Merge branch '4.3' into 4.4

* 4.3:
  Do not extend the new SF 4.3 ControllerEvent so we can make it final
  Backported return type violation bugfixes.
  [FrameworkBundle] Fix BrowserKit assertions to make them compatible with Panther

src/Symfony/Component/Form/Tests/Extension/Validator/EventListener/ValidationListenerTest.php

@@ -26,6 +26,7 @@ use Symfony\Component\Form\FormFactoryBuilder;
 use Symfony\Component\Form\FormFactoryInterface;
 use Symfony\Component\Validator\ConstraintViolation;
 use Symfony\Component\Validator\ConstraintViolationInterface;
+use Symfony\Component\Validator\ConstraintViolationList;
 use Symfony\Component\Validator\Context\ExecutionContextInterface;
 use Symfony\Component\Validator\Validation;
 use Symfony\Component\Validator\Validator\ValidatorInterface;
@@ -166,7 +167,7 @@ class DummyValidator implements ValidatorInterface
 
     public function validate($value, $constraints = null, $groups = null)
     {
-        return [$this->violation];
+        return new ConstraintViolationList([$this->violation]);
     }
 
     public function validateProperty($object, $propertyName, $groups = null)

src/Symfony/Component/Form/Tests/Fixtures/FooType.php

@@ -17,5 +17,6 @@ class FooType extends AbstractType
 {
     public function getParent()
     {
+        return null;
     }
 }

src/Symfony/Component/HttpKernel/Event/FilterControllerArgumentsEvent.php

@@ -17,7 +17,7 @@ use Symfony\Component\HttpKernel\HttpKernelInterface;
 /**
  * @deprecated since Symfony 4.3, use ControllerArgumentsEvent instead
  */
-class FilterControllerArgumentsEvent extends ControllerEvent
+class FilterControllerArgumentsEvent extends FilterControllerEvent
 {
     private $arguments;
 

src/Symfony/Component/Mime/composer.json

@@ -24,6 +24,9 @@
         "egulias/email-validator": "^2.0",
         "symfony/dependency-injection": "^3.4|^4.1|^5.0"
     },
+    "conflict": {
+        "symfony/mailer": "<4.4"
+    },
     "autoload": {
         "psr-4": { "Symfony\\Component\\Mime\\": "" },
         "exclude-from-classmap": [

src/Symfony/Component/Security/Core/Encoder/EncoderAwareInterface.php

@@ -22,7 +22,7 @@ interface EncoderAwareInterface
      * If the method returns null, the standard way to retrieve the encoder
      * will be used instead.
      *
-     * @return string
+     * @return string|null
      */
     public function getEncoderName();
 }

src/Symfony/Component/Security/Core/User/User.php

@@ -71,6 +71,7 @@ final class User implements UserInterface, EquatableInterface, AdvancedUserInter
      */
     public function getSalt()
     {
+        return null;
     }
 
     /**