core/lib/Drupal/Core/Routing/LocalAwareRedirectResponseTrait.php

LocalAwareRedirectResponseTrait.php

 /**
   * {@inheritdoc}
   */
  protected function isLocal($url) {
    print $url;
    var_dump(UrlHelper::externalIsLocal($url, $this->getRequestContext()->getCompleteBaseUrl()));
    var_dump($this->getRequestContext()->getCompleteBaseUrl());
    return !UrlHelper::isExternal($url) || UrlHelper::externalIsLocal($url, $this->getRequestContext()->getCompleteBaseUrl());
  }