Add ErrorController to preview and render errors

UPGRADE-4.4.md

@@ -217,9 +217,25 @@ TwigBridge
 TwigBundle
 ----------
 
- * Deprecated default value `twig.controller.exception::showAction` of the `twig.exception_controller` configuration option, 
+ * Deprecated `twig.exception_controller` configuration option, set it to "null" and use `framework.error_controller` instead:
-   set it to `null` instead. This will also change the default error response format according to https://tools.ietf.org/html/rfc7807
+ 
-   for `json`, `xml`, `atom` and `txt` formats:
+   Before:
+   ```yaml
+   twig:
+       exception_controller: 'App\Controller\MyExceptionController'
+   ```
+   
+   After:
+   ```yaml
+   twig:
+       exception_controller: null
+
+   framework:
+       error_controller: 'App\Controller\MyExceptionController'
+   ```
+ 
+   The new default exception controller will also change the error response content according to 
+   https://tools.ietf.org/html/rfc7807 for `json`, `xml`, `atom` and `txt` formats:
    
    Before:
    ```json
@@ -240,7 +256,8 @@ TwigBundle
    }
    ```
    
- * Deprecated the `ExceptionController` and all built-in error templates, use the error renderer mechanism of the `ErrorRenderer` component
+ * Deprecated the `ExceptionController` and `PreviewErrorController` controllers, use `ErrorController` from the HttpKernel component instead
+ * Deprecated all built-in error templates, use the error renderer mechanism of the `ErrorRenderer` component
  * Deprecated loading custom error templates in non-html formats. Custom HTML error pages based on Twig keep working as before: 
 
    Before (`templates/bundles/TwigBundle/Exception/error.jsonld.twig`):

UPGRADE-5.0.md

@@ -538,8 +538,8 @@ TwigBundle
  * The default value (`false`) of the `twig.strict_variables` configuration option has been changed to `%kernel.debug%`.
  * The `transchoice` tag and filter have been removed, use the `trans` ones instead with a `%count%` parameter.
  * Removed support for legacy templates directories `src/Resources/views/` and `src/Resources/<BundleName>/views/`, use `templates/` and `templates/bundles/<BundleName>/` instead.
- * The default value (`twig.controller.exception::showAction`) of the `twig.exception_controller` configuration option has been changed to `null`.
+ * The `twig.exception_controller` configuration option has been removed, use `framework.error_controller` instead.
- * Removed `ExceptionController` class and all built-in error templates
+ * Removed `ExceptionController`, `PreviewErrorController` classes and all built-in error templates
 
 TwigBridge
 ----------

src/Symfony/Bundle/FrameworkBundle/CHANGELOG.md

@@ -14,7 +14,8 @@ CHANGELOG
  * Deprecated `routing.loader.service`, use `routing.loader.container` instead.
  * Not tagging service route loaders with `routing.route_loader` has been deprecated.
  * Overriding the methods `KernelTestCase::tearDown()` and `WebTestCase::tearDown()` without the `void` return-type is deprecated.
- 
+ * Added new `error_controller` configuration to handle system exceptions
+
 4.3.0
 -----
 

src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Configuration.php

@@ -28,7 +28,6 @@ use Symfony\Component\Lock\Store\SemaphoreStore;
 use Symfony\Component\Mailer\Mailer;
 use Symfony\Component\Messenger\MessageBusInterface;
 use Symfony\Component\PropertyInfo\PropertyInfoExtractorInterface;
-use Symfony\Component\Security\Csrf\CsrfTokenManagerInterface;
 use Symfony\Component\Serializer\Serializer;
 use Symfony\Component\Translation\Translator;
 use Symfony\Component\Validator\Validation;
@@ -84,6 +83,9 @@ class Configuration implements ConfigurationInterface
                     ->beforeNormalization()->ifString()->then(function ($v) { return [$v]; })->end()
                     ->prototype('scalar')->end()
                 ->end()
+                ->scalarNode('error_controller')
+                    ->defaultValue('error_controller')
+                ->end()
             ->end()
         ;
 

src/Symfony/Bundle/FrameworkBundle/DependencyInjection/FrameworkExtension.php

@@ -212,6 +212,7 @@ class FrameworkExtension extends Extension
         $container->setParameter('kernel.http_method_override', $config['http_method_override']);
         $container->setParameter('kernel.trusted_hosts', $config['trusted_hosts']);
         $container->setParameter('kernel.default_locale', $config['default_locale']);
+        $container->setParameter('kernel.error_controller', $config['error_controller']);
 
         if (!$container->hasParameter('debug.file_link_format')) {
             if (!$container->hasParameter('templating.helper.code.file_link_format')) {

src/Symfony/Bundle/FrameworkBundle/Resources/config/debug_prod.xml

@@ -21,8 +21,6 @@
             <argument>%kernel.debug%</argument>
             <argument type="service" id="debug.file_link_formatter" />
             <argument>%kernel.debug%</argument>
-            <argument>%kernel.charset%</argument>
-            <argument type="service" id="error_renderer" on-invalid="null" />
         </service>
 
         <service id="debug.file_link_formatter" class="Symfony\Component\HttpKernel\Debug\FileLinkFormatter">

src/Symfony/Bundle/FrameworkBundle/Resources/config/routing/errors.xml

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+
+<routes xmlns="http://symfony.com/schema/routing"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://symfony.com/schema/routing https://symfony.com/schema/routing/routing-1.0.xsd">
+
+    <route id="_preview_error" path="/{code}.{_format}">
+        <default key="_controller">error_controller::preview</default>
+        <default key="_format">html</default>
+        <requirement key="code">\d+</requirement>
+    </route>
+</routes>

src/Symfony/Bundle/FrameworkBundle/Resources/config/schema/symfony-1.0.xsd

@@ -41,6 +41,7 @@
         <xsd:attribute name="secret" type="xsd:string" />
         <xsd:attribute name="default-locale" type="xsd:string" />
         <xsd:attribute name="test" type="xsd:boolean" />
+        <xsd:attribute name="error-controller" type="xsd:string" />
     </xsd:complexType>
 
     <xsd:complexType name="form">

src/Symfony/Bundle/FrameworkBundle/Resources/config/web.xml

@@ -88,5 +88,19 @@
         <service id="disallow_search_engine_index_response_listener" class="Symfony\Component\HttpKernel\EventListener\DisallowRobotsIndexingListener">
             <tag name="kernel.event_subscriber" />
         </service>
+
+        <service id="error_controller" class="Symfony\Component\HttpKernel\Controller\ErrorController" public="true">
+            <argument type="service" id="http_kernel" />
+            <argument>%kernel.error_controller%</argument>
+            <argument type="service" id="error_renderer" />
+        </service>
+
+        <service id="exception_listener" class="Symfony\Component\HttpKernel\EventListener\ExceptionListener">
+            <tag name="kernel.event_subscriber" />
+            <tag name="monolog.logger" channel="request" />
+            <argument>%kernel.error_controller%</argument>
+            <argument type="service" id="logger" on-invalid="null" />
+            <argument>%kernel.debug%</argument>
+        </service>
     </services>
 </container>

src/Symfony/Bundle/FrameworkBundle/Tests/Command/CacheClearCommand/Fixture/TestAppKernel.php

@@ -38,7 +38,7 @@ class TestAppKernel extends Kernel
 
     public function setAnnotatedClassCache(array $annotatedClasses)
     {
-        $annotatedClasses = array_diff($annotatedClasses, ['Symfony\Bundle\WebProfilerBundle\Controller\ExceptionController', 'Symfony\Bundle\TwigBundle\Controller\ExceptionController']);
+        $annotatedClasses = array_diff($annotatedClasses, ['Symfony\Bundle\WebProfilerBundle\Controller\ExceptionController', 'Symfony\Bundle\TwigBundle\Controller\ExceptionController', 'Symfony\Bundle\TwigBundle\Controller\PreviewErrorController']);
 
         parent::setAnnotatedClassCache($annotatedClasses);
     }

src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/ConfigurationTest.php

@@ -373,6 +373,7 @@ class ConfigurationTest extends TestCase
                 'transports' => [],
                 'enabled' => !class_exists(FullStack::class) && class_exists(Mailer::class),
             ],
+            'error_controller' => 'error_controller',
         ];
     }
 }

src/Symfony/Bundle/FrameworkBundle/Tests/Functional/app/BundlePaths/config.yml

@@ -8,4 +8,4 @@ framework:
 
 twig:
     strict_variables: '%kernel.debug%'
-    exception_controller: ~
+    exception_controller: null # to be removed in 5.0

src/Symfony/Bundle/FrameworkBundle/Tests/Functional/app/Fragment/config.yml

@@ -7,4 +7,4 @@ framework:
 
 twig:
     strict_variables: '%kernel.debug%'
-    exception_controller: ~
+    exception_controller: null # to be removed in 5.0

src/Symfony/Bundle/SecurityBundle/Tests/Functional/MissingUserProviderTest.php

@@ -15,13 +15,15 @@ class MissingUserProviderTest extends AbstractWebTestCase
 {
     public function testUserProviderIsNeeded()
     {
-        $this->expectException('Symfony\Component\Config\Definition\Exception\InvalidConfigurationException');
+        $client = $this->createClient(['test_case' => 'MissingUserProvider', 'root_config' => 'config.yml', 'debug' => true]);
-        $this->expectExceptionMessage('"default" firewall requires a user provider but none was defined.');
-        $client = $this->createClient(['test_case' => 'MissingUserProvider', 'root_config' => 'config.yml']);
 
         $client->request('GET', '/', [], [], [
             'PHP_AUTH_USER' => 'username',
             'PHP_AUTH_PW' => 'pa$$word',
         ]);
+
+        $response = $client->getResponse();
+        $this->assertSame(500, $response->getStatusCode());
+        $this->stringContains('"default" firewall requires a user provider but none was defined.', $response->getContent());
     }
 }

src/Symfony/Bundle/SecurityBundle/Tests/Functional/app/ExceptionController.php

@@ -1,37 +0,0 @@
-<?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\Bundle\SecurityBundle\Tests\Functional\app;
-
-use Symfony\Component\ErrorRenderer\ErrorRenderer;
-use Symfony\Component\ErrorRenderer\ErrorRenderer\HtmlErrorRenderer;
-use Symfony\Component\ErrorRenderer\ErrorRenderer\JsonErrorRenderer;
-use Symfony\Component\ErrorRenderer\Exception\FlattenException;
-use Symfony\Component\HttpFoundation\Request;
-use Symfony\Component\HttpFoundation\Response;
-
-class ExceptionController
-{
-    private $errorRenderer;
-
-    public function __construct()
-    {
-        $this->errorRenderer = new ErrorRenderer([
-            new HtmlErrorRenderer(),
-            new JsonErrorRenderer(),
-        ]);
-    }
-
-    public function __invoke(Request $request, FlattenException $exception)
-    {
-        return new Response($this->errorRenderer->render($exception, $request->getPreferredFormat()), $exception->getStatusCode());
-    }
-}

src/Symfony/Bundle/SecurityBundle/Tests/Functional/app/JsonLogin/bundles.php

@@ -12,6 +12,5 @@
 return [
     new Symfony\Bundle\SecurityBundle\SecurityBundle(),
     new Symfony\Bundle\FrameworkBundle\FrameworkBundle(),
-    new Symfony\Bundle\TwigBundle\TwigBundle(),
     new Symfony\Bundle\SecurityBundle\Tests\Functional\Bundle\JsonLoginBundle\JsonLoginBundle(),
 ];

src/Symfony/Bundle/SecurityBundle/Tests/Functional/app/JsonLogin/config.yml

@@ -1,5 +1,5 @@
 imports:
-    - { resource: ./../config/default.yml }
+    - { resource: ./../config/framework.yml }
 
 security:
     encoders:

src/Symfony/Bundle/SecurityBundle/Tests/Functional/app/JsonLogin/custom_handlers.yml

@@ -1,5 +1,5 @@
 imports:
-    - { resource: ./../config/default.yml }
+    - { resource: ./../config/framework.yml }
 
 security:
     encoders:

src/Symfony/Bundle/SecurityBundle/Tests/Functional/app/config/twig.yml

@@ -2,4 +2,4 @@
 twig:
     debug:            '%kernel.debug%'
     strict_variables: '%kernel.debug%'
-    exception_controller: Symfony\Bundle\SecurityBundle\Tests\Functional\app\ExceptionController
+    exception_controller: null # to be removed in 5.0

src/Symfony/Bundle/TwigBundle/CHANGELOG.md

@@ -7,8 +7,9 @@ CHANGELOG
  * marked the `TemplateIterator` as `internal`
  * added HTML comment to beginning and end of `exception_full.html.twig`
  * added a new `TwigHtmlErrorRenderer` for `html` format, integrated with the `ErrorRenderer` component 
- * deprecated `ExceptionController` class and all built-in error templates in favor of the new error renderer mechanism
+ * deprecated `ExceptionController` and `PreviewErrorController` controllers, use `ErrorController` from the `HttpKernel` component instead 
- * deprecated default value `twig.controller.exception::showAction` of `twig.exception_controller` configuration option, set it to `null` instead
+ * deprecated all built-in error templates in favor of the new error renderer mechanism
+ * deprecated `twig.exception_controller` configuration option, set it to "null" and use `framework.error_controller` configuration instead
 
 4.2.0
 -----

src/Symfony/Bundle/TwigBundle/Controller/ExceptionController.php

@@ -19,7 +19,7 @@ use Twig\Environment;
 use Twig\Error\LoaderError;
 use Twig\Loader\ExistsLoaderInterface;
 
-@trigger_error(sprintf('The "%s" class is deprecated since Symfony 4.4, use the ErrorRenderer component instead.', ExceptionController::class), E_USER_DEPRECATED);
+@trigger_error(sprintf('The "%s" class is deprecated since Symfony 4.4, use "%s" instead.', ExceptionController::class, \Symfony\Component\HttpKernel\Controller\ErrorController::class), E_USER_DEPRECATED);
 
 /**
  * ExceptionController renders error or exception pages for a given
@@ -28,7 +28,7 @@ use Twig\Loader\ExistsLoaderInterface;
  * @author Fabien Potencier <fabien@symfony.com>
  * @author Matthias Pigulla <mp@webfactory.de>
  *
- * @deprecated since Symfony 4.4, use the ErrorRenderer component instead.
+ * @deprecated since Symfony 4.4, use Symfony\Component\HttpKernel\Controller\ErrorController instead.
  */
 class ExceptionController
 {

src/Symfony/Bundle/TwigBundle/Controller/PreviewErrorController.php

@@ -11,39 +11,35 @@
 
 namespace Symfony\Bundle\TwigBundle\Controller;
 
-use Symfony\Component\ErrorRenderer\ErrorRenderer;
 use Symfony\Component\ErrorRenderer\Exception\FlattenException;
 use Symfony\Component\HttpFoundation\Request;
-use Symfony\Component\HttpFoundation\Response;
 use Symfony\Component\HttpKernel\HttpKernelInterface;
 
+@trigger_error(sprintf('The "%s" class is deprecated since Symfony 4.4, use the "%s" instead.', PreviewErrorController::class, \Symfony\Component\HttpKernel\Controller\ErrorController::class), E_USER_DEPRECATED);
+
 /**
  * PreviewErrorController can be used to test error pages.
  *
  * It will create a test exception and forward it to another controller.
  *
  * @author Matthias Pigulla <mp@webfactory.de>
+ *
+ * @deprecated since Symfony 4.4, use the Symfony\Component\HttpKernel\Controller\ErrorController instead.
  */
 class PreviewErrorController
 {
     protected $kernel;
     protected $controller;
-    private $errorRenderer;
 
-    public function __construct(HttpKernelInterface $kernel, $controller, ErrorRenderer $errorRenderer = null)
+    public function __construct(HttpKernelInterface $kernel, $controller)
     {
         $this->kernel = $kernel;
         $this->controller = $controller;
-        $this->errorRenderer = $errorRenderer;
     }
 
     public function previewErrorPageAction(Request $request, $code)
     {
-        $exception = FlattenException::createFromThrowable(new \Exception('Something has intentionally gone wrong.'), $code, ['X-Debug' => false]);
+        $exception = FlattenException::createFromThrowable(new \Exception('Something has intentionally gone wrong.'), $code);
-
-        if (null === $this->controller && null !== $this->errorRenderer) {
-            return new Response($this->errorRenderer->render($exception, $request->getPreferredFormat()), $code);
-        }
 
         /*
          * This Request mimics the parameters set by

src/Symfony/Bundle/TwigBundle/DependencyInjection/Compiler/ExceptionListenerPass.php

@@ -18,6 +18,8 @@ use Symfony\Component\DependencyInjection\ContainerBuilder;
  * Registers the Twig exception listener if Twig is registered as a templating engine.
  *
  * @author Fabien Potencier <fabien@symfony.com>
+ *
+ * @internal
  */
 class ExceptionListenerPass implements CompilerPassInterface
 {
@@ -27,13 +29,18 @@ class ExceptionListenerPass implements CompilerPassInterface
             return;
         }
 
-        // register the exception controller only if Twig is enabled and required dependencies do exist
+        // to be removed in 5.0
-        if (!class_exists('Symfony\Component\ErrorRenderer\Exception\FlattenException') || !interface_exists('Symfony\Component\EventDispatcher\EventSubscriberInterface')) {
+        // register the exception listener only if it's currently used, else use the provided by FrameworkBundle
+        if (null === $container->getParameter('twig.exception_listener.controller') && $container->hasDefinition('exception_listener')) {
             $container->removeDefinition('twig.exception_listener');
-        } elseif ($container->hasParameter('templating.engines')) {
+        } else {
-            $engines = $container->getParameter('templating.engines');
+            $container->removeDefinition('exception_listener');
-            if (!\in_array('twig', $engines)) {
+
-                $container->removeDefinition('twig.exception_listener');
+            if ($container->hasParameter('templating.engines')) {
+                $engines = $container->getParameter('templating.engines');
+                if (!\in_array('twig', $engines, true)) {
+                    $container->removeDefinition('twig.exception_listener');
+                }
             }
         }
     }

src/Symfony/Bundle/TwigBundle/DependencyInjection/Configuration.php

@@ -36,10 +36,18 @@ class Configuration implements ConfigurationInterface
             ->children()
                 ->scalarNode('exception_controller')
                     ->defaultValue(static function () {
-                        @trigger_error('Relying on the default value ("twig.controller.exception::showAction") of the "twig.exception_controller" configuration option is deprecated since Symfony 4.4, set it to "null" explicitly instead, which will be the new default in 5.0.', E_USER_DEPRECATED);
+                        @trigger_error('The "twig.exception_controller" configuration key has been deprecated in Symfony 4.4, set it to "null" and use "framework.error_controller" configuration key instead.', E_USER_DEPRECATED);
 
                         return 'twig.controller.exception::showAction';
                     })
+                    ->validate()
+                        ->ifTrue(static function ($v) { return null !== $v; })
+                        ->then(static function ($v) {
+                            @trigger_error('The "twig.exception_controller" configuration key has been deprecated in Symfony 4.4, set it to "null" and use "framework.error_controller" configuration key instead.', E_USER_DEPRECATED);
+
+                            return $v;
+                        })
+                    ->end()
                 ->end()
             ->end()
         ;

src/Symfony/Bundle/TwigBundle/Resources/config/twig.xml

@@ -134,6 +134,7 @@
             <argument>%twig.exception_listener.controller%</argument>
             <argument type="service" id="logger" on-invalid="null" />
             <argument>%kernel.debug%</argument>
+            <deprecated>The "%service_id%" service is deprecated since Symfony 4.4.</deprecated>
         </service>
 
         <service id="twig.controller.exception" class="Symfony\Bundle\TwigBundle\Controller\ExceptionController" public="true">
@@ -145,7 +146,7 @@
         <service id="twig.controller.preview_error" class="Symfony\Bundle\TwigBundle\Controller\PreviewErrorController" public="true">
             <argument type="service" id="http_kernel" />
             <argument>%twig.exception_listener.controller%</argument>
-            <argument type="service" id="error_renderer" on-invalid="null" />
+            <deprecated>The "%service_id%" service is deprecated since Symfony 4.4.</deprecated>
         </service>
 
         <service id="twig.configurator.environment" class="Symfony\Bundle\TwigBundle\DependencyInjection\Configurator\EnvironmentConfigurator">

src/Symfony/Bundle/TwigBundle/Tests/Controller/PreviewErrorControllerTest.php

@@ -18,6 +18,9 @@ use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpFoundation\Response;
 use Symfony\Component\HttpKernel\HttpKernelInterface;
 
+/**
+ * @group legacy
+ */
 class PreviewErrorControllerTest extends TestCase
 {
     public function testForwardRequestToConfiguredController()

src/Symfony/Bundle/TwigBundle/Tests/DependencyInjection/ConfigurationTest.php

@@ -21,7 +21,7 @@ class ConfigurationTest extends TestCase
     {
         $input = [
             'strict_variables' => false, // to be removed in 5.0 relying on default
-            'exception_controller' => null, // to be removed in 5.0 relying on default
+            'exception_controller' => null, // to be removed in 5.0
             'form_themes' => ['form_div_layout.html.twig'],
         ];
 
@@ -45,14 +45,14 @@ class ConfigurationTest extends TestCase
 
     /**
      * @group legacy
-     * @expectedDeprecation Relying on the default value ("twig.controller.exception::showAction") of the "twig.exception_controller" configuration option is deprecated since Symfony 4.4, set it to "null" explicitly instead, which will be the new default in 5.0.
+     * @expectedDeprecation The "twig.exception_controller" configuration key has been deprecated in Symfony 4.4, set it to "null" and use "framework.error_controller" configuration key instead.
      */
     public function testGetExceptionControllerDefault()
     {
         $processor = new Processor();
-        $config = $processor->processConfiguration(new Configuration(), [[]]);
+        $config = $processor->processConfiguration(new Configuration(), [['exception_controller' => 'exception_controller']]);
 
-        $this->assertSame('twig.controller.exception::showAction', $config['exception_controller']);
+        $this->assertSame('exception_controller', $config['exception_controller']);
     }
 
     public function testGlobalsAreNotNormalized()

src/Symfony/Bundle/TwigBundle/Tests/DependencyInjection/Fixtures/php/customTemplateEscapingGuesser.php

@@ -4,5 +4,5 @@ $container->loadFromExtension('twig', [
     'autoescape_service' => 'my_project.some_bundle.template_escaping_guesser',
     'autoescape_service_method' => 'guess',
     'strict_variables' => false, // to be removed in 5.0 relying on default
-    'exception_controller' => null, // to be removed in 5.0 relying on default
+    'exception_controller' => null, // to be removed in 5.0
 ]);

src/Symfony/Bundle/TwigBundle/Tests/DependencyInjection/Fixtures/php/empty.php

@@ -2,5 +2,5 @@
 
 $container->loadFromExtension('twig', [
     'strict_variables' => false, // to be removed in 5.0 relying on default
-    'exception_controller' => null, // to be removed in 5.0 relying on default
+    'exception_controller' => null, // to be removed in 5.0
 ]);

src/Symfony/Bundle/TwigBundle/Tests/DependencyInjection/Fixtures/php/formats.php

@@ -12,5 +12,5 @@ $container->loadFromExtension('twig', [
         'thousands_separator' => '.',
     ],
     'strict_variables' => false, // to be removed in 5.0 relying on default
-    'exception_controller' => null, // to be removed in 5.0 relying on default
+    'exception_controller' => null, // to be removed in 5.0
 ]);

src/Symfony/Bundle/TwigBundle/Tests/DependencyInjection/Fixtures/php/full.php

@@ -17,7 +17,7 @@ $container->loadFromExtension('twig', [
     'charset' => 'ISO-8859-1',
     'debug' => true,
     'strict_variables' => true,
-    'exception_controller' => null,
+    'exception_controller' => null, // to be removed in 5.0
     'default_path' => '%kernel.project_dir%/Fixtures/templates',
     'paths' => [
         'path1',

src/Symfony/Bundle/TwigBundle/Tests/DependencyInjection/TwigExtensionTest.php

@@ -32,7 +32,7 @@ class TwigExtensionTest extends TestCase
         $container->registerExtension(new TwigExtension());
         $container->loadFromExtension('twig', [
             'strict_variables' => false, // to be removed in 5.0 relying on default
-            'exception_controller' => null, // to be removed in 5.0 relying on default
+            'exception_controller' => null, // to be removed in 5.0
         ]);
         $this->compileContainer($container);
 

src/Symfony/Bundle/TwigBundle/Tests/Functional/NoTemplatingEntryTest.php

@@ -68,7 +68,7 @@ class NoTemplatingEntryKernel extends Kernel
                 ])
                 ->loadFromExtension('twig', [
                     'strict_variables' => false, // to be removed in 5.0 relying on default
-                    'exception_controller' => null, // to be removed in 5.0 relying on default
+                    'exception_controller' => null, // to be removed in 5.0
                     'default_path' => __DIR__.'/templates',
                 ])
             ;

src/Symfony/Component/HttpKernel/CHANGELOG.md

@@ -13,6 +13,7 @@ CHANGELOG
    current directory or with a glob pattern. The fallback directories have never been advocated
    so you likely do not use those in any app based on the SF Standard or Flex edition.
  * Marked all dispatched event classes as `@final`
+ * Added `ErrorController` to enable the preview and error rendering mechanism
 
 4.3.0
 -----

src/Symfony/Component/HttpKernel/Controller/ErrorController.php

@@ -0,0 +1,67 @@
+<?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\HttpKernel\Controller;
+
+use Symfony\Component\ErrorRenderer\ErrorRenderer;
+use Symfony\Component\ErrorRenderer\Exception\ErrorRendererNotFoundException;
+use Symfony\Component\ErrorRenderer\Exception\FlattenException;
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpFoundation\Response;
+use Symfony\Component\HttpKernel\HttpKernelInterface;
+
+/**
+ * Renders error or exception pages from a given FlattenException.
+ *
+ * @author Yonel Ceruto <yonelceruto@gmail.com>
+ * @author Matthias Pigulla <mp@webfactory.de>
+ */
+class ErrorController
+{
+    private $kernel;
+    private $controller;
+    private $errorRenderer;
+
+    public function __construct(HttpKernelInterface $kernel, $controller, ErrorRenderer $errorRenderer)
+    {
+        $this->kernel = $kernel;
+        $this->controller = $controller;
+        $this->errorRenderer = $errorRenderer;
+    }
+
+    public function __invoke(Request $request, FlattenException $exception): Response
+    {
+        try {
+            return new Response($this->errorRenderer->render($exception, $request->getPreferredFormat()), $exception->getStatusCode(), $exception->getHeaders());
+        } catch (ErrorRendererNotFoundException $e) {
+            return new Response($this->errorRenderer->render($exception), $exception->getStatusCode(), $exception->getHeaders());
+        }
+    }
+
+    public function preview(Request $request, int $code): Response
+    {
+        $exception = FlattenException::createFromThrowable(new \Exception('This is a sample exception.'), $code, ['X-Debug' => false]);
+
+        /*
+         * This Request mimics the parameters set by
+         * \Symfony\Component\HttpKernel\EventListener\ExceptionListener::duplicateRequest, with
+         * the additional "showException" flag.
+         */
+        $subRequest = $request->duplicate(null, null, [
+            '_controller' => $this->controller,
+            'exception' => $exception,
+            'logger' => null,
+            'showException' => false,
+        ]);
+
+        return $this->kernel->handle($subRequest, HttpKernelInterface::SUB_REQUEST);
+    }
+}

src/Symfony/Component/HttpKernel/EventListener/DebugHandlersListener.php

@@ -16,15 +16,9 @@ use Symfony\Component\Console\ConsoleEvents;
 use Symfony\Component\Console\Event\ConsoleEvent;
 use Symfony\Component\Console\Output\ConsoleOutputInterface;
 use Symfony\Component\ErrorHandler\ErrorHandler;
-use Symfony\Component\ErrorRenderer\ErrorRenderer;
-use Symfony\Component\ErrorRenderer\ErrorRenderer\HtmlErrorRenderer;
-use Symfony\Component\ErrorRenderer\Exception\ErrorRendererNotFoundException;
 use Symfony\Component\EventDispatcher\Event;
 use Symfony\Component\EventDispatcher\EventSubscriberInterface;
-use Symfony\Component\HttpFoundation\Request;
-use Symfony\Component\HttpFoundation\Response;
 use Symfony\Component\HttpKernel\Debug\FileLinkFormatter;
-use Symfony\Component\HttpKernel\Event\GetResponseForExceptionEvent;
 use Symfony\Component\HttpKernel\Event\KernelEvent;
 use Symfony\Component\HttpKernel\KernelEvents;
 
@@ -44,8 +38,6 @@ class DebugHandlersListener implements EventSubscriberInterface
     private $scream;
     private $fileLinkFormat;
     private $scope;
-    private $charset;
-    private $errorRenderer;
     private $firstCall = true;
     private $hasTerminatedWithException;
 
@@ -57,7 +49,7 @@ class DebugHandlersListener implements EventSubscriberInterface
      * @param string|FileLinkFormatter|null $fileLinkFormat   The format for links to source files
      * @param bool                          $scope            Enables/disables scoping mode
      */
-    public function __construct(callable $exceptionHandler = null, LoggerInterface $logger = null, $levels = E_ALL, ?int $throwAt = E_ALL, bool $scream = true, $fileLinkFormat = null, bool $scope = true, string $charset = null, ErrorRenderer $errorRenderer = null)
+    public function __construct(callable $exceptionHandler = null, LoggerInterface $logger = null, $levels = E_ALL, ?int $throwAt = E_ALL, bool $scream = true, $fileLinkFormat = null, bool $scope = true)
     {
         $this->exceptionHandler = $exceptionHandler;
         $this->logger = $logger;
@@ -66,8 +58,6 @@ class DebugHandlersListener implements EventSubscriberInterface
         $this->scream = $scream;
         $this->fileLinkFormat = $fileLinkFormat;
         $this->scope = $scope;
-        $this->charset = $charset;
-        $this->errorRenderer = $errorRenderer;
     }
 
     /**
@@ -142,33 +132,6 @@ class DebugHandlersListener implements EventSubscriberInterface
         }
     }
 
-    /**
-     * @internal
-     */
-    public function onKernelException(GetResponseForExceptionEvent $event)
-    {
-        if (!$this->hasTerminatedWithException || !$event->isMasterRequest()) {
-            return;
-        }
-
-        $debug = $this->scream && $this->scope;
-        $controller = function (Request $request) use ($debug) {
-            if (null === $this->errorRenderer) {
-                $this->errorRenderer = new ErrorRenderer([new HtmlErrorRenderer($debug, $this->charset, $this->fileLinkFormat)]);
-            }
-
-            $e = $request->attributes->get('exception');
-
-            try {
-                return new Response($this->errorRenderer->render($e, $request->getPreferredFormat()), $e->getStatusCode(), $e->getHeaders());
-            } catch (ErrorRendererNotFoundException $_) {
-                return new Response($this->errorRenderer->render($e), $e->getStatusCode(), $e->getHeaders());
-            }
-        };
-
-        (new ExceptionListener($controller, $this->logger, $debug))->onKernelException($event);
-    }
-
     public static function getSubscribedEvents()
     {
         $events = [KernelEvents::REQUEST => ['configure', 2048]];
@@ -177,8 +140,6 @@ class DebugHandlersListener implements EventSubscriberInterface
             $events[ConsoleEvents::COMMAND] = ['configure', 2048];
         }
 
-        $events[KernelEvents::EXCEPTION] = ['onKernelException', -2048];
-
         return $events;
     }
 }

src/Symfony/Component/HttpKernel/Tests/Controller/ErrorControllerTest.php

@@ -0,0 +1,123 @@
+<?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\HttpKernel\Tests\Controller;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\ErrorRenderer\ErrorRenderer;
+use Symfony\Component\ErrorRenderer\ErrorRenderer\HtmlErrorRenderer;
+use Symfony\Component\ErrorRenderer\ErrorRenderer\JsonErrorRenderer;
+use Symfony\Component\ErrorRenderer\Exception\FlattenException;
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpFoundation\Response;
+use Symfony\Component\HttpKernel\Controller\ErrorController;
+use Symfony\Component\HttpKernel\Exception\HttpException;
+use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;
+use Symfony\Component\HttpKernel\HttpKernelInterface;
+
+class ErrorControllerTest extends TestCase
+{
+    /**
+     * @dataProvider getInvokeControllerDataProvider
+     */
+    public function testInvokeController(Request $request, FlattenException $exception, int $statusCode, string $content)
+    {
+        $kernel = $this->getMockBuilder(HttpKernelInterface::class)->getMock();
+        $errorRenderer = new ErrorRenderer([new HtmlErrorRenderer(), new JsonErrorRenderer()]);
+        $controller = new ErrorController($kernel, null, $errorRenderer);
+        $response = $controller($request, $exception);
+
+        $this->assertSame($statusCode, $response->getStatusCode());
+        self::assertStringContainsString($content, strtr($response->getContent(), ["\n" => '', '    ' => '']));
+    }
+
+    public function getInvokeControllerDataProvider()
+    {
+        yield 'default status code and HTML format' => [
+            new Request(),
+            FlattenException::createFromThrowable(new \Exception()),
+            500,
+            'The server returned a "500 Internal Server Error".',
+        ];
+
+        yield 'custom status code' => [
+            new Request(),
+            FlattenException::createFromThrowable(new NotFoundHttpException('Page not found.')),
+            404,
+            'The server returned a "404 Not Found".',
+        ];
+
+        $request = new Request();
+        $request->attributes->set('_format', 'json');
+        yield 'custom format via _format attribute' => [
+            $request,
+            FlattenException::createFromThrowable(new \Exception('foo')),
+            500,
+            '{"title": "Internal Server Error","status": 500,"detail": "foo"}',
+        ];
+
+        $request = new Request();
+        $request->headers->set('Accept', 'application/json');
+        yield 'custom format via Accept header' => [
+            $request,
+            FlattenException::createFromThrowable(new HttpException(405, 'Invalid request.')),
+            405,
+            '{"title": "Method Not Allowed","status": 405,"detail": "Invalid request."}',
+        ];
+
+        $request = new Request();
+        $request->headers->set('Content-Type', 'application/json');
+        yield 'custom format via Content-Type header' => [
+            $request,
+            FlattenException::createFromThrowable(new HttpException(405, 'Invalid request.')),
+            405,
+            '{"title": "Method Not Allowed","status": 405,"detail": "Invalid request."}',
+        ];
+
+        $request = new Request();
+        $request->attributes->set('_format', 'unknown');
+        yield 'default HTML format for unknown formats' => [
+            $request,
+            FlattenException::createFromThrowable(new HttpException(405, 'Invalid request.')),
+            405,
+            'The server returned a "405 Method Not Allowed".',
+        ];
+    }
+
+    public function testPreviewController()
+    {
+        $_controller = 'error_controller';
+        $code = 404;
+
+        $kernel = $this->getMockBuilder(HttpKernelInterface::class)->getMock();
+        $kernel
+            ->expects($this->once())
+            ->method('handle')
+            ->with(
+                $this->callback(function (Request $request) use ($_controller, $code) {
+                    $exception = $request->attributes->get('exception');
+
+                    $this->assertSame($_controller, $request->attributes->get('_controller'));
+                    $this->assertInstanceOf(FlattenException::class, $exception);
+                    $this->assertSame($code, $exception->getStatusCode());
+                    $this->assertFalse($request->attributes->get('showException'));
+
+                    return true;
+                }),
+                $this->equalTo(HttpKernelInterface::SUB_REQUEST)
+            )
+            ->willReturn($response = new Response());
+
+        $controller = new ErrorController($kernel, $_controller, new ErrorRenderer([]));
+
+        $this->assertSame($response, $controller->preview(new Request(), $code));
+    }
+}

src/Symfony/Component/HttpKernel/Tests/EventListener/DebugHandlersListenerTest.php

@@ -101,7 +101,6 @@ class DebugHandlersListenerTest extends TestCase
         $xListeners = [
             KernelEvents::REQUEST => [[$listener, 'configure']],
             ConsoleEvents::COMMAND => [[$listener, 'configure']],
-            KernelEvents::EXCEPTION => [[$listener, 'onKernelException']],
         ];
         $this->assertSame($xListeners, $dispatcher->getListeners());