[DEPRECATION] : deprecated support for Traversable in method ResizeFormListener::PreSubmit

UPGRADE-3.1.md

@@ -15,6 +15,9 @@ Form
 
  * The `choices_as_values` option of the `ChoiceType` has been deprecated and
    will be removed in Symfony 4.0.
+ * Support for data objects that implements both `\Traversable` and `\ArrayAccess`
+   in `ResizeFormListener::preSubmit` method has been deprecated and will be
+   removed in Symfony 4.0.
 
 HttpKernel
 ----------

UPGRADE-4.0.md

@@ -13,6 +13,8 @@ Form
 ----
 
  * The `choices_as_values` option of the `ChoiceType` has been removed.
+ * Support for data objects that implements both `\Traversable` and
+   `\ArrayAccess` in `ResizeFormListener::preSubmit` method has been removed
 
 Serializer
 ----------

src/Symfony/Component/Form/CHANGELOG.md

@@ -5,6 +5,8 @@ CHANGELOG
 -----
 
  * deprecated the "choices_as_values" option of ChoiceType
+ * deprecated support for data objects that implements both `\Traversable` and
+   `\ArrayAccess` in `ResizeFormListener::preSubmit` method
 
 3.0.0
 -----

src/Symfony/Component/Form/Extension/Core/EventListener/ResizeFormListener.php

@@ -102,6 +102,10 @@ class ResizeFormListener implements EventSubscriberInterface
         $form = $event->getForm();
         $data = $event->getData();
 
+        if ($data instanceof \Traversable && $data instanceof \ArrayAccess) {
+            @trigger_error('Support for objects implementing both \Traversable and \ArrayAccess is deprecated since version 3.1 and will be removed in 4.0. Use an array instead.', E_USER_DEPRECATED);
+        }
+
         if (null === $data || '' === $data) {
             $data = array();
         }