Re: [PATCH v4 8/9] commit: use config-based hooks

> As part of the adoption of config-based hooks, teach run_commit_hook()
> to call hook.h instead of run-command.h. This covers 'pre-commit',
> 'commit-msg', and 'prepare-commit-msg'. Additionally, ask the hook
> library - not run-command - whether any hooks will be run, as it's
> possible hooks may exist in the config but not the hookdir.
> 
> Signed-off-by: Emily Shaffer <emilyshaffer@google.com>
> ---
>   builtin/commit.c                                 |  3 ++-
>   builtin/merge.c                                  |  3 ++-
>   commit.c                                         | 13 ++++++++++++-
>   t/t7503-pre-commit-and-pre-merge-commit-hooks.sh | 13 +++++++++++++
>   4 files changed, 29 insertions(+), 3 deletions(-)
> 
> diff --git a/builtin/commit.c b/builtin/commit.c
> index 69ac78d5e5..a19c6478eb 100644
> --- a/builtin/commit.c
> +++ b/builtin/commit.c
> @@ -36,6 +36,7 @@
>   #include "help.h"
>   #include "commit-reach.h"
>   #include "commit-graph.h"
> +#include "hook.h"
>   
>   static const char * const builtin_commit_usage[] = {
>   	N_("git commit [<options>] [--] <pathspec>..."),
> @@ -985,7 +986,7 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
>   		return 0;
>   	}
>   
> -	if (!no_verify && find_hook("pre-commit")) {
> +	if (!no_verify && hook_exists("pre-commit")) {
>   		/*
>   		 * Re-read the index as pre-commit hook could have updated it,
>   		 * and write it out as a tree.  We must do this before we invoke
> diff --git a/builtin/merge.c b/builtin/merge.c
> index 74829a838e..c1a9d0083d 100644
> --- a/builtin/merge.c
> +++ b/builtin/merge.c
> @@ -41,6 +41,7 @@
>   #include "commit-reach.h"
>   #include "wt-status.h"
>   #include "commit-graph.h"
> +#include "hook.h"
>   
>   #define DEFAULT_TWOHEAD (1<<0)
>   #define DEFAULT_OCTOPUS (1<<1)
> @@ -829,7 +830,7 @@ static void prepare_to_commit(struct commit_list *remoteheads)
>   	 * and write it out as a tree.  We must do this before we invoke
>   	 * the editor and after we invoke run_status above.
>   	 */
> -	if (find_hook("pre-merge-commit"))
> +	if (hook_exists("pre-merge-commit"))
>   		discard_cache();
>   	read_cache_from(index_file);
>   	strbuf_addbuf(&msg, &merge_msg);
> diff --git a/commit.c b/commit.c
> index 4ce8cb38d5..c7a243e848 100644
> --- a/commit.c
> +++ b/commit.c
> @@ -21,6 +21,7 @@
>   #include "commit-reach.h"
>   #include "run-command.h"
>   #include "shallow.h"
> +#include "hook.h"
>   
>   static struct commit_extra_header *read_commit_extra_header_lines(const char *buf, size_t len, const char **);
>   
> @@ -1632,8 +1633,13 @@ int run_commit_hook(int editor_is_used, const char *index_file,
>   {
>   	struct strvec hook_env = STRVEC_INIT;
>   	va_list args;
> +	const char *arg;
> +	struct strvec hook_args = STRVEC_INIT;
> +	struct strbuf hook_name = STRBUF_INIT;
>   	int ret;
>   
> +	strbuf_addstr(&hook_name, name);

>   	strvec_pushf(&hook_env, "GIT_INDEX_FILE=%s", index_file);
>   
>   	/*
> @@ -1643,9 +1649,14 @@ int run_commit_hook(int editor_is_used, const char *index_file,
>   		strvec_push(&hook_env, "GIT_EDITOR=:");
>   
>   	va_start(args, name);
> -	ret = run_hook_ve(hook_env.v, name, args);
> +	while ((arg = va_arg(args, const char *)))
> +		strvec_push(&hook_args, arg);
>   	va_end(args);
> +
> +	ret = run_hooks(hook_env.v, &hook_name, &hook_args);
>   	strvec_clear(&hook_env);
> +	strvec_clear(&hook_args);
> +	strbuf_release(&hook_name);
>   
>   	return ret;
>   }
> diff --git a/t/t7503-pre-commit-and-pre-merge-commit-hooks.sh b/t/t7503-pre-commit-and-pre-merge-commit-hooks.sh
> index b3485450a2..cef8085dcc 100755
> --- a/t/t7503-pre-commit-and-pre-merge-commit-hooks.sh
> +++ b/t/t7503-pre-commit-and-pre-merge-commit-hooks.sh
> @@ -103,6 +103,19 @@ test_expect_success 'with succeeding hook' '
>   	test_cmp expected_hooks actual_hooks
>   '
>   
> +# NEEDSWORK: when 'git hook add' and 'git hook remove' have been added, use that
> +# instead
> +test_expect_success 'with succeeding hook (config-based)' '
> +	test_when_finished "git config --unset hook.pre-commit.command success.sample" &&
> +	test_when_finished "rm -f expected_hooks actual_hooks" &&
> +	git config hook.pre-commit.command "$HOOKDIR/success.sample" &&
> +	echo "$HOOKDIR/success.sample" >expected_hooks &&
> +	echo "more" >>file &&
> +	git add file &&
> +	git commit -m "more" &&
> +	test_cmp expected_hooks actual_hooks
> +'
> +
>   test_expect_success 'with succeeding hook (merge)' '
>   	test_when_finished "rm -f \"$PREMERGE\" expected_hooks actual_hooks" &&
>   	cp "$HOOKDIR/success.sample" "$PREMERGE" &&
>