On Mon, Mar 15 2021, ZheNing Hu via GitGitGadget wrote:
> From: ZheNing Hu <adlternative@xxxxxxxxx>
>
> Historically, Git has supported the 'Signed-off-by' commit trailer
> using the '--signoff' and the '-s' option from the command line.
> But users may need to provide other trailer information from the
> command line such as "Helped-by", "Reported-by", "Mentored-by",
>
> Now implement a new `--trailer <token>[(=|:)<value>]` option to pass
> other trailers to `interpret-trailers` and insert them into commit
> messages.
I paged through v1-v8, looking mostly good so far. Some comments:
> Signed-off-by: ZheNing Hu <adlternative@xxxxxxxxx>
> ---
> Documentation/git-commit.txt | 9 ++++++++-
> builtin/commit.c | 23 +++++++++++++++++++++++
> t/t7502-commit-porcelain.sh | 20 ++++++++++++++++++++
> 3 files changed, 51 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/git-commit.txt b/Documentation/git-commit.txt
> index 17150fa7eabe..f74d320f0c96 100644
> --- a/Documentation/git-commit.txt
> +++ b/Documentation/git-commit.txt
> @@ -14,7 +14,7 @@ SYNOPSIS
> [--allow-empty-message] [--no-verify] [-e] [--author=<author>]
> [--date=<date>] [--cleanup=<mode>] [--[no-]status]
> [-i | -o] [--pathspec-from-file=<file> [--pathspec-file-nul]]
> - [-S[<keyid>]] [--] [<pathspec>...]
> + [-S[<keyid>]] [--] [<pathspec>...] [(--trailer <token>[(=|:)<value>])...]
>
> DESCRIPTION
> -----------
> @@ -166,6 +166,13 @@ The `-m` option is mutually exclusive with `-c`, `-C`, and `-F`.
>
> include::signoff-option.txt[]
>
> +--trailer <token>[(=|:)<value>]::
> + Specify a (<token>, <value>) pair that should be applied as a
> + trailer. (e.g. `git commit --trailer "Signed-off-by:C O Mitter \
> + <committer@xxxxxxxxxxx>" --trailer "Helped-by:C O Mitter \
> + <committer@xxxxxxxxxxx>"` will add the "Signed-off-by" trailer
> + and the "Helped-by" trailer in the commit message.)
> + See linkgit:git-interpret-trailers[1] for details.
> -n::
> --no-verify::
> This option bypasses the pre-commit and commit-msg hooks.
> diff --git a/builtin/commit.c b/builtin/commit.c
> index 739110c5a7f6..250e93d977df 100644
> --- a/builtin/commit.c
> +++ b/builtin/commit.c
> @@ -113,6 +113,7 @@ static int config_commit_verbose = -1; /* unspecified */
> static int no_post_rewrite, allow_empty_message, pathspec_file_nul;
> static char *untracked_files_arg, *force_date, *ignore_submodule_arg, *ignored_arg;
> static char *sign_commit, *pathspec_from_file;
> +static struct strvec trailer_args = STRVEC_INIT;
>
> /*
> * The default commit message cleanup mode will remove the lines
> @@ -131,6 +132,14 @@ static struct strbuf message = STRBUF_INIT;
>
> static enum wt_status_format status_format = STATUS_FORMAT_UNSPECIFIED;
>
> +static int opt_pass_trailer(const struct option *opt, const char *arg, int unset)
> +{
> + BUG_ON_OPT_NEG(unset);
> +
> + strvec_pushl(&trailer_args, "--trailer", arg, NULL);
> + return 0;
> +}
> +
> static int opt_parse_porcelain(const struct option *opt, const char *arg, int unset)
> {
> enum wt_status_format *value = (enum wt_status_format *)opt->value;
> @@ -958,6 +967,19 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
>
> fclose(s->fp);
>
> + if (trailer_args.nr) {
> + struct child_process run_trailer = CHILD_PROCESS_INIT;
> +
> + strvec_pushl(&run_trailer.args, "interpret-trailers",
> + "--in-place", "--if-exists=add",
> + git_path_commit_editmsg(), NULL);
> + strvec_pushv(&run_trailer.args, trailer_args.v);
> + run_trailer.git_cmd = 1;
> + if (run_command(&run_trailer))
> + strvec_clear(&run_trailer.args);
This is git-commit, shouldn't we die() here instead of ignoring errors
in sub-processes?
> + strvec_clear(&trailer_args);
> + }
> +
> /*
> * Reject an attempt to record a non-merge empty commit without
> * explicit --allow-empty. In the cherry-pick case, it may be
> @@ -1507,6 +1529,7 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
> OPT_STRING(0, "fixup", &fixup_message, N_("commit"), N_("use autosquash formatted message to fixup specified commit")),
> OPT_STRING(0, "squash", &squash_message, N_("commit"), N_("use autosquash formatted message to squash specified commit")),
> OPT_BOOL(0, "reset-author", &renew_authorship, N_("the commit is authored by me now (used with -C/-c/--amend)")),
> + OPT_CALLBACK_F(0, "trailer", NULL, N_("trailer"), N_("trailer(s) to add"), PARSE_OPT_NONEG, opt_pass_trailer),
> OPT_BOOL('s', "signoff", &signoff, N_("add a Signed-off-by trailer")),
Not required for this change, but perhaps a change here to N_() (if we
can get it to fit) + doc update saying that we prefer
--trailer="Signed-Off-By: to --signoff"? More on that later.
> OPT_FILENAME('t', "template", &template_file, N_("use specified template file")),
> OPT_BOOL('e', "edit", &edit_flag, N_("force edit of commit")),
> diff --git a/t/t7502-commit-porcelain.sh b/t/t7502-commit-porcelain.sh
> index 6396897cc818..0acf23799931 100755
> --- a/t/t7502-commit-porcelain.sh
> +++ b/t/t7502-commit-porcelain.sh
> @@ -154,6 +154,26 @@ test_expect_success 'sign off' '
>
> '
>
> +test_expect_success 'trailer' '
> + >file1 &&
> + git add file1 &&
> + git commit -s --trailer "Signed-off-by:C O Mitter1 <committer1@xxxxxxxxxxx>" \
> + --trailer "Helped-by:C O Mitter2 <committer2@xxxxxxxxxxx>" \
> + --trailer "Reported-by:C O Mitter3 <committer3@xxxxxxxxxxx>" \
> + --trailer "Mentored-by:C O Mitter4 <committer4@xxxxxxxxxxx>" \
> + -m "hello" &&
> + git cat-file commit HEAD >commit.msg &&
> + sed -e "1,7d" commit.msg >actual &&
> + cat >expected <<-\EOF &&
> + Signed-off-by: C O Mitter <committer@xxxxxxxxxxx>
> + Signed-off-by: C O Mitter1 <committer1@xxxxxxxxxxx>
> + Helped-by: C O Mitter2 <committer2@xxxxxxxxxxx>
> + Reported-by: C O Mitter3 <committer3@xxxxxxxxxxx>
> + Mentored-by: C O Mitter4 <committer4@xxxxxxxxxxx>
> + EOF
> + test_cmp expected actual
> +'
> +
How does this interact with cases where the user has configured
"trailer.separators" to have a value that doesn't contain ":"? I
haven't tested, but my reading of git-interpret-trailers(1) is that if
you supplied "=" instead that case would just work:
By default only : is recognized as a trailer separator, except that
= is always accepted on the command line for compatibility with
other git commands.
I don't know if that does the right thing in the presence of
--if-exists=add.
So it would be good to update these tests so you test:
* For the --if-exists=add case at all, there's no tests for it
now. I.e. add some trailers manually to the commit (via -F or
whatever) and then see if they get added to, replacet etc.
* Ditto but for the user having configured trailer.separators (see the
test_config helper for how to set config in a test). I.e. if it's "="
does adding trailers work, how about if it's "=" on the CLI but the
config/commit message has ";" instead of ":" or something?
* Hrm, actually I think tweaking "-c trailer.ifexists" won't work at
all, since the CLI switch would override it. I honestly don't know,
but why not not supply it and keep the addIfDifferentNeighbor
default?
If it's essential that seems like a good test / documentation
addition...
* For the above -c ... case I can't think of a good way to deal with it
that doesn't involve pulling in git_trailer_config() into
git_commit_config(), but perhaps the least nasty way is to just set a
flag in git_commit_config() if we see a "trailer.ifexists" flag, and
if so don't provide "--if-exists=add", if there's no config (this
will include "git -c ... commit" we set provide "--if-exists=add" )
or as noted above, maybe we can skip the whole thing and use the
addIfDifferentNeighbor default.
And, not needed for this patch but worth thinking about:
* We pass through --trailer to git-interpret-trailers, what should we
do about the other options? Should git-commit eventually support
--trailer-where and pass it along as --where to
git-interpret-trailers, or is "git -c trailer.where=... commit" good
enough?
* It would be good to test for and document if that "-c trailer.*"
trick works (no reason it shouldn't). I.e. to add something like this
after what you have (along with tests, and check if it's even true):
Only the `--trailer` argument to
linkgit:git-interpret-trailers[1] is supported. Other
pass-through switches may be added in the future, but currently
you'll need to pass arguments to
linkgit:git-interpret-trailers[1] along as config, e.g. `git -c
trailer.where=start commit [...] --trailer=[...]`.
* We have a longer-term goal of having the .mailmap apply to trailers,
it would be nice if git-interpret-trailers had some fuzzy-matching to
check if the RHS of a trailer is a name/E-Mail pair, and if so did
stricter validation on it with the ident functions we use for fsck
etc. (that's copied & subtly different in several different places in
the codebase, unfortunately[1]).
More thoughts:
* Having written all the above I checked how --signoff is implemented.
It seems to me to be a good idea to (at least for testing) convert
the --signoff trailer to your implementation. We have plenty of tests
for it, does migrating it over pass or fail those?
* I also agree with Junio that we shouldn't have a --fixed-by or
whatever and wouldn't add --signoff today, but it seems very useful
to me to have a shortcut like:
--trailer "Signed-off-by"
I.e. omitting the value, or:
--trailer "Signed-off-by="
Or some other thing we deem sufficiently useful/sane
syntax/unambiguous.n
Then the value would be provided by fmt_name(WANT_COMMITTER_IDENT)
just as we do in append_signoff() now. I think a *very common* case
for this would be something like:
git commit --amend -v --trailer "Reviewed-by"
And it would be useful to help that along and not have to do:
git commit --amend -v --trailer "Reviewed-by=$(git config user.name) <$(git config user.email)>"
Or worse yet, manually typo your name/e-mail address, as I'm sure I
and many others will inevitably do when using this option...
1. https://lore.kernel.org/git/87bld8ov9q.fsf@xxxxxxxxxxxxxxxxxxx/
