On the PayPal Direct connection we have specified currencies supported by the PayPal Payment method. As such, when a currency that is not on this list is provided, the Payments form falls back to the default currency "USD", with a message "Your currency was unsupported. Processing will take place using USD, if you decide to continue." (example link).
The currencies configuration on DonationInterface consists of all the currencies supported by all the payment methods each Payment Processor integrates with. We can do either of 2 approaches:
- Manually setup a list of supported currencies for each payment method in the DI-Gravy config. Downside to this is we have to manually update this whenever a country is added on the Gravy region details configuration.
- Use the Gravy API to look up support for the country/currency combination and use the fallback when the combination is not supported.