path: worktree_git_path() should not use file relocation

git_path is a convenience function that usually produces a string
$GIT_DIR/<path>.  Since v2.5.0-rc0~143^2~35 (git_path(): be aware of
file relocation in $GIT_DIR, 2014-11-30), as a side benefit callers
get support for path relocation variables like $GIT_OBJECT_DIRECTORY:

- git_path("index") is $GIT_INDEX_FILE when set
- git_path("info/grafts") is $GIT_GRAFTS_FILE when set
- git_path("objects/<foo>") is $GIT_OBJECT_DIRECTORY/<foo> when set
- git_path("hooks/<foo>") is <foo> under core.hookspath when set
- git_path("refs/<foo>") etc (see path.c::common_list) is relative
to $GIT_COMMON_DIR instead of $GIT_DIR

worktree_git_path, by comparison, is designed to resolve files in a
specific worktree's git dir.  Unfortunately, it shares code with
git_path and performs the same relocation.  The result is that paths
that are meant to be relative to the specified worktree's git dir end
up replaced by paths from environment variables within the current git
dir.

Luckily, no current callers pass such arguments.  The relocation was
noticed when testing the result of merging two patches under review,
one of which introduces a caller:

* The first patch made git prune check the index file in each
worktree's git dir (using worktree_git_path(wt, "index")) for
objects not to prune.  This would trigger the unwanted relocation
when GIT_INDEX_FILE is set, causing objects reachable from the
index to be pruned.

* The second patch simplified the relocation logic for index,
info/grafts, objects, and hooks to happen unconditionally instead of
based on whether environment or configuration variables are set.
This caused the relocation to trigger even when GIT_INDEX_FILE is
not set.

[jn: rewrote commit message; skipping all relocation instead of just
GIT_INDEX_FILE]

Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/path.c b/path.c
index 76a872297e507f7580c0c24a8b307f4d8188e21e..2bdd0044f084a4e16c662f553d92abcded358210 100644 (file)
--- a/path.c
+++ b/path.c
@@ -411,7 +411,8 @@ static void do_git_path(const struct repository *repo,
                strbuf_addch(buf, '/');
        gitdir_len = buf->len;
        strbuf_vaddf(buf, fmt, args);
-       adjust_git_path(repo, buf, gitdir_len);
+       if (!wt)
+               adjust_git_path(repo, buf, gitdir_len);
        strbuf_cleanup_path(buf);
 }