REST API: Terms: Allow sorting by term_order

lib/compat/wordpress-6.8/class-gutenberg-rest-terms-controller-6-8.php

@@ -0,0 +1,25 @@
+<?php
+/**
+ * REST API: Gutenberg_REST_Terms_Controller_6_8 class
+ *
+ * @package    gutenberg
+ * @subpackage REST_API
+ * @since      6.8.0
+ */
+class Gutenberg_REST_Terms_Controller_6_8 extends WP_REST_Terms_Controller {
+	/**
+	 * Retrieves the query params for collections.
+	 *
+	 * @since 4.7.0
+	 * @since 6.8.0 Added 'term_order' to the list of allowed orderby parameters.
+	 *
+	 * @return array Collection parameters.
+	 */
+	public function get_collection_params() {
+		$query_params = parent::get_collection_params();
+
+		$query_params['orderby']['enum'][] = 'term_order';
+
+		return $query_params;
+	}
+}

lib/compat/wordpress-6.8/rest-api.php

@@ -0,0 +1,30 @@
+<?php
+/**
+ * PHP and WordPress configuration compatibility functions for the Gutenberg
+ * editor plugin changes related to REST API.
+ *
+ * @package gutenberg
+ */
+
+if ( ! defined( 'ABSPATH' ) ) {
+	die( 'Silence is golden.' );
+}
+
+/**
+ * Overrides the default 'WP_REST_Terms_Controller' class for all taxonomies upon registration.
+ *
+ * @return array The updated taxonomy registration arguments.
+ */
+function gutenberg_override_terms_controller_6_8( $args, $taxonomy ) {
+	if ( empty( $args['show_in_rest'] ) ) {
+		return $args;
+	}
+
+	if ( isset( $args['rest_controller_class'] ) && 'WP_REST_Terms_Controller' !== $args['rest_controller_class'] ) {
+		return $args;
+	}
+
+	$args['rest_controller_class'] = Gutenberg_REST_Terms_Controller_6_8::class;
+	return $args;
+}
+add_filter( 'register_taxonomy_args', 'gutenberg_override_terms_controller_6_8', 10, 2 );

lib/load.php

@@ -49,6 +49,8 @@ function gutenberg_is_experiment_enabled( $name ) {
 	// WordPress 6.8 compat.
 	require __DIR__ . '/compat/wordpress-6.8/block-comments.php';
 	require __DIR__ . '/compat/wordpress-6.8/class-gutenberg-rest-comment-controller-6-8.php';
+	require __DIR__ . '/compat/wordpress-6.8/class-gutenberg-rest-terms-controller-6-8.php';
+	require __DIR__ . '/compat/wordpress-6.8/rest-api.php';
 
 	// Plugin specific code.
 	require_once __DIR__ . '/class-wp-rest-global-styles-controller-gutenberg.php';