Issue #3359649 by arnested, shalini_jha, alexpott, arunkumark, cilefen,...

    ];

    $routes = $event->getRouteCollection();

    foreach ($route_names as $route_name) {

      if ($route = $routes->get($route_name)) {

      if (($route = $routes->get($route_name)) && $route->hasRequirement('_format')) {

        $formats = explode('|', $route->getRequirement('_format'));

        $formats = array_unique(array_merge($formats, $this->serializerFormats));

        $route->setRequirement('_format', implode('|', $formats));

<?php

declare(strict_types=1);

namespace Drupal\user_route_alter_test\Routing;

use Drupal\Core\Routing\RouteSubscriberBase;

use Drupal\Core\Routing\RoutingEvents;

use Symfony\Component\Routing\RouteCollection;

/**

 * Alter the 'user.pass.http' route.

 */

class RouteSubscriber extends RouteSubscriberBase {

  /**

   * {@inheritdoc}

   */

  protected function alterRoutes(RouteCollection $collection): void {

    if ($route = $collection->get('user.pass.http')) {

      $route->setRequirements([]);

      $route->setRequirement('_access', 'FALSE');

    }

  }

  /**

   * {@inheritdoc}

   */

  public static function getSubscribedEvents(): array {

    $events = parent::getSubscribedEvents();

    // Ensure this event is triggered before

    // \Drupal\serialization\EventSubscriber\UserRouteAlterSubscriber.

    $events[RoutingEvents::ALTER] = ['onAlterRoutes', 1];

    return $events;

  }

}

name: 'User route alter test support'

description: 'Provides test support for user route alter tests.'

type: module

version: VERSION

services:

  _defaults:

    autoconfigure: true

  Drupal\user_route_alter_test\Routing\RouteSubscriber: ~

<?php

declare(strict_types=1);

namespace Drupal\Tests\serialization\Kernel;

use Drupal\KernelTests\KernelTestBase;

/**

 * Tests that the user routes can be altered.

 *

 * @group serialization

 */

class UserRouteAlterTest extends KernelTestBase {

  /**

   * {@inheritdoc}

   */

  protected static $modules = [

    'serialization',

    'user',

    'user_route_alter_test',

  ];

  /**

   * Tests the altered 'user.login.http' route.

   */

  public function testUserAlteredRoute(): void {

    /** @var \Drupal\Core\Routing\RouteProviderInterface $route_provider */

    $route_provider = $this->container->get('router.route_provider');

    // Ensure '_format' is set for the 'user.login.http' route.

    $requirements = $route_provider->getRouteByName('user.login.http')->getRequirements();

    $this->assertArrayHasKey('_format', $requirements, 'user.login.http route has "_format" requirement');

    $this->assertEquals('json|xml', $requirements['_format'], 'user.login.http route "_format" requirement is "json|xml"');

    // Ensure the '_access' requirement is set to FALSE for the 'user.pass.http'

    // route.

    $requirements = $route_provider->getRouteByName('user.pass.http')->getRequirements();

    $this->assertArrayHasKey('_access', $requirements, 'user.pass.http route has "_access" requirement');

    $this->assertEquals('FALSE', $requirements['_access'], 'user.pass.http route "_access" requirement is "FALSE"');

    // Ensure '_format' is not set for the 'user.pass.http' route.

    $this->assertArrayNotHasKey('_format', $requirements, 'user.pass.http route does not have "_format" requirement');

  }

}