Merge branch 'nd/worktree-cleanup-post-head-protection'

Further preparatory clean-up for "worktree" feature continues.

* nd/worktree-cleanup-post-head-protection:
  worktree: simplify prefixing paths
  worktree: avoid 0{40}, too many zeroes, hard to read
  worktree.c: use is_dot_or_dotdot()
  git-worktree.txt: keep subcommand listing in alphabetical order
  worktree.c: rewrite mark_current_worktree() to avoid strbuf
  completion: support git-worktree

Documentation/git-worktree.txt

@@ -10,8 +10,8 @@ SYNOPSIS
 --------
 [verse]
 'git worktree add' [-f] [--detach] [--checkout] [-b <new-branch>] <path> [<branch>]
-'git worktree prune' [-n] [-v] [--expire <expire>]
 'git worktree list' [--porcelain]
+'git worktree prune' [-n] [-v] [--expire <expire>]
 
 DESCRIPTION
 -----------
@@ -55,10 +55,6 @@ If `<branch>` is omitted and neither `-b` nor `-B` nor `--detached` used,
 then, as a convenience, a new branch based at HEAD is created automatically,
 as if `-b $(basename <path>)` was specified.
 
-prune::
-
-Prune working tree information in $GIT_DIR/worktrees.
-
 list::
 
 List details of each worktree.  The main worktree is listed first, followed by
@@ -66,6 +62,10 @@ 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).
 
+prune::
+
+Prune working tree information in $GIT_DIR/worktrees.
+
 OPTIONS
 -------
 

builtin/worktree.c

@@ -13,8 +13,8 @@
 
 static const char * const worktree_usage[] = {
 	N_("git worktree add [<options>] <path> [<branch>]"),
-	N_("git worktree prune [<options>]"),
 	N_("git worktree list [<options>]"),
+	N_("git worktree prune [<options>]"),
 	NULL
 };
 
@@ -95,7 +95,7 @@ static void prune_worktrees(void)
 	if (!dir)
 		return;
 	while ((d = readdir(dir)) != NULL) {
-		if (!strcmp(d->d_name, ".") || !strcmp(d->d_name, ".."))
+		if (is_dot_or_dotdot(d->d_name))
 			continue;
 		strbuf_reset(&reason);
 		if (!prune_worktree(d->d_name, &reason))
@@ -262,7 +262,7 @@ static int add_worktree(const char *path, const char *refname,
 	 */
 	strbuf_reset(&sb);
 	strbuf_addf(&sb, "%s/HEAD", sb_repo.buf);
-	write_file(sb.buf, "0000000000000000000000000000000000000000");
+	write_file(sb.buf, sha1_to_hex(null_sha1));
 	strbuf_reset(&sb);
 	strbuf_addf(&sb, "%s/commondir", sb_repo.buf);
 	write_file(sb.buf, "../..");
@@ -337,7 +337,7 @@ static int add(int ac, const char **av, const char *prefix)
 	if (ac < 1 || ac > 2)
 		usage_with_options(worktree_usage, options);
 
-	path = prefix ? prefix_filename(prefix, strlen(prefix), av[0]) : av[0];
+	path = prefix_filename(prefix, strlen(prefix), av[0]);
 	branch = ac < 2 ? "HEAD" : av[1];
 
 	if (!strcmp(branch, "-"))
@@ -470,6 +470,8 @@ int cmd_worktree(int ac, const char **av, const char *prefix)
 
 	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"))

contrib/completion/git-completion.bash

@@ -2691,6 +2691,29 @@ _git_whatchanged ()
 	_git_log
 }
 
+_git_worktree ()
+{
+	local subcommands="add list prune"
+	local subcommand="$(__git_find_on_cmdline "$subcommands")"
+	if [ -z "$subcommand" ]; then
+		__gitcomp "$subcommands"
+	else
+		case "$subcommand,$cur" in
+		add,--*)
+			__gitcomp "--detach"
+			;;
+		list,--*)
+			__gitcomp "--porcelain"
+			;;
+		prune,--*)
+			__gitcomp "--dry-run --expire --verbose"
+			;;
+		*)
+			;;
+		esac
+	fi
+}
+
 __git_main ()
 {
 	local i c=1 command __git_dir

worktree.c

@@ -153,21 +153,19 @@ done:
 
 static void mark_current_worktree(struct worktree **worktrees)
 {
-	struct strbuf git_dir = STRBUF_INIT;
-	struct strbuf path = STRBUF_INIT;
+	char *git_dir = xstrdup(absolute_path(get_git_dir()));
 	int i;
 
-	strbuf_addstr(&git_dir, absolute_path(get_git_dir()));
 	for (i = 0; worktrees[i]; i++) {
 		struct worktree *wt = worktrees[i];
-		strbuf_addstr(&path, absolute_path(get_worktree_git_dir(wt)));
-		wt->is_current = !fspathcmp(git_dir.buf, path.buf);
-		strbuf_reset(&path);
-		if (wt->is_current)
+		const char *wt_git_dir = get_worktree_git_dir(wt);
+
+		if (!fspathcmp(git_dir, absolute_path(wt_git_dir))) {
+			wt->is_current = 1;
 			break;
+		}
 	}
-	strbuf_release(&git_dir);
-	strbuf_release(&path);
+	free(git_dir);
 }
 
 struct worktree **get_worktrees(void)
@@ -189,7 +187,7 @@ struct worktree **get_worktrees(void)
 	if (dir) {
 		while ((d = readdir(dir)) != NULL) {
 			struct worktree *linked = NULL;
-			if (!strcmp(d->d_name, ".") || !strcmp(d->d_name, ".."))
+			if (is_dot_or_dotdot(d->d_name))
 				continue;
 
 			if ((linked = get_linked_worktree(d->d_name))) {