Make child themes inherit parent's style variations

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

@@ -664,33 +664,61 @@ public static function clean_cached_data() {
 		static::$i18n_schema              = null;
 	}
 
+	/**
+	 * Returns an array of all nested json files within a given directory.
+	 *
+	 * @since 6.2.0
+	 *
+	 * @param string $dir The directory to recursively iterate and list files of.
+	 * @return array The merged array.
+	 */
+	private static function recursively_iterate_json( $dir ) {
+		$nested_files      = new RecursiveIteratorIterator( new RecursiveDirectoryIterator( $dir ) );
+		$nested_json_files = iterator_to_array( new RegexIterator( $nested_files, '/^.+\.json$/i', RecursiveRegexIterator::GET_MATCH ) );
+		return $nested_json_files;
+	}
+
+
 	/**
 	 * 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.
 	 *
 	 * @return array
 	 */
 	public static function get_style_variations() {
-		$variations     = array();
-		$base_directory = get_stylesheet_directory() . '/styles';
+		$variation_files    = array();
+		$variations         = array();
+		$base_directory     = get_stylesheet_directory() . '/styles';
+		$template_directory = get_template_directory() . '/styles';
 		if ( is_dir( $base_directory ) ) {
-			$nested_files      = new RecursiveIteratorIterator( new RecursiveDirectoryIterator( $base_directory ) );
-			$nested_html_files = iterator_to_array( new RegexIterator( $nested_files, '/^.+\.json$/i', RecursiveRegexIterator::GET_MATCH ) );
-			ksort( $nested_html_files );
-			foreach ( $nested_html_files as $path => $file ) {
-				$decoded_file = wp_json_file_decode( $path, array( 'associative' => true ) );
-				if ( is_array( $decoded_file ) ) {
-					$translated = static::translate( $decoded_file, wp_get_theme()->get( 'TextDomain' ) );
-					$variation  = ( new WP_Theme_JSON( $translated ) )->get_raw_data();
-					if ( empty( $variation['title'] ) ) {
-						$variation['title'] = basename( $path, '.json' );
+			$variation_files = static::recursively_iterate_json( $base_directory );
+		}
+		if ( is_dir( $template_directory ) && $template_directory !== $base_directory ) {
+			$variation_files_parent = static::recursively_iterate_json( $template_directory );
+			// If the child and parent variation file basename are the same, only include the child theme's.
+			foreach ( $variation_files_parent as $parent_path => $parent ) {
+				foreach ( $variation_files as $child_path => $child ) {
+					if ( basename( $parent_path ) === basename( $child_path ) ) {
+						unset( $variation_files_parent[ $parent_path ] );
 					}
-					$variations[] = $variation;
 				}
 			}
+			$variation_files = array_merge( $variation_files, $variation_files_parent );
+		}
+		ksort( $variation_files );
+		foreach ( $variation_files as $path => $file ) {
+			$decoded_file = wp_json_file_decode( $path, array( 'associative' => true ) );
+			if ( is_array( $decoded_file ) ) {
+				$translated = static::translate( $decoded_file, wp_get_theme()->get( 'TextDomain' ) );
+				$variation  = ( new WP_Theme_JSON( $translated ) )->get_raw_data();
+				if ( empty( $variation['title'] ) ) {
+					$variation['title'] = basename( $path, '.json' );
+				}
+				$variations[] = $variation;
+			}
 		}
 		return $variations;
 	}
-
 }

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

@@ -0,0 +1,18 @@
+{
+	"version": 2,
+	"settings": {
+		"blocks": {
+			"core/post-title": {
+				"color": {
+					"palette": [
+						{
+							"slug": "dark",
+							"name": "Dark",
+							"color": "#010101"
+						}
+					]
+				}
+			}
+		}
+	}
+}

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

@@ -0,0 +1,18 @@
+{
+	"version": 2,
+	"settings": {
+		"blocks": {
+			"core/post-title": {
+				"color": {
+					"palette": [
+						{
+							"slug": "light",
+							"name": "Light",
+							"color": "#f1f1f1"
+						}
+					]
+				}
+			}
+		}
+	}
+}

tests/phpunit/data/themedir1/block-theme/theme.json

@@ -124,4 +124,4 @@
 			"area": "header"
 		}
 	]
-}
+}

tests/phpunit/tests/theme/wpThemeJsonResolver.php

@@ -235,7 +235,7 @@ public function test_translations_are_applied() {
 		);
 		$this->assertSame(
 			'Wariant motywu blokowego',
-			$style_variations[0]['title']
+			$style_variations[1]['title']
 		);
 	}
 
@@ -920,10 +920,10 @@ public function test_get_style_variations_returns_all_variations() {
 		$expected_settings = array(
 			array(
 				'version'  => 2,
-				'title'    => 'variation-a',
+				'title'    => 'variation-b',
 				'settings' => array(
 					'blocks' => array(
-						'core/paragraph' => array(
+						'core/post-title' => array(
 							'color' => array(
 								'palette' => array(
 									'theme' => array(
@@ -941,20 +941,25 @@ public function test_get_style_variations_returns_all_variations() {
 			),
 			array(
 				'version'  => 2,
-				'title'    => 'variation-b',
+				'title'    => 'Block theme variation',
 				'settings' => array(
+					'color' => array(
+						'palette' => array(
+							'theme' => array(
+								array(
+									'slug'  => 'foreground',
+									'name'  => 'Foreground',
+									'color' => '#3F67C6',
+								),
+							),
+						),
+					),
+				),
+				'styles' => array(
 					'blocks' => array(
 						'core/post-title' => array(
-							'color' => array(
-								'palette' => array(
-									'theme' => array(
-										array(
-											'slug'  => 'light',
-											'name'  => 'Light',
-											'color' => '#f1f1f1',
-										),
-									),
-								),
+							'typography' => array(
+								'fontWeight' => '700',
 							),
 						),
 					),