worktree: simplify find_shared_symref() memory ownership model

Storing the worktrees list in a static variable meant that
find_shared_symref() had to rebuild the list on each call (which is
inefficient when the call site is in a loop), and also that each call
invalidated the pointer returned by the previous call (which is
confusing).

Instead, make it the caller’s responsibility to pass in the worktrees
list and manage its lifetime.

Signed-off-by: Anders Kaseorg <andersk@mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 8 insertions, 6 deletions

diff --git a/branch.c b/branch.c
index 85777b939b..c66b222abd 100644
--- a/branch.c
+++ b/branch.c
@@ -357,14 +357,16 @@ void remove_branch_state(struct repository *r, int verbose)
 
 void die_if_checked_out(const char *branch, int ignore_current_worktree)
 {
+	struct worktree **worktrees = get_worktrees();
 	const struct worktree *wt;
 
-	wt = find_shared_symref("HEAD", branch);
-	if (!wt || (ignore_current_worktree && wt->is_current))
-		return;
-	skip_prefix(branch, "refs/heads/", &branch);
-	die(_("'%s' is already checked out at '%s'"),
-	    branch, wt->path);
+	wt = find_shared_symref(worktrees, "HEAD", branch);
+	if (wt && (!ignore_current_worktree || !wt->is_current)) {
+		skip_prefix(branch, "refs/heads/", &branch);
+		die(_("'%s' is already checked out at '%s'"), branch, wt->path);
+	}
+
+	free_worktrees(worktrees);
 }
 
 int replace_each_worktree_head_symref(const char *oldref, const char *newref,