--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/wp/wp-includes/class-wp-navigation-fallback.php Fri Sep 05 18:40:08 2025 +0200
@@ -0,0 +1,303 @@
+<?php
+/**
+ * WP_Navigation_Fallback class
+ *
+ * Manages fallback behavior for Navigation menus.
+ *
+ * @package WordPress
+ * @subpackage Navigation
+ * @since 6.3.0
+ */
+
+/**
+ * Manages fallback behavior for Navigation menus.
+ *
+ * @access public
+ * @since 6.3.0
+ */
+class WP_Navigation_Fallback {
+
+ /**
+ * Updates the wp_navigation custom post type schema, in order to expose
+ * additional fields in the embeddable links of WP_REST_Navigation_Fallback_Controller.
+ *
+ * The Navigation Fallback endpoint may embed the full Navigation Menu object
+ * into the response as the `self` link. By default, the Posts Controller
+ * will only expose a limited subset of fields but the editor requires
+ * additional fields to be available in order to utilize the menu.
+ *
+ * Used with the `rest_wp_navigation_item_schema` hook.
+ *
+ * @since 6.4.0
+ *
+ * @param array $schema The schema for the `wp_navigation` post.
+ * @return array The modified schema.
+ */
+ public static function update_wp_navigation_post_schema( $schema ) {
+ // Expose top level fields.
+ $schema['properties']['status']['context'] = array_merge( $schema['properties']['status']['context'], array( 'embed' ) );
+ $schema['properties']['content']['context'] = array_merge( $schema['properties']['content']['context'], array( 'embed' ) );
+
+ /*
+ * Exposes sub properties of content field.
+ * These sub properties aren't exposed by the posts controller by default,
+ * for requests where context is `embed`.
+ *
+ * @see WP_REST_Posts_Controller::get_item_schema()
+ */
+ $schema['properties']['content']['properties']['raw']['context'] = array_merge( $schema['properties']['content']['properties']['raw']['context'], array( 'embed' ) );
+ $schema['properties']['content']['properties']['rendered']['context'] = array_merge( $schema['properties']['content']['properties']['rendered']['context'], array( 'embed' ) );
+ $schema['properties']['content']['properties']['block_version']['context'] = array_merge( $schema['properties']['content']['properties']['block_version']['context'], array( 'embed' ) );
+
+ /*
+ * Exposes sub properties of title field.
+ * These sub properties aren't exposed by the posts controller by default,
+ * for requests where context is `embed`.
+ *
+ * @see WP_REST_Posts_Controller::get_item_schema()
+ */
+ $schema['properties']['title']['properties']['raw']['context'] = array_merge( $schema['properties']['title']['properties']['raw']['context'], array( 'embed' ) );
+
+ return $schema;
+ }
+
+ /**
+ * Gets (and/or creates) an appropriate fallback Navigation Menu.
+ *
+ * @since 6.3.0
+ *
+ * @return WP_Post|null the fallback Navigation Post or null.
+ */
+ public static function get_fallback() {
+ /**
+ * Filters whether or not a fallback should be created.
+ *
+ * @since 6.3.0
+ *
+ * @param bool $create Whether to create a fallback navigation menu. Default true.
+ */
+ $should_create_fallback = apply_filters( 'wp_navigation_should_create_fallback', true );
+
+ $fallback = static::get_most_recently_published_navigation();
+
+ if ( $fallback || ! $should_create_fallback ) {
+ return $fallback;
+ }
+
+ $fallback = static::create_classic_menu_fallback();
+
+ if ( $fallback && ! is_wp_error( $fallback ) ) {
+ // Return the newly created fallback post object which will now be the most recently created navigation menu.
+ return $fallback instanceof WP_Post ? $fallback : static::get_most_recently_published_navigation();
+ }
+
+ $fallback = static::create_default_fallback();
+
+ if ( $fallback && ! is_wp_error( $fallback ) ) {
+ // Return the newly created fallback post object which will now be the most recently created navigation menu.
+ return $fallback instanceof WP_Post ? $fallback : static::get_most_recently_published_navigation();
+ }
+
+ return null;
+ }
+
+ /**
+ * Finds the most recently published `wp_navigation` post type.
+ *
+ * @since 6.3.0
+ *
+ * @return WP_Post|null the first non-empty Navigation or null.
+ */
+ private static function get_most_recently_published_navigation() {
+
+ $parsed_args = array(
+ 'post_type' => 'wp_navigation',
+ 'no_found_rows' => true,
+ 'update_post_meta_cache' => false,
+ 'update_post_term_cache' => false,
+ 'order' => 'DESC',
+ 'orderby' => 'date',
+ 'post_status' => 'publish',
+ 'posts_per_page' => 1,
+ );
+
+ $navigation_post = new WP_Query( $parsed_args );
+
+ if ( count( $navigation_post->posts ) > 0 ) {
+ return $navigation_post->posts[0];
+ }
+
+ return null;
+ }
+
+ /**
+ * Creates a Navigation Menu post from a Classic Menu.
+ *
+ * @since 6.3.0
+ *
+ * @return int|WP_Error The post ID of the default fallback menu or a WP_Error object.
+ */
+ private static function create_classic_menu_fallback() {
+ // See if we have a classic menu.
+ $classic_nav_menu = static::get_fallback_classic_menu();
+
+ if ( ! $classic_nav_menu ) {
+ return new WP_Error( 'no_classic_menus', __( 'No Classic Menus found.' ) );
+ }
+
+ // If there is a classic menu then convert it to blocks.
+ $classic_nav_menu_blocks = WP_Classic_To_Block_Menu_Converter::convert( $classic_nav_menu );
+
+ if ( is_wp_error( $classic_nav_menu_blocks ) ) {
+ return $classic_nav_menu_blocks;
+ }
+
+ if ( empty( $classic_nav_menu_blocks ) ) {
+ return new WP_Error( 'cannot_convert_classic_menu', __( 'Unable to convert Classic Menu to blocks.' ) );
+ }
+
+ // Create a new navigation menu from the classic menu.
+ $classic_menu_fallback = wp_insert_post(
+ array(
+ 'post_content' => $classic_nav_menu_blocks,
+ 'post_title' => $classic_nav_menu->name,
+ 'post_name' => $classic_nav_menu->slug,
+ 'post_status' => 'publish',
+ 'post_type' => 'wp_navigation',
+ ),
+ true // So that we can check whether the result is an error.
+ );
+
+ return $classic_menu_fallback;
+ }
+
+ /**
+ * Determines the most appropriate classic navigation menu to use as a fallback.
+ *
+ * @since 6.3.0
+ *
+ * @return WP_Term|null The most appropriate classic navigation menu to use as a fallback.
+ */
+ private static function get_fallback_classic_menu() {
+ $classic_nav_menus = wp_get_nav_menus();
+
+ if ( ! $classic_nav_menus || is_wp_error( $classic_nav_menus ) ) {
+ return null;
+ }
+
+ $nav_menu = static::get_nav_menu_at_primary_location();
+
+ if ( $nav_menu ) {
+ return $nav_menu;
+ }
+
+ $nav_menu = static::get_nav_menu_with_primary_slug( $classic_nav_menus );
+
+ if ( $nav_menu ) {
+ return $nav_menu;
+ }
+
+ return static::get_most_recently_created_nav_menu( $classic_nav_menus );
+ }
+
+
+ /**
+ * Sorts the classic menus and returns the most recently created one.
+ *
+ * @since 6.3.0
+ *
+ * @param WP_Term[] $classic_nav_menus Array of classic nav menu term objects.
+ * @return WP_Term The most recently created classic nav menu.
+ */
+ private static function get_most_recently_created_nav_menu( $classic_nav_menus ) {
+ usort(
+ $classic_nav_menus,
+ static function ( $a, $b ) {
+ return $b->term_id - $a->term_id;
+ }
+ );
+
+ return $classic_nav_menus[0];
+ }
+
+ /**
+ * Returns the classic menu with the slug `primary` if it exists.
+ *
+ * @since 6.3.0
+ *
+ * @param WP_Term[] $classic_nav_menus Array of classic nav menu term objects.
+ * @return WP_Term|null The classic nav menu with the slug `primary` or null.
+ */
+ private static function get_nav_menu_with_primary_slug( $classic_nav_menus ) {
+ foreach ( $classic_nav_menus as $classic_nav_menu ) {
+ if ( 'primary' === $classic_nav_menu->slug ) {
+ return $classic_nav_menu;
+ }
+ }
+
+ return null;
+ }
+
+
+ /**
+ * Gets the classic menu assigned to the `primary` navigation menu location
+ * if it exists.
+ *
+ * @since 6.3.0
+ *
+ * @return WP_Term|null The classic nav menu assigned to the `primary` location or null.
+ */
+ private static function get_nav_menu_at_primary_location() {
+ $locations = get_nav_menu_locations();
+
+ if ( isset( $locations['primary'] ) ) {
+ $primary_menu = wp_get_nav_menu_object( $locations['primary'] );
+
+ if ( $primary_menu ) {
+ return $primary_menu;
+ }
+ }
+
+ return null;
+ }
+
+ /**
+ * Creates a default Navigation Block Menu fallback.
+ *
+ * @since 6.3.0
+ *
+ * @return int|WP_Error The post ID of the default fallback menu or a WP_Error object.
+ */
+ private static function create_default_fallback() {
+
+ $default_blocks = static::get_default_fallback_blocks();
+
+ // Create a new navigation menu from the fallback blocks.
+ $default_fallback = wp_insert_post(
+ array(
+ 'post_content' => $default_blocks,
+ 'post_title' => _x( 'Navigation', 'Title of a Navigation menu' ),
+ 'post_name' => 'navigation',
+ 'post_status' => 'publish',
+ 'post_type' => 'wp_navigation',
+ ),
+ true // So that we can check whether the result is an error.
+ );
+
+ return $default_fallback;
+ }
+
+ /**
+ * Gets the rendered markup for the default fallback blocks.
+ *
+ * @since 6.3.0
+ *
+ * @return string default blocks markup to use a the fallback.
+ */
+ private static function get_default_fallback_blocks() {
+ $registry = WP_Block_Type_Registry::get_instance();
+
+ // If `core/page-list` is not registered then use empty blocks.
+ return $registry->is_registered( 'core/page-list' ) ? '<!-- wp:page-list /-->' : '';
+ }
+}