merge(third_party/git): Merge squashed git subtree at v2.23.0 r/373

Merge commit '1b593e1ea4d2af0f6444d9a7788d5d99abd6fde5' as 'third_party/git'

1 files changed, 987 insertions, 0 deletions

diff --git a/third_party/git/builtin/worktree.c b/third_party/git/builtin/worktree.c
new file mode 100644
index 0000000000..a5bb02b207
--- /dev/null
+++ b/third_party/git/builtin/worktree.c
@@ -0,0 +1,987 @@
+#include "cache.h"
+#include "checkout.h"
+#include "config.h"
+#include "builtin.h"
+#include "dir.h"
+#include "parse-options.h"
+#include "argv-array.h"
+#include "branch.h"
+#include "refs.h"
+#include "run-command.h"
+#include "sigchain.h"
+#include "submodule.h"
+#include "refs.h"
+#include "utf8.h"
+#include "worktree.h"
+
+static const char * const worktree_usage[] = {
+	N_("git worktree add [<options>] <path> [<commit-ish>]"),
+	N_("git worktree list [<options>]"),
+	N_("git worktree lock [<options>] <path>"),
+	N_("git worktree move <worktree> <new-path>"),
+	N_("git worktree prune [<options>]"),
+	N_("git worktree remove [<options>] <worktree>"),
+	N_("git worktree unlock <path>"),
+	NULL
+};
+
+struct add_opts {
+	int force;
+	int detach;
+	int quiet;
+	int checkout;
+	int keep_locked;
+};
+
+static int show_only;
+static int verbose;
+static int guess_remote;
+static timestamp_t expire;
+
+static int git_worktree_config(const char *var, const char *value, void *cb)
+{
+	if (!strcmp(var, "worktree.guessremote")) {
+		guess_remote = git_config_bool(var, value);
+		return 0;
+	}
+
+	return git_default_config(var, value, cb);
+}
+
+static int delete_git_dir(const char *id)
+{
+	struct strbuf sb = STRBUF_INIT;
+	int ret;
+
+	strbuf_addstr(&sb, git_common_path("worktrees/%s", id));
+	ret = remove_dir_recursively(&sb, 0);
+	if (ret < 0 && errno == ENOTDIR)
+		ret = unlink(sb.buf);
+	if (ret)
+		error_errno(_("failed to delete '%s'"), sb.buf);
+	strbuf_release(&sb);
+	return ret;
+}
+
+static void delete_worktrees_dir_if_empty(void)
+{
+	rmdir(git_path("worktrees")); /* ignore failed removal */
+}
+
+static int prune_worktree(const char *id, struct strbuf *reason)
+{
+	struct stat st;
+	char *path;
+	int fd;
+	size_t len;
+	ssize_t read_result;
+
+	if (!is_directory(git_path("worktrees/%s", id))) {
+		strbuf_addf(reason, _("Removing worktrees/%s: not a valid directory"), id);
+		return 1;
+	}
+	if (file_exists(git_path("worktrees/%s/locked", id)))
+		return 0;
+	if (stat(git_path("worktrees/%s/gitdir", id), &st)) {
+		strbuf_addf(reason, _("Removing worktrees/%s: gitdir file does not exist"), id);
+		return 1;
+	}
+	fd = open(git_path("worktrees/%s/gitdir", id), O_RDONLY);
+	if (fd < 0) {
+		strbuf_addf(reason, _("Removing worktrees/%s: unable to read gitdir file (%s)"),
+			    id, strerror(errno));
+		return 1;
+	}
+	len = xsize_t(st.st_size);
+	path = xmallocz(len);
+
+	read_result = read_in_full(fd, path, len);
+	if (read_result < 0) {
+		strbuf_addf(reason, _("Removing worktrees/%s: unable to read gitdir file (%s)"),
+			    id, strerror(errno));
+		close(fd);
+		free(path);
+		return 1;
+	}
+	close(fd);
+
+	if (read_result != len) {
+		strbuf_addf(reason,
+			    _("Removing worktrees/%s: short read (expected %"PRIuMAX" bytes, read %"PRIuMAX")"),
+			    id, (uintmax_t)len, (uintmax_t)read_result);
+		free(path);
+		return 1;
+	}
+	while (len && (path[len - 1] == '\n' || path[len - 1] == '\r'))
+		len--;
+	if (!len) {
+		strbuf_addf(reason, _("Removing worktrees/%s: invalid gitdir file"), id);
+		free(path);
+		return 1;
+	}
+	path[len] = '\0';
+	if (!file_exists(path)) {
+		free(path);
+		if (stat(git_path("worktrees/%s/index", id), &st) ||
+		    st.st_mtime <= expire) {
+			strbuf_addf(reason, _("Removing worktrees/%s: gitdir file points to non-existent location"), id);
+			return 1;
+		} else {
+			return 0;
+		}
+	}
+	free(path);
+	return 0;
+}
+
+static void prune_worktrees(void)
+{
+	struct strbuf reason = STRBUF_INIT;
+	DIR *dir = opendir(git_path("worktrees"));
+	struct dirent *d;
+	if (!dir)
+		return;
+	while ((d = readdir(dir)) != NULL) {
+		if (is_dot_or_dotdot(d->d_name))
+			continue;
+		strbuf_reset(&reason);
+		if (!prune_worktree(d->d_name, &reason))
+			continue;
+		if (show_only || verbose)
+			printf("%s\n", reason.buf);
+		if (show_only)
+			continue;
+		delete_git_dir(d->d_name);
+	}
+	closedir(dir);
+	if (!show_only)
+		delete_worktrees_dir_if_empty();
+	strbuf_release(&reason);
+}
+
+static int prune(int ac, const char **av, const char *prefix)
+{
+	struct option options[] = {
+		OPT__DRY_RUN(&show_only, N_("do not remove, show only")),
+		OPT__VERBOSE(&verbose, N_("report pruned working trees")),
+		OPT_EXPIRY_DATE(0, "expire", &expire,
+				N_("expire working trees older than <time>")),
+		OPT_END()
+	};
+
+	expire = TIME_MAX;
+	ac = parse_options(ac, av, prefix, options, worktree_usage, 0);
+	if (ac)
+		usage_with_options(worktree_usage, options);
+	prune_worktrees();
+	return 0;
+}
+
+static char *junk_work_tree;
+static char *junk_git_dir;
+static int is_junk;
+static pid_t junk_pid;
+
+static void remove_junk(void)
+{
+	struct strbuf sb = STRBUF_INIT;
+	if (!is_junk || getpid() != junk_pid)
+		return;
+	if (junk_git_dir) {
+		strbuf_addstr(&sb, junk_git_dir);
+		remove_dir_recursively(&sb, 0);
+		strbuf_reset(&sb);
+	}
+	if (junk_work_tree) {
+		strbuf_addstr(&sb, junk_work_tree);
+		remove_dir_recursively(&sb, 0);
+	}
+	strbuf_release(&sb);
+}
+
+static void remove_junk_on_signal(int signo)
+{
+	remove_junk();
+	sigchain_pop(signo);
+	raise(signo);
+}
+
+static const char *worktree_basename(const char *path, int *olen)
+{
+	const char *name;
+	int len;
+
+	len = strlen(path);
+	while (len && is_dir_sep(path[len - 1]))
+		len--;
+
+	for (name = path + len - 1; name > path; name--)
+		if (is_dir_sep(*name)) {
+			name++;
+			break;
+		}
+
+	*olen = len;
+	return name;
+}
+
+static void validate_worktree_add(const char *path, const struct add_opts *opts)
+{
+	struct worktree **worktrees;
+	struct worktree *wt;
+	int locked;
+
+	if (file_exists(path) && !is_empty_dir(path))
+		die(_("'%s' already exists"), path);
+
+	worktrees = get_worktrees(0);
+	/*
+	 * find_worktree()'s suffix matching may undesirably find the main
+	 * rather than a linked worktree (for instance, when the basenames
+	 * of the main worktree and the one being created are the same).
+	 * We're only interested in linked worktrees, so skip the main
+	 * worktree with +1.
+	 */
+	wt = find_worktree(worktrees + 1, NULL, path);
+	if (!wt)
+		goto done;
+
+	locked = !!worktree_lock_reason(wt);
+	if ((!locked && opts->force) || (locked && opts->force > 1)) {
+		if (delete_git_dir(wt->id))
+		    die(_("unable to re-add worktree '%s'"), path);
+		goto done;
+	}
+
+	if (locked)
+		die(_("'%s' is a missing but locked worktree;\nuse 'add -f -f' to override, or 'unlock' and 'prune' or 'remove' to clear"), path);
+	else
+		die(_("'%s' is a missing but already registered worktree;\nuse 'add -f' to override, or 'prune' or 'remove' to clear"), path);
+
+done:
+	free_worktrees(worktrees);
+}
+
+static int add_worktree(const char *path, const char *refname,
+			const struct add_opts *opts)
+{
+	struct strbuf sb_git = STRBUF_INIT, sb_repo = STRBUF_INIT;
+	struct strbuf sb = STRBUF_INIT;
+	const char *name;
+	struct child_process cp = CHILD_PROCESS_INIT;
+	struct argv_array child_env = ARGV_ARRAY_INIT;
+	unsigned int counter = 0;
+	int len, ret;
+	struct strbuf symref = STRBUF_INIT;
+	struct commit *commit = NULL;
+	int is_branch = 0;
+	struct strbuf sb_name = STRBUF_INIT;
+
+	validate_worktree_add(path, opts);
+
+	/* is 'refname' a branch or commit? */
+	if (!opts->detach && !strbuf_check_branch_ref(&symref, refname) &&
+	    ref_exists(symref.buf)) {
+		is_branch = 1;
+		if (!opts->force)
+			die_if_checked_out(symref.buf, 0);
+	}
+	commit = lookup_commit_reference_by_name(refname);
+	if (!commit)
+		die(_("invalid reference: %s"), refname);
+
+	name = worktree_basename(path, &len);
+	strbuf_add(&sb, name, path + len - name);
+	sanitize_refname_component(sb.buf, &sb_name);
+	if (!sb_name.len)
+		BUG("How come '%s' becomes empty after sanitization?", sb.buf);
+	strbuf_reset(&sb);
+	name = sb_name.buf;
+	git_path_buf(&sb_repo, "worktrees/%s", name);
+	len = sb_repo.len;
+	if (safe_create_leading_directories_const(sb_repo.buf))
+		die_errno(_("could not create leading directories of '%s'"),
+			  sb_repo.buf);
+
+	while (mkdir(sb_repo.buf, 0777)) {
+		counter++;
+		if ((errno != EEXIST) || !counter /* overflow */)
+			die_errno(_("could not create directory of '%s'"),
+				  sb_repo.buf);
+		strbuf_setlen(&sb_repo, len);
+		strbuf_addf(&sb_repo, "%d", counter);
+	}
+	name = strrchr(sb_repo.buf, '/') + 1;
+
+	junk_pid = getpid();
+	atexit(remove_junk);
+	sigchain_push_common(remove_junk_on_signal);
+
+	junk_git_dir = xstrdup(sb_repo.buf);
+	is_junk = 1;
+
+	/*
+	 * lock the incomplete repo so prune won't delete it, unlock
+	 * after the preparation is over.
+	 */
+	strbuf_addf(&sb, "%s/locked", sb_repo.buf);
+	if (!opts->keep_locked)
+		write_file(sb.buf, "initializing");
+	else
+		write_file(sb.buf, "added with --lock");
+
+	strbuf_addf(&sb_git, "%s/.git", path);
+	if (safe_create_leading_directories_const(sb_git.buf))
+		die_errno(_("could not create leading directories of '%s'"),
+			  sb_git.buf);
+	junk_work_tree = xstrdup(path);
+
+	strbuf_reset(&sb);
+	strbuf_addf(&sb, "%s/gitdir", sb_repo.buf);
+	write_file(sb.buf, "%s", real_path(sb_git.buf));
+	write_file(sb_git.buf, "gitdir: %s/worktrees/%s",
+		   real_path(get_git_common_dir()), name);
+	/*
+	 * This is to keep resolve_ref() happy. We need a valid HEAD
+	 * or is_git_directory() will reject the directory. Any value which
+	 * looks like an object ID will do since it will be immediately
+	 * replaced by the symbolic-ref or update-ref invocation in the new
+	 * worktree.
+	 */
+	strbuf_reset(&sb);
+	strbuf_addf(&sb, "%s/HEAD", sb_repo.buf);
+	write_file(sb.buf, "%s", sha1_to_hex(null_sha1));
+	strbuf_reset(&sb);
+	strbuf_addf(&sb, "%s/commondir", sb_repo.buf);
+	write_file(sb.buf, "../..");
+
+	argv_array_pushf(&child_env, "%s=%s", GIT_DIR_ENVIRONMENT, sb_git.buf);
+	argv_array_pushf(&child_env, "%s=%s", GIT_WORK_TREE_ENVIRONMENT, path);
+	cp.git_cmd = 1;
+
+	if (!is_branch)
+		argv_array_pushl(&cp.args, "update-ref", "HEAD",
+				 oid_to_hex(&commit->object.oid), NULL);
+	else {
+		argv_array_pushl(&cp.args, "symbolic-ref", "HEAD",
+				 symref.buf, NULL);
+		if (opts->quiet)
+			argv_array_push(&cp.args, "--quiet");
+	}
+
+	cp.env = child_env.argv;
+	ret = run_command(&cp);
+	if (ret)
+		goto done;
+
+	if (opts->checkout) {
+		cp.argv = NULL;
+		argv_array_clear(&cp.args);
+		argv_array_pushl(&cp.args, "reset", "--hard", NULL);
+		if (opts->quiet)
+			argv_array_push(&cp.args, "--quiet");
+		cp.env = child_env.argv;
+		ret = run_command(&cp);
+		if (ret)
+			goto done;
+	}
+
+	is_junk = 0;
+	FREE_AND_NULL(junk_work_tree);
+	FREE_AND_NULL(junk_git_dir);
+
+done:
+	if (ret || !opts->keep_locked) {
+		strbuf_reset(&sb);
+		strbuf_addf(&sb, "%s/locked", sb_repo.buf);
+		unlink_or_warn(sb.buf);
+	}
+
+	/*
+	 * Hook failure does not warrant worktree deletion, so run hook after
+	 * is_junk is cleared, but do return appropriate code when hook fails.
+	 */
+	if (!ret && opts->checkout) {
+		const char *hook = find_hook("post-checkout");
+		if (hook) {
+			const char *env[] = { "GIT_DIR", "GIT_WORK_TREE", NULL };
+			cp.git_cmd = 0;
+			cp.no_stdin = 1;
+			cp.stdout_to_stderr = 1;
+			cp.dir = path;
+			cp.env = env;
+			cp.argv = NULL;
+			cp.trace2_hook_name = "post-checkout";
+			argv_array_pushl(&cp.args, absolute_path(hook),
+					 oid_to_hex(&null_oid),
+					 oid_to_hex(&commit->object.oid),
+					 "1", NULL);
+			ret = run_command(&cp);
+		}
+	}
+
+	argv_array_clear(&child_env);
+	strbuf_release(&sb);
+	strbuf_release(&symref);
+	strbuf_release(&sb_repo);
+	strbuf_release(&sb_git);
+	strbuf_release(&sb_name);
+	return ret;
+}
+
+static void print_preparing_worktree_line(int detach,
+					  const char *branch,
+					  const char *new_branch,
+					  int force_new_branch)
+{
+	if (force_new_branch) {
+		struct commit *commit = lookup_commit_reference_by_name(new_branch);
+		if (!commit)
+			printf_ln(_("Preparing worktree (new branch '%s')"), new_branch);
+		else
+			printf_ln(_("Preparing worktree (resetting branch '%s'; was at %s)"),
+				  new_branch,
+				  find_unique_abbrev(&commit->object.oid, DEFAULT_ABBREV));
+	} else if (new_branch) {
+		printf_ln(_("Preparing worktree (new branch '%s')"), new_branch);
+	} else {
+		struct strbuf s = STRBUF_INIT;
+		if (!detach && !strbuf_check_branch_ref(&s, branch) &&
+		    ref_exists(s.buf))
+			printf_ln(_("Preparing worktree (checking out '%s')"),
+				  branch);
+		else {
+			struct commit *commit = lookup_commit_reference_by_name(branch);
+			if (!commit)
+				die(_("invalid reference: %s"), branch);
+			printf_ln(_("Preparing worktree (detached HEAD %s)"),
+				  find_unique_abbrev(&commit->object.oid, DEFAULT_ABBREV));
+		}
+		strbuf_release(&s);
+	}
+}
+
+static const char *dwim_branch(const char *path, const char **new_branch)
+{
+	int n;
+	const char *s = worktree_basename(path, &n);
+	const char *branchname = xstrndup(s, n);
+	struct strbuf ref = STRBUF_INIT;
+
+	UNLEAK(branchname);
+	if (!strbuf_check_branch_ref(&ref, branchname) &&
+	    ref_exists(ref.buf)) {
+		strbuf_release(&ref);
+		return branchname;
+	}
+
+	*new_branch = branchname;
+	if (guess_remote) {
+		struct object_id oid;
+		const char *remote =
+			unique_tracking_name(*new_branch, &oid, NULL);
+		return remote;
+	}
+	return NULL;
+}
+
+static int add(int ac, const char **av, const char *prefix)
+{
+	struct add_opts opts;
+	const char *new_branch_force = NULL;
+	char *path;
+	const char *branch;
+	const char *new_branch = NULL;
+	const char *opt_track = NULL;
+	struct option options[] = {
+		OPT__FORCE(&opts.force,
+			   N_("checkout <branch> even if already checked out in other worktree"),
+			   PARSE_OPT_NOCOMPLETE),
+		OPT_STRING('b', NULL, &new_branch, N_("branch"),
+			   N_("create a new branch")),
+		OPT_STRING('B', NULL, &new_branch_force, N_("branch"),
+			   N_("create or reset a branch")),
+		OPT_BOOL(0, "detach", &opts.detach, N_("detach HEAD at named commit")),
+		OPT_BOOL(0, "checkout", &opts.checkout, N_("populate the new working tree")),
+		OPT_BOOL(0, "lock", &opts.keep_locked, N_("keep the new working tree locked")),
+		OPT__QUIET(&opts.quiet, N_("suppress progress reporting")),
+		OPT_PASSTHRU(0, "track", &opt_track, NULL,
+			     N_("set up tracking mode (see git-branch(1))"),
+			     PARSE_OPT_NOARG | PARSE_OPT_OPTARG),
+		OPT_BOOL(0, "guess-remote", &guess_remote,
+			 N_("try to match the new branch name with a remote-tracking branch")),
+		OPT_END()
+	};
+
+	memset(&opts, 0, sizeof(opts));
+	opts.checkout = 1;
+	ac = parse_options(ac, av, prefix, options, worktree_usage, 0);
+	if (!!opts.detach + !!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);
+
+	path = prefix_filename(prefix, av[0]);
+	branch = ac < 2 ? "HEAD" : av[1];
+
+	if (!strcmp(branch, "-"))
+		branch = "@{-1}";
+
+	if (new_branch_force) {
+		struct strbuf symref = STRBUF_INIT;
+
+		new_branch = new_branch_force;
+
+		if (!opts.force &&
+		    !strbuf_check_branch_ref(&symref, new_branch) &&
+		    ref_exists(symref.buf))
+			die_if_checked_out(symref.buf, 0);
+		strbuf_release(&symref);
+	}
+
+	if (ac < 2 && !new_branch && !opts.detach) {
+		const char *s = dwim_branch(path, &new_branch);
+		if (s)
+			branch = s;
+	}
+
+	if (ac == 2 && !new_branch && !opts.detach) {
+		struct object_id oid;
+		struct commit *commit;
+		const char *remote;
+
+		commit = lookup_commit_reference_by_name(branch);
+		if (!commit) {
+			remote = unique_tracking_name(branch, &oid, NULL);
+			if (remote) {
+				new_branch = branch;
+				branch = remote;
+			}
+		}
+	}
+	if (!opts.quiet)
+		print_preparing_worktree_line(opts.detach, branch, new_branch, !!new_branch_force);
+
+	if (new_branch) {
+		struct child_process cp = CHILD_PROCESS_INIT;
+		cp.git_cmd = 1;
+		argv_array_push(&cp.args, "branch");
+		if (new_branch_force)
+			argv_array_push(&cp.args, "--force");
+		if (opts.quiet)
+			argv_array_push(&cp.args, "--quiet");
+		argv_array_push(&cp.args, new_branch);
+		argv_array_push(&cp.args, branch);
+		if (opt_track)
+			argv_array_push(&cp.args, opt_track);
+		if (run_command(&cp))
+			return -1;
+		branch = new_branch;
+	} else if (opt_track) {
+		die(_("--[no-]track can only be used if a new branch is created"));
+	}
+
+	UNLEAK(path);
+	UNLEAK(opts);
+	return add_worktree(path, branch, &opts);
+}
+
+static void show_worktree_porcelain(struct worktree *wt)
+{
+	printf("worktree %s\n", wt->path);
+	if (wt->is_bare)
+		printf("bare\n");
+	else {
+		printf("HEAD %s\n", oid_to_hex(&wt->head_oid));
+		if (wt->is_detached)
+			printf("detached\n");
+		else if (wt->head_ref)
+			printf("branch %s\n", wt->head_ref);
+	}
+	printf("\n");
+}
+
+static void show_worktree(struct worktree *wt, int path_maxlen, int abbrev_len)
+{
+	struct strbuf sb = STRBUF_INIT;
+	int cur_path_len = strlen(wt->path);
+	int path_adj = cur_path_len - utf8_strwidth(wt->path);
+
+	strbuf_addf(&sb, "%-*s ", 1 + path_maxlen + path_adj, wt->path);
+	if (wt->is_bare)
+		strbuf_addstr(&sb, "(bare)");
+	else {
+		strbuf_addf(&sb, "%-*s ", abbrev_len,
+				find_unique_abbrev(&wt->head_oid, DEFAULT_ABBREV));
+		if (wt->is_detached)
+			strbuf_addstr(&sb, "(detached HEAD)");
+		else if (wt->head_ref) {
+			char *ref = shorten_unambiguous_ref(wt->head_ref, 0);
+			strbuf_addf(&sb, "[%s]", ref);
+			free(ref);
+		} else
+			strbuf_addstr(&sb, "(error)");
+	}
+	printf("%s\n", sb.buf);
+
+	strbuf_release(&sb);
+}
+
+static void measure_widths(struct worktree **wt, int *abbrev, int *maxlen)
+{
+	int i;
+
+	for (i = 0; wt[i]; i++) {
+		int sha1_len;
+		int path_len = strlen(wt[i]->path);
+
+		if (path_len > *maxlen)
+			*maxlen = path_len;
+		sha1_len = strlen(find_unique_abbrev(&wt[i]->head_oid, *abbrev));
+		if (sha1_len > *abbrev)
+			*abbrev = sha1_len;
+	}
+}
+
+static int list(int ac, const char **av, const char *prefix)
+{
+	int porcelain = 0;
+
+	struct option options[] = {
+		OPT_BOOL(0, "porcelain", &porcelain, N_("machine-readable output")),
+		OPT_END()
+	};
+
+	ac = parse_options(ac, av, prefix, options, worktree_usage, 0);
+	if (ac)
+		usage_with_options(worktree_usage, options);
+	else {
+		struct worktree **worktrees = get_worktrees(GWT_SORT_LINKED);
+		int path_maxlen = 0, abbrev = DEFAULT_ABBREV, i;
+
+		if (!porcelain)
+			measure_widths(worktrees, &abbrev, &path_maxlen);
+
+		for (i = 0; worktrees[i]; i++) {
+			if (porcelain)
+				show_worktree_porcelain(worktrees[i]);
+			else
+				show_worktree(worktrees[i], path_maxlen, abbrev);
+		}
+		free_worktrees(worktrees);
+	}
+	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;
+
+	ac = parse_options(ac, av, prefix, options, worktree_usage, 0);
+	if (ac != 1)
+		usage_with_options(worktree_usage, options);
+
+	worktrees = get_worktrees(0);
+	wt = find_worktree(worktrees, prefix, av[0]);
+	if (!wt)
+		die(_("'%s' is not a working tree"), av[0]);
+	if (is_main_worktree(wt))
+		die(_("The main working tree cannot be locked or unlocked"));
+
+	old_reason = worktree_lock_reason(wt);
+	if (old_reason) {
+		if (*old_reason)
+			die(_("'%s' is already locked, reason: %s"),
+			    av[0], old_reason);
+		die(_("'%s' is already locked"), av[0]);
+	}
+
+	write_file(git_common_path("worktrees/%s/locked", wt->id),
+		   "%s", reason);
+	free_worktrees(worktrees);
+	return 0;
+}
+
+static int unlock_worktree(int ac, const char **av, const char *prefix)
+{
+	struct option options[] = {
+		OPT_END()
+	};
+	struct worktree **worktrees, *wt;
+	int ret;
+
+	ac = parse_options(ac, av, prefix, options, worktree_usage, 0);
+	if (ac != 1)
+		usage_with_options(worktree_usage, options);
+
+	worktrees = get_worktrees(0);
+	wt = find_worktree(worktrees, prefix, av[0]);
+	if (!wt)
+		die(_("'%s' is not a working tree"), av[0]);
+	if (is_main_worktree(wt))
+		die(_("The main working tree cannot be locked or unlocked"));
+	if (!worktree_lock_reason(wt))
+		die(_("'%s' is not locked"), av[0]);
+	ret = unlink_or_warn(git_common_path("worktrees/%s/locked", wt->id));
+	free_worktrees(worktrees);
+	return ret;
+}
+
+static void validate_no_submodules(const struct worktree *wt)
+{
+	struct index_state istate = { NULL };
+	struct strbuf path = STRBUF_INIT;
+	int i, found_submodules = 0;
+
+	if (is_directory(worktree_git_path(wt, "modules"))) {
+		/*
+		 * There could be false positives, e.g. the "modules"
+		 * directory exists but is empty. But it's a rare case and
+		 * this simpler check is probably good enough for now.
+		 */
+		found_submodules = 1;
+	} else if (read_index_from(&istate, worktree_git_path(wt, "index"),
+				   get_worktree_git_dir(wt)) > 0) {
+		for (i = 0; i < istate.cache_nr; i++) {
+			struct cache_entry *ce = istate.cache[i];
+			int err;
+
+			if (!S_ISGITLINK(ce->ce_mode))
+				continue;
+
+			strbuf_reset(&path);
+			strbuf_addf(&path, "%s/%s", wt->path, ce->name);
+			if (!is_submodule_populated_gently(path.buf, &err))
+				continue;
+
+			found_submodules = 1;
+			break;
+		}
+	}
+	discard_index(&istate);
+	strbuf_release(&path);
+
+	if (found_submodules)
+		die(_("working trees containing submodules cannot be moved or removed"));
+}
+
+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 = NULL;
+	char *path;
+
+	ac = parse_options(ac, av, prefix, options, worktree_usage, 0);
+	if (ac != 2)
+		usage_with_options(worktree_usage, options);
+
+	path = prefix_filename(prefix, av[1]);
+	strbuf_addstr(&dst, path);
+	free(path);
+
+	worktrees = get_worktrees(0);
+	wt = find_worktree(worktrees, prefix, av[0]);
+	if (!wt)
+		die(_("'%s' is not a working tree"), av[0]);
+	if (is_main_worktree(wt))
+		die(_("'%s' is a main working tree"), av[0]);
+	if (is_directory(dst.buf)) {
+		const char *sep = find_last_dir_sep(wt->path);
+
+		if (!sep)
+			die(_("could not figure out destination name from '%s'"),
+			    wt->path);
+		strbuf_trim_trailing_dir_sep(&dst);
+		strbuf_addstr(&dst, sep);
+	}
+	if (file_exists(dst.buf))
+		die(_("target '%s' already exists"), dst.buf);
+
+	validate_no_submodules(wt);
+
+	if (force < 2)
+		reason = worktree_lock_reason(wt);
+	if (reason) {
+		if (*reason)
+			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;\nuse 'move -f -f' to override or unlock first"));
+	}
+	if (validate_worktree(wt, &errmsg, 0))
+		die(_("validation failed, cannot move working tree: %s"),
+		    errmsg.buf);
+	strbuf_release(&errmsg);
+
+	if (rename(wt->path, dst.buf) == -1)
+		die_errno(_("failed to move '%s' to '%s'"), wt->path, dst.buf);
+
+	update_worktree_location(wt, dst.buf);
+
+	strbuf_release(&dst);
+	free_worktrees(worktrees);
+	return 0;
+}
+
+/*
+ * Note, "git status --porcelain" is used to determine if it's safe to
+ * delete a whole worktree. "git status" does not ignore user
+ * configuration, so if a normal "git status" shows "clean" for the
+ * user, then it's ok to remove it.
+ *
+ * This assumption may be a bad one. We may want to ignore
+ * (potentially bad) user settings and only delete a worktree when
+ * it's absolutely safe to do so from _our_ point of view because we
+ * know better.
+ */
+static void check_clean_worktree(struct worktree *wt,
+				 const char *original_path)
+{
+	struct argv_array child_env = ARGV_ARRAY_INIT;
+	struct child_process cp;
+	char buf[1];
+	int ret;
+
+	/*
+	 * Until we sort this out, all submodules are "dirty" and
+	 * will abort this function.
+	 */
+	validate_no_submodules(wt);
+
+	argv_array_pushf(&child_env, "%s=%s/.git",
+			 GIT_DIR_ENVIRONMENT, wt->path);
+	argv_array_pushf(&child_env, "%s=%s",
+			 GIT_WORK_TREE_ENVIRONMENT, wt->path);
+	memset(&cp, 0, sizeof(cp));
+	argv_array_pushl(&cp.args, "status",
+			 "--porcelain", "--ignore-submodules=none",
+			 NULL);
+	cp.env = child_env.argv;
+	cp.git_cmd = 1;
+	cp.dir = wt->path;
+	cp.out = -1;
+	ret = start_command(&cp);
+	if (ret)
+		die_errno(_("failed to run 'git status' on '%s'"),
+			  original_path);
+	ret = xread(cp.out, buf, sizeof(buf));
+	if (ret)
+		die(_("'%s' is dirty, use --force to delete it"),
+		    original_path);
+	close(cp.out);
+	ret = finish_command(&cp);
+	if (ret)
+		die_errno(_("failed to run 'git status' on '%s', code %d"),
+			  original_path, ret);
+}
+
+static int delete_git_work_tree(struct worktree *wt)
+{
+	struct strbuf sb = STRBUF_INIT;
+	int ret = 0;
+
+	strbuf_addstr(&sb, wt->path);
+	if (remove_dir_recursively(&sb, 0)) {
+		error_errno(_("failed to delete '%s'"), sb.buf);
+		ret = -1;
+	}
+	strbuf_release(&sb);
+	return ret;
+}
+
+static int remove_worktree(int ac, const char **av, const char *prefix)
+{
+	int force = 0;
+	struct option options[] = {
+		OPT__FORCE(&force,
+			 N_("force removal even if worktree is dirty or locked"),
+			 PARSE_OPT_NOCOMPLETE),
+		OPT_END()
+	};
+	struct worktree **worktrees, *wt;
+	struct strbuf errmsg = STRBUF_INIT;
+	const char *reason = NULL;
+	int ret = 0;
+
+	ac = parse_options(ac, av, prefix, options, worktree_usage, 0);
+	if (ac != 1)
+		usage_with_options(worktree_usage, options);
+
+	worktrees = get_worktrees(0);
+	wt = find_worktree(worktrees, prefix, av[0]);
+	if (!wt)
+		die(_("'%s' is not a working tree"), av[0]);
+	if (is_main_worktree(wt))
+		die(_("'%s' is a main working tree"), av[0]);
+	if (force < 2)
+		reason = worktree_lock_reason(wt);
+	if (reason) {
+		if (*reason)
+			die(_("cannot remove a locked working tree, lock reason: %s\nuse 'remove -f -f' to override or unlock first"),
+			    reason);
+		die(_("cannot remove a locked working tree;\nuse 'remove -f -f' to override or unlock first"));
+	}
+	if (validate_worktree(wt, &errmsg, WT_VALIDATE_WORKTREE_MISSING_OK))
+		die(_("validation failed, cannot remove working tree: %s"),
+		    errmsg.buf);
+	strbuf_release(&errmsg);
+
+	if (file_exists(wt->path)) {
+		if (!force)
+			check_clean_worktree(wt, av[0]);
+
+		ret |= delete_git_work_tree(wt);
+	}
+	/*
+	 * continue on even if ret is non-zero, there's no going back
+	 * from here.
+	 */
+	ret |= delete_git_dir(wt->id);
+	delete_worktrees_dir_if_empty();
+
+	free_worktrees(worktrees);
+	return ret;
+}
+
+int cmd_worktree(int ac, const char **av, const char *prefix)
+{
+	struct option options[] = {
+		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);
+	usage_with_options(worktree_usage, options);
+}