF
 	)
 '
 
-test_expect_failure 'fetch conflict: criss-cross args' '
+test_expect_success 'fetch conflict: criss-cross args' '
 	setup_repository xaa \
 		"+refs/heads/*:refs/remotes/origin/*" && (
 		cd xaa &&
 		git fetch origin \
 			refs/heads/branch1:refs/remotes/origin/branch2 \
-			refs/heads/branch2:refs/remotes/origin/branch1
+			refs/heads/branch2:refs/remotes/origin/branch1 2>error &&
+		verify_stderr <<-\EOF
+		warning: refs/remotes/origin/branch1 usually tracks refs/heads/branch1, not refs/heads/branch2
+		warning: refs/remotes/origin/branch2 usually tracks refs/heads/branch2, not refs/heads/branch1
+		EOF
 	)
 '
 
-- 
1.8.4.1