Empty shippingOptions (ab)used as error

[marcoscaceres]

Related to #594.

Consider the following situation, where no shippingOptions are given, but requestShipping: true:

const methods = [{ supportedMethods: ["basic-card"] }];
const details = {
  total: {
    label: "Total due",
    amount: { currency: "USD", value: "1.0" },
  },
};
const options = {
  requestShipping: true,
};

const request = new PaymentRequest(methods, details, options);

Given the fix in #591, it should be perfectly ok to await a PaymentResponse without needing the user to pick a (non-existent) shipping option:

const response = await request.show();

Right now, the above ends in user frustration, because they are told:

But technically, the .shippingAddress could be provided to the site, and they could then resolve the shippingOption locally and would be a solution to #537 "Shipping Address Validation - Suggest Alternate Address").

[marcoscaceres]

To be clear: my proposal is to allow .shippingOptions to be empty. Don't (ab)use that to be an error in the payment sheet.

[marcoscaceres]

Also related #548.

[adrianba]

Agreed not to do this.