Backport theme.json version 3 migrations

src/wp-includes/block-editor.php

@@ -814,6 +814,7 @@ function get_block_editor_theme_styles() {
  * Returns the classic theme supports settings for block editor.
  *
  * @since 6.2.0
+ * @since 6.6.0 Add support for 'editor-spacing-sizes' theme support.
  *
  * @return array The classic theme supports settings.
  */
@@ -844,5 +845,10 @@ function get_classic_theme_supports_block_editor_settings() {
 		$theme_settings['gradients'] = $gradient_presets;
 	}
 
+	$spacing_sizes = current( (array) get_theme_support( 'editor-spacing-sizes' ) );
+	if ( false !== $spacing_sizes ) {
+		$theme_settings['spacingSizes'] = $spacing_sizes;
+	}
+
 	return $theme_settings;
 }

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

@@ -39,7 +39,7 @@ class WP_Theme_JSON_Data {
 	 * @param array  $data   Array following the theme.json specification.
 	 * @param string $origin The origin of the data: default, theme, user.
 	 */
-	public function __construct( $data = array(), $origin = 'theme' ) {
+	public function __construct( $data = array( 'version' => WP_Theme_JSON::LATEST_SCHEMA ), $origin = 'theme' ) {
 		$this->origin     = $origin;
 		$this->theme_json = new WP_Theme_JSON( $data, $this->origin );
 	}

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

@@ -220,6 +220,7 @@ protected static function has_same_registered_blocks( $origin ) {
 	 * @since 5.8.0
 	 * @since 5.9.0 Theme supports have been inlined and the `$theme_support_data` argument removed.
 	 * @since 6.0.0 Added an `$options` parameter to allow the theme data to be returned without theme supports.
+	 * @since 6.6.0 Add support for 'default-font-sizes' and 'default-spacing-sizes' theme supports.
 	 *
 	 * @param array $deprecated Deprecated. Not used.
 	 * @param array $options {
@@ -243,7 +244,7 @@ public static function get_theme_data( $deprecated = array(), $options = array()
 				$theme_json_data = static::read_json_file( $theme_json_file );
 				$theme_json_data = static::translate( $theme_json_data, $wp_theme->get( 'TextDomain' ) );
 			} else {
-				$theme_json_data = array();
+				$theme_json_data = array( 'version' => WP_Theme_JSON::LATEST_SCHEMA );
 			}
 
 			/**
@@ -310,6 +311,32 @@ public static function get_theme_data( $deprecated = array(), $options = array()
 			}
 			$theme_support_data['settings']['color']['defaultGradients'] = $default_gradients;
 
+			if ( ! isset( $theme_support_data['settings']['typography'] ) ) {
+				$theme_support_data['settings']['typography'] = array();
+			}
+			$default_font_sizes = false;
+			if ( current_theme_supports( 'default-font-sizes' ) ) {
+				$default_font_sizes = true;
+			}
+			if ( ! isset( $theme_support_data['settings']['typography']['fontSizes'] ) ) {
+				// If the theme does not have any font sizes, we still want to show the core one.
+				$default_font_sizes = true;
+			}
+			$theme_support_data['settings']['typography']['defaultFontSizes'] = $default_font_sizes;
+
+			if ( ! isset( $theme_support_data['settings']['spacing'] ) ) {
+				$theme_support_data['settings']['spacing'] = array();
+			}
+			$default_spacing_sizes = false;
+			if ( current_theme_supports( 'default-spacing-sizes' ) ) {
+				$default_spacing_sizes = true;
+			}
+			if ( ! isset( $theme_support_data['settings']['spacing']['spacingSizes'] ) ) {
+				// If the theme does not have any spacing sizes, we still want to show the core one.
+				$default_spacing_sizes = true;
+			}
+			$theme_support_data['settings']['spacing']['defaultSpacingSizes'] = $default_spacing_sizes;
+
 			if ( ! isset( $theme_support_data['settings']['shadow'] ) ) {
 				$theme_support_data['settings']['shadow'] = array();
 			}
@@ -359,7 +386,7 @@ public static function get_block_data() {
 			return static::$blocks;
 		}
 
-		$config = array( 'version' => 2 );
+		$config = array( 'version' => WP_Theme_JSON::LATEST_SCHEMA );
 		foreach ( $blocks as $block_name => $block_type ) {
 			if ( isset( $block_type->supports['__experimentalStyle'] ) ) {
 				$config['styles']['blocks'][ $block_name ] = static::remove_json_comments( $block_type->supports['__experimentalStyle'] );
@@ -494,6 +521,7 @@ public static function get_user_data_from_wp_global_styles( $theme, $create_post
 	 * Returns the user's origin config.
 	 *
 	 * @since 5.9.0
+	 * @since 6.6.0 The 'isGlobalStylesUserThemeJSON' flag is left on the user data.
 	 *
 	 * @return WP_Theme_JSON Entity that holds styles for user data.
 	 */
@@ -531,14 +559,18 @@ public static function get_user_data() {
 				isset( $decoded_data['isGlobalStylesUserThemeJSON'] ) &&
 				$decoded_data['isGlobalStylesUserThemeJSON']
 			) {
-				unset( $decoded_data['isGlobalStylesUserThemeJSON'] );
 				$config = $decoded_data;
 			}
 		}
 
 		/** This filter is documented in wp-includes/class-wp-theme-json-resolver.php */
-		$theme_json   = apply_filters( 'wp_theme_json_data_user', new WP_Theme_JSON_Data( $config, 'custom' ) );
-		static::$user = $theme_json->get_theme_json();
+		$theme_json = apply_filters( 'wp_theme_json_data_user', new WP_Theme_JSON_Data( $config, 'custom' ) );
+		$config     = $theme_json->get_data();
+
+		// Needs to be set for schema migrations of user data.
+		$config['isGlobalStylesUserThemeJSON'] = true;
+
+		static::$user = new WP_Theme_JSON( $config, 'custom' );
 
 		return static::$user;
 	}
@@ -586,7 +618,6 @@ public static function get_merged_data( $origin = 'custom' ) {
 		$result = new WP_Theme_JSON();
 		$result->merge( static::get_core_data() );
 		if ( 'default' === $origin ) {
-			$result->set_spacing_sizes();
 			return $result;
 		}
 
@@ -597,12 +628,10 @@ public static function get_merged_data( $origin = 'custom' ) {
 
 		$result->merge( static::get_theme_data() );
 		if ( 'theme' === $origin ) {
-			$result->set_spacing_sizes();
 			return $result;
 		}
 
 		$result->merge( static::get_user_data() );
-		$result->set_spacing_sizes();
 
 		return $result;
 	}

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

@@ -35,6 +35,7 @@ class WP_Theme_JSON_Schema {
 	 * Function that migrates a given theme.json structure to the last version.
 	 *
 	 * @since 5.9.0
+	 * @since 6.6.0 Migrate up to v3.
 	 *
 	 * @param array $theme_json The structure to migrate.
 	 *
@@ -47,8 +48,14 @@ public static function migrate( $theme_json ) {
 			);
 		}
 
-		if ( 1 === $theme_json['version'] ) {
-			$theme_json = self::migrate_v1_to_v2( $theme_json );
+		// Migrate each version in order starting with the current version.
+		switch ( $theme_json['version'] ) {
+			case 1:
+				$theme_json = self::migrate_v1_to_v2( $theme_json );
+				// no break
+			case 2:
+				$theme_json = self::migrate_v2_to_v3( $theme_json );
+				// no break
 		}
 
 		return $theme_json;
@@ -84,6 +91,88 @@ private static function migrate_v1_to_v2( $old ) {
 		return $new;
 	}
 
+	/**
+	 * Migrates from v2 to v3.
+	 *
+	 * - Sets settings.typography.defaultFontSizes to false.
+	 *
+	 * @since 6.6.0
+	 *
+	 * @param array $old Data to migrate.
+	 *
+	 * @return array Data with defaultFontSizes set to false.
+	 */
+	private static function migrate_v2_to_v3( $old ) {
+		// Copy everything.
+		$new = $old;
+
+		// Set the new version.
+		$new['version'] = 3;
+
+		/*
+		 * Remaining changes do not need to be applied to the custom origin,
+		 * as they should take on the value of the theme origin.
+		 */
+		if (
+			isset( $new['isGlobalStylesUserThemeJSON'] ) &&
+			true === $new['isGlobalStylesUserThemeJSON']
+		) {
+			return $new;
+		}
+
+		/*
+		 * Even though defaultFontSizes and defaultSpacingSizes are new
+		 * settings, we need to migrate them as they each control
+		 * PRESETS_METADATA prevent_override values which were previously
+		 * hardcoded to false. This only needs to happen when the theme provides
+		 * fontSizes or spacingSizes as they could match the default ones and
+		 * affect the generated CSS.
+		 */
+		if ( isset( $old['settings']['typography']['fontSizes'] ) ) {
+			if ( ! isset( $new['settings'] ) ) {
+				$new['settings'] = array();
+			}
+			if ( ! isset( $new['settings']['typography'] ) ) {
+				$new['settings']['typography'] = array();
+			}
+			$new['settings']['typography']['defaultFontSizes'] = false;
+		}
+
+		/*
+		 * Similarly to defaultFontSizes, we need to migrate defaultSpacingSizes
+		 * as it controls the PRESETS_METADATA prevent_override which was
+		 * previously hardcoded to false. This only needs to happen when the
+		 * theme provided spacing sizes via spacingSizes or spacingScale.
+		 */
+		if (
+			isset( $old['settings']['spacing']['spacingSizes'] ) ||
+			isset( $old['settings']['spacing']['spacingScale'] )
+		) {
+			if ( ! isset( $new['settings'] ) ) {
+				$new['settings'] = array();
+			}
+			if ( ! isset( $new['settings']['spacing'] ) ) {
+				$new['settings']['spacing'] = array();
+			}
+			$new['settings']['spacing']['defaultSpacingSizes'] = false;
+		}
+
+		/*
+		 * In v3 spacingSizes is merged with the generated spacingScale sizes
+		 * instead of completely replacing them. The v3 behavior is what was
+		 * documented for the v2 schema, but the code never actually did work
+		 * that way. Instead of surprising users with a behavior change two
+		 * years after the fact at the same time as a v3 update is introduced,
+		 * we'll continue using the "bugged" behavior for v2 themes. And treat
+		 * the "bug fix" as a breaking change for v3.
+		 */
+		if ( isset( $old['settings']['spacing']['spacingSizes'] ) ) {
+			unset( $new['settings']['spacing']['spacingScale'] );
+		}
+
+		return $new;
+	}
+
 	/**
 	 * Processes the settings subtree.
 	 *