// fix bug on Cart rule update in validateOrder

classes/PaymentModule.php

@@ -324,9 +324,14 @@ abstract class PaymentModuleCore extends Module
 						}
 
 						$order->addCartRule($cartRule->id, $cartRule->name, $value);
+
 						if ($id_order_state != Configuration::get('PS_OS_ERROR') AND $id_order_state != Configuration::get('PS_OS_CANCELED'))
-							$cartRule->quantity = $cartRule->quantity - 1;
-						$cartRule->update();
+						{
+							// Create a new instance of Cart Rule without id_lang, in order to update it quantity
+							$cart_rule_to_update = new CartRule($cartRule->id);
+							$cart_rule_to_update->quantity = $cart_rule_to_update->quantity - 1;
+							$cart_rule_to_update->update();
+						}
 
 						$cartRulesList .= '
 						<tr style="background-color:#EBECEE;">

classes/order/Order.php

@@ -975,6 +975,11 @@ class OrderCore extends ObjectModel
 
 	/**
 	 * @deprecated 1.5.0.1
+	 * @see Order::addCartRule()
+	 * @param $id_cart_rule
+	 * @param $name
+	 * @param $value
+	 * @return bool
 	 */
 	public function addDiscount($id_cart_rule, $name, $value)
 	{
@@ -982,6 +987,13 @@ class OrderCore extends ObjectModel
 		return Order::addCartRule($id_cart_rule, $name, $value);
 	}
 
+	/**
+	 * @since 1.5.0.1
+	 * @param $id_cart_rule
+	 * @param $name
+	 * @param $value
+	 * @return bool
+	 */
 	public function addCartRule($id_cart_rule, $name, $value)
 	{
 		return Db::getInstance()->AutoExecute(_DB_PREFIX_.'order_cart_rule', array('id_order' => (int)$this->id, 'id_cart_rule' => (int)$id_cart_rule, 'name' => pSQL($name), 'value' => (float)$value), 'INSERT');