Subject: Re: [PATCH 07/27] git hook run: add an --ignore-missing flag

From: Emily Shaffer <[email-masked]>
Date: Fri, 2 Jul 2021 16:47:24 -0700

On Thu, Jun 17, 2021 at 12:22:41PM +0200, Ævar Arnfjörð Bjarmason wrote:
> 
> For certain one-shot hooks we'd like to optimistically run them, and
> not complain if they don't exist. This will be used by send-email in a
> subsequent commit.
> 
> Signed-off-by: Ævar Arnfjörð Bjarmason <[email-masked]>
> ---
>  Documentation/git-hook.txt | 10 +++++++++-
>  builtin/hook.c             |  8 +++++++-
>  t/t1800-hook.sh            |  7 ++++++-
>  3 files changed, 22 insertions(+), 3 deletions(-)
> 
> diff --git a/Documentation/git-hook.txt b/Documentation/git-hook.txt
> index 660d6a992a..097fb9de63 100644
> --- a/Documentation/git-hook.txt
> +++ b/Documentation/git-hook.txt
> @@ -8,7 +8,7 @@ git-hook - run git hooks
>  SYNOPSIS
>  --------
>  [verse]
> -'git hook' run <hook-name> [-- <hook-args>]
> +'git hook' run [--ignore-missing] <hook-name> [-- <hook-args>]
>  
>  DESCRIPTION
>  -----------
> @@ -29,6 +29,14 @@ optional `--` (or `--end-of-options`, see linkgit:gitcli[7]). The
>  arguments (if any) differ by hook name, see linkgit:githooks[5] for
>  what those are.
>  
> +OPTIONS
> +-------
> +
> +--ignore-missing::
> +	Ignore any missing hook by quietly returning zero. Used for
> +	tools that want to do a blind one-shot run of a hook that may
> +	or may not be present.
> +
>  SEE ALSO
>  --------
>  linkgit:githooks[5]
> diff --git a/builtin/hook.c b/builtin/hook.c
> index 7714d31ef1..47e0de7bbc 100644
> --- a/builtin/hook.c
> +++ b/builtin/hook.c
> @@ -22,10 +22,13 @@ static int run(int argc, const char **argv, const char *prefix)
>  	int i;
>  	struct run_hooks_opt opt = RUN_HOOKS_OPT_INIT;
>  	int rc = 0;
> +	int ignore_missing = 0;
>  	const char *hook_name;
>  	const char *hook_path;
>  
>  	struct option run_options[] = {
> +		OPT_BOOL(0, "ignore-missing", &ignore_missing,
> +			 N_("exit quietly with a zero exit code if the requested hook cannot be found")),
>  		OPT_END(),
>  	};
>  
> @@ -49,11 +52,14 @@ static int run(int argc, const char **argv, const char *prefix)
>  	/*
>  	 * We are not using run_hooks() because we'd like to detect
>  	 * missing hooks. Let's find it ourselves and call
> -	 * run_found_hooks() instead.
> +	 * run_found_hooks() instead...
>  	 */
>  	hook_name = argv[0];
>  	hook_path = find_hook(hook_name);
>  	if (!hook_path) {
> +		/* ... act like run_hooks() under --ignore-missing */
> +		if (ignore_missing)
> +			return 0;
>  		error("cannot find a hook named %s", hook_name);
>  		return 1;
>  	}

Have started to rebase the configgy stuff on top of this series, and the
final implementation here is kind of confusing to me. The difference
between run_hooks() and run_found_hooks() is the behavior when there's
no hook to run; but you're checking for missing hooks before you even
let them try to run here in builtin/hook.c. So is it really necessary to
have the two methods? I think I'm missing something?

> diff --git a/t/t1800-hook.sh b/t/t1800-hook.sh
> index ecd517b162..542e551628 100755
> --- a/t/t1800-hook.sh
> +++ b/t/t1800-hook.sh
> @@ -23,7 +23,12 @@ test_expect_success 'git hook run: nonexistent hook' '
>  	test_cmp stderr.expect stderr.actual
>  '
>  
> -test_expect_success 'git hook run: basic' '
> +test_expect_success 'git hook run: nonexistent hook with --ignore-missing' '
> +	git hook run --ignore-missing does-not-exist 2>stderr.actual &&
> +	test_must_be_empty stderr.actual
> +'
> +
> +test_expect_success 'git hook run -- basic' '
>  	write_script .git/hooks/test-hook <<-EOF &&
>  	echo Test hook
>  	EOF
> -- 
> 2.32.0.576.g59759b6ca7d
>