[Paypal & Stripe] Failed checkout attempts add a persistent transaction fee

[filipefurtad0]

Description

If a Paypal transaction fails on checkout and a transaction fee is associated to that payment, the respective amount will be added to that order, as many times as checkout attempts (with Paypal).

This leads to an inconsistent state of the order / fail cascade, in which:

• checking out with cash is possible, but the order total will contain those ghost transaction fees ⚠️ :
• checkout with Stripe will explode 💥 : display (the warning below) and resets the cart which is a good thing. It also triggers this bugsnag error:

https://app.bugsnag.com/yaycode/openfoodnetwork-uk/errors/61ebce343d0f08000872149b?event_id=625e8a3d0093606c2ee10000&i=sk&m=nw

Expected Behavior

Failed checkout attempts using Paypal should not add a persistent transaction fee.

Actual Behaviour

Failed checkout attempts using Paypal should not add a persistent transaction fee.

Steps to Reproduce

As Admin:

1. Set up a transaction fee on a Paypal payment method
2. Edit the Paypal settings: for a valid Signature add an empty space after it 👀

As Customer:
3. Checkout on that shop, selecting that payment method
4. Notice the error on checkout
5. Check your cart, and notice the transaction fee was added
6. Empty your cart, and start over from step 3.
7. Notice the previously added transaction fee is still on the cart: transaction fees add up...
8.1 Complete this funky order using Stripe -> 💥 -> Cart should be reset.
8.2 8.1 Complete this funky order using Cash -> Order is completed with the ghost transaction fees included in the order total ⚠️

Animated Gif/Screenshot

Workaround

There are some ways to deal with the bug, but it can go unnoticed.
I'd say this is an S2 but feel free to change if you disagree.

Severity

bug-s2: a non-critical feature is broken, no workaround

Your Environment

• Version used: v4.1.26
• Browser name and version: Firefox 99
• Operating System and version (desktop or mobile): 20.04

Possible Fix

[RachL]

@filipefurtad0 this is reproductible with the new checkout as well? If not I would recommend switching these users to split checkout and not deal with this bug apart from trying to automate the test.

[filipefurtad0]

That's a good point Rachel 👀

But unfortunately, it breaks anyway in different way though. With split checkout enabled, starting on step 6 (above), leads to error 500:

For the dev picking this up, the error 500 appears on the server log:

I, [2022-04-20 09:47:48#21788]  INFO -- : Started GET "/checkout/summary" for 2.82.201.180 at 2022-04-20 09:47:48 +0000
I, [2022-04-20 09:47:48#21788]  INFO -- : Processing by SplitCheckoutController#edit as HTML
I, [2022-04-20 09:47:48#21788]  INFO -- :   Parameters: {"step"=>"summary"}
I, [2022-04-20 09:47:48#21788]  INFO -- :   Rendered split_checkout/edit.html.haml within layouts/darkswarm (Duration: 18.8ms | Allocations: 6603)
I, [2022-04-20 09:47:48#21788]  INFO -- :   Rendered layout layouts/darkswarm.html.haml (Duration: 19.0ms | Allocations: 6645)
I, [2022-04-20 09:47:48#21788]  INFO -- : Completed 500 Internal Server Error in 79ms (ActiveRecord: 22.5ms | Allocations: 24280)
I, [2022-04-20 09:47:48#21788]  INFO -- [Bugsnag]: Notifying https://notify.bugsnag.com of NoMethodError
F, [2022-04-20 09:47:48#21788] FATAL -- :   
ActionView::Template::Error (undefined method `name' for nil:NilClass):
    45:       %span.summary-label
    46:         = t("split_checkout.step1.delivery_address.title")
    47:       %span.summary-value
    48:         = @order.shipping_method.name
    49:       %div
    50:       = @order.shipping_method.description

So, from the /shop page, and after emptying the cart the shopper is being redirected to the /checkout/summary page - this is at least what I gather from the log above. At that stage, shipping address is not set, so this line fails:
48: = @order.shipping_method.name

(I think a similar redirection inconsistency might be happening in issue is happening in issue #9056 - but I'm not sure)

[jibees]

About the last comment, and the error that you saw @filipefurtad0 : i'm pretty sure I've already seen it but I've not Paypal activated on my local setup (only 'cash on collection' and 'stripe')...

[filipefurtad0]

Great, thanks for that feedback JB. It doesn't look like it relates to payment methods but rather to addresses and/or shipping methods...

[filipefurtad0]

Following this detailed description - thanks @RonellaG - the bug is reproducible as well when checking out with Stripe. For instance, using:

• card 4000000000000002
• having the enterprise fee over that payment method set as a flat percent; the bug does not occur with Stripe for a flat rate, or at least I could not reproduce it with this card error

Updating the issue name.

[filipefurtad0]

Hey @georgethoppil ,

While not preventing the creation of the ghost transaction fees, this comments seems related, as also here on the /cart page, the user can't seem to re-start an order:
#9131 (comment)