Canceling order with a coupon code for logged in users FAILS

[gkopec]

Preconditions (*)

1. OpenMage 19.4.10
2. It's probably Magento bug but hard to say and it actually doesn't matter

Steps to reproduce (*)

1. Create or use a Coupon Code (Shopping Cart Price Rules) and leave Uses per Customer field empty or put 0.
2. Use this code for order placed by Logged in User
3. Make sure to choose a payment method which won't create an invoice or change the order state. The order should be in pending state.
4. Go to admin panel and try to cancel the order

Expected result (*)

1. The order should be canceled

Actual result (*)

1. Order can not be canceled message.
2. Mysql Exception:

Integrity constraint violation: 1452 Cannot add or update a child row: a foreign key constraint fails (`open_mage`.`salesrule_customer`, CONSTRAINT `FK_SALESRULE_CUSTOMER_RULE_ID_SALESRULE_RULE_ID` FOREIGN KEY (`rule_id`) REFERENCES `salesrule` (`rule_id`) ON DELETE CASCADE ON UPDATE CASCADE) in /Volumes/Workspace/om/shop/magento/lib/Zend/Db/Statement/Pdo.php:228

Reason:

In Mage_SalesRule_Model_Observer:162 system is trying to decrease the code usage amount in salesrule_customer but there's no entity to change. Used promo rule had no limitation per user, so Magento didn't create an entry after order placement.

My solution:

It could check if the entity exists ($object->getId()) before trying to manipulate it.
Mage_SalesRule_Model_Observer:162
instead:

if ($customerCoupon = Mage::getModel('salesrule/rule_customer')->loadByCustomerRule($customerId, $coupon->getRuleId())) {

use

$customerCoupon = Mage::getModel('salesrule/rule_customer')->loadByCustomerRule($customerId, $coupon->getRuleId());
if ($customerCoupon->getId()) {

[luigifab]

Same problem, I found the same solution but not why. #1220

[gkopec]

Fixed by #1473