bug #24535 [TwigBridge] fix BC for FormExtension if renderer is FormRenderer (dmaicher)

This PR was squashed before being merged into the 3.4 branch (closes #24535).

Discussion
----------

[TwigBridge] fix BC for FormExtension if renderer is FormRenderer

| Q             | A
| ------------- | ---
| Branch?       | 3.4
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | https://github.com/symfony/symfony/issues/24533
| License       | MIT
| Doc PR        | -

This fixes some issues within FormExtension since the renderer is now a `FormRenderer`.

Commits
-------

4a2f608f1e [TwigBridge] fix BC for FormExtension if renderer is FormRenderer

src/Symfony/Bridge/Twig/Extension/FormExtension.php

@@ -54,7 +54,7 @@ class FormExtension extends AbstractExtension implements InitRuntimeInterface
     {
         if ($this->renderer instanceof TwigRendererInterface) {
             $this->renderer->setEnvironment($environment);
-        } elseif (null !== $this->renderer) {
+        } elseif (is_array($this->renderer)) {
             $this->renderer[2] = $environment;
         }
     }
@@ -118,7 +118,7 @@ class FormExtension extends AbstractExtension implements InitRuntimeInterface
 
             if (is_array($this->renderer)) {
                 $renderer = $this->renderer[0]->get($this->renderer[1]);
-                if (isset($this->renderer[2])) {
+                if (isset($this->renderer[2]) && $renderer instanceof TwigRendererInterface) {
                     $renderer->setEnvironment($this->renderer[2]);
                 }
                 $this->renderer = $renderer;

src/Symfony/Bridge/Twig/Tests/Extension/FormExtensionTest.php

@@ -0,0 +1,76 @@
+<?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\Bridge\Twig\Tests\Extension;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Bridge\Twig\Extension\FormExtension;
+use Symfony\Bridge\Twig\Form\TwigRendererInterface;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+use Symfony\Component\Form\FormRendererInterface;
+use Twig\Environment;
+
+/**
+ * @group legacy
+ */
+class FormExtensionTest extends TestCase
+{
+    /**
+     * @dataProvider rendererDataProvider
+     */
+    public function testInitRuntimeAndAccessRenderer($rendererConstructor, $expectedAccessedRenderer)
+    {
+        $extension = new FormExtension($rendererConstructor);
+        $extension->initRuntime($this->getMockBuilder(Environment::class)->disableOriginalConstructor()->getMock());
+        $this->assertSame($expectedAccessedRenderer, $extension->renderer);
+    }
+
+    /**
+     * @dataProvider rendererDataProvider
+     */
+    public function testAccessRendererAndInitRuntime($rendererConstructor, $expectedAccessedRenderer)
+    {
+        $extension = new FormExtension($rendererConstructor);
+        $this->assertSame($expectedAccessedRenderer, $extension->renderer);
+        $extension->initRuntime($this->getMockBuilder(Environment::class)->disableOriginalConstructor()->getMock());
+    }
+
+    public function rendererDataProvider()
+    {
+        $twigRenderer = $this->getMockBuilder(TwigRendererInterface::class)->getMock();
+        $twigRenderer->expects($this->once())
+            ->method('setEnvironment');
+
+        yield array($twigRenderer, $twigRenderer);
+
+        $twigRenderer = $this->getMockBuilder(TwigRendererInterface::class)->getMock();
+        $twigRenderer->expects($this->once())
+            ->method('setEnvironment');
+
+        $container = $this->getMockBuilder(ContainerInterface::class)->getMock();
+        $container->expects($this->once())
+            ->method('get')
+            ->with('service_id')
+            ->willReturn($twigRenderer);
+
+        yield array(array($container, 'service_id'), $twigRenderer);
+
+        $formRenderer = $this->getMockBuilder(FormRendererInterface::class)->getMock();
+
+        $container = $this->getMockBuilder(ContainerInterface::class)->getMock();
+        $container->expects($this->once())
+            ->method('get')
+            ->with('service_id')
+            ->willReturn($formRenderer);
+
+        yield array(array($container, 'service_id'), $formRenderer);
+    }
+}

src/Symfony/Bridge/Twig/composer.json

@@ -22,6 +22,7 @@
     "require-dev": {
         "fig/link-util": "^1.0",
         "symfony/asset": "~2.8|~3.0|~4.0",
+        "symfony/dependency-injection": "~2.8|~3.0|~4.0",
         "symfony/finder": "~2.8|~3.0|~4.0",
         "symfony/form": "~3.4|~4.0",
         "symfony/http-foundation": "^3.3.11|~4.0",