Load page templates via theme.json abstractions (#28700)

lib/class-wp-theme-json-resolver.php

@@ -24,7 +24,7 @@ class WP_Theme_JSON_Resolver {
 	 *
 	 * @var WP_Theme_JSON
 	 */
-	private $theme = null;
+	private static $theme = null;
 
 	/**
 	 * Container for data coming from the user.
@@ -258,27 +258,39 @@ private static function get_core_origin() {
 	}
 
 	/**
-	 * Returns the theme's origin config.
+	 * Returns the theme's data.
 	 *
-	 * It uses the theme support data if
-	 * the theme hasn't declared any via theme.json.
+	 * Data from theme.json can be augmented via the
+	 * $theme_support_data variable. This is useful, for example,
+	 * to backfill the gaps in theme.json that a theme has declared
+	 * via add_theme_supports.
+	 *
+	 * Note that if the same data is present in theme.json
+	 * and in $theme_support_data, the theme.json's is not overwritten.
 	 *
 	 * @param array $theme_support_data Theme support data in theme.json format.
 	 *
 	 * @return WP_Theme_JSON Entity that holds theme data.
 	 */
-	private function get_theme_origin( $theme_support_data = array() ) {
-		$theme_json_data = self::get_from_file( locate_template( 'experimental-theme.json' ) );
-		self::translate_presets( $theme_json_data, wp_get_theme()->get( 'TextDomain' ) );
+	public function get_theme_data( $theme_support_data = array() ) {
+		if ( null === self::$theme ) {
+			$theme_json_data = self::get_from_file( locate_template( 'experimental-theme.json' ) );
+			self::translate_presets( $theme_json_data, wp_get_theme()->get( 'TextDomain' ) );
+			self::$theme = new WP_Theme_JSON( $theme_json_data );
+		}
+
+		if ( empty( $theme_support_data ) ) {
+			return self::$theme;
+		}
 
 		/*
 		 * We want the presets and settings declared in theme.json
 		 * to override the ones declared via add_theme_support.
 		 */
-		$this->theme = new WP_Theme_JSON( $theme_support_data );
-		$this->theme->merge( new WP_Theme_JSON( $theme_json_data ) );
+		$with_theme_supports = new WP_Theme_JSON( $theme_support_data );
+		$with_theme_supports->merge( self::$theme );
 
-		return $this->theme;
+		return $with_theme_supports;
 	}
 
 	/**
@@ -395,15 +407,15 @@ public function get_origin( $theme_support_data = array(), $origin = 'user', $me
 		if ( ( 'user' === $origin ) && $merged ) {
 			$result = new WP_Theme_JSON();
 			$result->merge( self::get_core_origin() );
-			$result->merge( $this->get_theme_origin( $theme_support_data ) );
+			$result->merge( $this->get_theme_data( $theme_support_data ) );
 			$result->merge( self::get_user_origin() );
 			return $result;
 		}
 
 		if ( ( 'theme' === $origin ) && $merged ) {
 			$result = new WP_Theme_JSON();
 			$result->merge( self::get_core_origin() );
-			$result->merge( $this->get_theme_origin( $theme_support_data ) );
+			$result->merge( $this->get_theme_data( $theme_support_data ) );
 			return $result;
 		}
 
@@ -412,7 +424,7 @@ public function get_origin( $theme_support_data = array(), $origin = 'user', $me
 		}
 
 		if ( 'theme' === $origin ) {
-			return $this->get_theme_origin( $theme_support_data );
+			return $this->get_theme_data( $theme_support_data );
 		}
 
 		return self::get_core_origin();

lib/class-wp-theme-json.php

@@ -103,7 +103,8 @@ class WP_Theme_JSON {
 	 * }
 	 */
 	const SCHEMA = array(
-		'styles'   => array(
+		'pageTemplates' => null,
+		'styles'        => array(
 			'border'     => array(
 				'radius' => null,
 				'color'  => null,
@@ -134,7 +135,7 @@ class WP_Theme_JSON {
 				'textTransform'  => null,
 			),
 		),
-		'settings' => array(
+		'settings'      => array(
 			'border'     => array(
 				'customRadius' => null,
 				'customColor'  => null,
@@ -1050,6 +1051,19 @@ public function get_settings() {
 		}
 	}
 
+	/**
+	 * Returns the page templates of the current theme.
+	 *
+	 * @return array
+	 */
+	public function get_page_templates() {
+		if ( ! isset( $this->theme_json['pageTemplates'] ) ) {
+			return array();
+		} else {
+			return $this->theme_json['pageTemplates'];
+		}
+	}
+
 	/**
 	 * Returns the stylesheet that results of processing
 	 * the theme.json structure this object represents.

lib/full-site-editing/page-templates.php

@@ -17,17 +17,12 @@ function gutenberg_load_block_page_templates( $templates, $theme, $post ) {
 	if ( ! gutenberg_is_fse_theme() ) {
 		return $templates;
 	}
-	$config_file = locate_template( 'experimental-theme.json' );
-	if ( ! file_exists( $config_file ) ) {
-		return $templates;
-	}
-	$data           = json_decode(
-		file_get_contents( $config_file ),
-		true
-	);
+
+	$resolver       = new WP_Theme_JSON_Resolver();
+	$data           = $resolver->get_theme_data()->get_page_templates();
 	$page_templates = array();
-	if ( isset( $data['pageTemplates'] ) ) {
-		foreach ( $data['pageTemplates']  as $key => $page_template ) {
+	if ( isset( $data ) ) {
+		foreach ( $data  as $key => $page_template ) {
 			if ( ( ! isset( $page_template['postTypes'] ) && 'page' === $post->post_type ) ||
 				( isset( $page_template['postTypes'] ) && in_array( $post->post_type, $page_template['postTypes'], true ) )
 			) {

lib/load.php

@@ -91,6 +91,12 @@ function gutenberg_is_experiment_enabled( $name ) {
 if ( ! class_exists( 'WP_Block_Template ' ) ) {
 	require __DIR__ . '/full-site-editing/class-wp-block-template.php';
 }
+
+// These are used by some FSE features
+// as well as global styles.
+require __DIR__ . '/class-wp-theme-json.php';
+require __DIR__ . '/class-wp-theme-json-resolver.php';
+
 require __DIR__ . '/full-site-editing/full-site-editing.php';
 require __DIR__ . '/full-site-editing/block-templates.php';
 require __DIR__ . '/full-site-editing/default-template-types.php';
@@ -109,8 +115,6 @@ function gutenberg_is_experiment_enabled( $name ) {
 require __DIR__ . '/navigation.php';
 require __DIR__ . '/navigation-page.php';
 require __DIR__ . '/experiments-page.php';
-require __DIR__ . '/class-wp-theme-json.php';
-require __DIR__ . '/class-wp-theme-json-resolver.php';
 require __DIR__ . '/global-styles.php';
 require __DIR__ . '/query-utils.php';
 

phpunit/class-wp-theme-json-test.php

@@ -736,4 +736,27 @@ function test_remove_insecure_properties_removes_unsafe_preset_settings() {
 		);
 		$this->assertEqualSetsWithIndex( $expected, $result );
 	}
+
+	function test_get_page_templates() {
+		$theme_json = new WP_Theme_JSON(
+			array(
+				'pageTemplates' => array(
+					'page-home' => array(
+						'title' => 'Some title',
+					),
+				),
+			)
+		);
+
+		$page_templates = $theme_json->get_page_templates();
+
+		$this->assertEqualSetsWithIndex(
+			$page_templates,
+			array(
+				'page-home' => array(
+					'title' => 'Some title',
+				),
+			)
+		);
+	}
 }