wp-includes/blocks/navigation.php:1049Retrieves the appropriate fallback to be used on the front of the site when there is no menu assigned to the Nav block.
arrayOne hook fires while block_core_navigation_get_fallback_blocks() runs, in this order:
Filters the fallback experience for the Navigation block.
function block_core_navigation_get_fallback_blocks() { $page_list_fallback = array( array( 'blockName' => 'core/page-list', 'innerContent' => array(), 'attrs' => array(), ), ); $registry = WP_Block_Type_Registry::get_instance(); // If `core/page-list` is not registered then return empty blocks. $fallback_blocks = $registry->is_registered( 'core/page-list' ) ? $page_list_fallback : array(); $navigation_post = WP_Navigation_Fallback::get_fallback(); // Use the first non-empty Navigation as fallback if available. if ( $navigation_post ) { $parsed_blocks = parse_blocks( $navigation_post->post_content ); $maybe_fallback = block_core_navigation_filter_out_empty_blocks( $parsed_blocks ); // Normalizing blocks may result in an empty array of blocks if they were all `null` blocks. // In this case default to the (Page List) fallback. $fallback_blocks = ! empty( $maybe_fallback ) ? $maybe_fallback : $fallback_blocks; // Run Block Hooks algorithm to inject hooked blocks. // We have to run it here because we need the post ID of the Navigation block to track ignored hooked blocks. $markup = block_core_navigation_insert_hooked_blocks( $fallback_blocks, $navigation_post ); $blocks = parse_blocks( $markup ); if ( isset( $blocks[0]['innerBlocks'] ) ) { $fallback_blocks = $blocks[0]['innerBlocks']; } } /** * Filters the fallback experience for the Navigation block. * * Returning a falsey value will opt out of the fallback and cause the block not to render. * To customise the blocks provided return an array of blocks - these should be valid * children of the `core/navigation` block. * * @since 5.9.0 * * @param array[] $fallback_blocks default fallback blocks provided by the default block mechanic. */ return apply_filters( 'block_core_navigation_render_fallback', $fallback_blocks );}Introduced in 5.9.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/blocks/navigation.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.