Merge branch 'ps/refs-files-remove-empty-parent'

When a ref creation at refs/heads/foo/bar fails, the files backend
now removes refs/heads/foo/ if the directory is otherwise not used.

* ps/refs-files-remove-empty-parent:
  refs/files: remove empty parent dirs when ref creation fails

Author: gitster

refs/files-backend.c

@@ -2760,6 +2760,8 @@ static void files_transaction_cleanup(struct files_ref_store *refs,
 
 		if (lock) {
 			unlock_ref(lock);
+			try_remove_empty_parents(refs, update->refname,
+						 REMOVE_EMPTY_PARENTS_REF);
 			update->backend_data = NULL;
 		}
 	}

t/t1400-update-ref.sh

@@ -2349,4 +2349,23 @@ test_expect_success 'update-ref should also create reflog for HEAD' '
 	test_cmp expect actual
 '
 
+test_expect_success REFFILES 'empty directories are pruned when aborting a transaction' '
+	test_path_is_missing .git/refs/heads/nested &&
+	git update-ref --stdin <<-EOF &&
+	create refs/heads/nested/something HEAD
+	prepare
+	abort
+	EOF
+	test_path_is_missing .git/refs/heads/nested
+'
+
+test_expect_success REFFILES 'empty directories are pruned when not committing' '
+	test_path_is_missing .git/refs/heads/nested &&
+	git update-ref --stdin <<-EOF &&
+	create refs/heads/nested/something HEAD
+	prepare
+	EOF
+	test_path_is_missing .git/refs/heads/nested
+'
+
 test_done