remote: improve sorting of "configure for git push" list

The data structure used to store this list is a string_list
of sources with the destination in the util member. The
current code just sorts on the source; if a single source is
pushed to two different destination refs at a remote, then
the order in which they are printed is non-deterministic.

This patch implements a comparison using both fields.
Besides being a little nicer on the eyes, giving a stable
sort prevents false negatives in the test suite when
comparing output.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin-remote.c

@@ -931,6 +931,20 @@ int add_push_to_show_info(struct string_list_item *push_item, void *cb_data)
 	return 0;
 }
 
+/*
+ * Sorting comparison for a string list that has push_info
+ * structs in its util field
+ */
+static int cmp_string_with_push(const void *va, const void *vb)
+{
+	const struct string_list_item *a = va;
+	const struct string_list_item *b = vb;
+	const struct push_info *a_push = a->util;
+	const struct push_info *b_push = b->util;
+	int cmp = strcmp(a->string, b->string);
+	return cmp ? cmp : strcmp(a_push->dest, b_push->dest);
+}
+
 int show_push_info_item(struct string_list_item *item, void *cb_data)
 {
 	struct show_info *show_info = cb_data;
@@ -1041,7 +1055,8 @@ static int show(int argc, const char **argv)
 
 		info.width = info.width2 = 0;
 		for_each_string_list(add_push_to_show_info, &states.push, &info);
-		sort_string_list(info.list);
+		qsort(info.list->items, info.list->nr,
+			sizeof(*info.list->items), cmp_string_with_push);
 		if (info.list->nr)
 			printf("  Local ref%s configured for 'git push'%s:\n",
 				info.list->nr > 1 ? "s" : "",