Themes: Introduce wp_theme_has_theme_json() for public consumption.

Adds `wp_theme_has_theme_json()` for public consumption, to replace the private internal Core-only `WP_Theme_JSON_Resolver::theme_has_support()` method. This new global function checks if a theme or its parent has a `theme.json` file.

For performance, results are cached as an integer `1` or `0` in the `'theme_json'` group with `'wp_theme_has_theme_json'` key. This is a non-persistent cache. Why? To make the derived data from `theme.json` is always fresh from the potential modifications done via hooks that can use dynamic data (modify the stylesheet depending on some option, settings depending on user permissions, etc.).

Also adds a new public function `wp_clean_theme_json_cache()` to clear the cache on `'switch_theme'` and `start_previewing_theme'`.

References:
* [WordPress/gutenberg#45168 Gutenberg PR 45168] Add `wp_theme_has_theme_json` as a public API to know whether a theme has a `theme.json`.
* [WordPress/gutenberg#45380 Gutenberg PR 45380] Deprecate `WP_Theme_JSON_Resolver:theme_has_support()`.
* [WordPress/gutenberg#46150 Gutenberg PR 46150] Make `theme.json` object caches non-persistent.
* [WordPress/gutenberg#45979 Gutenberg PR 45979] Don't check if constants set by `wp_initial_constants()` are defined.
* [WordPress/gutenberg#45950 Gutenberg PR 45950] Cleaner logic in `wp_theme_has_theme_json`.

Follow-up to [54493], [53282], [52744], [52049], [50959].

Props oandregal, afragen, alexstine, aristath, azaozz, costdev, flixos90, hellofromTonya, mamaduka, mcsf, ocean90, spacedmonkey.
Fixes #56975.

git-svn-id: https://develop.svn.wordpress.org/trunk@55086 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/edit-form-blocks.php

@@ -203,7 +203,7 @@ static function( $classes ) {
 		'unlockNonce' => wp_create_nonce( 'update-post_' . $post->ID ),
 		'ajaxUrl'     => admin_url( 'admin-ajax.php' ),
 	),
-	'supportsLayout'       => WP_Theme_JSON_Resolver::theme_has_support(),
+	'supportsLayout'       => wp_theme_has_theme_json(),
 	'supportsTemplateMode' => current_theme_supports( 'block-templates' ),
 
 	// Whether or not to load the 'postcustom' meta box is stored as a user meta

src/wp-admin/site-editor.php

@@ -74,7 +74,7 @@ static function( $classes ) {
 	'styles'                    => get_block_editor_theme_styles(),
 	'defaultTemplateTypes'      => $indexed_template_types,
 	'defaultTemplatePartAreas'  => get_allowed_block_template_part_areas(),
-	'supportsLayout'            => WP_Theme_JSON_Resolver::theme_has_support(),
+	'supportsLayout'            => wp_theme_has_theme_json(),
 	'supportsTemplatePartsMode' => ! wp_is_block_theme() && current_theme_supports( 'block-template-parts' ),
 	'__unstableHomeTemplate'    => $home_template,
 );

src/wp-includes/block-editor.php

@@ -417,7 +417,7 @@ function get_block_editor_settings( array $custom_settings, $block_editor_contex
 		}
 	}
 
-	if ( WP_Theme_JSON_Resolver::theme_has_support() ) {
+	if ( wp_theme_has_theme_json() ) {
 		$block_classes = array(
 			'css'            => 'styles',
 			'__unstableType' => 'theme',

src/wp-includes/block-patterns.php

@@ -139,7 +139,7 @@ function _register_remote_theme_patterns() {
 		return;
 	}
 
-	if ( ! WP_Theme_JSON_Resolver::theme_has_support() ) {
+	if ( ! wp_theme_has_theme_json() ) {
 		return;
 	}
 

src/wp-includes/block-supports/layout.php

@@ -464,7 +464,7 @@ function wp_restore_group_inner_container( $block_content, $block ) {
 	);
 
 	if (
-		WP_Theme_JSON_Resolver::theme_has_support() ||
+		wp_theme_has_theme_json() ||
 		1 === preg_match( $group_with_inner_container_regex, $block_content ) ||
 		( isset( $block['attrs']['layout']['type'] ) && 'flex' === $block['attrs']['layout']['type'] )
 	) {
@@ -527,7 +527,7 @@ function wp_restore_image_outer_container( $block_content, $block ) {
 )/iUx";
 
 	if (
-		WP_Theme_JSON_Resolver::theme_has_support() ||
+		wp_theme_has_theme_json() ||
 		0 === preg_match( $image_with_align, $block_content, $matches )
 	) {
 		return $block_content;

src/wp-includes/block-template-utils.php

@@ -347,7 +347,7 @@ function _get_block_templates_files( $template_type ) {
  * @return array Template item.
  */
 function _add_block_template_info( $template_item ) {
-	if ( ! WP_Theme_JSON_Resolver::theme_has_support() ) {
+	if ( ! wp_theme_has_theme_json() ) {
 		return $template_item;
 	}
 
@@ -370,7 +370,7 @@ function _add_block_template_info( $template_item ) {
  * @return array Template info.
  */
 function _add_block_template_part_area_info( $template_info ) {
-	if ( WP_Theme_JSON_Resolver::theme_has_support() ) {
+	if ( wp_theme_has_theme_json() ) {
 		$theme_data = WP_Theme_JSON_Resolver::get_theme_data( array(), array( 'with_supports' => false ) )->get_template_parts();
 	}
 

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

@@ -57,14 +57,6 @@ class WP_Theme_JSON_Resolver {
 	 */
 	protected static $theme = null;
 
-	/**
-	 * Whether or not the theme supports theme.json.
-	 *
-	 * @since 5.8.0
-	 * @var bool
-	 */
-	protected static $theme_has_support = null;
-
 	/**
 	 * Container for data coming from the user.
 	 *
@@ -295,7 +287,7 @@ public static function get_theme_data( $deprecated = array(), $options = array()
 		 * and merge the static::$theme upon that.
 		 */
 		$theme_support_data = WP_Theme_JSON::get_from_editor_settings( get_default_block_editor_settings() );
-		if ( ! static::theme_has_support() ) {
+		if ( ! wp_theme_has_theme_json() ) {
 			if ( ! isset( $theme_support_data['settings']['color'] ) ) {
 				$theme_support_data['settings']['color'] = array();
 			}
@@ -421,11 +413,11 @@ public static function get_user_data_from_wp_global_styles( $theme, $create_post
 		/*
 		 * Bail early if the theme does not support a theme.json.
 		 *
-		 * Since WP_Theme_JSON_Resolver::theme_has_support() only supports the active
+		 * Since wp_theme_has_theme_json() only supports the active
 		 * theme, the extra condition for whether $theme is the active theme is
 		 * present here.
 		 */
-		if ( $theme->get_stylesheet() === get_stylesheet() && ! static::theme_has_support() ) {
+		if ( $theme->get_stylesheet() === get_stylesheet() && ! wp_theme_has_theme_json() ) {
 			return array();
 		}
 
@@ -602,18 +594,14 @@ public static function get_user_global_styles_post_id() {
 	 *
 	 * @since 5.8.0
 	 * @since 5.9.0 Added a check in the parent theme.
+	 * @deprecated 6.2.0 Use wp_theme_has_theme_json() instead.
 	 *
 	 * @return bool
 	 */
 	public static function theme_has_support() {
-		if ( ! isset( static::$theme_has_support ) ) {
-			static::$theme_has_support = (
-				static::get_file_path_from_theme( 'theme.json' ) !== '' ||
-				static::get_file_path_from_theme( 'theme.json', true ) !== ''
-			);
-		}
+		_deprecated_function( __METHOD__, '6.2.0', 'wp_theme_has_theme_json()' );
 
-		return static::$theme_has_support;
+		return wp_theme_has_theme_json();
 	}
 
 	/**
@@ -656,7 +644,6 @@ public static function clean_cached_data() {
 		static::$theme                    = null;
 		static::$user                     = null;
 		static::$user_custom_post_type_id = null;
-		static::$theme_has_support        = null;
 		static::$i18n_schema              = null;
 	}
 

src/wp-includes/default-filters.php

@@ -346,8 +346,8 @@
 add_action( 'init', '_register_core_block_patterns_and_categories' );
 add_action( 'init', 'check_theme_switched', 99 );
 add_action( 'init', array( 'WP_Block_Supports', 'init' ), 22 );
-add_action( 'switch_theme', array( 'WP_Theme_JSON_Resolver', 'clean_cached_data' ) );
-add_action( 'start_previewing_theme', array( 'WP_Theme_JSON_Resolver', 'clean_cached_data' ) );
+add_action( 'switch_theme', 'wp_clean_theme_json_cache' );
+add_action( 'start_previewing_theme', 'wp_clean_theme_json_cache' );
 add_action( 'after_switch_theme', '_wp_menus_changed' );
 add_action( 'after_switch_theme', '_wp_sidebars_changed' );
 add_action( 'wp_print_styles', 'print_emoji_styles' );

src/wp-includes/global-styles-and-settings.php

@@ -102,7 +102,7 @@ function wp_get_global_stylesheet( $types = array() ) {
 
 	$tree = WP_Theme_JSON_Resolver::get_merged_data();
 
-	$supports_theme_json = WP_Theme_JSON_Resolver::theme_has_support();
+	$supports_theme_json = wp_theme_has_theme_json();
 	if ( empty( $types ) && ! $supports_theme_json ) {
 		$types = array( 'variables', 'presets', 'base-layout-styles' );
 	} elseif ( empty( $types ) ) {
@@ -184,7 +184,7 @@ function wp_get_global_styles_svg_filters() {
 		}
 	}
 
-	$supports_theme_json = WP_Theme_JSON_Resolver::theme_has_support();
+	$supports_theme_json = wp_theme_has_theme_json();
 
 	$origins = array( 'default', 'theme', 'custom' );
 	if ( ! $supports_theme_json ) {
@@ -255,3 +255,72 @@ function ( $item ) {
 		}
 	}
 }
+
+/**
+ * Checks whether a theme or its parent has a theme.json file.
+ *
+ * @since 6.2.0
+ *
+ * @return bool Returns true if theme or its parent has a theme.json file, false otherwise.
+ */
+function wp_theme_has_theme_json() {
+	/*
+	 * By using the 'theme_json' group, this data is marked to be non-persistent across requests.
+	 * @see `wp_cache_add_non_persistent_groups()`.
+	 *
+	 * The rationale for this is to make sure derived data from theme.json
+	 * is always fresh from the potential modifications done via hooks
+	 * that can use dynamic data (modify the stylesheet depending on some option,
+	 * settings depending on user permissions, etc.).
+	 * For some of the existing hooks to modify theme.json behavior:
+	 * @see https://make.wordpress.org/core/2022/10/10/filters-for-theme-json-data/
+	 *
+	 * A different alternative considered was to invalidate the cache upon certain
+	 * events such as options add/update/delete, user meta, etc.
+	 * It was judged not enough, hence this approach.
+	 * @see https://github.com/WordPress/gutenberg/pull/45372
+	 */
+	$cache_group       = 'theme_json';
+	$cache_key         = 'wp_theme_has_theme_json';
+	$theme_has_support = wp_cache_get( $cache_key, $cache_group );
+
+	/*
+	 * $theme_has_support is stored as an int in the cache.
+	 *
+	 * The reason not to store it as a boolean is to avoid working
+	 * with the $found parameter which apparently had some issues in some implementations
+	 * @see https://developer.wordpress.org/reference/functions/wp_cache_get/
+	 *
+	 * Ignore cache when `WP_DEBUG` is enabled, so it doesn't interfere with the theme
+	 * developer's workflow.
+	 *
+	 * @todo Replace `WP_DEBUG` once an "in development mode" check is available in Core.
+	 */
+	if ( ! WP_DEBUG && is_int( $theme_has_support ) ) {
+		return (bool) $theme_has_support;
+	}
+
+	// Does the theme have its own theme.json?
+	$theme_has_support = is_readable( get_stylesheet_directory() . '/theme.json' );
+
+	// Look up the parent if the child does not have a theme.json.
+	if ( ! $theme_has_support ) {
+		$theme_has_support = is_readable( get_template_directory() . '/theme.json' );
+	}
+
+	$theme_has_support = $theme_has_support ? 1 : 0;
+
+	wp_cache_set( $cache_key, $theme_has_support, $cache_group );
+
+	return (bool) $theme_has_support;
+}
+
+/**
+ * Cleans the caches under the theme_json group.
+ *
+ * @since 6.2.0
+ */
+function wp_clean_theme_json_cache() {
+	wp_cache_delete( 'wp_theme_has_theme_json', 'theme_json' );
+	WP_Theme_JSON_Resolver::clean_cached_data();
+}

src/wp-includes/load.php

@@ -753,7 +753,7 @@ function wp_start_object_cache() {
 			)
 		);
 
-		wp_cache_add_non_persistent_groups( array( 'counts', 'plugins' ) );
+		wp_cache_add_non_persistent_groups( array( 'counts', 'plugins', 'theme_json' ) );
 	}
 
 	$first_init = false;

src/wp-includes/ms-blogs.php

@@ -575,7 +575,7 @@ function switch_to_blog( $new_blog_id, $deprecated = null ) {
 				);
 			}
 
-			wp_cache_add_non_persistent_groups( array( 'counts', 'plugins' ) );
+			wp_cache_add_non_persistent_groups( array( 'counts', 'plugins', 'theme_json' ) );
 		}
 	}
 
@@ -666,7 +666,7 @@ function restore_current_blog() {
 				);
 			}
 
-			wp_cache_add_non_persistent_groups( array( 'counts', 'plugins' ) );
+			wp_cache_add_non_persistent_groups( array( 'counts', 'plugins', 'theme_json' ) );
 		}
 	}
 

src/wp-includes/script-loader.php

@@ -1620,7 +1620,7 @@ function wp_default_styles( $styles ) {
 	);
 
 	// Only load the default layout and margin styles for themes without theme.json file.
-	if ( ! WP_Theme_JSON_Resolver::theme_has_support() ) {
+	if ( ! wp_theme_has_theme_json() ) {
 		$wp_edit_blocks_dependencies[] = 'wp-editor-classic-layout-styles';
 	}
 
@@ -3667,7 +3667,7 @@ function _wp_theme_json_webfonts_handler() {
  * @since 6.1.0
  */
 function wp_enqueue_classic_theme_styles() {
-	if ( ! WP_Theme_JSON_Resolver::theme_has_support() ) {
+	if ( ! wp_theme_has_theme_json() ) {
 		$suffix = wp_scripts_get_suffix();
 		wp_register_style( 'classic-theme-styles', '/' . WPINC . "/css/classic-themes$suffix.css", array(), true );
 		wp_enqueue_style( 'classic-theme-styles' );
@@ -3685,7 +3685,7 @@ function wp_enqueue_classic_theme_styles() {
  * @return array A filtered array of editor settings.
  */
 function wp_add_editor_classic_theme_styles( $editor_settings ) {
-	if ( WP_Theme_JSON_Resolver::theme_has_support() ) {
+	if ( wp_theme_has_theme_json() ) {
 		return $editor_settings;
 	}
 

src/wp-includes/theme-templates.php

@@ -209,7 +209,7 @@ function the_block_template_skip_link() {
  * @since 5.8.0
  */
 function wp_enable_block_templates() {
-	if ( wp_is_block_theme() || WP_Theme_JSON_Resolver::theme_has_support() ) {
+	if ( wp_is_block_theme() || wp_theme_has_theme_json() ) {
 		add_theme_support( 'block-templates' );
 	}
 }

tests/phpunit/data/themedir1/block-theme-child-no-theme-json/style.css

@@ -0,0 +1,8 @@
+/*
+Theme Name: Block Theme Child with no theme.json
+Theme URI: https://wordpress.org/
+Description: For testing purposes only.
+Template: block-theme
+Version: 1.0.0
+Text Domain: block-theme-child-no-theme-json
+*/

tests/phpunit/data/themedir1/default-child-no-theme-json/style.css

@@ -0,0 +1,8 @@
+/*
+Theme Name: Default Child Theme with no theme.json
+Theme URI: https://wordpress.org/
+Description: For testing purposes only.
+Template: default
+Version: 1.0.0
+Text Domain: default-child-no-theme-json
+*/

tests/phpunit/includes/abstract-testcase.php

@@ -401,7 +401,7 @@ public static function flush_cache() {
 			)
 		);
 
-		wp_cache_add_non_persistent_groups( array( 'counts', 'plugins' ) );
+		wp_cache_add_non_persistent_groups( array( 'counts', 'plugins', 'theme_json' ) );
 	}
 
 	/**

tests/phpunit/tests/theme/themeDir.php

@@ -163,6 +163,7 @@ public function test_theme_list() {
 		$theme_names = array_keys( $themes );
 		$expected    = array(
 			'WordPress Default',
+			'Default Child Theme with no theme.json',
 			'Sandbox',
 			'Stylesheet Only',
 			'My Theme',
@@ -177,6 +178,7 @@ public function test_theme_list() {
 			'REST Theme',
 			'Block Theme',
 			'Block Theme Child Theme',
+			'Block Theme Child with no theme.json',
 			'Block Theme Child Theme With Fluid Typography',
 			'Block Theme [0.4.0]',
 			'Block Theme [1.0.0] in subdirectory',