Merge branch 'nd/worktree-list-fixup' into maint

The output from "git worktree list" was made in readdir() order,
and was unstable.

* nd/worktree-list-fixup:
  worktree list: keep the list sorted
  worktree.c: get_worktrees() takes a new flag argument
  get_worktrees() must return main worktree as first item even on error
  worktree: reorder an if statement
  worktree.c: zero new 'struct worktree' on allocation

branch.c

@@ -348,7 +348,7 @@ void die_if_checked_out(const char *branch, int ignore_current_worktree)
 int replace_each_worktree_head_symref(const char *oldref, const char *newref)
 {
 	int ret = 0;
-	struct worktree **worktrees = get_worktrees();
+	struct worktree **worktrees = get_worktrees(0);
 	int i;
 
 	for (i = 0; worktrees[i]; i++) {

builtin/branch.c

@@ -531,7 +531,7 @@ static void print_ref_list(struct ref_filter *filter, struct ref_sorting *sortin
 
 static void reject_rebase_or_bisect_branch(const char *target)
 {
-	struct worktree **worktrees = get_worktrees();
+	struct worktree **worktrees = get_worktrees(0);
 	int i;
 
 	for (i = 0; worktrees[i]; i++) {

builtin/worktree.c

@@ -388,7 +388,7 @@ static void show_worktree_porcelain(struct worktree *wt)
 		printf("HEAD %s\n", sha1_to_hex(wt->head_sha1));
 		if (wt->is_detached)
 			printf("detached\n");
-		else
+		else if (wt->head_ref)
 			printf("branch %s\n", wt->head_ref);
 	}
 	printf("\n");
@@ -406,10 +406,12 @@ static void show_worktree(struct worktree *wt, int path_maxlen, int abbrev_len)
 	else {
 		strbuf_addf(&sb, "%-*s ", abbrev_len,
 				find_unique_abbrev(wt->head_sha1, DEFAULT_ABBREV));
-		if (!wt->is_detached)
+		if (wt->is_detached)
+			strbuf_addstr(&sb, "(detached HEAD)");
+		else if (wt->head_ref)
 			strbuf_addf(&sb, "[%s]", shorten_unambiguous_ref(wt->head_ref, 0));
 		else
-			strbuf_addstr(&sb, "(detached HEAD)");
+			strbuf_addstr(&sb, "(error)");
 	}
 	printf("%s\n", sb.buf);
 
@@ -445,7 +447,7 @@ static int list(int ac, const char **av, const char *prefix)
 	if (ac)
 		usage_with_options(worktree_usage, options);
 	else {
-		struct worktree **worktrees = get_worktrees();
+		struct worktree **worktrees = get_worktrees(GWT_SORT_LINKED);
 		int path_maxlen = 0, abbrev = DEFAULT_ABBREV, i;
 
 		if (!porcelain)
@@ -476,7 +478,7 @@ static int lock_worktree(int ac, const char **av, const char *prefix)
 	if (ac != 1)
 		usage_with_options(worktree_usage, options);
 
-	worktrees = get_worktrees();
+	worktrees = get_worktrees(0);
 	wt = find_worktree(worktrees, prefix, av[0]);
 	if (!wt)
 		die(_("'%s' is not a working tree"), av[0]);
@@ -509,7 +511,7 @@ static int unlock_worktree(int ac, const char **av, const char *prefix)
 	if (ac != 1)
 		usage_with_options(worktree_usage, options);
 
-	worktrees = get_worktrees();
+	worktrees = get_worktrees(0);
 	wt = find_worktree(worktrees, prefix, av[0]);
 	if (!wt)
 		die(_("'%s' is not a working tree"), av[0]);

t/t2027-worktree-list.sh

@@ -96,4 +96,44 @@ test_expect_success 'bare repo cleanup' '
 	rm -rf bare1
 '
 
+test_expect_success 'broken main worktree still at the top' '
+	git init broken-main &&
+	(
+		cd broken-main &&
+		test_commit new &&
+		git worktree add linked &&
+		cat >expected <<-EOF &&
+		worktree $(pwd)
+		HEAD $_z40
+
+		EOF
+		cd linked &&
+		echo "worktree $(pwd)" >expected &&
+		echo "ref: .broken" >../.git/HEAD &&
+		git worktree list --porcelain | head -n 3 >actual &&
+		test_cmp ../expected actual &&
+		git worktree list | head -n 1 >actual.2 &&
+		grep -F "(error)" actual.2
+	)
+'
+
+test_expect_success 'linked worktrees are sorted' '
+	mkdir sorted &&
+	git init sorted/main &&
+	(
+		cd sorted/main &&
+		test_tick &&
+		test_commit new &&
+		git worktree add ../first &&
+		git worktree add ../second &&
+		git worktree list --porcelain | grep ^worktree >actual
+	) &&
+	cat >expected <<-EOF &&
+	worktree $(pwd)/sorted/main
+	worktree $(pwd)/sorted/first
+	worktree $(pwd)/sorted/second
+	EOF
+	test_cmp expected sorted/main/actual
+'
+
 test_done

worktree.c

@@ -88,21 +88,13 @@ static struct worktree *get_main_worktree(void)
 
 	strbuf_addf(&path, "%s/HEAD", get_git_common_dir());
 
-	if (parse_ref(path.buf, &head_ref, &is_detached) < 0)
-		goto done;
-
-	worktree = xmalloc(sizeof(struct worktree));
+	worktree = xcalloc(1, sizeof(*worktree));
 	worktree->path = strbuf_detach(&worktree_path, NULL);
-	worktree->id = NULL;
 	worktree->is_bare = is_bare;
-	worktree->head_ref = NULL;
 	worktree->is_detached = is_detached;
-	worktree->is_current = 0;
+	if (!parse_ref(path.buf, &head_ref, &is_detached))
 		add_head_info(&head_ref, worktree);
-	worktree->lock_reason = NULL;
-	worktree->lock_reason_valid = 0;
 
-done:
 	strbuf_release(&path);
 	strbuf_release(&worktree_path);
 	strbuf_release(&head_ref);
@@ -138,16 +130,11 @@ static struct worktree *get_linked_worktree(const char *id)
 	if (parse_ref(path.buf, &head_ref, &is_detached) < 0)
 		goto done;
 
-	worktree = xmalloc(sizeof(struct worktree));
+	worktree = xcalloc(1, sizeof(*worktree));
 	worktree->path = strbuf_detach(&worktree_path, NULL);
 	worktree->id = xstrdup(id);
-	worktree->is_bare = 0;
-	worktree->head_ref = NULL;
 	worktree->is_detached = is_detached;
-	worktree->is_current = 0;
 	add_head_info(&head_ref, worktree);
-	worktree->lock_reason = NULL;
-	worktree->lock_reason_valid = 0;
 
 done:
 	strbuf_release(&path);
@@ -173,7 +160,14 @@ static void mark_current_worktree(struct worktree **worktrees)
 	free(git_dir);
 }
 
-struct worktree **get_worktrees(void)
+static int compare_worktree(const void *a_, const void *b_)
+{
+	const struct worktree *const *a = a_;
+	const struct worktree *const *b = b_;
+	return fspathcmp((*a)->path, (*b)->path);
+}
+
+struct worktree **get_worktrees(unsigned flags)
 {
 	struct worktree **list = NULL;
 	struct strbuf path = STRBUF_INIT;
@@ -183,8 +177,7 @@ struct worktree **get_worktrees(void)
 
 	list = xmalloc(alloc * sizeof(struct worktree *));
 
-	if ((list[counter] = get_main_worktree()))
-		counter++;
+	list[counter++] = get_main_worktree();
 
 	strbuf_addf(&path, "%s/worktrees", get_git_common_dir());
 	dir = opendir(path.buf);
@@ -205,6 +198,13 @@ struct worktree **get_worktrees(void)
 	ALLOC_GROW(list, counter + 1, alloc);
 	list[counter] = NULL;
 
+	if (flags & GWT_SORT_LINKED)
+		/*
+		 * don't sort the first item (main worktree), which will
+		 * always be the first
+		 */
+		QSORT(list + 1, counter - 1, compare_worktree);
+
 	mark_current_worktree(list);
 	return list;
 }
@@ -341,7 +341,7 @@ const struct worktree *find_shared_symref(const char *symref,
 
 	if (worktrees)
 		free_worktrees(worktrees);
-	worktrees = get_worktrees();
+	worktrees = get_worktrees(0);
 
 	for (i = 0; worktrees[i]; i++) {
 		struct worktree *wt = worktrees[i];

worktree.h

@@ -15,6 +15,8 @@ struct worktree {
 
 /* Functions for acting on the information about worktrees. */
 
+#define GWT_SORT_LINKED (1 << 0) /* keeps linked worktrees sorted */
+
 /*
  * Get the worktrees.  The primary worktree will always be the first returned,
  * and linked worktrees will be pointed to by 'next' in each subsequent
@@ -23,7 +25,7 @@ struct worktree {
  * The caller is responsible for freeing the memory from the returned
  * worktree(s).
  */
-extern struct worktree **get_worktrees(void);
+extern struct worktree **get_worktrees(unsigned flags);
 
 /*
  * Return git dir of the worktree. Note that the path may be relative.