Re: [GSOC PATCH v3] commit: avoid scanning trailing comments when 'core.commentChar' is "auto"

[Ayush Chandekar <ayu.chandekar@gmail.com>]

On Tue, Jul 1, 2025 at 6:47 PM Phillip Wood <phillip.wood123@gmail.com> wrote:
>
> Hi Ayush
>
> On 30/06/2025 19:25, Ayush Chandekar wrote:
> >
> > Range-diff with v2:
> > 1:  4e74e7a9a6 ! 1:  693f890a36 commit: avoid scanning trailing comments when 'core.commentChar' is "auto"
> >      @@ Commit message
> >
> >           The "auto" value for core.commentchar was introduced in the commit
> >           84c9dc2c5a (commit: allow core.commentChar=auto for character auto
> >      -    selection, 2014-05-17) but did not exhibt this issue at that time.
> >      +    selection, 2014-05-17) but did not exhibit this issue at that time.
> >
> >           The bug was introduced in commit a6c2654f83 (rebase -m: fix --signoff
> >           with conflicts, 2024-04-18) where Git started writing conflict comments
> >      @@ t/t3418-rebase-continue.sh: test_expect_success 'there is no --no-reschedule-fai
> >        '
> >
> >       +test_expect_success 'no change in comment character due to conflicts markers with core.commentChar=auto' '
> >      -+       test_commit base file &&
> >       +       git checkout -b branch-a &&
> >      -+       test_commit A file &&
> >      -+       git checkout -b branch-b base &&
> >      -+       test_commit B file &&
> >      ++       test_commit A F1 &&
> >      ++       git checkout -b branch-b HEAD^ &&
> >      ++       test_commit B F1 &&
> >       +       test_must_fail git rebase branch-a &&
> >      -+       printf "B\nA\n" >file &&
> >      -+       git add file &&
> >      ++       printf "B\nA\n" >F1 &&
> >      ++       git add F1 &&
> >       +       GIT_EDITOR="cat >actual" git -c core.commentChar=auto rebase --continue &&
> >       +       # Check that "#" is still the comment character.
> >      -+       test_grep "^# Changes to be committed:$" actual
> >      ++       test_grep "^# Changes to be committed" actual
> >       +'
> >       +
> >        test_orig_head_helper () {
>
> The changes here look good but I think we want to update the config
> parsing as well so that comment_line_str is reset to '#' when
> core.commentString=auto. We probably want to do that in its own commit.
>
> Thanks
>
> Phillip
>

maybe something like this?

--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -912,8 +912,10 @@ static int prepare_to_commit(const char
*index_file, const char *prefix,
        if (fwrite(sb.buf, 1, sb.len, s->fp) < sb.len)
                die_errno(_("could not write commit template"));

-       if (auto_comment_line_char)
+       if (auto_comment_line_char){
+               comment_line_str = "#";
                adjust_comment_line_char(&sb);
+       }
        strbuf_release(&sb);

or we can do it inside the `adjust_comment_line()` function.

Thanks!

Ayush