Component used: Navigation
Version used: 1.0.0-alpha01
Devices/Android versions reproduced on: All

When I call navigate method in fragment's onResume, app crashes with IllegalStateException. Including sample project to reproduce bug in attachment.

override fun onResume() {
super.onResume()
findNavController().navigate(R.id.action_firstFragment_to_secondFragment)
}

Stack trace:

java.lang.RuntimeException: Unable to resume activity {com.navigationbug.navigationbug/com.navigationbug.navigationbug.MainActivity}: java.lang.IllegalStateException: FragmentManager is already executing transactions
at android.app.ActivityThread.performResumeActivity(ActivityThread.java:3788)
at android.app.ActivityThread.handleResumeActivity(ActivityThread.java:3828)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3036)
at android.app.ActivityThread.-wrap11(Unknown Source:0)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1696)
at android.os.Handler.dispatchMessage(Handler.java:105)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6938)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:327)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1374)
Caused by: java.lang.IllegalStateException: FragmentManager is already executing transactions
at android.support.v4.app.FragmentManagerImpl.ensureExecReady(FragmentManager.java:2179)
at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:2239)
at android.support.v4.app.FragmentManagerImpl.executePendingTransactions(FragmentManager.java:784)
at androidx.navigation.fragment.FragmentNavigator.navigate(FragmentNavigator.java:157)
at androidx.navigation.fragment.FragmentNavigator.navigate(FragmentNavigator.java:45)
at androidx.navigation.NavDestination.navigate(NavDestination.java:341)
at androidx.navigation.NavController.navigate(NavController.java:618)
at androidx.navigation.NavController.navigate(NavController.java:565)
at androidx.navigation.NavController.navigate(NavController.java:553)
at com.navigationbug.navigationbug.FirstFragment.onResume(FirstFragment.kt:19)
at android.support.v4.app.Fragment.performResume(Fragment.java:2390)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1474)
at android.support.v4.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManager.java:1759)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1827)
at android.support.v4.app.FragmentManagerImpl.dispatchStateChange(FragmentManager.java:3244)
at android.support.v4.app.FragmentManagerImpl.dispatchResume(FragmentManager.java:3212)
at android.support.v4.app.Fragment.performResume(Fragment.java:2396)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1474)
at android.support.v4.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManager.java:1759)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1827)
at android.support.v4.app.FragmentManagerImpl.dispatchStateChange(FragmentManager.java:3244)
at android.support.v4.app.FragmentManagerImpl.dispatchResume(FragmentManager.java:3212)
at android.support.v4.app.FragmentController.dispatchResume(FragmentController.java:217)
at android.support.v4.app.FragmentActivity.onResumeFragments(FragmentActivity.java:509)
at android.support.v4.app.FragmentActivity.onPostResume(FragmentActivity.java:498)
at android.support.v7.app.AppCompatActivity.onPostResume(AppCompatActivity.java:171)
at android.app.Activity.performResume(Activity.java:7368)
at android.app.ActivityThread.performResumeActivity(ActivityThread.java:3763)
at android.app.ActivityThread.handleResumeActivity(ActivityThread.java:3828)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3036)
at android.app.ActivityThread.-wrap11(Unknown Source:0)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1696)
at android.os.Handler.dispatchMessage(Handler.java:105)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6938)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:327)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1374)