set_git_dir: handle feeding gitdir to itself

Ideally we'd free the existing gitdir field before assigning
the new one, to avoid a memory leak. But we can't do so
safely because some callers do the equivalent of:

  set_git_dir(get_git_dir());

We can detect that case as a noop, but there are even more
complicated cases like:

  set_git_dir(remove_leading_path(worktree, get_git_dir());

where we really do need to do some work, but the original
string must remain valid.

Rather than put the burden on callers to make a copy of the
string (only to free it later, since we'll make a copy of it
ourselves), let's solve the problem inside set_git_dir(). We
can make a copy of the pointer for the old gitdir, and then
avoid freeing it until after we've made our new copy.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 0 insertions, 5 deletions

diff --git a/setup.c b/setup.c
index 23950173fc..6d8380acd2 100644
--- a/setup.c
+++ b/setup.c
@@ -399,11 +399,6 @@ void setup_work_tree(void)
 	if (getenv(GIT_WORK_TREE_ENVIRONMENT))
 		setenv(GIT_WORK_TREE_ENVIRONMENT, ".", 1);
 
-	/*
-	 * NEEDSWORK: this call can essentially be set_git_dir(get_git_dir())
-	 * which can cause some problems when trying to free the old value of
-	 * gitdir.
-	 */
 	set_git_dir(remove_leading_path(git_dir, work_tree));
 	initialized = 1;
 }