Issue #3410222 by alexpott: Autowiring does not support nullable types

core/lib/Drupal/Core/DependencyInjection/AutowireTrait.php

@@ -28,7 +28,7 @@ public static function create(ContainerInterface $container) {
     if (method_exists(static::class, '__construct')) {
       $constructor = new \ReflectionMethod(static::class, '__construct');
       foreach ($constructor->getParameters() as $parameter) {
-        $service = (string) $parameter->getType();
+        $service = ltrim((string) $parameter->getType(), '?');
         foreach ($parameter->getAttributes(Autowire::class) as $attribute) {
           $service = (string) $attribute->newInstance()->value;
         }

core/modules/system/tests/modules/system_test/src/Controller/SystemTestController.php

@@ -6,6 +6,7 @@
 use Drupal\Core\Cache\CacheableResponse;
 use Drupal\Core\Controller\ControllerBase;
 use Drupal\Core\Messenger\MessengerInterface;
+use Drupal\Core\PageCache\ResponsePolicy\KillSwitch;
 use Drupal\Core\Security\TrustedCallbackInterface;
 use Drupal\Core\Render\RendererInterface;
 use Drupal\Core\Render\Markup;
@@ -70,6 +71,12 @@ class SystemTestController extends ControllerBase implements TrustedCallbackInte
    *   The renderer.
    * @param \Drupal\Core\Messenger\MessengerInterface $messenger
    *   The messenger service.
+   * @param \Drupal\Core\PageCache\ResponsePolicy\KillSwitch|null $killSwitch
+   *   The page cache kill switch. This is here to test nullable types with
+   *   \Drupal\Core\DependencyInjection\AutowireTrait::create().
+   * @param \Drupal\Core\PageCache\ResponsePolicy\KillSwitch|null $killSwitch2
+   *   The page cache kill switch. This is here to test nullable types with
+   *   \Drupal\Core\DependencyInjection\AutowireTrait::create().
    */
   public function __construct(
     #[Autowire(service: 'lock')]
@@ -79,6 +86,8 @@ public function __construct(
     AccountInterface $current_user,
     RendererInterface $renderer,
     MessengerInterface $messenger,
+    public ?KillSwitch $killSwitch = NULL,
+    public KillSwitch|null $killSwitch2 = NULL,
   ) {
     $this->lock = $lock;
     $this->persistentLock = $persistent_lock;

core/tests/Drupal/KernelTests/Core/Controller/ControllerBaseTest.php

@@ -26,6 +26,7 @@ class ControllerBaseTest extends KernelTestBase {
    * @covers ::create
    */
   public function testCreate() {
+    /** @var \Drupal\system_test\Controller\SystemTestController $controller */
     $controller = $this->container->get('class_resolver')->getInstanceFromDefinition(SystemTestController::class);
 
     $property = new \ReflectionProperty(SystemTestController::class, 'lock');
@@ -36,6 +37,10 @@ public function testCreate() {
 
     $property = new \ReflectionProperty(SystemTestController::class, 'currentUser');
     $this->assertSame($this->container->get('current_user'), $property->getValue($controller));
+
+    // Test nullables types.
+    $this->assertSame($this->container->get('page_cache_kill_switch'), $controller->killSwitch);
+    $this->assertSame($this->container->get('page_cache_kill_switch'), $controller->killSwitch2);
   }
 
   /**