[PATCH v2 22/26] worktree: add "lock" command

@@ -11,6 +11,7 @@ SYNOPSIS
 [verse]
 'git worktree add' [-f] [--detach] [-b <new-branch>] <path> [<branch>]
 'git worktree list' [--porcelain]
+'git worktree lock' [--reason <string>] <path>
 'git worktree prune' [-n] [-v] [--expire <expire>]
 
 DESCRIPTION

@@ -61,6 +62,12 @@ each of the linked worktrees.  The output details include if the worktree is
 bare, the revision currently checked out, and the branch currently checked out
 (or 'detached HEAD' if none).
 
+lock::
+
+When a worktree is locked, it cannot be pruned, moved or deleted. For
+example, if the worktree is on portable device that is not available
+when "git worktree <command>" is executed.
+
 prune::
 
 Prune working tree information in $GIT_DIR/worktrees.

@@ -104,6 +111,9 @@ OPTIONS
 --expire <time>::
 	With `prune`, only expire unused working trees older than <time>.
 
+--reason <string>:
+	An explanation why the worktree is locked.
+
 DETAILS
 -------
 Each linked working tree has a private sub-directory in the repository's

@@ -220,8 +230,6 @@ performed manually, such as:
 - `remove` to remove a linked working tree and its administrative files (and
   warn if the working tree is dirty)
 - `mv` to move or rename a working tree and update its administrative files
-- `lock` to prevent automatic pruning of administrative files (for instance,
-  for a working tree on a portable device)
 
 GIT
 ---

@@ -14,6 +14,7 @@
 static const char * const worktree_usage[] = {
 	N_("git worktree add [<options>] <path> [<branch>]"),
 	N_("git worktree list [<options>]"),
+	N_("git worktree lock [<options>] <path>"),
 	N_("git worktree prune [<options>]"),
 	NULL
 };

@@ -445,6 +446,44 @@ static int list(int ac, const char **av, const char *prefix)
 	return 0;
 }
 
+static int lock_worktree(int ac, const char **av, const char *prefix)
+{
+	const char *reason = "", *old_reason;
+	struct option options[] = {
+		OPT_STRING(0, "reason", &reason, N_("string"),
+			   N_("reason for locking")),
+		OPT_END()
+	};
+	struct worktree **worktrees, *wt;
+	struct strbuf dst = STRBUF_INIT;
+
+	ac = parse_options(ac, av, prefix, options, worktree_usage, 0);
+	if (ac != 1)
+		usage_with_options(worktree_usage, options);
+
+	strbuf_addstr(&dst, prefix_filename(prefix,
+					    strlen(prefix),
+					    av[0]));
+
+	worktrees = get_worktrees();
+	wt = find_worktree_by_path(worktrees, dst.buf);
+	if (!wt)
+		die(_("'%s' is not a working directory"), av[0]);
+	if (is_main_worktree(wt))
+		die(_("'%s' is a main working directory"), av[0]);
+
+	old_reason = is_worktree_locked(wt);
+	if (old_reason) {
+		if (*old_reason)
+			die(_("already locked, reason: %s"), old_reason);
+		die(_("already locked, no reason"));
+	}
+
+	write_file(git_common_path("worktrees/%s/locked", wt->id),
+		   "%s", reason);
+	return 0;
+}
+
 int cmd_worktree(int ac, const char **av, const char *prefix)
 {
 	struct option options[] = {

@@ -461,5 +500,7 @@ int cmd_worktree(int ac, const char **av, const char *prefix)
 		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);
 	usage_with_options(worktree_usage, options);
 }

@@ -2596,7 +2596,7 @@ _git_whatchanged ()
 
 _git_worktree ()
 {
-	local subcommands="add list prune"
+	local subcommands="add list lock prune"
 	local subcommand="$(__git_find_on_cmdline "$subcommands")"
 	if [ -z "$subcommand" ]; then
 		__gitcomp "$subcommands"

@@ -2608,6 +2608,9 @@ _git_worktree ()
 		list,--*)
 			__gitcomp "--porcelain"
 			;;
+		lock,--*)
+			__gitcomp "--reason"
+			;;
 		prune,--*)
 			__gitcomp "--dry-run --expire --verbose"
 			;;

@@ -0,0 +1,34 @@
+#!/bin/sh
+
+test_description='test git worktree move, remove, lock and unlock'
+
+. ./test-lib.sh
+
+test_expect_success 'setup' '
+	test_commit init &&
+	git worktree add source &&
+	git worktree list --porcelain | grep "^worktree" >actual &&
+	cat <<-EOF >expected &&
+	worktree $TRASH_DIRECTORY
+	worktree $TRASH_DIRECTORY/source
+	EOF
+	test_cmp expected actual
+'
+
+test_expect_success 'lock main worktree' '
+	test_must_fail git worktree lock .
+'
+
+test_expect_success 'lock linked worktree' '
+	git worktree lock --reason hahaha source &&
+	echo hahaha >expected &&
+	test_cmp expected .git/worktrees/source/locked
+'
+
+test_expect_success 'lock worktree twice' '
+	test_must_fail git worktree lock source &&
+	echo hahaha >expected &&
+	test_cmp expected .git/worktrees/source/locked
+'
+
+test_done