Ticket #48266: 48266.1.diff

src/wp-includes/rest-api.php

@@ -744 +744 @@
                 $ref   = &$fields_as_keyed;
                 while ( count( $parts ) > 1 ) {
                         $next         = array_shift( $parts );
-                        $ref[ $next ] = array();
+                        $ref[ $next ] = isset( $ref[ $next ] ) ? $ref[ $next ] : array();
                         $ref          = &$ref[ $next ];
                 }
                 $last         = array_shift( $parts );
-                $ref[ $last ] = true;
+                $ref[ $last ] = array();
         }
 
         if ( wp_is_numeric_array( $data ) ) {

tests/phpunit/tests/rest-api.php

@@ -560 +560 @@
                 );
         }
 
+        /**
+         * Ensure that specifying two sibling properties in _fields causes both to be included.
+         *
+         * @ticket 42094
+         */
+        public function test_rest_filter_response_fields_include_all_specified_siblings() {
+                $response = new WP_REST_Response();
+
+                $response->set_data(
+                        array(
+                                'meta' => array(
+                                        'key1' => 1,
+                                        'key2' => 2,
+                                ),
+                        )
+                );
+                $request = array(
+                        '_fields' => 'meta.key1,meta.key2',
+                );
+
+                $response = rest_filter_response_fields( $response, null, $request );
+                $this->assertEquals(
+                        array(
+                                'meta' => array(
+                                        'key1' => 1,
+                                        'key2' => 2,
+                                ),
+                        ),
+                        $response->get_data()
+                );
+        }
+
         /**
          * @ticket 42094
          */