Ticket #17447: 17447.3.diff

src/wp-includes/post-functions.php

@@ -992 +992 @@
 
         // Sanitize post type name
         $post_type = sanitize_key( $post_type );
+        $args      = wp_parse_args( $args );
 
         /**
          * Filter the arguments for registering a post type.
          *
          * @since 4.4.0
          *
-         * @param array|string $args      Array or string of arguments for registering a post type.
-         * @param string       $post_type Post type key.
+         * @param array  $args      Array of arguments for registering a post type.
+         * @param string $post_type Post type key.
          */
         $args = apply_filters( 'register_post_type_args', $args, $post_type );
 
@@ -1031 +1032 @@
                 '_builtin'             => false,
                 '_edit_link'           => 'post.php?post=%d',
         );
-        $args = wp_parse_args( $args, $defaults );
+        $args = array_merge( $defaults, $args );
         $args = (object) $args;
 
         $args->name = $post_type;