Re: [RFC PATCH] prefix_path: show gitdir when arg is outside repo

> From: Emily Shaffer <emilyshaffer@google.com>
> 
> When developing a script, it can be painful to understand why Git thinks
> something is outside the current repo, if the current repo isn't what
> the user thinks it is. Since this can be tricky to diagnose, especially
> in cases like submodules or nested worktrees, let's give the user a hint
> about which repository is offended about that path.
> 
> Signed-off-by: Emily Shaffer <emilyshaffer@google.com>
> ---
> This one comes from a user feature request. This user is running some
> Git client commands on a build machine somewhere and finding it hard to
> reason about the cause of the "outside repo" error.
> 
> I see two arguments:
> 
> For:
>  - A user checking their own `pwd` might still not come to the same
>    conclusion Git does about the current repo, if their filesystem is in
>    some weird state
>  - This warning is intended for human eyes (die(), stderr) so it's reasonable
>    to give some info to make the human's life easier
> 
> Against:
>  - It's chatty, especially given the absolute directory. This may be a
>    pretty common mistake ('git add' with thumbfingers?) so it could be
>    chatty, frequently - not great.
>    (Sidebar: Just including the relative directory is really not very
>    useful - since you're still left thinking, "relative to where?")

> diff --git a/pathspec.c b/pathspec.c
> index 128f27fcb7..5d661df5cf 100644
> --- a/pathspec.c
> +++ b/pathspec.c
> @@ -439,7 +439,8 @@ static void init_pathspec_item(struct pathspec_item *item, unsigned flags,
>  		match = prefix_path_gently(prefix, prefixlen,
>  					   &prefixlen, copyfrom);
>  		if (!match)
> -			die(_("%s: '%s' is outside repository"), elt, copyfrom);
> +			die(_("%s: '%s' is outside repository at '%s'"), elt,
> +			    copyfrom, absolute_path(get_git_dir()));