PromiseKit 6: Cannot invoke 'then' with an argument list of type '((String, String) -> Promise<Data>)'

Question

I have a when(fulfilled: [Thenable]) that returns Promise<(String, String)>, however when I try to use these arguments in my then block I receive the following error:

Cannot invoke 'then' with an argument list of type '((String, String) -> Promise)

My code is as follows:

func fetchAll(includeClosed: Bool) -> Promise<AccountInformation> {
    return when(fulfilled: [auth.currentUserIdPromise(), auth.getIdToken()])
        .then { (uid, token) in self.db.get(userID: uid, uri: "accounts", token: token) }
        .then { /* Some more stuff */ }
   }
}

In case it isn't clear, auth.currentUserIdPromise() and auth.getIdToken() both resolve to String and db.get returns a promise.

Things I've tried:

• Explicitly expressing types
• Clean and build

Does anyone know how I can resolve this issue?

Thanks in advance :)

Answer 1

I also posted this question to PromiseKit on GitHub and it turns out I was using the wrong 'when':

WAS: return when(fulfilled: [auth.currentUserIdPromise(), auth.getIdToken()])

NOW: return when(fulfilled: auth.currentUserIdPromise(), auth.getIdToken())

The former returns an array, whereas the latter returns a tuple.

https://github.com/mxcl/PromiseKit/issues/943