diff --git a/Documentation/MyFirstObjectWalk.txt b/Documentation/MyFirstObjectWalk.txt
index c33d22a..a06c712 100644
--- a/Documentation/MyFirstObjectWalk.txt
+++ b/Documentation/MyFirstObjectWalk.txt
@@ -734,8 +734,8 @@
 	} else {
 		trace_printf(
 			_("Filtered object walk with filterspec 'tree:1'.\n"));
-		CALLOC_ARRAY(rev->filter, 1);
-		parse_list_objects_filter(rev->filter, "tree:1");
+
+		parse_list_objects_filter(&rev->filter, "tree:1");
 	}
 	traverse_commit_list(rev, walken_show_commit,
 			     walken_show_object, NULL);