fixed exception handling when an exception is thrown in the before filter (closes #260)

src/Silex/Application.php

@@ -550,7 +550,12 @@ class Application extends \Pimple implements HttpKernelInterface, EventSubscribe
     {
         if (!$this->beforeDispatched) {
             $this->beforeDispatched = true;
+            try {
                 $this['dispatcher']->dispatch(SilexEvents::BEFORE, $event);
+            } catch (\Exception $e) {
+                // as we are already handling an exception, ignore this one
+                // even if it might have been thrown on purpose by the developer
+            }
         }
 
         $errorEvent = new GetResponseForErrorEvent($this, $event->getRequest(), $event->getRequestType(), $event->getException());

tests/Silex/Tests/BeforeAfterFilterTest.php

@@ -163,7 +163,18 @@ class BeforeAfterFilterTest extends \PHPUnit_Framework_TestCase
         $this->assertEquals(2, $i);
     }
 
-    public function testRequestShouldBePopulatedOnBefore() {
+    public function testBeforeFilterExceptionsWhenHandlingAnException()
+    {
+        $app = new Application();
+
+        $app->before(function () { throw new \RuntimeException(''); });
+
+        // even if the before filter throws an exception, we must have the 404
+        $this->assertEquals(404, $app->handle(Request::create('/'))->getStatusCode());
+    }
+
+    public function testRequestShouldBePopulatedOnBefore()
+    {
         $app = new Application();
 
         $app->before(function () use ($app) {