symfony · fabpot · Aug 29, 2018 · Aug 26, 2018
diff --git a/src/Symfony/Component/Messenger/DependencyInjection/MessengerPass.php b/src/Symfony/Component/Messenger/DependencyInjection/MessengerPass.php
@@ -114,7 +114,7 @@ private function registerHandlers(ContainerBuilder $container, array $busIds)
                         $method = $method[0];
                     }
 
-                    if (!\class_exists($messageClass)) {
+                    if (!\class_exists($messageClass) && !\interface_exists($messageClass)) {
                         $messageClassLocation = isset($tag['handles']) ? 'declared in your tag attribute "handles"' : $r->implementsInterface(MessageSubscriberInterface::class) ? sprintf('returned by method "%s::getHandledMessages()"', $r->getName()) : sprintf('used as argument type in method "%s::%s()"', $r->getName(), $method);
 
                         throw new RuntimeException(sprintf('Invalid handler service "%s": message class "%s" %s does not exist.', $serviceId, $messageClass, $messageClassLocation));

diff --git a/src/Symfony/Component/Messenger/Handler/Locator/ContainerHandlerLocator.php b/src/Symfony/Component/Messenger/Handler/Locator/ContainerHandlerLocator.php
@@ -30,12 +30,39 @@ public function __construct(ContainerInterface $container)
     public function resolve($message): callable
     {
         $messageClass = \get_class($message);
-        $handlerKey = 'handler.'.$messageClass;
 
-        if (!$this->container->has($handlerKey)) {
+        if (null === $handler = $this->resolveFromClass($messageClass)) {
             throw new NoHandlerForMessageException(sprintf('No handler for message "%s".', $messageClass));
         }
 
-        return $this->container->get($handlerKey);
+        return $handler;
+    }
+
+    private function resolveFromClass($class): ?callable
+    {
+        if ($handler = $this->getHandler($class)) {
+            return $handler;
+        }
+
+        foreach (class_implements($class, false) as $interface) {
+            if ($handler = $this->getHandler($interface)) {
+                return $handler;
+            }
+        }
+
+        foreach (class_parents($class, false) as $parent) {
+            if ($handler = $this->getHandler($parent)) {
+                return $handler;
+            }
+        }
+
+        return null;
+    }
+
+    private function getHandler($class)
+    {
+        $handlerKey = 'handler.'.$class;
+
+        return $this->container->has($handlerKey) ? $this->container->get($handlerKey) : null;
     }
 }
diff --git a/src/Symfony/Component/Messenger/Tests/Asynchronous/Middleware/SendMessageMiddlewareTest.php b/src/Symfony/Component/Messenger/Tests/Asynchronous/Middleware/SendMessageMiddlewareTest.php
@@ -16,7 +16,7 @@
 use Symfony\Component\Messenger\Asynchronous\Routing\SenderLocatorInterface;
 use Symfony\Component\Messenger\Asynchronous\Transport\ReceivedMessage;
 use Symfony\Component\Messenger\Envelope;
-use Symfony\Component\Messenger\Tests\Asynchronous\Routing\ChildDummyMessage;
+use Symfony\Component\Messenger\Tests\Fixtures\ChildDummyMessage;
 use Symfony\Component\Messenger\Tests\Fixtures\DummyMessage;
 use Symfony\Component\Messenger\Tests\Fixtures\DummyMessageInterface;
 use Symfony\Component\Messenger\Transport\SenderInterface;

diff --git a/src/Symfony/Component/Messenger/Tests/Asynchronous/Routing/SenderLocatorTest.php b/src/Symfony/Component/Messenger/Tests/Asynchronous/Routing/SenderLocatorTest.php
@@ -14,6 +14,7 @@
 use PHPUnit\Framework\TestCase;
 use Symfony\Component\DependencyInjection\Container;
 use Symfony\Component\Messenger\Asynchronous\Routing\SenderLocator;
+use Symfony\Component\Messenger\Tests\Fixtures\ChildDummyMessage;
 use Symfony\Component\Messenger\Tests\Fixtures\DummyMessage;
 use Symfony\Component\Messenger\Tests\Fixtures\DummyMessageInterface;
 use Symfony\Component\Messenger\Tests\Fixtures\SecondMessage;
@@ -88,7 +89,3 @@ public function testItSuppo
8000
rtsAWildcardInsteadOfTheMessageClass()
         $this->assertSame($apiSender, $locator->getSenderForMessage(new SecondMessage()));
     }
 }
-
-class ChildDummyMessage extends DummyMessage
-{
-}
diff --git a/src/Symfony/Component/Messenger/Tests/Fixtures/ChildDummyMessage.php b/src/Symfony/Component/Messenger/Tests/Fixtures/ChildDummyMessage.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\Messenger\Tests\Fixtures;
+
+class ChildDummyMessage extends DummyMessage
+{
+}
diff --git a/src/Symfony/Component/Messenger/Tests/Handler/Locator/ContainerHandlerLocatorTest.php b/src/Symfony/Component/Messenger/Tests/Handler/Locator/ContainerHandlerLocatorTest.php
@@ -0,0 +1,62 @@
+<?php
+
+namespace Symfony\Component\Messenger\Tests\Handler\Locator;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\DependencyInjection\Container;
+use Symfony\Component\Messenger\Handler\Locator\ContainerHandlerLocator;
+use Symfony\Component\Messenger\Tests\Fixtures\ChildDummyMessage;
+use Symfony\Component\Messenger\Tests\Fixtures\DummyMessage;
+use Symfony\Component\Messenger\Tests\Fixtures\DummyMessageInterface;
+
+class ContainerHandlerLocatorTest extends TestCase
+{
+    public function testItLocatesHandlerUsingTheMessageClass()
+    {
+        $handler = function () {};
+
+        $container = new Container();
+        $container->set('handler.'.DummyMessage::class, $handler);
+
+        $locator = new ContainerHandlerLocator($container);
+        $resolvedHandler = $locator->resolve(new DummyMessage('Hey'));
+
+        $this->assertSame($handler, $resolvedHandler);
+    }
+
+    /**
+     * @expectedException \Symfony\Component\Messenger\Exception\NoHandlerForMessageException
+     * @expectedExceptionMessage No handler for message "Symfony\Component\Messenger\Tests\Fixtures\DummyMessage"
+     */
+    public function testThrowsNoHandlerException()
+    {
+        $locator = new ContainerHandlerLocator(new Container());
+        $locator->resolve(new DummyMessage('Hey'));
+    }
+
+    public function testResolveMessageViaTheirInterface()
+    {
+        $handler = function () {};
+
+        $container = new Container();
+        $container->set('handler.'.DummyMessageInterface::class, $handler);
+
+        $locator = new ContainerHandlerLocator($container);
+        $resolvedHandler = $locator->resolve(new DummyMessage('Hey'));
+
+        $this->assertSame($handler, $resolvedHandler);
+    }
+
+    public function testResolveMessageViaTheirParentClass()
+    {
+        $handler = function () {};
+
+        $container = new Container();
+        $container->set('handler.'.DummyMessage::class, $handler);
+
+        $locator = new ContainerHandlerLocator($container);
+        $resolvedHandler = $locator->resolve(new ChildDummyMessage('Hey'));
+
+        $this->assertSame($handler, $resolvedHandler);
+    }
+}