Component used: Navigation Component
Version used: 1.0.0-alpha02
Devices/Android versions reproduced on: Emulator API 28, Samsung J5 API 25

Sample project attached.

I'm trying to create a custom Navigator and custom NavDestination that would animate ConstraintLayout (but any custom NavDestination would cause this issue).
Intended behaviour is shown in attached video: Layout_animations.webm

However, when I rotate the screen, while the navigation is on the custom destination, the application crashes.
The crash is caused by an unknown destination, which can only be added after custom navigator.
If I add custom destination in nav_main.xml, the app will also crash, because the navigator is not yet added.

This issue could be fixed by extending NavHostFragment, but I would need to override the whole onCreate() method.
I would need to add my custom navigator right after the line:
mNavController = new NavController(context);

I can think of 2 possible solutions in the library:
1. Delegate creating of NavController, so that a custom NavController can be provided in the XML layout file.
2. Call a new protected method "NavHostFragment.onNavControllerCreated(NavController)" right after the NavController is created, that could be overridden in a custom NavHostFragment, before the graph is created.

If there is any solution to my problem that I didn't think of, please provide a more exhaustive example in the documentation: https://developer.android.com/topic/libraries/architecture/navigation/navigation-add-new

Stack trace:

2018-06-25 10:54:28.356 14543-14543/it.czerwinski.customnavigatorexample E/AndroidRuntime: FATAL EXCEPTION: main
Process: it.czerwinski.customnavigatorexample, PID: 14543
java.lang.RuntimeException: Unable to start activity ComponentInfo{it.czerwinski.customnavigatorexample/it.czerwinski.customnavigatorexample.MainActivity}: android.view.InflateException: Binary XML file line #10: Binary XML file line #10: Error inflating class fragment
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2925)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3060)
at android.app.ActivityThread.handleRelaunchActivityInner(ActivityThread.java:4792)
at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:4711)
at android.app.servertransaction.ActivityRelaunchItem.execute(ActivityRelaunchItem.java:69)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:110)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:70)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1800)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6649)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:826)
Caused by: android.view.InflateException: Binary XML file line #10: Binary XML file line #10: Error inflating class fragment
Caused by: android.view.InflateException: Binary XML file line #10: Error inflating class fragment
Caused by: java.lang.IllegalStateException: unknown destination during restore: it.czerwinski.customnavigatorexample:id/animatedLayoutDestination
at androidx.navigation.NavController.onGraphCreated(NavController.java:424)
at androidx.navigation.NavController.setGraph(NavController.java:386)
at androidx.navigation.NavController.restoreState(NavController.java:742)
at androidx.navigation.fragment.NavHostFragment.onCreate(NavHostFragment.java:215)
at androidx.fragment.app.Fragment.performCreate(Fragment.java:2400)
at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManager.java:1418)
at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManager.java:1684)
at androidx.fragment.app.FragmentManagerImpl.onCreateView(FragmentManager.java:3772)
at androidx.fragment.app.FragmentController.onCreateView(FragmentController.java:120)
at androidx.fragment.app.FragmentActivity.dispatchFragmentsOnCreateView(FragmentActivity.java:395)
at androidx.fragment.app.FragmentActivity.onCreateView(FragmentActivity.java:377)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:780)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:730)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:863)
at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:824)
at android.view.LayoutInflater.inflate(LayoutInflater.java:515)
at android.view.LayoutInflater.inflate(LayoutInflater.java:423)
at android.view.LayoutInflater.inflate(LayoutInflater.java:374)
at androidx.appcompat.app.AppCompatDelegateImpl.setContentView(AppCompatDelegateImpl.java:467)
at androidx.appcompat.app.AppCompatActivity.setContentView(AppCompatActivity.java:140)
at it.czerwinski.customnavigatorexample.MainActivity.onCreate(MainActivity.kt:15)
at android.app.Activity.performCreate(Activity.java:7130)
at android.app.Activity.performCreate(Activity.java:7121)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1262)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2905)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3060)
at android.app.ActivityThread.handleRelaunchActivityInner(ActivityThread.java:4792)
at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:4711)
2018-06-25 10:54:28.356 14543-14543/it.czerwinski.customnavigatorexample E/AndroidRuntime: at android.app.servertransaction.ActivityRelaunchItem.execute(ActivityRelaunchItem.java:69)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:110)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:70)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1800)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6649)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:826)