Ticket #38486: 38486.2.diff

src/wp-includes/nav-menu-template.php

@@ -447 +447 @@
                                 $classes[] = 'menu-item-home';
                 }
 
+                // Get the custom post types
+                $custom_post_types = get_post_types( array(
+                        '_builtin' => false,
+                        'public'   => true,
+                ),
+                        'names', 'and' );
+
                 // back-compat with wp_page_menu: add "current_page_parent" to static home page link for any non-page query
-                if ( ! empty( $home_page_id ) && 'post_type' == $menu_item->type && empty( $wp_query->is_page ) && $home_page_id == $menu_item->object_id )
+                if ( ! empty( $home_page_id ) && 'post_type' == $menu_item->type && empty( $wp_query->is_page ) && $home_page_id == $menu_item->object_id && ! is_post_type_archive( $custom_post_types ) && ! is_singular( $custom_post_types ) )
                         $classes[] = 'current_page_parent';
 
+                // Check if we are on a single view of a custom post type
+                if ( is_singular( $custom_post_types ) ) {
+                        // get the post type.
+                        $custom_post_type = get_post_type();
+
+                        // Check if the currently looped menu item is a post type archive item for this custom post type.
+                        if ( 'post_type_archive' === $menu_item->type && $custom_post_type === $menu_item->object ) {
+                                // add the current_page_parent class to the menu item.
+                                $classes[] = 'current_page_parent';
+                        }
+                }
+
                 $menu_items[$key]->classes = array_unique( $classes );
         }
         $active_ancestor_item_ids = array_filter( array_unique( $active_ancestor_item_ids ) );