In some cases, Stripe will return the result of a transaction with
a faulty HTTP Status (e.g. 4XX statuses) - not because the request
was malformed, but because the payment failed. It is a bit unfortunate
that Stripe would not differentiate between payment status and request
validity, but that's the state of things.
This commit ensures that such a response will be logged correctly, by
making the call to `raise_for_status` conditionnal on the response object's
status code and internal structure, forwarding the response's json to the
validation flow if the status is in the 4XX range and a `code` key is
found in the response, as described in https://stripe.com/docs/error-codes
While testing this fix, it became apparent that some error message
processing in the frontend was not correctly handled as well - instead
of purely rejecting the promise, a failed payment should still send its
payload to the backend, to allow the server to put the transaction in
the correct state according to the response.
Damien Bouvy
525d363b56