[RFC PATCH] notes: add prepend command

[RFC PATCH] notes: add prepend command

[Bence Ferdinandy]

When a note is detailing commit history, it makes sense to keep the
latest change on top, but unlike adding things at the bottom with
"git notes append" this can only be done manually. Add a

    git notes prepend

command, which works exactly like the append command, except that it
inserts the text before the current contents of the note instead of
after.

Signed-off-by: Bence Ferdinandy <bence@ferdinandy.com>
---

Notes:
    RFC v1: Cf.
        https://lore.kernel.org/git/20241023153736.257733-1-bence@ferdinandy.com/T/#m5b6644827590c2518089ab84f936a970c4e9be0f
    
        For that particular series I've used
        git rev-list HEAD~8..HEAD | xargs -i git notes append {} -m "v12: no change"
        for a quick-start on updating notes, when only 1 note needed to be
        really edited with meaningful content, and for some of the patches
        you now need to scroll a bit to actually find that "no change" text,
        instead of seeing it right at the top.

 builtin/notes.c | 32 ++++++++++++++++++++++++++------
 1 file changed, 26 insertions(+), 6 deletions(-)

diff --git a/builtin/notes.c b/builtin/notes.c
index 8c26e45526..cf158cab1c 100644
--- a/builtin/notes.c
+++ b/builtin/notes.c
@@ -35,6 +35,7 @@ static const char * const git_notes_usage[] = {
 	N_("git notes [--ref <notes-ref>] add [-f] [--allow-empty] [--[no-]separator|--separator=<paragraph-break>] [--[no-]stripspace] [-m <msg> | -F <file> | (-c | -C) <object>] [<object>]"),
 	N_("git notes [--ref <notes-ref>] copy [-f] <from-object> <to-object>"),
 	N_("git notes [--ref <notes-ref>] append [--allow-empty] [--[no-]separator|--separator=<paragraph-break>] [--[no-]stripspace] [-m <msg> | -F <file> | (-c | -C) <object>] [<object>]"),
+	N_("git notes [--ref <notes-ref>] prepend [--allow-empty] [--[no-]separator|--separator=<paragraph-break>] [--[no-]stripspace] [-m <msg> | -F <file> | (-c | -C) <object>] [<object>]"),
 	N_("git notes [--ref <notes-ref>] edit [--allow-empty] [<object>]"),
 	N_("git notes [--ref <notes-ref>] show [<object>]"),
 	N_("git notes [--ref <notes-ref>] merge [-v | -q] [-s <strategy>] <notes-ref>"),
@@ -644,7 +645,8 @@ static int copy(int argc, const char **argv, const char *prefix)
 	return retval;
 }
 
-static int append_edit(int argc, const char **argv, const char *prefix)
+
+static int append_prepend_edit(int argc, const char **argv, const char *prefix, int prepend)
 {
 	int allow_empty = 0;
 	const char *object_ref;
@@ -716,11 +718,18 @@ static int append_edit(int argc, const char **argv, const char *prefix)
 
 		if (!prev_buf)
 			die(_("unable to read %s"), oid_to_hex(note));
-		if (size)
-			strbuf_add(&buf, prev_buf, size);
-		if (d.buf.len && size)
-			append_separator(&buf);
-		strbuf_insert(&d.buf, 0, buf.buf, buf.len);
+		if (prepend) {
+			if (d.buf.len && size)
+				append_separator(&buf);
+			if (size)
+				strbuf_add(&buf, prev_buf, size);
+		} else {
+			if (size)
+				strbuf_add(&buf, prev_buf, size);
+			if (d.buf.len && size)
+				append_separator(&buf);
+		}
+		strbuf_insert(&d.buf, prepend ? d.buf.len : 0, buf.buf, buf.len);
 
 		free(prev_buf);
 		strbuf_release(&buf);
@@ -745,6 +754,16 @@ static int append_edit(int argc, const char **argv, const char *prefix)
 	return 0;
 }
 
+static int prepend_edit(int argc, const char **argv, const char *prefix)
+{
+	return append_prepend_edit(argc, argv, prefix, 1);
+}
+
+static int append_edit(int argc, const char **argv, const char *prefix)
+{
+	return append_prepend_edit(argc, argv, prefix, 0);
+}
+
 static int show(int argc, const char **argv, const char *prefix)
 {
 	const char *object_ref;
@@ -1116,6 +1135,7 @@ int cmd_notes(int argc,
 		OPT_SUBCOMMAND("add", &fn, add),
 		OPT_SUBCOMMAND("copy", &fn, copy),
 		OPT_SUBCOMMAND("append", &fn, append_edit),
+		OPT_SUBCOMMAND("prepend", &fn, prepend_edit),
 		OPT_SUBCOMMAND("edit", &fn, append_edit),
 		OPT_SUBCOMMAND("show", &fn, show),
 		OPT_SUBCOMMAND("merge", &fn, merge),
-- 
2.47.0.119.g5b706304f7.dirty

Re: [RFC PATCH] notes: add prepend command

[Taylor Blau]

On Wed, Oct 23, 2024 at 10:14:24PM +0200, Bence Ferdinandy wrote:
> When a note is detailing commit history, it makes sense to keep the
> latest change on top, but unlike adding things at the bottom with
> "git notes append" this can only be done manually. Add a
>
>     git notes prepend
>
> command, which works exactly like the append command, except that it
> inserts the text before the current contents of the note instead of
> after.

Hmmm. I am not sure that I see the widespread need for such a tool. If
this is specific to your use-case, I think a custom script and
`$GIT_EDITOR` would do the trick.

Thanks,
Taylor

Re: [RFC PATCH] notes: add prepend command

[Bence Ferdinandy]

On Wed Oct 23, 2024 at 22:20, Taylor Blau <me@ttaylorr.com> wrote:
> On Wed, Oct 23, 2024 at 10:14:24PM +0200, Bence Ferdinandy wrote:
>> When a note is detailing commit history, it makes sense to keep the
>> latest change on top, but unlike adding things at the bottom with
>> "git notes append" this can only be done manually. Add a
>>
>>     git notes prepend
>>
>> command, which works exactly like the append command, except that it
>> inserts the text before the current contents of the note instead of
>> after.
>
> Hmmm. I am not sure that I see the widespread need for such a tool. If
> this is specific to your use-case, I think a custom script and
> `$GIT_EDITOR` would do the trick.

Couldn't the same argument be made for append? Imho, it's a missing symmetry.
Ofc it's probably not quite hard to script around this.

Re: [RFC PATCH] notes: add prepend command

[Đoàn Trần Công Danh]

On 2024-10-23 22:14:24+0200, Bence Ferdinandy <bence@ferdinandy.com> wrote:
> -static int append_edit(int argc, const char **argv, const char *prefix)
> +
> +static int append_prepend_edit(int argc, const char **argv, const char *prefix, int prepend)
>  {
>  	int allow_empty = 0;
>  	const char *object_ref;
> @@ -716,11 +718,18 @@ static int append_edit(int argc, const char **argv, const char *prefix)
>  
>  		if (!prev_buf)
>  			die(_("unable to read %s"), oid_to_hex(note));
> -		if (size)
> -			strbuf_add(&buf, prev_buf, size);
> -		if (d.buf.len && size)
> -			append_separator(&buf);
> -		strbuf_insert(&d.buf, 0, buf.buf, buf.len);
> +		if (prepend) {
> +			if (d.buf.len && size)
> +				append_separator(&buf);
> +			if (size)
> +				strbuf_add(&buf, prev_buf, size);
> +		} else {
> +			if (size)
> +				strbuf_add(&buf, prev_buf, size);
> +			if (d.buf.len && size)
> +				append_separator(&buf);
> +		}
> +		strbuf_insert(&d.buf, prepend ? d.buf.len : 0, buf.buf, buf.len);
>  
>  		free(prev_buf);
>  		strbuf_release(&buf);

Without prejudice about whether we should take this command.
(I think we shouldn't, just like we shouldn't top-posting).

I think this diff should be written like this for easier reasoning:

----- 8< -----------------
@@ -711,19 +713,27 @@ static int append_edit(int argc, const char **argv, const char *prefix)
 		/* Append buf to previous note contents */
 		unsigned long size;
 		enum object_type type;
-		struct strbuf buf = STRBUF_INIT;
 		char *prev_buf = repo_read_object_file(the_repository, note, &type, &size);
 
 		if (!prev_buf)
 			die(_("unable to read %s"), oid_to_hex(note));
-		if (size)
+		if (!size) {
+			// no existing notes, use whatever we have here
+		} else if (prepend) {
+			if (d.buf.len)
+				append_separator(&d.buf);
+			strbuf_add(&d.buf, prev_buf, size);
+		} else {
+			struct strbuf buf = STRBUF_INIT;
 			strbuf_add(&buf, prev_buf, size);
-		if (d.buf.len && size)
-			append_separator(&buf);
-		strbuf_insert(&d.buf, 0, buf.buf, buf.len);
+			if (d.buf.len)
+				append_separator(&buf);
+			strbuf_addbuf(&buf, &d.buf);
+			strbuf_swap(&buf, &d.buf);
+			strbuf_release(&buf);
+		}
 
 		free(prev_buf);
-		strbuf_release(&buf);
 	}
 
 	if (d.buf.len || allow_empty) {
-------------- 8< --------------------

Even if we don't take this subcommand, I think we should re-write the
append part, so:
- we can see the append logic better,
- we can avoid the `strbuf_insert` which will require memmove/memcpy.

Well, the second point is micro-optimisation, so take it with a grain
of salt.


Also tests.
-------------- 8< -----------------------
diff --git a/t/t3301-notes.sh b/t/t3301-notes.sh
index 99137fb235731..5a7ad40fde6a8 100755
--- a/t/t3301-notes.sh
+++ b/t/t3301-notes.sh
@@ -558,6 +558,20 @@ test_expect_success 'listing non-existing notes fails' '
 	test_must_be_empty actual
 '
 
+test_expect_success 'append: specify a separator with an empty arg' '
+	test_when_finished git notes remove HEAD &&
+	cat >expect <<-\EOF &&
+	notes-2
+
+	notes-1
+	EOF
+
+	git notes add -m "notes-1" &&
+	git notes prepend --separator="" -m "notes-2" &&
+	git notes show >actual &&
+	test_cmp expect actual
+'
+
 test_expect_success 'append: specify a separator with an empty arg' '
 	test_when_finished git notes remove HEAD &&
 	cat >expect <<-\EOF &&
----------- >8 --------------


-- 
Danh

Re: [RFC PATCH] notes: add prepend command

[Bence Ferdinandy]

On Thu Oct 24, 2024 at 13:19, Đoàn Trần Công Danh <congdanhqx@gmail.com> wrote:
> On 2024-10-23 22:14:24+0200, Bence Ferdinandy <bence@ferdinandy.com> wrote:
>> -static int append_edit(int argc, const char **argv, const char *prefix)
>> +
>> +static int append_prepend_edit(int argc, const char **argv, const char *prefix, int prepend)
>>  {
>>  	int allow_empty = 0;
>>  	const char *object_ref;
>> @@ -716,11 +718,18 @@ static int append_edit(int argc, const char **argv, const char *prefix)
>>  
>>  		if (!prev_buf)
>>  			die(_("unable to read %s"), oid_to_hex(note));
>> -		if (size)
>> -			strbuf_add(&buf, prev_buf, size);
>> -		if (d.buf.len && size)
>> -			append_separator(&buf);
>> -		strbuf_insert(&d.buf, 0, buf.buf, buf.len);
>> +		if (prepend) {
>> +			if (d.buf.len && size)
>> +				append_separator(&buf);
>> +			if (size)
>> +				strbuf_add(&buf, prev_buf, size);
>> +		} else {
>> +			if (size)
>> +				strbuf_add(&buf, prev_buf, size);
>> +			if (d.buf.len && size)
>> +				append_separator(&buf);
>> +		}
>> +		strbuf_insert(&d.buf, prepend ? d.buf.len : 0, buf.buf, buf.len);
>>  
>>  		free(prev_buf);
>>  		strbuf_release(&buf);
>
> Without prejudice about whether we should take this command.
> (I think we shouldn't, just like we shouldn't top-posting).

Again, I do not feel very strongly, about this patch, since it's not that hard
to do with a script, but I don't think the analogy with top-posting is
appropriate. It's usually not a discussion going on in the comments, and
prepending might happen for any reason. The ordering of content in a note may
not even be temporal in nature (although to be fair, I have personally never
used it for anything else than versioning patches).

The specific use-case came up in patch versioning (pointed out by Kristoffer),
where in a longer series with many iterations, seeing the "v1024: no change" at
the top would save reviewers from having to scroll an indefinite amount in the
particular patch just to find that they actually don't need to look at that
one, since it hasn't changed since the previous iteration they saw. In this
sense having the newest at the top rather than the bottom would be more
natural. I'd think probably even new reviewers jumping in during the middle
might not be very interested in the beginning.

>
> I think this diff should be written like this for easier reasoning:
>
> ----- 8< -----------------
> @@ -711,19 +713,27 @@ static int append_edit(int argc, const char **argv, const char *prefix)
>  		/* Append buf to previous note contents */
>  		unsigned long size;
>  		enum object_type type;
> -		struct strbuf buf = STRBUF_INIT;
>  		char *prev_buf = repo_read_object_file(the_repository, note, &type, &size);
>  
>  		if (!prev_buf)
>  			die(_("unable to read %s"), oid_to_hex(note));
> -		if (size)
> +		if (!size) {
> +			// no existing notes, use whatever we have here
> +		} else if (prepend) {
> +			if (d.buf.len)
> +				append_separator(&d.buf);
> +			strbuf_add(&d.buf, prev_buf, size);
> +		} else {
> +			struct strbuf buf = STRBUF_INIT;
>  			strbuf_add(&buf, prev_buf, size);
> -		if (d.buf.len && size)
> -			append_separator(&buf);
> -		strbuf_insert(&d.buf, 0, buf.buf, buf.len);
> +			if (d.buf.len)
> +				append_separator(&buf);
> +			strbuf_addbuf(&buf, &d.buf);
> +			strbuf_swap(&buf, &d.buf);
> +			strbuf_release(&buf);
> +		}
>  
>  		free(prev_buf);
> -		strbuf_release(&buf);
>  	}
>  
>  	if (d.buf.len || allow_empty) {
> -------------- 8< --------------------
>
> Even if we don't take this subcommand, I think we should re-write the
> append part, so:
> - we can see the append logic better,
> - we can avoid the `strbuf_insert` which will require memmove/memcpy.

Thanks, I do find this a bit more easier to read indeed.

>
> Well, the second point is micro-optimisation, so take it with a grain
> of salt.
>
>
> Also tests.
> -------------- 8< -----------------------
> diff --git a/t/t3301-notes.sh b/t/t3301-notes.sh
> index 99137fb235731..5a7ad40fde6a8 100755
> --- a/t/t3301-notes.sh
> +++ b/t/t3301-notes.sh
> @@ -558,6 +558,20 @@ test_expect_success 'listing non-existing notes fails' '
>  	test_must_be_empty actual
>  '
>  
> +test_expect_success 'append: specify a separator with an empty arg' '
> +	test_when_finished git notes remove HEAD &&
> +	cat >expect <<-\EOF &&
> +	notes-2
> +
> +	notes-1
> +	EOF
> +
> +	git notes add -m "notes-1" &&
> +	git notes prepend --separator="" -m "notes-2" &&
> +	git notes show >actual &&
> +	test_cmp expect actual
> +'
> +
>  test_expect_success 'append: specify a separator with an empty arg' '
>  	test_when_finished git notes remove HEAD &&
>  	cat >expect <<-\EOF &&
> ----------- >8 --------------

Thanks! I didn't look at tests (and documentation) before it was clear if the
idea got a green light or not, but I guess if it does, this would cover tests.

Best,
Bence

-- 
bence.ferdinandy.com