merged branch Tobion/patch-2 (PR #5240)

Commits
-------

9e5d5a4 [Form] fix static method call

Discussion
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[Form] fix static method call

`allowDataWalking` was called statically, but wasnt defined as such.

src/Symfony/Component/Form/Extension/Validator/Constraints/FormValidator.php

@@ -53,7 +53,7 @@ public function validate($form, Constraint $constraint)
             // Validate the form data only if transformation succeeded
             $path = $this->context->getPropertyPath();
             $graphWalker = $this->context->getGraphWalker();
-            $groups = $this->getValidationGroups($form);
+            $groups = self::getValidationGroups($form);
 
             if (!empty($path)) {
                 $path .= '.';
@@ -126,7 +126,7 @@ public function validate($form, Constraint $constraint)
      *
      * @return Boolean Whether the graph walker may walk the data.
      */
-    private function allowDataWalking(FormInterface $form)
+    private static function allowDataWalking(FormInterface $form)
     {
         $data = $form->getData();
 
@@ -158,7 +158,7 @@ private function allowDataWalking(FormInterface $form)
      *
      * @return array The validation groups.
      */
-    private function getValidationGroups(FormInterface $form)
+    private static function getValidationGroups(FormInterface $form)
     {
         do {
             $groups = $form->getConfig()->getOption('validation_groups');