worktree: teach 'move' to override lock when --force given twice

For consistency with "add -f -f", which allows a missing but locked
worktree path to be re-used, allow "move -f -f" to override a lock,
as well, as a convenience.

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

Documentation/git-worktree.txt

@@ -125,6 +125,9 @@ OPTIONS
 	manually). This option overrides these safeguards. To add a missing but
 	locked working tree path, specify `--force` twice.
 +
+`move` refuses to move a locked working tree unless `--force` is specified
+twice.
++
 `remove` refuses to remove an unclean working tree unless `--force` is used.
 
 -b <new-branch>::

builtin/worktree.c

@@ -740,13 +740,17 @@ static void validate_no_submodules(const struct worktree *wt)
 
 static int move_worktree(int ac, const char **av, const char *prefix)
 {
+	int force = 0;
 	struct option options[] = {
+		OPT__FORCE(&force,
+			 N_("force move even if worktree is dirty or locked"),
+			 PARSE_OPT_NOCOMPLETE),
 		OPT_END()
 	};
 	struct worktree **worktrees, *wt;
 	struct strbuf dst = STRBUF_INIT;
 	struct strbuf errmsg = STRBUF_INIT;
-	const char *reason;
+	const char *reason = NULL;
 	char *path;
 
 	ac = parse_options(ac, av, prefix, options, worktree_usage, 0);
@@ -777,12 +781,13 @@ static int move_worktree(int ac, const char **av, const char *prefix)
 
 	validate_no_submodules(wt);
 
-	reason = is_worktree_locked(wt);
+	if (force < 2)
+		reason = is_worktree_locked(wt);
 	if (reason) {
 		if (*reason)
-			die(_("cannot move a locked working tree, lock reason: %s"),
+			die(_("cannot move a locked working tree, lock reason: %s\nuse 'move -f -f' to override or unlock first"),
 			    reason);
-		die(_("cannot move a locked working tree"));
+		die(_("cannot move a locked working tree;\nuse 'move -f -f' to override or unlock first"));
 	}
 	if (validate_worktree(wt, &errmsg, 0))
 		die(_("validation failed, cannot move working tree: %s"),

t/t2028-worktree-move.sh

@@ -98,6 +98,20 @@ test_expect_success 'move worktree to another dir' '
 	test_cmp expected2 actual2
 '
 
+test_expect_success 'move locked worktree (force)' '
+	test_when_finished "
+		git worktree unlock flump || :
+		git worktree remove flump || :
+		git worktree unlock ploof || :
+		git worktree remove ploof || :
+		" &&
+	git worktree add --detach flump &&
+	git worktree lock flump &&
+	test_must_fail git worktree move flump ploof" &&
+	test_must_fail git worktree move --force flump ploof" &&
+	git worktree move --force --force flump ploof
+'
+
 test_expect_success 'remove main worktree' '
 	test_must_fail git worktree remove .
 '