Try code from WordPress/gutenberg#58389

Author: getdave

src/wp-includes/blocks/navigation-link.php

@@ -323,70 +323,40 @@ function build_variation_for_navigation_link( $entity, $kind ) {
 }
 
 /**
- * Register a variation for a post type / taxonomy for the navigation link block.
+ * Filters the registered variations for a block type.
+ * Returns the dynamically built variations for all post-types and taxonomies.
  *
- * @param array $variation Variation array from build_variation_for_navigation_link.
- * @return void
- */
-function block_core_navigation_link_register_variation( $variation ) {
-	// Directly set the variations on the registered block type
-	// because there's no server side registration for variations (see #47170).
-	$navigation_block_type = WP_Block_Type_Registry::get_instance()->get_registered( 'core/navigation-link' );
-	// If the block is not registered yet, bail early.
-	// Variation will be registered in register_block_core_navigation_link then.
-	if ( ! $navigation_block_type ) {
-		return;
-	}
-
-	$navigation_block_type->variations = array_merge(
-		$navigation_block_type->variations,
-		array( $variation )
-	);
-}
-
-/**
- * Unregister a variation for a post type / taxonomy for the navigation link block.
+ * @since 6.5.0
  *
- * @param string $name Name of the post type / taxonomy (which was used as variation name).
- * @return void
+ * @param array         $variations Array of registered variations for a block type.
+ * @param WP_Block_Type $block_type The full block type object.
  */
-function block_core_navigation_link_unregister_variation( $name ) {
-	// Directly get the variations from the registered block type
-	// because there's no server side (un)registration for variations (see #47170).
-	$navigation_block_type = WP_Block_Type_Registry::get_instance()->get_registered( 'core/navigation-link' );
-	// If the block is not registered (yet), there's no need to remove a variation.
-	if ( ! $navigation_block_type || empty( $navigation_block_type->variations ) ) {
-		return;
+function block_core_navigation_link_filter_variations( $variations, $block_type ) {
+	if ( 'core/navigation-link' !== $block_type->name ) {
+		return $variations;
 	}
-	$variations = $navigation_block_type->variations;
-	// Search for the variation and remove it from the array.
-	foreach ( $variations as $i => $variation ) {
-		if ( $variation['name'] === $name ) {
-			unset( $variations[ $i ] );
-			break;
-		}
-	}
-	// Reindex array after removing one variation.
-	$navigation_block_type->variations = array_values( $variations );
+
+	$generated_variations = build_navigation_link_block_variations();
+	// TODO: Mabe check if there are already variations for this post type/taxonomy?
+	return array_merge( $variations, $generated_variations );
 }
 
 /**
- * Register the navigation link block.
  * Returns an array of variations for the navigation link block.
  *
  * @return array
  */
 function build_navigation_link_block_variations() {
-	// This will only handle post types and taxonomies registered until this point (init on priority 9).
-	// See action hooks below for other post types and taxonomies.
-	// See https://github.com/WordPress/gutenberg/issues/53826 for details.
+	// This will only handle post types and taxonomies registered until this point.
 	$post_types = get_post_types( array( 'show_in_nav_menus' => true ), 'objects' );
 	$taxonomies = get_taxonomies( array( 'show_in_nav_menus' => true ), 'objects' );
 
-	// Use two separate arrays as a way to order the variations in the UI.
-	// Known variations (like Post Link and Page Link) are added to the
-	// `built_ins` array. Variations for custom post types and taxonomies are
-	// added to the `variations` array and will always appear after `built-ins.
+	/*
+	 * Use two separate arrays as a way to order the variations in the UI.
+	 * Known variations (like Post Link and Page Link) are added to the
+	 * `built_ins` array. Variations for custom post types and taxonomies are
+	 * added to the `variations` array and will always appear after `built-ins.
+	 */
 	$built_ins  = array();
 	$variations = array();
 
@@ -415,7 +385,7 @@ function build_navigation_link_block_variations() {
 }
 
 /**
- * Register the navigation link block.
+ * Registers the navigation link block.
  *
  * @uses render_block_core_navigation()
  * @throws WP_Error An WP_Error exception parsing the block definition.
@@ -424,69 +394,13 @@ function register_block_core_navigation_link() {
 	register_block_type_from_metadata(
 		__DIR__ . '/navigation-link',
 		array(
-			'render_callback'    => 'render_block_core_navigation_link',
-			'variation_callback' => 'build_navigation_link_block_variations',
+			'render_callback' => 'render_block_core_navigation_link',
 		)
 	);
-
-	// Register actions for all post types and taxonomies, to add variations when they are registered.
-	// All post types/taxonomies registered before register_block_core_navigation_link, will be handled by that function.
-	add_action( 'registered_post_type', 'block_core_navigation_link_register_post_type_variation', 10, 2 );
-	add_action( 'registered_taxonomy', 'block_core_navigation_link_register_taxonomy_variation', 10, 3 );
 }
 add_action( 'init', 'register_block_core_navigation_link' );
-
-// Handle unregistering of post types and taxonomies and remove the variations.
-add_action( 'unregistered_post_type', 'block_core_navigation_link_unregister_post_type_variation' );
-add_action( 'unregistered_taxonomy', 'block_core_navigation_link_unregister_taxonomy_variation' );
-
 /**
- * Register custom post type variations for navigation link on post type registration
- * Handles all post types registered after the block is registered in register_navigation_link_post_type_variations
- *
- * @param string       $post_type The post type name passed from registered_post_type action hook.
- * @param WP_Post_Type $post_type_object The post type object passed from registered_post_type.
- * @return void
+ * Use this filter to create all variations for post types / taxonomies dynamically.
+ * Do not use variation_callback, to also account for unregistering post types/taxonomies later on.
  */
-function block_core_navigation_link_register_post_type_variation( $post_type, $post_type_object ) {
-	if ( $post_type_object->show_in_nav_menus ) {
-		$variation = build_variation_for_navigation_link( $post_type_object, 'post-type' );
-		block_core_navigation_link_register_variation( $variation );
-	}
-}
-
-/**
- * Register a custom taxonomy variation for navigation link on taxonomy registration
- * Handles all taxonomies registered after the block is registered in register_navigation_link_post_type_variations
- *
- * @param string       $taxonomy Taxonomy slug.
- * @param array|string $object_type Object type or array of object types.
- * @param array        $args Array of taxonomy registration arguments.
- * @return void
- */
-function block_core_navigation_link_register_taxonomy_variation( $taxonomy, $object_type, $args ) {
-	if ( isset( $args['show_in_nav_menus'] ) && $args['show_in_nav_menus'] ) {
-		$variation = build_variation_for_navigation_link( (object) $args, 'post-type' );
-		block_core_navigation_link_register_variation( $variation );
-	}
-}
-
-/**
- * Unregisters a custom post type variation for navigation link on post type unregistration.
- *
- * @param string $post_type The post type name passed from unregistered_post_type action hook.
- * @return void
- */
-function block_core_navigation_link_unregister_post_type_variation( $post_type ) {
-	block_core_navigation_link_unregister_variation( $post_type );
-}
-
-/**
- * Unregisters a custom taxonomy variation for navigation link on taxonomy unregistration.
- *
- * @param string $taxonomy The taxonomy name passed from unregistered_taxonomy action hook.
- * @return void
- */
-function block_core_navigation_link_unregister_taxonomy_variation( $taxonomy ) {
-	block_core_navigation_link_unregister_variation( $taxonomy );
-}
+add_action( 'get_block_type_variations', 'block_core_navigation_link_filter_variations', 10, 2 );