Re: [PATCH] commit: skip discarding the index if there is no pre-commit hook

> If there is not a pre-commit hook, there is no reason to discard
> the index and reread it.
>
> This change checks to presence of a pre-commit hook and then only
> discards the index if there was one.
>
> Signed-off-by: Kevin Willford <kewillf@microsoft.com>
> ---

>  builtin/commit.c | 29 +++++++++++++++++++++--------
>  1 file changed, 21 insertions(+), 8 deletions(-)
>
> diff --git a/builtin/commit.c b/builtin/commit.c
> index e7a2cb6285..443949d87b 100644
> --- a/builtin/commit.c
> +++ b/builtin/commit.c
> @@ -671,12 +671,22 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
>  	const char *hook_arg2 = NULL;
>  	int clean_message_contents = (cleanup_mode != CLEANUP_NONE);
>  	int old_display_comment_prefix;
> +	const char *precommit_hook = NULL;
>  
>  	/* This checks and barfs if author is badly specified */
>  	determine_author_info(author_ident);
>  
> -	if (!no_verify && run_commit_hook(use_editor, index_file, "pre-commit", NULL))
> -		return 0;
> +
> +	if (!no_verify) {
> +		/*
> +		 * Check to see if there is a pre-commit hook
> +		 * If there not one we can skip discarding the index later on
> +		 */
> +		precommit_hook = find_hook("pre-commit");
> +		if (precommit_hook &&
> +		    run_commit_hook(use_editor, index_file, "pre-commit", NULL))
> +			return 0;
> +	}
>  
>  	if (squash_message) {
>  		/*
> @@ -940,12 +950,15 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
>  		return 0;
>  	}
>  
> -	/*
> -	 * 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
> -	 * the editor and after we invoke run_status above.
> -	 */
> -	discard_cache();
> +	if (!no_verify && precommit_hook) {
> +		/*
> +		 * 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
> +		 * the editor and after we invoke run_status above.
> +		 */
> +		discard_cache();
> +	}
> +
>  	read_cache_from(index_file);
>  	if (update_main_cache_tree(0)) {
>  		error(_("Error building trees"));