fixed Twig provider on Symfony 3.4

src/Silex/Provider/TwigServiceProvider.php

@@ -27,6 +27,8 @@ use Symfony\Bridge\Twig\Extension\WebLinkExtension;
 use Symfony\Bridge\Twig\Form\TwigRendererEngine;
 use Symfony\Bridge\Twig\Form\TwigRenderer;
 use Symfony\Bridge\Twig\Extension\HttpKernelRuntime;
+use Symfony\Component\Form\FormRenderer;
+use Symfony\Component\HttpKernel\Kernel;
 use Symfony\Component\WebLink\HttpHeaderSerializer;
 
 /**
@@ -126,7 +128,11 @@ class TwigServiceProvider implements ServiceProviderInterface
                     $app['twig.form.renderer'] = function ($app) {
                         $csrfTokenManager = isset($app['csrf.token_manager']) ? $app['csrf.token_manager'] : null;
 
+                        if (Kernel::VERSION_ID < 30400) {
                             return new TwigRenderer($app['twig.form.engine'], $csrfTokenManager);
+                        }
+
+                        return new FormRenderer($app['twig.form.engine'], $csrfTokenManager);
                     };
 
                     $twig->addExtension(new FormExtension(class_exists(HttpKernelRuntime::class) ? null : $app['twig.form.renderer']));
@@ -186,10 +192,17 @@ class TwigServiceProvider implements ServiceProviderInterface
         };
 
         $app['twig.runtimes'] = function ($app) {
-            return [
+            $runtimes = [
                 HttpKernelRuntime::class => 'twig.runtime.httpkernel',
-                TwigRenderer::class => 'twig.form.renderer',
             ];
+
+            if (Kernel::VERSION_ID < 30400) {
+                $runtimes[TwigRenderer::class] = 'twig.form.renderer';
+            } else {
+                $runtimes[FormRenderer::class] = 'twig.form.renderer';
+            }
+
+            return $runtimes;
         };
 
         $app['twig.runtime_loader'] = function ($app) {

tests/Silex/Tests/Provider/TwigServiceProviderTest.php

@@ -20,6 +20,7 @@ use Silex\Provider\TwigServiceProvider;
 use Silex\Provider\AssetServiceProvider;
 use Symfony\Bridge\Twig\Extension\WebLinkExtension;
 use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpKernel\Kernel;
 use Symfony\Component\WebLink\HttpHeaderSerializer;
 
 /**
@@ -109,9 +110,13 @@ class TwigServiceProviderTest extends TestCase
         $app->register(new CsrfServiceProvider());
         $app->register(new TwigServiceProvider());
 
-        $this->assertInstanceOf('Twig_Environment', $app['twig'], 'Service twig is created successful.');
-        $this->assertInstanceOf('Symfony\Bridge\Twig\Form\TwigRendererEngine', $app['twig.form.engine'], 'Service twig.form.engine is created successful.');
-        $this->assertInstanceOf('Symfony\Bridge\Twig\Form\TwigRenderer', $app['twig.form.renderer'], 'Service twig.form.renderer is created successful.');
+        $this->assertInstanceOf('Twig_Environment', $app['twig']);
+        $this->assertInstanceOf('Symfony\Bridge\Twig\Form\TwigRendererEngine', $app['twig.form.engine']);
+        if (Kernel::VERSION_ID < 30400) {
+            $this->assertInstanceOf('Symfony\Bridge\Twig\Form\TwigRenderer', $app['twig.form.renderer']);
+        } else {
+            $this->assertInstanceOf('Symfony\Component\Form\FormRenderer', $app['twig.form.renderer']);
+        }
     }
 
     public function testFormWithoutCsrf()