code: protected function addDefaultPrimaryKey(&$fields)
      {
          foreach ($fields as $field) {
              if (false !== strripos($field['decorators'], 'primarykey()')) {
                  return;
              }
          }
          array_unshift($fields, ['property' => 'id', 'decorators' => 'primaryKey()']);
      }
docs: Adds default primary key to fields list if there's no primary key specified.
  @param array $fields parsed fields
  @since 2.0.7