Protocol-defined APIs marked with @discardableResult don't propagate to implementations

[palpatim]

Thanks for adding this ! After I updated my project to 1.1.0, removing derived data and cleaning the build, I still receive the 'unsused' warning. What do I miss ?

I am sure I have the correct version :

    @discardableResult
    func signIn(username: String?,
                password: String?,
                options: AuthSignInOperation.Request.Options?,
                listener: AuthSignInOperation.ResultListener?) -> AuthSignInOperation

Originally posted by @sebsto in #633 (comment)

[palpatim]

As noted in https://bugs.swift.org/browse/SR-7186, this is actually expected behavior in Swift, which I neglected to validate down the call chain. :( Will fix.

[palpatim]

Released in https://github.com/aws-amplify/amplify-ios/releases/tag/v1.1.1

[sebsto]

Thanks for addressing this.
Looks like Amplify.Hub.listendid not wen through
https://github.com/aws-amplify/amplify-ios/blob/main/Amplify/Categories/Hub/HubCategoryBehavior.swift#L26 and related implementations

[palpatim]

That's intentional--Hub APIs don't return an AmplifyOperation, they return a cancellation token, similar to what Publisher.sink() does. The Combine flavor of Hub is Hub.publisher(for:), but as with other Combine flavored APIs, the result of accessing the publisher is not discardable.

[sebsto]

Thanks Tim for the explanation.