wp_render_layout_support_flag( string $block_content, array $block ): string

955function wp_render_layout_support_flag( $block_content, $block ) {956	static $global_styles = null;957 958	$block_type            = WP_Block_Type_Registry::get_instance()->get_registered( $block['blockName'] );959	$block_supports_layout = block_has_support( $block_type, 'layout', false ) || block_has_support( $block_type, '__experimentalLayout', false );960	$style_attr            = $block['attrs']['style'] ?? array();961	/*962	 * A block with no layout support and no style attribute at all cannot963	 * produce layout output, so return before resolving global settings.964	 *965	 * Resolving settings is not read-only: on a cold cache it queries the966	 * user's `wp_global_styles` post, which fires `the_posts`. A callback on967	 * that hook that renders blocks re-enters this filter, and the content it968	 * renders at that point is the global styles post itself, which parses to a969	 * single block with no name and no attributes. Without this return that970	 * block resolves settings again and the recursion has no base case.971	 */972	if ( ! $block_supports_layout && empty( $style_attr ) ) {973		return $block_content;974	}975 976	$global_settings          = wp_get_global_settings();977	$viewport_settings        = $global_settings['viewport'] ?? null;978	$responsive_media_queries = WP_Theme_JSON::get_viewport_media_queries( $viewport_settings );979	$child_layout             = $style_attr['layout'] ?? null;980 981	/*982	 * Collect responsive viewport child layout overrides so that a block with983	 * only responsive child layout (no base child layout) is still processed.984	 */985	$viewport_child_layouts = array();986	foreach ( $responsive_media_queries as $breakpoint => $media_query ) {987		$viewport_child = wp_get_layout_child_values( $style_attr[ $breakpoint ]['layout'] ?? null );988 989		if ( ! empty( $viewport_child ) ) {990			$viewport_child_layouts[ $breakpoint ] = array(991				'media_query'  => $media_query,992				'child_layout' => $viewport_child,993			);994		}995	}996 997	if ( ! $block_supports_layout && ! $child_layout && empty( $viewport_child_layouts ) ) {998		return $block_content;999	}1000 1001	$outer_class_names = array();1002 1003	// Child layout specific logic.1004	if ( $child_layout || ! empty( $viewport_child_layouts ) ) {1005		$base_child_layout = wp_get_layout_child_values( $child_layout );1006		$parent_layout     = $block['parentLayout'] ?? array();1007		/*1008		 * Generates a unique class for child block layout styles.1009		 *1010		 * To ensure consistent class generation across different page renders,1011		 * only properties that affect layout styling are used. These properties1012		 * come from `$block['attrs']['style']['layout']`, viewport overrides in1013		 * `$block['attrs']['style'][$breakpoint]['layout']`, and `$block['parentLayout']`.1014		 *1015		 * As long as these properties coincide, the generated class will be the same.1016		 */1017		$container_content_hash_input = array(1018			'layout'       => $base_child_layout,1019			'parentLayout' => array_intersect_key(1020				$parent_layout,1021				array_flip( array( 'minimumColumnWidth', 'columnCount' ) )1022			),1023		);1024 1025		foreach ( $viewport_child_layouts as $breakpoint => $viewport_data ) {1026			$container_content_hash_input[ $breakpoint ] = $viewport_data['child_layout'];1027		}1028 1029		$container_content_class = wp_unique_id_from_values(1030			$container_content_hash_input,1031			'wp-container-content-'1032		);1033 1034		$child_layout_styles = wp_get_child_layout_style_rules( ".$container_content_class", $base_child_layout, $parent_layout );