symfony · fabpot · Oct 5, 2025 · Jul 27, 2025
diff --git a/src/Symfony/Bundle/FrameworkBundle/CHANGELOG.md b/src/Symfony/Bundle/FrameworkBundle/CHANGELOG.md
@@ -14,6 +14,7 @@ CHANGELOG
  * Add support for configuring workflow places with glob patterns matching consts/backed enums
  * Add support for configuring the `CachingHttpClient`
  * Add support for weighted transitions in workflows
+ * Add support for union types with `Symfony\Component\EventDispatcher\Attribute\AsEventListener`
 
 7.3
 ---

diff --git a/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/FrameworkExtension.php b/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/FrameworkExtension.php
@@ -774,13 +774,32 @@ public function load(array $configs, ContainerBuilder $container): void
 
         $container->registerAttributeForAutoconfiguration(AsEventListener::class, static function (ChildDefinition $definition, AsEventListener $attribute, \ReflectionClass|\ReflectionMethod $reflector) {
             $tagAttributes = get_object_vars($attribute);
-            if ($reflector instanceof \ReflectionMethod) {
-                if (isset($tagAttributes['method'])) {
-                    throw new LogicException(\sprintf('AsEventListener attribute cannot declare a method on "%s::%s()".', $reflector->class, $reflector->name));
+
+            if (!$reflector instanceof \ReflectionMethod) {
+                $definition->addTag('kernel.event_listener', $tagAttributes);
+
+                return;
+            }
+
+            if (isset($tagAttributes['method'])) {
+                throw new LogicException(\sprintf('AsEventListener attribute cannot declare a method on "%s::%s()".', $reflector->class, $reflector->name));
+            }
+
+            $tagAttributes['method'] = $reflector->getName();
+
+            if (!$eventArg = $reflector->getParameters()[0] ?? null) {
+                throw new LogicException(\sprintf('AsEventListener attribute requires the first argument of "%s::%s()" to be an event object.', $reflector->class, $reflector->name));
+            }
+
+            $types = ($type = $eventArg->getType() instanceof \ReflectionUnionType ? $eventArg->getType()->getTypes() : [$eventArg->getType()]) ?: [];
+
+            foreach ($types as $type) {
+                if ($type instanceof \ReflectionNamedType && !$type->isBuiltin()) {
+                    $tagAttributes['event'] = $type->getName();
+
+                    $definition->addTag('kernel.event_listener', $tagAttributes);
                 }
-                $tagAttributes['method'] = $reflector->getName();
             }
-            $definition->addTag('kernel.event_listener', $tagAttributes);
         });
         $container->registerAttributeForAutoconfiguration(AsController::class, static function (ChildDefinition $definition, AsController $attribute): void {
             $definition->addTag('controller.service_arguments');

diff --git a/...Symfony/Component/EventDispatcher/Tests/DependencyInjection/RegisterListenersPassTest.php b/...Symfony/Component/EventDispatcher/Tests/DependencyInjection/RegisterListenersPassTest.php
@@ -24,8 +24,10 @@
 use Symfony\Component\EventDispatcher\DependencyInjection\RegisterListenersPass;
 use Symfony\Component\EventDispatcher\EventSubscriberInterface;
 use Symfony\Component\EventDispatcher\Tests\Fixtures\CustomEvent;
+use Symfony\Component\EventDispatcher\Tests\Fixtures\DummyEvent;
 use Symfony\Component\EventDispatcher\Tests\Fixtures\TaggedInvokableListener;
 use Symfony\Component\EventDispatcher\Tests\Fixtures\TaggedMultiListener;
+use Symfony\Component\EventDispatcher\Tests\Fixtures\TaggedUnionTypeListener;
 
 class RegisterListenersPassTest extends TestCase
 {
@@ -356,6 +358,70 @@ static function (ChildDefinition $definition, AsEventListener $attribute, \Refle
         $this->assertEquals($expectedCalls, $definition->getMethodCalls());
     }
 
+    public function testTaggedMethodUnionTypeEventListener()
+    {
+        $container = new ContainerBuilder();
+        $container->registerAttributeForAutoconfiguration(AsEventListener::class,
+            static function (ChildDefinition $definition, AsEventListener $attribute, \ReflectionClass|\ReflectionMethod $reflector) {
+                $tagAttributes = get_object_vars($attribute);
+
+                if (!$reflector instanceof \ReflectionMethod) {
+                    $definition->addTag('kernel.event_listener', $tagAttributes);
+
+                    return;
+                }
+
+                if (isset($tagAttributes['method'])) {
+                    throw new \LogicException(\sprintf('AsEventListener attribute cannot declare a method on "%s::%s()".', $reflector->class, $reflector->name));
+                }
+
+                $tagAttributes['method'] = $reflector->getName();
+
+                if (!$eventArg = $reflector->getParameters()[0] ?? null) {
+                    throw new \LogicException(\sprintf('AsEventListener attribute requires the first argument of "%s::%s()" to be an event object.', $reflector->class, $reflector->name));
+                }
+
+                $types = ($type = $eventArg->getType() instanceof \ReflectionUnionType ? $eventArg->getType()->getTypes() : [$eventArg->getType()]) ?: [];
+
+                foreach ($types as $type) {
+                    if ($type instanceof \ReflectionNamedType && !$type->isBuiltin()) {
+                        $tagAttributes['event'] = $type->getName();
+
+                        $definition->addTag('kernel.event_listener', $tagAttributes);
+                    }
+                }
+            });
+
+        $container->register('foo', TaggedUnionTypeListener::class)->setAutoconfigured(true);
+        $container->register('event_dispatcher', \stdClass::class);
+
+        (new AttributeAutoconfigurationPass())->process($container);
+        (new ResolveInstanceofConditionalsPass())->process($container);
+        (new RegisterListenersPass())->process($container);
+
+        $definition = $container->getDefinition('event_dispatcher');
+        $expectedCalls = [
+            [
+                'addListener',
+                [
+                    CustomEvent::class,
+                    [new ServiceClosureArgument(new Reference('foo')), 'onUnionEvent'],
+                    0,
+                ],
+            ],
+            [
+                'addListener',
+                [
+                    DummyEvent::class,
+                    [new ServiceClosureArgument(new Reference('foo')), 'onUnionEvent'],
+                    0,
+                ],
+            ],
+        ];
+
+        $this->assertEquals($expectedCalls, $definition->getMethodCalls());
+    }
+
     public function testAliasedEventListener()
     {
         $container = new ContainerBuilder();

diff --git a/src/Symfony/Component/EventDispatcher/Tests/Fixtures/DummyEvent.php b/src/Symfony/Component/EventDispatcher/Tests/Fixtures/DummyEvent.php
@@ -0,0 +1,16 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\EventDispatcher\Tests\Fixtures;
+
+final class DummyEvent
+{
+}
diff --git a/src/Symfony/Component/EventDispatcher/Tests/Fixtures/TaggedUnionTypeListener.php b/src/Symfony/Component/EventDispatcher/Tests/Fixtures/TaggedUnionTypeListener.php
@@ -0,0 +1,22 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\EventDispatcher\Tests\Fixtures;
+
+use Symfony\Component\EventDispatcher\Attribute\AsEventListener;
+
+final class TaggedUnionTypeListener
+{
+    #[AsEventListener]
+    public function onUnionEvent(CustomEvent|DummyEvent $event): void
+    {
+    }
+}