Avoid calling gutenberg_ functions within code shipped through WordPress Core

lib/compat/wordpress-5.8/index.php

@@ -103,3 +103,43 @@ function build_query_vars_from_query_block( $block, $page ) {
 		return $query;
 	}
 }
+
+/**
+ * Ensures that a core legacy widget has a key when on a version of WordPress earlier than 5.8.
+ *
+ * This can be removed once the plugin's minimum version of WordPress is increased to 5.8.
+ *
+ * @param string $widget_key The widget key.
+ * @param string $id_base    The widget ID base.
+ * @return string The widget key.
+ */
+function gutenberg_filter_core_legacy_widget_key( $widget_key, $id_base ) {
+	global $wp_widget_factory;
+
+	if ( method_exists( $wp_widget_factory, 'get_widget_key' ) ) {
+		return $widget_key;
+	}
+
+	return gutenberg_get_widget_key( $id_base );
+}
+add_filter( 'render_block_core_legacy_widget_key', 'gutenberg_filter_core_legacy_widget_key', 10, 2 );
+
+/**
+ * Ensures that a core legacy widget object is found when on a version of WordPress earlier than 5.8.
+ *
+ * This can be removed once the plugin's minimum version of WordPress is increased to 5.8.
+ *
+ * @param string $widget_object The widget object.
+ * @param string $id_base       The widget ID base.
+ * @return WP_Widget|null The widget object.
+ */
+function gutenberg_filter_core_legacy_widget_object( $widget_object, $id_base ) {
+	global $wp_widget_factory;
+
+	if ( method_exists( $wp_widget_factory, 'get_widget_object' ) ) {
+		return $widget_object;
+	}
+
+	return gutenberg_get_widget_object( $id_base );
+}
+add_filter( 'render_block_core_legacy_widget_object', 'gutenberg_filter_core_legacy_widget_object', 10, 2 );

packages/block-library/src/post-template/index.php

@@ -93,15 +93,16 @@ function register_block_core_post_template() {
  * It triggers a developer warning and then calls the renamed
  * block's `render_callback` function output.
  *
- * This can be removed when WordPress 5.9 is released.
+ * @since 5.8.0
+ * @access private
  *
  * @param array    $attributes Block attributes.
  * @param string   $content    Block default content.
  * @param WP_Block $block      Block instance.
  *
  * @return string Returns the output of the query, structured using the layout defined by the block's inner blocks.
  */
-function render_legacy_query_loop_block( $attributes, $content, $block ) {
+function wp_render_legacy_query_loop_block( $attributes, $content, $block ) {
 	trigger_error(
 		/* translators: %1$s: Block type */
 		sprintf( __( 'Block %1$s has been renamed to Post Template. %1$s will be supported until WordPress version 5.9.' ), $block->name ),
@@ -115,11 +116,12 @@ function render_legacy_query_loop_block( $attributes, $content, $block ) {
  * This ensures backwards compatibility for any users running the Gutenberg
  * plugin who have used Query Loop prior to its renaming.
  *
- * This can be removed when WordPress 5.9 is released.
+ * @since 5.8.0
+ * @access private
  *
  * @see https://github.com/WordPress/gutenberg/pull/32514
  */
-function gutenberg_register_legacy_query_loop_block() {
+function wp_register_legacy_query_loop_block() {
 	$registry = WP_Block_Type_Registry::get_instance();
 	if ( $registry->is_registered( 'core/query-loop' ) ) {
 		unregister_block_type( 'core/query-loop' );
@@ -141,9 +143,9 @@ function gutenberg_register_legacy_query_loop_block() {
 				'align'    => true,
 			),
 			'style'             => 'wp-block-post-template',
-			'render_callback'   => 'render_legacy_query_loop_block',
+			'render_callback'   => 'wp_render_legacy_query_loop_block',
 			'skip_inner_blocks' => true,
 		)
 	);
 }
-add_action( 'init', 'gutenberg_register_legacy_query_loop_block' );
+add_action( 'init', 'wp_register_legacy_query_loop_block' );

packages/widgets/src/blocks/legacy-widget/index.php

@@ -24,15 +24,38 @@ function render_block_core_legacy_widget( $attributes ) {
 		return '';
 	}
 
-	$id_base = $attributes['idBase'];
+	$id_base       = $attributes['idBase'];
+	$widget_key    = '';
+	$widget_object = null;
+
 	if ( method_exists( $wp_widget_factory, 'get_widget_key' ) && method_exists( $wp_widget_factory, 'get_widget_object' ) ) {
 		$widget_key    = $wp_widget_factory->get_widget_key( $id_base );
 		$widget_object = $wp_widget_factory->get_widget_object( $id_base );
-	} else {
-		$widget_key    = gutenberg_get_widget_key( $id_base );
-		$widget_object = gutenberg_get_widget_object( $id_base );
 	}
 
+	/**
+	 * Filters the core legacy widget block key.
+	 *
+	 * @since 5.8.0
+	 *
+	 * @param string $widget_key The widget key.
+	 * @param string $id_base    The widget ID base.
+	 * @param array  $attributes The block attributes.
+	 */
+	$widget_key = apply_filters( 'render_block_core_legacy_widget_key', $widget_key, $id_base, $attributes );
+
+	/**
+	 * Filters the Core legacy widget object.
+	 *
+	 * @since 5.8.0
+	 *
+	 * @param null|WP_Widget $widget_object The widget object.
+	 * @param string         $widget_key    The widget key.
+	 * @param string $id_base               The widget ID base.
+	 * @param array  $attributes            The block attributes.
+	 */
+	$widget_object = apply_filters( 'render_block_core_legacy_widget_object', $widget_object, $widget_key, $id_base, $attributes );
+
 	if ( ! $widget_key || ! $widget_object ) {
 		return '';
 	}