symfony
diff --git a/‎src/Symfony/Component/Messenger/DependencyInjection/MessengerPass.php
Copy file name to clipboardExpand all lines: src/Symfony/Component/Messenger/DependencyInjection/MessengerPass.php
+1-1Lines changed: 1 addition & 1 deletion b/‎src/Symfony/Component/Messenger/DependencyInjection/MessengerPass.php
Copy file name to clipboardExpand all lines: src/Symfony/Component/Messenger/DependencyInjection/MessengerPass.php
+1-1Lines changed: 1 addition & 1 deletion
diff --git a/‎src/Symfony/Component/Messenger/Handler/Locator/ContainerHandlerLocator.php
Copy file name to clipboardExpand all lines: src/Symfony/Component/Messenger/Handler/Locator/ContainerHandlerLocator.php
+18-3Lines changed: 18 additions & 3 deletions b/‎src/Symfony/Component/Messenger/Handler/Locator/ContainerHandlerLocator.php
Copy file name to clipboardExpand all lines: src/Symfony/Component/Messenger/Handler/Locator/ContainerHandlerLocator.php
+18-3Lines changed: 18 additions & 3 deletions
diff --git a/‎src/Symfony/Component/Messenger/Tests/Handler/Locator/ContainerHandlerLocatorTest.php
Copy file name to clipboard
+48Lines changed: 48 additions & 0 deletions b/‎src/Symfony/Component/Messenger/Tests/Handler/Locator/ContainerHandlerLocatorTest.php
Copy file name to clipboard
+48Lines changed: 48 additions & 0 deletions
@@ -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));
 
@@ -30,12 +30,27 @@ 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
+    {
+        $handlerKey = 'handler.'.$class;
+        if ($this->container->has($handlerKey)) {
+            return $this->container->get($handlerKey);
+        }
+
+        foreach (class_implements($class, false) as $interface) {
+            if ($handler = $this->resolveFromClass($interface)) {
+                return $handler;
+            }
+        }
+
+        return null;
     }
 }
@@ -0,0 +1,48 @@
+<?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\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);
+    }
+}
Original file line number	Diff line number	Diff line change
`@@ -114,7 +114,7 @@ private function registerHandlers(ContainerBuilder $container, array $busIds)`
`114`	`114`	`$method = $method[0];`
`115`	`115`	`}`
`116`	`116`
`117`		`- if (!\class_exists($messageClass)) {`
	`117`	`+ if (!\class_exists($messageClass) && !\interface_exists($messageClass)) {`
`118`	`118`	`$messageClassLocation = isset($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);`
`119`	`119`
`120`	`120`	`throw new RuntimeException(sprintf('Invalid handler service "%s": message class "%s" %s does not exist.', $serviceId, $messageClass, $messageClassLocation));`