UpdateBasketItemAction::checkQuantity

private function checkQuantity(SaleBasket $basket): SaleResult
{
	$result = new SaleResult();

	$actualQuantityList = $this->getActualQuantityList($basket);
	SaleBasketComponentHelper::correctQuantityRatio($basket);

	$updatedQuantityList = $this->getActualQuantityList($basket);
	foreach ($updatedQuantityList as $basketCode => $itemQuantity)
	{
		if (!isset($actualQuantityList[$basketCode]) || $itemQuantity !== $actualQuantityList[$basketCode])
		{
			$result->addError(new MainError('quantity is incorrect'));
		}
	}

	return $result;
}