worktree: make --detach mutually exclusive with -b/-B

Be consistent with git-checkout which disallows this (not particularly
meaningful) combination.

Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/worktree.c

@@ -296,8 +296,8 @@ static int add(int ac, const char **av, const char *prefix)
 
 	memset(&opts, 0, sizeof(opts));
 	ac = parse_options(ac, av, prefix, options, worktree_usage, 0);
-	if (opts.new_branch && new_branch_force)
-		die(_("-b and -B are mutually exclusive"));
+	if (!!opts.detach + !!opts.new_branch + !!new_branch_force > 1)
+		die(_("-b, -B, and --detach are mutually exclusive"));
 	if (ac < 1 || ac > 2)
 		usage_with_options(worktree_usage, options);
 

t/t2025-worktree-add.sh

@@ -167,4 +167,16 @@ test_expect_success '"add" auto-vivify does not clobber existing branch' '
 	test_path_is_missing precious
 '
 
+test_expect_success '"add" -b/-B mutually exclusive' '
+	test_must_fail git worktree add -b poodle -B poodle bamboo master
+'
+
+test_expect_success '"add" -b/--detach mutually exclusive' '
+	test_must_fail git worktree add -b poodle --detach bamboo master
+'
+
+test_expect_success '"add" -B/--detach mutually exclusive' '
+	test_must_fail git worktree add -B poodle --detach bamboo master
+'
+
 test_done