Issue #2594777 by dawehner, Wim Leers, damiankloip: Accessing a non existing...

Issue #2594777 by dawehner, Wim Leers, damiankloip: Accessing a non existing format results in a 500

core/lib/Drupal/Core/EventSubscriber/DefaultExceptionSubscriber.php

@@ -165,6 +165,20 @@ protected function onJson(GetResponseForExceptionEvent $event) {
     $event->setResponse($response);
   }
 
+  /**
+   * Handles an HttpExceptionInterface exception for unknown formats.
+   *
+   * @param \Symfony\Component\HttpKernel\Event\GetResponseForExceptionEvent $event
+   *   The event to process.
+   */
+  protected function onFormatUnknown(GetResponseForExceptionEvent $event) {
+    /** @var \Symfony\Component\HttpKernel\Exception\HttpExceptionInterface|\Exception $exception */
+    $exception = $event->getException();
+
+    $response = new Response($exception->getMessage(), $exception->getStatusCode(), $exception->getHeaders());
+    $event->setResponse($response);
+  }
+
   /**
    * Handles errors for this subscriber.
    *
@@ -173,11 +187,17 @@ protected function onJson(GetResponseForExceptionEvent $event) {
    */
   public function onException(GetResponseForExceptionEvent $event) {
     $format = $this->getFormat($event->getRequest());
+    $exception = $event->getException();
 
-    // If it's an unrecognized format, assume HTML.
     $method = 'on' . $format;
     if (!method_exists($this, $method)) {
-      $method = 'onHtml';
+      if ($exception instanceof HttpExceptionInterface) {
+        $this->onFormatUnknown($event);
+      }
+      else {
+        $this->onHtml($event);
+      }
+      return;
     }
     $this->$method($event);
   }

core/tests/Drupal/Tests/Core/EventSubscriber/DefaultExceptionSubscriberTest.php

+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Tests\Core\EventSubscriber\DefaultExceptionSubscriberTest.
+ */
+
+namespace Drupal\Tests\Core\EventSubscriber;
+
+use Drupal\Core\EventSubscriber\DefaultExceptionSubscriber;
+use Drupal\Tests\UnitTestCase;
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpFoundation\Response;
+use Symfony\Component\HttpKernel\Event\GetResponseForExceptionEvent;
+use Symfony\Component\HttpKernel\Exception\MethodNotAllowedHttpException;
+use Symfony\Component\HttpKernel\HttpKernelInterface;
+
+/**
+ * @coversDefaultClass \Drupal\Core\EventSubscriber\DefaultExceptionSubscriber
+ * @group EventSubscriber
+ */
+class DefaultExceptionSubscriberTest extends UnitTestCase {
+
+  /**
+   * @covers ::onException
+   * @covers ::onFormatUnknown
+   */
+  public function testOnExceptionWithUnknownFormat() {
+    $config_factory = $this->getConfigFactoryStub();
+
+    // Format 'bananas' requested, yet only 'json' allowed.
+    $kernel = $this->prophesize(HttpKernelInterface::class);
+    $request = Request::create('/test?_format=bananas');
+    $e = new MethodNotAllowedHttpException(['json'], 'test message');
+    $event = new GetResponseForExceptionEvent($kernel->reveal(), $request, 'GET', $e);
+    $subscriber = new DefaultExceptionSubscriber($config_factory);
+    $subscriber->onException($event);
+    $response = $event->getResponse();
+
+    $this->assertInstanceOf(Response::class, $response);
+    $this->assertEquals('test message', $response->getContent());
+    $this->assertEquals(405, $response->getStatusCode());
+  }
+
+}