Re: [PATCH v2 4/7] stash push: avoid duplicate calls to preload_index()

[Junio C Hamano <gitster@pobox.com>]

Phillip Wood <phillip.wood123@gmail.com> writes:

> From: Phillip Wood <phillip.wood@dunelm.org.uk>
>
> do_stash_push() needs to load the index so it can check that any

Perhaps you meant do_push_stash()?

> pathspec argument refers to tracked files. To do that it calls
> repo_read_index_preload() which does not just load the index, it also
> calls preload_index() which lstat()s all the files to see which ones
> are up-to-date. do_create_stash() then calls repo_read_index_preload()
> for a second time which lstat()s all the changed paths again and then
> calls repo_refresh_and_write_index() which invokes preload_index() for a
> third time. So we're preloading the index three times when we only need
> to do it once. Avoid this by making the callers of do_create_stash()
> responsible for reading the index and use repo_read_index() rather
> than repo_read_index_preload(). This saves two lstat() calls per
> changed path.

The other caller of do_create_stash() is create_stash().  And it
does not need to call the preload version for the same reason.

> Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
> ---
>  builtin/stash.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/builtin/stash.c b/builtin/stash.c
> index aec79ed473..b4fe7465e4 100644
> --- a/builtin/stash.c
> +++ b/builtin/stash.c
> @@ -1526,7 +1526,6 @@ static enum create_result do_create_stash(const struct pathspec *ps,
>  
>  	prepare_fallback_ident("git stash", "git@stash");
>  
> -	repo_read_index_preload(the_repository, NULL, 0);
>  	if (repo_refresh_and_write_index(the_repository, REFRESH_QUIET, 0, 0,
>  					 NULL, NULL, NULL) < 0) {
>  		ret = error(_("could not write index"));
> @@ -1662,6 +1661,7 @@ static int create_stash(int argc, const char **argv, const char *prefix UNUSED,
>  
>  	memset(&ps, 0, sizeof(ps));
>  
> +	repo_read_index(the_repository);
>  	ret = do_create_stash(&ps, &stash_msg_buf, 0, 0, NULL, 0, &info,
>  			      NULL, 0);
>  	if (ret == CREATE_SUCCESS)
> @@ -1707,7 +1707,7 @@ static int do_push_stash(const struct pathspec *ps, const char *stash_msg, int q
>  		goto done;
>  	}
>  
> -	repo_read_index_preload(the_repository, NULL, 0);
> +	repo_read_index(the_repository);
>  	if (!include_untracked && ps->nr) {
>  		char *ps_matched = xcalloc(ps->nr, 1);