Block Styles: Extend block style variations as mechanism for achieving section styling

src/wp-includes/class-wp-theme-json-resolver.php

@@ -701,16 +701,46 @@ private static function recursively_iterate_json( $dir ) {
 		return $nested_json_files;
 	}
 
+	/**
+	 * Determines if a supplied style variation matches the provided scope.
+	 *
+	 * For backwards compatibility, if a variation does not define any scope
+	 * related property, e.g. `blockTypes`, it is assumed to be a theme style
+	 * variation.
+	 *
+	 * @since 6.6.0
+	 *
+	 * @param array  $variation Theme.json shaped style variation object.
+	 * @param string $scope     Scope to check e.g. theme, block etc.
+	 *
+	 * @return boolean
+	 */
+	private static function style_variation_has_scope( $variation, $scope ) {
+		if ( 'block' === $scope ) {
+			return isset( $variation['blockTypes'] );
+		}
+
+		if ( 'theme' === $scope ) {
+			return ! isset( $variation['blockTypes'] );
+		}
+
+		return false;
+	}
 
 	/**
 	 * Returns the style variations defined by the theme.
 	 *
 	 * @since 6.0.0
 	 * @since 6.2.0 Returns parent theme variations if theme is a child.
+	 * @since 6.6.0 Added configurable scope parameter to allow filtering
+	 *              theme.json partial files by the scope to which they
+	 *              can be applied e.g. theme vs block etc.
+	 *
+	 * @param string $scope The scope or type of style variation to retrieve e.g. theme, block etc.
 	 *
 	 * @return array
 	 */
-	public static function get_style_variations() {
+	public static function get_style_variations( $scope = 'theme' ) {
 		$variation_files    = array();
 		$variations         = array();
 		$base_directory     = get_stylesheet_directory() . '/styles';
@@ -733,7 +763,7 @@ public static function get_style_variations() {
 		ksort( $variation_files );
 		foreach ( $variation_files as $path => $file ) {
 			$decoded_file = wp_json_file_decode( $path, array( 'associative' => true ) );
-			if ( is_array( $decoded_file ) ) {
+			if ( is_array( $decoded_file ) && static::style_variation_has_scope( $decoded_file, $scope ) ) {
 				$translated = static::translate( $decoded_file, wp_get_theme()->get( 'TextDomain' ) );
 				$variation  = ( new WP_Theme_JSON( $translated ) )->get_raw_data();
 				if ( empty( $variation['title'] ) ) {

src/wp-includes/class-wp-theme-json.php

@@ -346,9 +346,11 @@ class WP_Theme_JSON {
 	 * @since 5.9.0 Renamed from `ALLOWED_TOP_LEVEL_KEYS` to `VALID_TOP_LEVEL_KEYS`,
 	 *              added the `customTemplates` and `templateParts` values.
 	 * @since 6.3.0 Added the `description` value.
+	 * @since 6.6.0 Added `blockTypes` to support block style variation theme.json partials.
 	 * @var string[]
 	 */
 	const VALID_TOP_LEVEL_KEYS = array(
+		'blockTypes',
 		'customTemplates',
 		'description',
 		'patterns',
@@ -823,6 +825,7 @@ protected static function do_opt_in_into_settings( &$context ) {
 	 * @since 5.8.0
 	 * @since 5.9.0 Added the `$valid_block_names` and `$valid_element_name` parameters.
 	 * @since 6.3.0 Added the `$valid_variations` parameter.
+	 * @since 6.6.0 Updated schema to allow extended block style variations.
 	 *
 	 * @param array $input               Structure to sanitize.
 	 * @param array $valid_block_names   List of valid block names.
@@ -881,6 +884,27 @@ protected static function sanitize( $input, $valid_block_names, $valid_element_n
 
 		$schema_styles_blocks   = array();
 		$schema_settings_blocks = array();
+
+		/*
+		 * Generate a schema for blocks.
+		 * - Block styles can contain `elements` & `variations` definitions.
+		 * - Variations definitions cannot be nested.
+		 * - Variations can contain styles for inner `blocks`.
+		 * - Variation inner `blocks` styles can contain `elements`.
+		 *
+		 * As each variation needs a `blocks` schema but further nested
+		 * inner `blocks`, the overall schema will be generated in multiple passes.
+		 */
+		foreach ( $valid_block_names as $block ) {
+			$schema_settings_blocks[ $block ]           = static::VALID_SETTINGS;
+			$schema_styles_blocks[ $block ]             = $styles_non_top_level;
+			$schema_styles_blocks[ $block ]['elements'] = $schema_styles_elements;
+		}
+
+		$block_style_variation_styles             = static::VALID_STYLES;
+		$block_style_variation_styles['blocks']   = $schema_styles_blocks;
+		$block_style_variation_styles['elements'] = $schema_styles_elements;
+
 		foreach ( $valid_block_names as $block ) {
 			// Build the schema for each block style variation.
 			$style_variation_names = array();
@@ -897,12 +921,9 @@ protected static function sanitize( $input, $valid_block_names, $valid_element_n
 
 			$schema_styles_variations = array();
 			if ( ! empty( $style_variation_names ) ) {
-				$schema_styles_variations = array_fill_keys( $style_variation_names, $styles_non_top_level );
+				$schema_styles_variations = array_fill_keys( $style_variation_names, $block_style_variation_styles );
 			}
 
-			$schema_settings_blocks[ $block ]             = static::VALID_SETTINGS;
-			$schema_styles_blocks[ $block ]               = $styles_non_top_level;
-			$schema_styles_blocks[ $block ]['elements']   = $schema_styles_elements;
 			$schema_styles_blocks[ $block ]['variations'] = $schema_styles_variations;
 		}
 
@@ -913,6 +934,12 @@ protected static function sanitize( $input, $valid_block_names, $valid_element_n
 		$schema['settings']['blocks']                     = $schema_settings_blocks;
 		$schema['settings']['typography']['fontFamilies'] = static::schema_in_root_and_per_origin( static::FONT_FAMILY_SCHEMA );
 
+		/*
+		 * Shared block style variations can be registered from the theme.json data so we can't
+		 * validate them against pre-registered block style variations.
+		 */
+		$schema['styles']['blocks']['variations'] = null;
+
 		// Remove anything that's not present in the schema.
 		foreach ( array( 'styles', 'settings' ) as $subtree ) {
 			if ( ! isset( $input[ $subtree ] ) ) {
@@ -1016,16 +1043,36 @@ protected static function prepend_to_selector( $selector, $to_prepend ) {
 	 * @since 5.9.0 Added `duotone` key with CSS selector.
 	 * @since 6.1.0 Added `features` key with block support feature level selectors.
 	 * @since 6.3.0 Refactored and stabilized selectors API.
+	 * @since 6.6.0 Updated to include block style variations from the block styles registry.
 	 *
 	 * @return array Block metadata.
 	 */
 	protected static function get_blocks_metadata() {
-		$registry = WP_Block_Type_Registry::get_instance();
-		$blocks   = $registry->get_all_registered();
+		$registry       = WP_Block_Type_Registry::get_instance();
+		$blocks         = $registry->get_all_registered();
+		$style_registry = WP_Block_Styles_Registry::get_instance();
 
 		// Is there metadata for all currently registered blocks?
 		$blocks = array_diff_key( $blocks, static::$blocks_metadata );
 		if ( empty( $blocks ) ) {
+			/*
+			 * New block styles may have been registered within WP_Block_Styles_Registry.
+			 * Update block metadata for any new block style variations.
+			 */
+			$registered_styles = $style_registry->get_all_registered();
+			foreach ( static::$blocks_metadata as $block_name => $block_metadata ) {
+				if ( ! empty( $registered_styles[ $block_name ] ) ) {
+					$style_selectors = $block_metadata['styleVariations'] ?? array();
+
+					foreach ( $registered_styles[ $block_name ] as $block_style ) {
+						if ( ! isset( $style_selectors[ $block_style['name'] ] ) ) {
+							$style_selectors[ $block_style['name'] ] = static::get_block_style_variation_selector( $block_style['name'], $block_metadata['selector'] );
+						}
+					}
+
+					static::$blocks_metadata[ $block_name ]['styleVariations'] = $style_selectors;
+				}
+			}
 			return static::$blocks_metadata;
 		}
 
@@ -1060,11 +1107,20 @@ protected static function get_blocks_metadata() {
 			}
 
 			// If the block has style variations, append their selectors to the block metadata.
+			$style_selectors = array();
 			if ( ! empty( $block_type->styles ) ) {
-				$style_selectors = array();
 				foreach ( $block_type->styles as $style ) {
 					$style_selectors[ $style['name'] ] = static::get_block_style_variation_selector( $style['name'], static::$blocks_metadata[ $block_name ]['selector'] );
 				}
+			}
+
+			// Block style variations can be registered through the WP_Block_Styles_Registry as well as block.json.
+			$registered_styles = $style_registry->get_registered_styles_for_block( $block_name );
+			foreach ( $registered_styles as $style ) {
+				$style_selectors[ $style['name'] ] = static::get_block_style_variation_selector( $style['name'], static::$blocks_metadata[ $block_name ]['selector'] );
+			}
+
+			if ( ! empty( $style_selectors ) ) {
 				static::$blocks_metadata[ $block_name ]['styleVariations'] = $style_selectors;
 			}
 		}
@@ -1158,16 +1214,18 @@ public function get_settings() {
 	 * @since 5.8.0
 	 * @since 5.9.0 Removed the `$type` parameter, added the `$types` and `$origins` parameters.
 	 * @since 6.3.0 Add fallback layout styles for Post Template when block gap support isn't available.
+	 * @since 6.6.0 Added `skip_root_layout_styles` option to omit layout styles if desired.
 	 *
 	 * @param string[] $types   Types of styles to load. Will load all by default. It accepts:
 	 *                          - `variables`: only the CSS Custom Properties for presets & custom ones.
 	 *                          - `styles`: only the styles section in theme.json.
 	 *                          - `presets`: only the classes for the presets.
 	 * @param string[] $origins A list of origins to include. By default it includes VALID_ORIGINS.
 	 * @param array    $options An array of options for now used for internal purposes only (may change without notice).
-	 *                          The options currently supported are 'scope' that makes sure all style are scoped to a
-	 *                          given selector, and root_selector which overwrites and forces a given selector to be
-	 *                          used on the root node.
+	 *                       The options currently supported are:
+	 *                       - 'scope' that makes sure all style are scoped to a given selector
+	 *                       - `root_selector` which overwrites and forces a given selector to be used on the root node
+	 *                       - `skip_root_layout_styles` which omits root layout styles from the generated stylesheet.
 	 * @return string The resulting stylesheet.
 	 */
 	public function get_stylesheet( $types = array( 'variables', 'styles', 'presets' ), $origins = null, $options = array() ) {
@@ -1220,7 +1278,7 @@ public function get_stylesheet( $types = array( 'variables', 'styles', 'presets'
 		}
 
 		if ( in_array( 'styles', $types, true ) ) {
-			if ( false !== $root_style_key ) {
+			if ( false !== $root_style_key && empty( $options['skip_root_layout_styles'] ) ) {
 				$stylesheet .= $this->get_root_layout_rules( $style_nodes[ $root_style_key ]['selector'], $style_nodes[ $root_style_key ] );
 			}
 			$stylesheet .= $this->get_block_classes( $style_nodes );
@@ -3114,6 +3172,7 @@ protected static function filter_slugs( $node, $slugs ) {
 	 *
 	 * @since 5.9.0
 	 * @since 6.3.2 Preserves global styles block variations when securing styles.
+	 * @since 6.6.0 Updated to allow variation element styles.
 	 *
 	 * @param array $theme_json Structure to sanitize.
 	 * @return array Sanitized structure.
@@ -3175,6 +3234,29 @@ public static function remove_insecure_properties( $theme_json ) {
 					}
 
 					$variation_output = static::remove_insecure_styles( $variation_input );
+
+					// Process a variation's elements and element pseudo selector styles.
+					if ( isset( $variation_input['elements'] ) ) {
+						foreach ( $valid_element_names as $element_name ) {
+							$element_input = $variation_input['elements'][ $element_name ] ?? null;
+							if ( $element_input ) {
+								$element_output = static::remove_insecure_styles( $element_input );
+
+								if ( isset( static::VALID_ELEMENT_PSEUDO_SELECTORS[ $element_name ] ) ) {
+									foreach ( static::VALID_ELEMENT_PSEUDO_SELECTORS[ $element_name ] as $pseudo_selector ) {
+										if ( isset( $element_input[ $pseudo_selector ] ) ) {
+											$element_output[ $pseudo_selector ] = static::remove_insecure_styles( $element_input[ $pseudo_selector ] );
+										}
+									}
+								}
+
+								if ( ! empty( $element_output ) ) {
+									_wp_array_set( $variation_output, array( 'elements', $element_name ), $element_output );
+								}
+							}
+						}
+					}
+
 					if ( ! empty( $variation_output ) ) {
 						_wp_array_set( $sanitized, $variation['path'], $variation_output );
 					}

src/wp-settings.php

@@ -366,6 +366,7 @@
 require ABSPATH . WPINC . '/block-supports/utils.php';
 require ABSPATH . WPINC . '/block-supports/align.php';
 require ABSPATH . WPINC . '/block-supports/background.php';
+require ABSPATH . WPINC . '/block-supports/block-style-variations.php';
 require ABSPATH . WPINC . '/block-supports/border.php';
 require ABSPATH . WPINC . '/block-supports/colors.php';
 require ABSPATH . WPINC . '/block-supports/custom-classname.php';

tests/phpunit/data/themedir1/block-theme-child-with-block-style-variations/style.css

@@ -0,0 +1,8 @@
+/*
+Theme Name: Block Theme Child With Block Style Variations Theme
+Theme URI: https://wordpress.org/
+Description: For testing purposes only.
+Template: block-theme
+Version: 1.0.0
+Text Domain: block-theme-child-with-block-style-variations
+*/

tests/phpunit/data/themedir1/block-theme-child-with-block-style-variations/styles/block-style-variation-a.json

@@ -0,0 +1,10 @@
+{
+	"version": 3,
+	"blockTypes": [ "core/group", "core/columns", "core/media-text" ],
+	"styles": {
+		"color": {
+			"background": "darkcyan",
+			"text": "aliceblue"
+		}
+	}
+}

tests/phpunit/data/themedir1/block-theme-child-with-block-style-variations/theme.json

@@ -0,0 +1,4 @@
+{
+	"$schema": "https://schemas.wp.org/trunk/theme.json",
+	"version": 3
+}

tests/phpunit/data/themedir1/block-theme/styles/block-style-variation-a.json

@@ -0,0 +1,10 @@
+{
+	"version": 3,
+	"blockTypes": [ "core/group", "core/columns" ],
+	"styles": {
+		"color": {
+			"background": "indigo",
+			"text": "plum"
+		}
+	}
+}

tests/phpunit/data/themedir1/block-theme/styles/block-style-variation-b.json

@@ -0,0 +1,10 @@
+{
+	"version": 3,
+	"blockTypes": [ "core/group", "core/columns" ],
+	"styles": {
+		"color": {
+			"background": "midnightblue",
+			"text": "lightblue"
+		}
+	}
+}