IssueTracker

Oh I forgot to mention that I thought it might be connected to this issue: https://issuetracker.google.com/issues/243778589. But after trying 2.5.2 I can say that the issue persists.

Please provide a minimal sample project along with the minimal steps to recreate the issue in the project.

Sorry for the delay. I got a working example here: https://github.com/Del-S/issues. The project is set up to crash when navigating to ThirdFragment (nested nav graph) with poping the graph.

I poked into it a little bit and it seems to be connected to SafeArgs gradle plugin. When safe args is used to navigate to ThirdFragment (with nested graph poped) it will try to recreate te parent but there were no arguments passed so it crashes.

Steps to reproduce:

1. Navigate from Second Fragment to Child nav graph (with non-nullable parameters).
2. Navigate to Third fragment using SafeArgs and the app crashes.

Crash log:

Process: cz.dels.issues, PID: 1743
java.lang.NullPointerException: null cannot be cast to non-null type kotlin.Long
at androidx.navigation.NavType$Companion$LongType$1.get(NavType.kt:352)
at androidx.navigation.NavType$Companion$LongType$1.get(NavType.kt:342)
at androidx.navigation.NavArgument.verify(NavArgument.kt:76)
at androidx.navigation.NavDestination.addInDefaultArgs(NavDestination.kt:502)
at androidx.navigation.NavController.addEntryToBackStack(NavController.kt:1865)
at androidx.navigation.NavController.addEntryToBackStack$default(NavController.kt:1813)
at androidx.navigation.NavController$navigate$4.invoke(NavController.kt:1721)
at androidx.navigation.NavController$navigate$4.invoke(NavController.kt:1719)
at androidx.navigation.NavController$NavControllerNavigatorState.push(NavController.kt:287)
at androidx.navigation.fragment.FragmentNavigator.navigate(FragmentNavigator.kt:246)
at androidx.navigation.fragment.FragmentNavigator.navigate(FragmentNavigator.kt:162)
at androidx.navigation.NavController.navigateInternal(NavController.kt:260)
at androidx.navigation.NavController.navigate(NavController.kt:1719)
at androidx.navigation.NavController.navigate(NavController.kt:1545)
at androidx.navigation.NavController.navigate(NavController.kt:1472)
at androidx.navigation.NavController.navigate(NavController.kt:1930)
at cz.dels.issues.SecondFragment.onViewCreated$lambda-0(SecondFragment.kt:38)
at cz.dels.issues.SecondFragment.$r8$lambda$XDYnOS_cYrafiNQ5rcCu1WCn0IE(Unknown Source:0)
at cz.dels.issues.SecondFragment$$ExternalSyntheticLambda0.onClick(Unknown Source:2)

Note: If in step 2 SaveArgs is not used then navigation works correctly. More information is here: https://github.com/Del-S/issues/blob/master/app/src/main/java/cz/dels/issues/SecondFragment.kt#L37.

Ups a typo: Navigate from Second First Fragment to Child nav graph (with non-nullable parameters).

Note: sorry for the spam but I am not able to edit my own comment.

This has been fixed and will be available in navigation 2.6.0-alpha08

The following release(s) address this bug.It is possible this bug has only been partially addressed:

• androidx.navigation:navigation-runtime:2.6.0-alpha08

Why this fix doesn't included in 2.3.3?

Re #10, yes, you're right this didn't make it into Navigation 2.3.3. Sorry about that. We'll look at doing a Navigation 2.3.4 with this fix.

I believe I'm facing another issue because of this fix:

When navigating to an activity that belongs to a dynamic module, the AbstractProgressFragment is not removed from the back stack. The line that's supposed to do it was moved from onResume to onViewCreated:

if (navigated) {
    findNavController().popBackStack()
    return
}

And onViewCreated is not called since we're coming back from another activity.

Moving that block back to the onResume method should solve the problem. In the meantime (as a workaround), I guess we can do as follows:

class CustomProgressFragment : AbstractProgressFragment() {

    private var navigated = false

    override fun onResume() {
        super.onResume()
        // Workaround:
        // AbstractProgressFragment is not being removed from the back stack when returning from another activity
        if (navigated) findNavController().popBackStack()
    }

    override fun onInstalled() {
        testing = true
    }
   
   ...
   ...
}

Update: Regarding the workaround I mentioned, this is the correct implementation of the onInstalled method

    override fun onInstalled() {
        navigated = true
    }

Re comment#13 - please file a separate bug with a sample project that reproduces your issue. onViewCreated() is indeed called when you return to the AbstractProgressFragment from another fragment, which is the only thing your newly loaded graph should have as its start destination. You...don't happen to have a start destination that is an activity destination? You shouldn't be using Dynamic Navigation at all in that case (as the system will auto-download the module your activity is in upon request).