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, 5 insertions, 1 deletions

diff --git a/builtin/notes.c b/builtin/notes.c
index 71c59583a1..7f60408dbb 100644
--- a/builtin/notes.c
+++ b/builtin/notes.c
@@ -861,15 +861,19 @@ static int merge(int argc, const char **argv, const char *prefix)
 		update_ref(msg.buf, default_notes_ref(), &result_oid, NULL, 0,
 			   UPDATE_REFS_DIE_ON_ERR);
 	else { /* Merge has unresolved conflicts */
+		struct worktree **worktrees;
 		const struct worktree *wt;
 		/* Update .git/NOTES_MERGE_PARTIAL with partial merge result */
 		update_ref(msg.buf, "NOTES_MERGE_PARTIAL", &result_oid, NULL,
 			   0, UPDATE_REFS_DIE_ON_ERR);
 		/* Store ref-to-be-updated into .git/NOTES_MERGE_REF */
-		wt = find_shared_symref("NOTES_MERGE_REF", default_notes_ref());
+		worktrees = get_worktrees();
+		wt = find_shared_symref(worktrees, "NOTES_MERGE_REF",
+					default_notes_ref());
 		if (wt)
 			die(_("a notes merge into %s is already in-progress at %s"),
 			    default_notes_ref(), wt->path);
+		free_worktrees(worktrees);
 		if (create_symref("NOTES_MERGE_REF", default_notes_ref(), NULL))
 			die(_("failed to store link to current notes ref (%s)"),
 			    default_notes_ref());