Merge branch 'sj/ref-contents-check-fix'

"git verify-refs" (and hence "git fsck --reference") started
erroring out in a repository in which secondary worktrees were
prepared with Git 2.43 or lower.

* sj/ref-contents-check-fix:
  fsck: ignore missing "refs" directory for linked worktrees

refs/files-backend.c

@@ -3762,6 +3762,9 @@ static int files_fsck_refs_dir(struct ref_store *ref_store,
 
 	iter = dir_iterator_begin(sb.buf, 0);
 	if (!iter) {
+		if (errno == ENOENT && !is_main_worktree(wt))
+			goto out;
+
 		ret = error_errno(_("cannot open directory %s"), sb.buf);
 		goto out;
 	}

t/t0602-reffiles-fsck.sh

@@ -110,6 +110,25 @@ test_expect_success 'ref name check should be adapted into fsck messages' '
 	)
 '
 
+test_expect_success 'no refs directory of worktree should not cause problems' '
+	test_when_finished "rm -rf repo" &&
+	git init repo &&
+	(
+		cd repo &&
+		test_commit initial &&
+		git worktree add --detach ./worktree &&
+
+		(
+			cd worktree &&
+			worktree_refdir="$(git rev-parse --git-dir)/refs" &&
+			# Simulate old directory layout
+			rmdir "$worktree_refdir" &&
+			git refs verify 2>err &&
+			test_must_be_empty err
+		)
+	)
+'
+
 test_expect_success 'ref name check should work for multiple worktrees' '
 	test_when_finished "rm -rf repo" &&
 	git init repo &&