Order creates an outstanding amount when using single use discount

[danaenz]

Silvershop Discounts dev-master
SS version 3.3

1. Create a few single use Coupons, which use a percentage (eg 99%) and apply to the whole order.
2. Open an incognito window
3. Make an order and apply a single use discount. This order will go through fine
4. In the same session, create a new order, using a new single use coupon. The order will appear to not apply the discount and have the full amount as the remaining to pay. The correct discounted amount goes through to the payment gateway (eg DPS) but the order does not get marked as Paid.

I've run into this issue consistently across SilverStripe, SilverShop and Discount versions. It has been notoriously hard to replicate, but the above should work.

[danaenz]

Interestingly, the Receipt notification does not display this problem.

[danaenz]

This is still a serious issue and we have been unable to find the cause despite many developer hours.

[wilr]

@danaenz So this is for a single use coupon used twice or 2 different single use coupons? Can you replicate on a clean checkout of the latest releases.

[christopherbolt]

Does this issue occur if you use a different gateway, perhaps just test with the dummy gateway and confirm. If the issue only happens when using DPS as your gateway then it may be caused by the same issue described here (unresolved). Because DPS notifies the site that the payment went through in the background (not part of the user session) any order data in session or requiring session isn't available which affects discounts.
silvershop/silvershop-core#705

[danaenz]

@christopherbolt this would definitely explain it! We haven't been able to replicate the issue on local test environments reliably. It would explain a lot, actually. I'll keep looking into it.

[beeonlinenz]

@danaenz did you ever make any progress with a fix for this?
I have a client with the same issue, i.e. DPS payments are still showing an 'outstanding' amount for discounted orders.

[danaenz]

Sorry @beeonlinenz , no progress yet. I'm actually working more with SwipeStripe now so haven't had the chance to try and solve this.

[christopherbolt]

Please see my related bug report where I have posted a solution to this issue: silvershop/silvershop-core#705

[wernerkrauss]

I had this issue on a project with unlimited discounts. The problem is, that the order is calculated somehow, but not saved to DB with multistep checkout.

I changed the setCoupon method to:

    public function setcoupon($data, $form)
    {
        $this->checkoutconfig()->setData($form->getData());

        $order = $this->checkoutconfig()->getOrder();
        $order->calculate();
        if ($order->isChanged()) {
            $order->write();
        }

       return $this->owner->redirect($this->NextStepLink());
    }

This seems to fix the error.

[wilr]

@wernerkrauss Did you want to send this as a PR?

[alex-dna]

I've used the onPayment hook to update the final order:

public function onPayment()
{
        $subtotal = $this->owner->Total();
        $total = $this->owner->calculate();
        $discounted = $total < $subtotal;

        if ($discounted === true) {
            $this->owner->setTotal($total);
            $this->owner->write();
        }
}