FSE: Allow child theme.json to be merged with parent theme.json (#35459)

* FSE: Allow child theme.json to be merged with parent theme.json * Update lib/class-wp-theme-json-resolver-gutenberg.php Co-authored-by: Ari Stathopoulos <aristath@gmail.com> * add a claifying comment * Update lib/class-wp-theme-json-resolver-gutenberg.php Co-authored-by: George Mamadashvili <georgemamadashvili@gmail.com> * Update lib/class-wp-theme-json-resolver-gutenberg.php Co-authored-by: George Mamadashvili <georgemamadashvili@gmail.com> * Fix lint error * Add directory flag to get_file_path_from_theme method Only use get_theme_file_path in theme_has_support check * Add unit tests for merging Co-authored-by: Ari Stathopoulos <aristath@gmail.com> Co-authored-by: George Mamadashvili <georgemamadashvili@gmail.com>
WordPress · Oct 18, 2021 · 9953bfc · 9953bfc
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commit 9953bfc
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Showing 4 changed files with 137 additions and 8 deletions.
diff --git a/lib/class-wp-theme-json-resolver-gutenberg.php b/lib/class-wp-theme-json-resolver-gutenberg.php
@@ -274,6 +274,18 @@ public static function get_theme_data( $theme_support_data = array() ) {
 			$theme_json_data = self::read_json_file( self::get_file_path_from_theme( 'theme.json' ) );
 			$theme_json_data = self::translate( $theme_json_data, wp_get_theme()->get( 'TextDomain' ) );
 			self::$theme     = new WP_Theme_JSON_Gutenberg( $theme_json_data );
+
+			if ( wp_get_theme()->parent() ) {
+				// Get parent theme.json.
+				$parent_theme_json_data = self::read_json_file( self::get_file_path_from_theme( 'theme.json', true ) );
+				$parent_theme_json_data = self::translate( $parent_theme_json_data, wp_get_theme()->parent()->get( 'TextDomain' ) );
+				$parent_theme           = new WP_Theme_JSON_Gutenberg( $parent_theme_json_data );
+
+				// Merge the child theme.json into the parent theme.json.
+				// The child theme takes precedence over the parent.
+				$parent_theme->merge( self::$theme );
+				self::$theme = $parent_theme;
+			}
 		}
 
 		if ( empty( $theme_support_data ) ) {
@@ -476,7 +488,7 @@ public static function get_user_custom_post_type_id() {
 	 */
 	public static function theme_has_support() {
 		if ( ! isset( self::$theme_has_support ) ) {
-			self::$theme_has_support = (bool) self::get_file_path_from_theme( 'theme.json' );
+			self::$theme_has_support = is_readable( get_theme_file_path( 'theme.json' ) );
 		}
 
 		return self::$theme_has_support;
@@ -490,15 +502,14 @@ public static function theme_has_support() {
 	 * otherwise returns the whole file path.
 	 *
 	 * @param string $file_name Name of the file.
+	 * @param bool   $template  Use template theme directroy. Default: false.
 	 * @return string The whole file path or empty if the file doesn't exist.
 	 */
-	private static function get_file_path_from_theme( $file_name ) {
-		$located   = '';
-		$candidate = get_theme_file_path( $file_name );
-		if ( is_readable( $candidate ) ) {
-			$located = $candidate;
-		}
-		return $located;
+	private static function get_file_path_from_theme( $file_name, $template = false ) {
+		$path      = $template ? get_template_directory() : get_stylesheet_directory();
+		$candidate = $path . '/' . $file_name;
+
+		return is_readable( $candidate ) ? $candidate : '';
 	}
 
 	/**

diff --git a/phpunit/class-wp-theme-json-resolver-test.php b/phpunit/class-wp-theme-json-resolver-test.php
@@ -255,4 +255,63 @@ function test_add_theme_supports_are_loaded_for_themes_without_theme_json() {
 		$this->assertSame( $color_palette, $settings['color']['palette']['theme'] );
 	}
 
+	function test_merges_child_theme_json_into_parent_theme_json() {
+		switch_theme( 'fse-child' );
+
+		$actual = WP_Theme_JSON_Resolver_Gutenberg::get_theme_data();
+
+		// Should merge settings.
+		$this->assertSame(
+			array(
+				'color'  => array(
+					'palette' => array(
+						'theme' => array(
+							array(
+								'slug'  => 'light',
+								'name'  => 'Light',
+								'color' => '#f3f4f6',
+							),
+							array(
+								'slug'  => 'primary',
+								'name'  => 'Primary',
+								'color' => '#3858e9',
+							),
+							array(
+								'slug'  => 'dark',
+								'name'  => 'Dark',
+								'color' => '#111827',
+							),
+						),
+					),
+					'custom'  => true,
+				),
+				'blocks' => array(
+					'core/paragraph' => array(
+						'color' => array(
+							'palette' => array(
+								'theme' => array(
+									array(
+										'slug'  => 'light',
+										'name'  => 'Light',
+										'color' => '#f3f4f6',
+									),
+								),
+							),
+						),
+					),
+				),
+			),
+			$actual->get_settings()
+		);
+
+		$this->assertSame(
+			$actual->get_custom_templates(),
+			array(
+				'page-home' => array(
+					'title'     => 'Homepage',
+					'postTypes' => array( 'page' ),
+				),
+			)
+		);
+	}
 }
diff --git a/phpunit/data/themedir1/fse-child/style.css b/phpunit/data/themedir1/fse-child/style.css
@@ -0,0 +1,8 @@
+/*
+Theme Name: FSE Child Theme
+Theme URI: https://wordpress.org/
+Description: For testing purposes only.
+Template: fse
+Version: 1.0.0
+Text Domain: fse-child
+*/
diff --git a/phpunit/data/themedir1/fse-child/theme.json b/phpunit/data/themedir1/fse-child/theme.json
@@ -0,0 +1,51 @@
+{
+	"version": 1,
+	"settings": {
+		"color": {
+			"palette": [
+				{
+					"slug": "light",
+					"name": "Light",
+					"color": "#f3f4f6"
+				},
+				{
+					"slug": "primary",
+					"name": "Primary",
+					"color": "#3858e9"
+				},
+				{
+					"slug": "dark",
+					"name": "Dark",
+					"color": "#111827"
+				}
+			],
+			"custom": true
+		},
+		"blocks": {
+			"core/paragraph": {
+				"color": {
+					"palette": [
+						{
+							"slug": "light",
+							"name": "Light",
+							"color": "#f3f4f6"
+						}
+					]
+				}
+			}
+		}
+	},
+	"customTemplates": [
+		{
+			"name": "page-home",
+			"title": "Homepage"
+		}
+	],
+	"templateParts": [
+		{
+			"name": "small-header",
+			"title": "Small Header",
+			"area": "header"
+		}
+	]
+}