Merge branch '4.2'

* 4.2:
  [HttpFoundation] Check file exists before unlink
  [Console] Fixed #29835: ConfirmationQuestion with default true for answer '0'
  [Cache] PDO-based cache pool table autocreation does not work
  [Translation] Concatenated translation messages
  [Form] ensure compatibility with older PHPUnit mocks
  [Serializer] Docblock about throwing exceptions on serializer
  [Cache] fix used variable name
  [Debug][ErrorHandler] Preserve our error handler when a logger set another one
  [Form] Changed UrlType input type to text when default_protocol is not null
  [Bugfix] MemcachedSessionHandler::close() must close connection
  Always pass $key to NullAdapter->createCacheItem

Author: nicolas-grekas

Tests/Controller/ControllerTraitTest.php

@@ -16,6 +16,7 @@
 use Symfony\Bundle\FrameworkBundle\Tests\TestCase;
 use Symfony\Component\DependencyInjection\Container;
 use Symfony\Component\Form\Form;
+use Symfony\Component\Form\FormConfigInterface;
 use Symfony\Component\HttpFoundation\BinaryFileResponse;
 use Symfony\Component\HttpFoundation\File\File;
 use Symfony\Component\HttpFoundation\JsonResponse;
@@ -488,8 +489,7 @@ public function testCreateNotFoundException()
 
     public function testCreateForm()
     {
-        $config = $this->getMockBuilder('Symfony\Component\Form\FormConfigInterface')->getMock();
-        $form = new Form($config);
+        $form = new Form($this->getMockBuilder(FormConfigInterface::class)->getMock());
 
         $formFactory = $this->getMockBuilder('Symfony\Component\Form\FormFactoryInterface')->getMock();
         $formFactory->expects($this->once())->method('create')->willReturn($form);