[HttpFoundation] Check if data passed to SessionBagProxy::initialize is an array

src/Symfony/Component/HttpFoundation/Session/Storage/NativeSessionStorage.php

@@ -430,7 +430,7 @@ class NativeSessionStorage implements SessionStorageInterface
 
         foreach ($bags as $bag) {
             $key = $bag->getStorageKey();
-            $session[$key] = isset($session[$key]) ? $session[$key] : [];
+            $session[$key] = isset($session[$key]) && \is_array($session[$key]) ? $session[$key] : [];
             $bag->initialize($session[$key]);
         }