Subject: setup: officially support --work-tree without --git-dir

The original intention of --work-tree was to allow people to work in a
subdirectory of their working tree that does not have an embedded .git
directory.  Because their working tree, which their $cwd was in, did not
have an embedded .git, they needed to use $GIT_DIR to specify where it is,
and because this meant there was no way to discover where the root level
of the working tree was, so we needed to add $GIT_WORK_TREE to tell git
where it was.

However, this facility has long been (mis)used by people's scripts to
start git from a working tree _with_ an embedded .git directory, let git
find .git directory, and then pretend as if an unrelated directory were
the associated working tree of the .git directory found by the discovery
process.  It happens to work in simple cases, and is not worth causing
"regression" to these scripts.

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

1 files changed, 19 insertions, 0 deletions

diff --git a/setup.c b/setup.c
index 3d732697af..dadc66659a 100644
--- a/setup.c
+++ b/setup.c
@@ -411,6 +411,15 @@ static const char *setup_discovered_git_dir(const char *gitdir,
 	if (check_repository_format_gently(gitdir, nongit_ok))
 		return NULL;
 
+	/* --work-tree is set without --git-dir; use discovered one */
+	if (getenv(GIT_WORK_TREE_ENVIRONMENT) || git_work_tree_cfg) {
+		if (offset != len && !is_absolute_path(gitdir))
+			gitdir = xstrdup(make_absolute_path(gitdir));
+		if (chdir(cwd))
+			die_errno("Could not come back to cwd");
+		return setup_explicit_git_dir(gitdir, cwd, len, nongit_ok);
+	}
+
 	/* #16.2, #17.2, #20.2, #21.2, #24, #25, #28, #29 (see t1510) */
 	if (is_bare_repository_cfg > 0) {
 		set_git_dir(offset == len ? gitdir : make_absolute_path(gitdir));
@@ -443,6 +452,16 @@ static const char *setup_bare_git_dir(char *cwd, int offset, int len, int *nongi
 	if (check_repository_format_gently(".", nongit_ok))
 		return NULL;
 
+	/* --work-tree is set without --git-dir; use discovered one */
+	if (getenv(GIT_WORK_TREE_ENVIRONMENT) || git_work_tree_cfg) {
+		const char *gitdir;
+
+		gitdir = offset == len ? "." : xmemdupz(cwd, offset);
+		if (chdir(cwd))
+			die_errno("Could not come back to cwd");
+		return setup_explicit_git_dir(gitdir, cwd, len, nongit_ok);
+	}
+
 	inside_git_dir = 1;
 	inside_work_tree = 0;
 	if (offset != len) {