Re: [PATCH 2/2] branch: drop unused worktrees variable

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

Jeff King <peff@peff.net> writes:

> After b489b9d9aa (branch: use branch_checked_out() when deleting refs,
> 2022-06-14), we no longer look at our local "worktrees" variable, since
> branch_checked_out() handles it under the hood. The compiler didn't
> notice the unused variable because we call functions to initialize and
> free it (so it's not totally unused, it just doesn't do anything
> useful).
>
> Signed-off-by: Jeff King <peff@peff.net>
> ---
> It would be neat if there was some way to mark a function as "this is
> just allocating a structure, with no useful side effects" and another as
> "this is just freeing", which would let the compiler notice that we
> don't do anything useful with the structure in between the two. I have a
> feeling adding such annotations might be more work than occasionally
> finding and cleaning up such useless variables, though. :)

Also it may be tricky to write correctly ;-)

I recently got rid of a Coccinelle rule I wrote quite a while ago
that was suggesting a completely bogus rewrite, and found it quite
satisfying.  After that experience, I got allergic to the idea of
having to make sure a mechanical rewrite suggested by the tool if it
gets too large X-<.

For this particular pattern, presumably we won't have too many of
them, though.

Thanks.

>  builtin/branch.c | 4 ----
>  1 file changed, 4 deletions(-)
>
> diff --git a/builtin/branch.c b/builtin/branch.c
> index f875952e7b..55cd9a6e99 100644
> --- a/builtin/branch.c
> +++ b/builtin/branch.c
> @@ -204,7 +204,6 @@ static void delete_branch_config(const char *branchname)
>  static int delete_branches(int argc, const char **argv, int force, int kinds,
>  			   int quiet)
>  {
> -	struct worktree **worktrees;
>  	struct commit *head_rev = NULL;
>  	struct object_id oid;
>  	char *name = NULL;
> @@ -242,8 +241,6 @@ static int delete_branches(int argc, const char **argv, int force, int kinds,
>  			die(_("Couldn't look up commit object for HEAD"));
>  	}
>  
> -	worktrees = get_worktrees();
> -
>  	for (i = 0; i < argc; i++, strbuf_reset(&bname)) {
>  		char *target = NULL;
>  		int flags = 0;
> @@ -314,7 +311,6 @@ static int delete_branches(int argc, const char **argv, int force, int kinds,
>  
>  	free(name);
>  	strbuf_release(&bname);
> -	free_worktrees(worktrees);
>  
>  	return ret;
>  }