REST API: Ensure empty meta is returned as an object in view context

Author: liaisontw

src/wp-includes/rest-api/endpoints/class-wp-rest-blocks-controller.php

@@ -58,8 +58,15 @@ public function filter_response_by_context( $data, $context ) {
 		unset( $data['content']['rendered'] );
 
 		// Add the core wp_pattern_sync_status meta as top level property to the response.
-		$data['wp_pattern_sync_status'] = $data['meta']['wp_pattern_sync_status'] ?? '';
-		unset( $data['meta']['wp_pattern_sync_status'] );
+		$meta                           = (array) $data['meta'];
+		$data['wp_pattern_sync_status'] = $meta['wp_pattern_sync_status'] ?? '';
+
+		if ( is_object( $data['meta'] ) ) {
+			unset( $data['meta']->wp_pattern_sync_status );
+		} else {
+			unset( $data['meta']['wp_pattern_sync_status'] );
+		}
+
 		return $data;
 	}
 

src/wp-includes/rest-api/fields/class-wp-rest-meta-fields.php

@@ -74,7 +74,8 @@ public function register_field() {
 	 *
 	 * @param int             $object_id Object ID to fetch meta for.
 	 * @param WP_REST_Request $request   Full details about the request.
-	 * @return array Array containing the meta values keyed by name.
+	 * @return array|object Array containing the meta values keyed by name,
+	 *                      or an empty object if to ensure JSON object encoding.
 	 */
 	public function get_value( $object_id, $request ) {
 		$fields   = $this->get_registered_fields();
@@ -105,6 +106,11 @@ public function get_value( $object_id, $request ) {
 			$response[ $name ] = $value;
 		}
 
+		// Use stdClass so that JSON result is {} and not [].
+		if ( empty( $response ) ) {
+			return (object) array();
+		}
+
 		return $response;
 	}
 
@@ -582,6 +588,10 @@ public static function prepare_value( $value, $request, $args ) {
 	 * @return array|false The meta array, if valid, false otherwise.
 	 */
 	public function check_meta_is_array( $value, $request, $param ) {
+		if ( is_object( $value ) ) {
+			$value = (array) $value;
+		}
+
 		if ( ! is_array( $value ) ) {
 			return false;
 		}