I've got the following code in my tab bar:

func tabBarController(_ tabBarController: UITabBarController, shouldSelect viewController: UIViewController) -> Bool {
    guard
        let navigationController = viewController as? UINavigationController,
        let rootViewController = navigationController.viewControllers.first // (1) derives the root view controller of the navigation controller preparing to be selected.
    else { return true }
}

My problem is that my UISplitViewControllers don't appear in rootViewController when I tap on them and print it's value. I read that they can't be rootViewControllers.

How do I find the UISplitViewController in the navigation stack of controllers, so I can allow or disallow user into the split view depending on whether they've entered required information.