Setting another coordinator as root does not remove previous coordinators navigation controller from window stack on iOS 12

[Rendel27]

Hello everyone,

There is a bug that prevents previous coordinators navigation controller (it's children and presented view controllers as well) to remove from UIApplication.shared.keyWindow's stack, when you set another coordinator as root:

let firstCoordinator = FirstCoordinator()
firstCoordinator.strongRouter.trigger(.another)

`
class FirstCoordinator: NavigationCoordinator {

override func prepareTransition(for route: FirstRoute) -> NavigationTransition {
    switch route {
    case .another:
        let secondCoordinator = SecondCoordinator()
        secondCoordinator.trigger(.pushSomething)
        return .present(secondCoordinator)
    }
}

}

class SecondCoordinator: NavigationCoordinator {

override func prepareTransition(for route: SecondRoute) -> NavigationTransition {
    switch route {
    case .push:
        DispatchQueue(label: "asdf").asyncAfter(deadline: .now() + 3) {
            DispatchQueue.main.async {
                let viewController = UIViewController()
                viewController.view.backgroundColor = UIColor(red: 0, green: 1, blue: 1, alpha: 0.5)
                UIApplication.shared.keyWindow?.rootViewController = viewController
            }
        }
        let viewController = UIViewController()
        viewController.view.backgroundColor = UIColor(red: 1, green: 1, blue: 0, alpha: 0.5)
        return .push(viewController)
    }
}

}
`

In this case if you check ui debugger you will see old view controllers and navigation controller in the stack.

NOTE: This happens on iOS 12 (and maybe 11 as well, but not sure).
It works good on iOS 13.

I have attached sample project too see the problem more detailed:
testMultiXCoordinator.zip

Thanks
Giorgi

[anthonygeranio]

@Rendel27 Did you fix this issue?

[Rendel27]

@Rendel27 Did you fix this issue?

Nope :( Have not tried it again

[d2vydov]

you can try to use this way:

    public override var viewController: UIViewController! {
        return autoreleaseController
    }
    
    private weak var autoreleaseController: UIViewController?
    
    ..
    
    override func prepareTransition(for route: SecondRoute) -> NavigationTransition {
    switch route {
    case .push:
        DispatchQueue(label: "asdf").asyncAfter(deadline: .now() + 3) {
            DispatchQueue.main.async {
                let viewController = UIViewController()
                viewController.view.backgroundColor = UIColor(red: 0, green: 1, blue: 1, alpha: 0.5)
                UIApplication.shared.keyWindow?.rootViewController = viewController
            }
        }
        let viewController = UIViewController()
        viewController.view.backgroundColor = UIColor(red: 1, green: 1, blue: 0, alpha: 0.5)
        autoreleaseController = viewController
        return .push(viewController)
    }