'() -> BindingTarget<Error>' is not convertible to '(Bool) -> BindingTarget<Error>'

[Isuru Nanayakkara]

I recently inherited a iOS project written using ReactiveSwift 3.1.0 and ReactiveCocoa 7.2.0. I'm tasked with updating it to Swift 5 and the latest ReactiveSwift versions.

I updated ReactiveSwift to 6.1.0 and ReactiveCocoa to 10.1.0. I'm not well versed in Reactive programming but I managed to convert a good portion of the existing codebase to the latest versions.

However I'm stuck at this particular part. The original programmer is not available anymore.

In this project, there is an extension on view controller to present error messages.

extension Reactive where Base: UIViewController {
    func presentError(animated: Bool = true) -> BindingTarget<Error> {
        return self.makeBindingTarget { $0.present(error: $1, animated: animated) }
    }

    func present(error: Error, animated: Bool = true, completion: (() -> Void)? = nil) {
        LogError("Presenting error: \(error.verboseDescription)")
        self.present(UIAlertController(error: error, completion: completion), animated: animated, completion: nil)
    }
}

In a view controller, I'm getting the below error at this line.

self.reactive.presentError() <~ self.viewModel.reportAction.errors.map { $0 }

'() -> BindingTarget' is not convertible to '(Bool) -> BindingTarget'

This is the relevant part in the view model.

private(set) var reportAction: Action<(User, ReportReason), Void, APIKit.Error>!

The only change that happened here is the errors type in viewModel.reportAction.errors.map { $0 } changed from public let errors: Signal<Error, NoError> to public let errors: Signal<Error, Never>. This is due to some changes done in the latest ReactiveSwift source.

That has apparently broken this piece of code. I'm not sure why the error is occurring and how to fix this part.

[Rui Peres]

I suspect that the issue is around the default value animated: Bool = true. Would it be possible for you to try something like like:

    func present(error: Error, completion: (() -> Void)? = nil) {
        LogError("Presenting error: \(error.verboseDescription)")
        self.present(UIAlertController(error: error, completion: completion), animated: true, completion: nil)
    }

Just to see if it works.

[Rui Peres]

Hello. 👋 Thanks for opening this issue. Due to inactivity, we will soft close the issue. If you feel that it should remain open, please let us know. 😄