Change the theme used for the user reset password page

Question

Drupal 8 - I have the following issue:

• Administrator user creates an account for a user
• User gets a welcome email with password reset link
• Upon browsing the link and passing through the hint page, the user reaches http://example.com/en/user/[USER-ID]/edit?pass-reset-token=[TOKEN]

The problem is that the password reset page uses the administrator theme, while I need it uses the default site theme.

Answer 1

You can use a RouteSubscriber to do that but it will also affect your user edit form and render it with the default site theme since it uses the same route name. The RouteSubscriber can't alter a route based on a query string parameter such as pass-reset-token

yourmodule/yourmodule.services.yml

services:
  yourmodule.routesubscriber:
    class: Drupal\yourmodule\Routing\YourmoduleRouteSubscriber
    tags:
      - { name: event_subscriber, priority: 1 }

yourmodule/src/Routing/YourmoduleRouteSubscriber.php

<?php

namespace Drupal\yourmodule\Routing;

use Drupal\Core\Routing\RouteSubscriberBase;
use Symfony\Component\Routing\RouteCollection;

/**
 * Custom route subscriber.
 */
class YourmoduleRouteSubscriber extends RouteSubscriberBase {

  /**
   * {@inheritdoc}
   */
  protected function alterRoutes(RouteCollection $collection) {
    if ($route = $collection->get('entity.user.edit_form')) {
      $options = $route->getOptions();
      $options['_custom_theme'] = 'yourthemename';
      $route->setOptions($options);
    }
  }

}