Issue #2841542 by Wim Leers:...

Issue #2841542 by Wim Leers: \Drupal\serialization\EventSubscriber\UserRouteAlterSubscriber has serializer service injected, but doesn't use it — also makes route rebuilding more expensive

core/modules/serialization/serialization.services.yml

@@ -88,4 +88,4 @@ services:
     class: Drupal\serialization\EventSubscriber\UserRouteAlterSubscriber
     tags:
       - { name: event_subscriber }
-    arguments: ['@serializer', '%serializer.formats%']
+    arguments: ['%serializer.formats%']

core/modules/serialization/src/EventSubscriber/UserRouteAlterSubscriber.php

@@ -5,20 +5,12 @@
 use Drupal\Core\Routing\RouteBuildEvent;
 use Drupal\Core\Routing\RoutingEvents;
 use Symfony\Component\EventDispatcher\EventSubscriberInterface;
-use Symfony\Component\Serializer\SerializerInterface;
 
 /**
  * Alters user authentication routes to support additional serialization formats.
  */
 class UserRouteAlterSubscriber implements EventSubscriberInterface {
 
-  /**
-   * The serializer.
-   *
-   * @var \Symfony\Component\Serializer\Serializer
-   */
-  protected $serializer;
-
   /**
    * The available serialization formats.
    *
@@ -29,13 +21,10 @@ class UserRouteAlterSubscriber implements EventSubscriberInterface {
   /**
    * UserRouteAlterSubscriber constructor.
    *
-   * @param \Symfony\Component\Serializer\SerializerInterface $serializer
-   *   The serializer service.
    * @param array $serializer_formats
    *   The available serializer formats.
    */
-  public function __construct(SerializerInterface $serializer, array $serializer_formats) {
-    $this->serializer = $serializer;
+  public function __construct(array $serializer_formats) {
     $this->serializerFormats = $serializer_formats;
   }