builtin/worktree.c: let parse-options parse subcommands

'git worktree' parses its subcommands with a long list of if
statements.  parse-options has just learned to parse subcommands, so
let's use that facility instead, with the benefits of shorter code,
handling missing or unknown subcommands, and listing subcommands for
Bash completion.

Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/worktree.c

@@ -1112,31 +1112,24 @@ static int repair(int ac, const char **av, const char *prefix)
 
 int cmd_worktree(int ac, const char **av, const char *prefix)
 {
+	parse_opt_subcommand_fn *fn = NULL;
 	struct option options[] = {
+		OPT_SUBCOMMAND("add", &fn, add),
+		OPT_SUBCOMMAND("prune", &fn, prune),
+		OPT_SUBCOMMAND("list", &fn, list),
+		OPT_SUBCOMMAND("lock", &fn, lock_worktree),
+		OPT_SUBCOMMAND("unlock", &fn, unlock_worktree),
+		OPT_SUBCOMMAND("move", &fn, move_worktree),
+		OPT_SUBCOMMAND("remove", &fn, remove_worktree),
+		OPT_SUBCOMMAND("repair", &fn, repair),
 		OPT_END()
 	};
 
 	git_config(git_worktree_config, NULL);
 
-	if (ac < 2)
-		usage_with_options(worktree_usage, options);
 	if (!prefix)
 		prefix = "";
-	if (!strcmp(av[1], "add"))
-		return add(ac - 1, av + 1, prefix);
-	if (!strcmp(av[1], "prune"))
-		return prune(ac - 1, av + 1, prefix);
-	if (!strcmp(av[1], "list"))
-		return list(ac - 1, av + 1, prefix);
-	if (!strcmp(av[1], "lock"))
-		return lock_worktree(ac - 1, av + 1, prefix);
-	if (!strcmp(av[1], "unlock"))
-		return unlock_worktree(ac - 1, av + 1, prefix);
-	if (!strcmp(av[1], "move"))
-		return move_worktree(ac - 1, av + 1, prefix);
-	if (!strcmp(av[1], "remove"))
-		return remove_worktree(ac - 1, av + 1, prefix);
-	if (!strcmp(av[1], "repair"))
-		return repair(ac - 1, av + 1, prefix);
-	usage_with_options(worktree_usage, options);
+
+	ac = parse_options(ac, av, prefix, options, worktree_usage, 0);
+	return fn(ac, av, prefix);
 }

git.c

@@ -627,7 +627,7 @@ static struct cmd_struct commands[] = {
 	{ "verify-tag", cmd_verify_tag, RUN_SETUP },
 	{ "version", cmd_version },
 	{ "whatchanged", cmd_whatchanged, RUN_SETUP },
-	{ "worktree", cmd_worktree, RUN_SETUP | NO_PARSEOPT },
+	{ "worktree", cmd_worktree, RUN_SETUP },
 	{ "write-tree", cmd_write_tree, RUN_SETUP },
 };