MAGETWO-50025: Extention attributes errors for CartItemInterface #3640

Author: Stanislav Idolov

app/code/Magento/Quote/Model/Cart/Totals/ItemConverter.php

@@ -8,6 +8,7 @@
 use Magento\Catalog\Helper\Product\ConfigurationPool;
 use Magento\Framework\Event\ManagerInterface as EventManager;
 use Magento\Framework\Api\DataObjectHelper;
+use Magento\Framework\Api\ExtensibleDataInterface;
 
 /**
  * Cart item totals converter.
@@ -68,6 +69,8 @@ public function modelToDataObject($item)
         $this->eventManager->dispatch('items_additional_data', ['item' => $item]);
         $items = $item->toArray();
         $items['options'] = $this->getFormattedOptionValue($item);
+        unset($items[ExtensibleDataInterface::EXTENSION_ATTRIBUTES_KEY]);
+
         $itemsData = $this->totalsItemFactory->create();
         $this->dataObjectHelper->populateWithArray(
             $itemsData,