feature #39843 [FrameworkBundle] Add renderForm() helper setting the …

…appropriate HTTP status code (dunglas)

This PR was squashed before being merged into the 5.3-dev branch.

Discussion
----------

[FrameworkBundle] Add renderForm() helper setting the appropriate HTTP status code

| Q             | A
| ------------- | ---
| Branch?       | 5.x
| Bug fix?      | no
| New feature?  | yes <!-- please update src/**/CHANGELOG.md files -->
| Deprecations? | no <!-- please update UPGRADE-*.md and src/**/CHANGELOG.md files -->
| Tickets       | n/a
| License       | MIT
| Doc PR        | todo

A 422 HTTP status code should be returned after the submission of an invalid form. Some libraries including [Turbo](hotwired/turbo#39) rely on this behavior and will not display the updated form (containing errors) unless this status code is present.

Rails also [recently switched to this behavior ](rails/rails#41026) by default for the same reason.

I propose to introduce a new helper method rendering the form and setting the appropriate status code. It makes the code cleaner:

```php
// src/Controller/TaskController.php

// ...
use Symfony\Component\HttpFoundation\Request;

class TaskController extends AbstractController
{
    public function new(Request $request): Response
    {
        $task = new Task();
        $form = $this->createForm(TaskType::class, $task);

        $form->handleRequest($request);
        if ($form->isSubmitted() && $form->isValid()) {
            $task = $form->getData();
            // ...

            return $this->redirectToRoute('task_success');
        }

        return $this->renderForm('task/new.html.twig', $form);
    }
}
```

Commits
-------

4c77e50 [FrameworkBundle] Add renderForm() helper setting the appropriate HTTP status code

src/Symfony/Bundle/FrameworkBundle/CHANGELOG.md

@@ -4,6 +4,7 @@ CHANGELOG
 5.3
 ---
 
+ * Added `AbstractController::renderForm()` to render a form and set the appropriate HTTP status code
  * Added support for configuring PHP error level to log levels
  * Added the `dispatcher` option to `debug:event-dispatcher`
  * Added the `event_dispatcher.dispatcher` tag

src/Symfony/Bundle/FrameworkBundle/Controller/AbstractController.php

@@ -17,6 +17,7 @@
 use Symfony\Component\DependencyInjection\Exception\ServiceNotFoundException;
 use Symfony\Component\DependencyInjection\ParameterBag\ContainerBagInterface;
 use Symfony\Component\Form\Extension\Core\Type\FormType;
+use Symfony\Component\Form\Form;
 use Symfony\Component\Form\FormBuilderInterface;
 use Symfony\Component\Form\FormFactoryInterface;
 use Symfony\Component\Form\FormInterface;
@@ -289,6 +290,22 @@ protected function stream(string $view, array $parameters = [], StreamedResponse
         return $response;
     }
 
+    /**
+     * Renders a form.
+     *
+     * The FormView instance is passed to the template in a variable named "form".
+     * If the form is invalid, a 422 status code is returned.
+     */
+    public function renderForm(string $view, FormInterface $form, array $parameters = [], Response $response = null): Response
+    {
+        $response = $this->render($view, ['form' => $form->createView()] + $parameters, $response);
+        if ($form->isSubmitted() && !$form->isValid()) {
+            $response->setStatusCode(Response::HTTP_UNPROCESSABLE_ENTITY);
+        }
+
+        return $response;
+    }
+
     /**
      * Returns a NotFoundHttpException.
      *

src/Symfony/Bundle/FrameworkBundle/Tests/Controller/AbstractControllerTest.php

@@ -18,6 +18,8 @@
 use Symfony\Component\DependencyInjection\ParameterBag\FrozenParameterBag;
 use Symfony\Component\Form\Form;
 use Symfony\Component\Form\FormConfigInterface;
+use Symfony\Component\Form\FormInterface;
+use Symfony\Component\Form\FormView;
 use Symfony\Component\HttpFoundation\BinaryFileResponse;
 use Symfony\Component\HttpFoundation\File\File;
 use Symfony\Component\HttpFoundation\JsonResponse;
@@ -31,6 +33,7 @@
 use Symfony\Component\Security\Core\User\User;
 use Symfony\Component\Serializer\SerializerInterface;
 use Symfony\Component\WebLink\Link;
+use Twig\Environment;
 
 class AbstractControllerTest extends TestCase
 {
@@ -371,7 +374,7 @@ public function testdenyAccessUnlessGranted()
 
     public function testRenderViewTwig()
     {
-        $twig = $this->getMockBuilder(\Twig\Environment::class)->disableOriginalConstructor()->getMock();
+        $twig = $this->getMockBuilder(Environment::class)->disableOriginalConstructor()->getMock();
         $twig->expects($this->once())->method('render')->willReturn('bar');
 
         $container = new Container();
@@ -385,7 +388,7 @@ public function testRenderViewTwig()
 
     public function testRenderTwig()
     {
-        $twig = $this->getMockBuilder(\Twig\Environment::class)->disableOriginalConstructor()->getMock();
+        $twig = $this->getMockBuilder(Environment::class)->disableOriginalConstructor()->getMock();
         $twig->expects($this->once())->method('render')->willReturn('bar');
 
         $container = new Container();
@@ -399,7 +402,7 @@ public function testRenderTwig()
 
     public function testStreamTwig()
     {
-        $twig = $this->getMockBuilder(\Twig\Environment::class)->disableOriginalConstructor()->getMock();
+        $twig = $this->getMockBuilder(Environment::class)->disableOriginalConstructor()->getMock();
 
         $container = new Container();
         $container->set('twig', $twig);
@@ -410,6 +413,52 @@ public function testStreamTwig()
         $this->assertInstanceOf(\Symfony\Component\HttpFoundation\StreamedResponse::class, $controller->stream('foo'));
     }
 
+    public function testRenderFormTwig()
+    {
+        $formView = new FormView();
+
+        $form = $this->getMockBuilder(FormInterface::class)->getMock();
+        $form->expects($this->once())->method('createView')->willReturn($formView);
+
+        $twig = $this->getMockBuilder(Environment::class)->disableOriginalConstructor()->getMock();
+        $twig->expects($this->once())->method('render')->with('foo', ['form' => $formView, 'bar' => 'bar'])->willReturn('bar');
+
+        $container = new Container();
+        $container->set('twig', $twig);
+
+        $controller = $this->createController();
+        $controller->setContainer($container);
+
+        $response = $controller->renderForm('foo', $form, ['bar' => 'bar']);
+
+        $this->assertTrue($response->isSuccessful());
+        $this->assertSame('bar', $response->getContent());
+    }
+
+    public function testRenderInvalidFormTwig()
+    {
+        $formView = new FormView();
+
+        $form = $this->getMockBuilder(FormInterface::class)->getMock();
+        $form->expects($this->once())->method('createView')->willReturn($formView);
+        $form->expects($this->once())->method('isSubmitted')->willReturn(true);
+        $form->expects($this->once())->method('isValid')->willReturn(false);
+
+        $twig = $this->getMockBuilder(Environment::class)->disableOriginalConstructor()->getMock();
+        $twig->expects($this->once())->method('render')->with('foo', ['form' => $formView, 'bar' => 'bar'])->willReturn('bar');
+
+        $container = new Container();
+        $container->set('twig', $twig);
+
+        $controller = $this->createController();
+        $controller->setContainer($container);
+
+        $response = $controller->renderForm('foo', $form, ['bar' => 'bar']);
+
+        $this->assertSame(Response::HTTP_UNPROCESSABLE_ENTITY, $response->getStatusCode());
+        $this->assertSame('bar', $response->getContent());
+    }
+
     public function testRedirectToRoute()
     {
         $router = $this->getMockBuilder(\Symfony\Component\Routing\RouterInterface::class)->getMock();