Improved exception on invalid message type

Author: yceruto

Exception/InvalidArgumentException.php

@@ -0,0 +1,19 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <[email protected]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Messenger\Exception;
+
+/**
+ * @author Yonel Ceruto <[email protected]>
+ */
+class InvalidArgumentException extends \InvalidArgumentException implements ExceptionInterface
+{
+}

MessageBus.php

@@ -11,6 +11,7 @@
 
 namespace Symfony\Component\Messenger;
 
+use Symfony\Component\Messenger\Exception\InvalidArgumentException;
 use Symfony\Component\Messenger\Middleware\MiddlewareInterface;
 
 /**
@@ -39,6 +40,10 @@ public function __construct(iterable $middlewareHandlers = array())
      */
     public function dispatch($message)
     {
+        if (!\is_object($message)) {
+            throw new InvalidArgumentException(sprintf('Invalid type for message argument. Expected object, but got "%s".', \gettype($message)));
+        }
+
         return \call_user_func($this->callableForNextMiddleware(0), $message);
     }
 

Tests/MessageBusTest.php

@@ -26,6 +26,15 @@ public function testItHasTheRightInterface()
         $this->assertInstanceOf(MessageBusInterface::class, $bus);
     }
 
+    /**
+     * @expectedException \Symfony\Component\Messenger\Exception\InvalidArgumentException
+     * @expectedExceptionMessage Invalid type for message argument. Expected object, but got "string".
+     */
+    public function testItDispatchInvalidMessageType()
+    {
+        (new MessageBus())->dispatch('wrong');
+    }
+
     public function testItCallsMiddlewareAndChainTheReturnValue()
     {
         $message = new DummyMessage('Hello');