PayPal Express (from PayFlow) - Can't create order with ampersand in product name and discount

Question

I've found issue that prevent using PayPal Express (from PayPal PayFlow).

Magento version: 1.9.2.1

Steps to reproduce:

1. Configure PayPal Payflow WITH Express checkout.
2. Go to frontend and add some product, that contains "&" or "=" symbol, to shopping cart
3. Apply any coupon that add discount
4. Click "Check out with PayPal" button (express checkout) on checkout page

Expected Result:

Customer should be redirected to PayPal and have ability to place order.

Actual Result:

Customer gets error message on shopping cart page:

PayPal gateway rejected the request. Field format error: 10413-The totals of the cart item amounts do not match order amounts.

If you try to create order with "PayPal Payflow" (credit card) - it works good, but express checkout isn't work correct with discounts.

Issue was reported to Magento: http://www.magentocommerce.com/bug-tracking/issue/index/id/1161

Answer 1

I've found two issues:

1. ITEMATM field wasn't filled, it tried to get value from incorrect field. Fix in this case: https://gist.github.com/ihor-sviziev/4716c6d79fb728078ddd
2. When product name contains "&" or "=" symbol - it should be specially escaped. I've found this special case in documentation. So for this case I also prepared fix: https://gist.github.com/ihor-sviziev/f804e689acd83b8ab5f0

I've applied those patches and now it works correct!