Re: [PATCH] rev-parse --git-path: fix output when running in a subdirectory

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

Johannes Schindelin <johannes.schindelin@gmx.de> writes:

> The problem lies deeper, much deeper...
> ... but it bought us many, many problems.

I think you are making a mountain out of molehill here.  
This looks like as an opposite problem of a bug that forgets to
prepend the prefix to relative pathnames given by the end user.

I do agree that some calling scripts may find it more convenient if
the output were relative to their current directory, and in that
sense, this is worth addressing.

However.

How long has "rev-parse --git-path" been around?  Had scripts in the
wild chance to learn to live with the "output is relative to the top
of the working tree" reality?  I think the answers are "since 2.5" and
"yes".

I do not think we can make this unconditionally without breaking
users.  We instead need something like a new "--git-path-relative"
option, similar in the spirit that output from "git diff" can be
made relative to the current directory with the "--relative" option.

Assuming that we are discussing the new behaviour that is
conditionally triggered, let's see the implementation.

> -			puts(git_path("%s", argv[i + 1]));
> +			path = git_path("%s", argv[i + 1]);
> +			if (prefix && !is_absolute_path(path))
> +				path = real_path(path);
> +			puts(path);

Duy, want to help me out here?  I am wondering if using a logic
similar to what is used by "cd t && git grep -e foo :/" to emit
paths as "../Documentation/CodingGuidelines" as relative to the
current working directory is more appropriate than forcing the
absolute path output here (and if so, it may be preferrable to use
the relative_path() helper to do so), or the paths to files in
$GIT_DIR are conceptually different enough from paths to files in
the working tree and it will be more robust to have the output as an
absolute path.

I am leaning toward the latter (i.e. the above use of real_path() is
simple and good), but I haven't thought things through and since we
have an area expert here in the thread...