Replacing a NavBackStackEntry's args doesn't cause recomposition [186392337]

Fixed

Bug

Status Update

No update yet.

Description

jo...@jossiwolf.de

created issue #1

Apr 26, 2021 01:36PM

Component used: Navigation-Compose Version used: 1.0.0-alpha10, Compose 1.0.0-beta05

A bit short on time, so just posting a simple repro here. When trying to navigate to a destination that is the current destination but with different arguments using NavOptions.launchSingleTop, the NavController will replace the current NavBackStackEntry's arguments. Consider the following example:

@Composable
fun App() {
    val navController = rememberNavController()
    NavHost(
        navController = navController,
        startDestination = "home?arg={arg}"
    ) {
        composable(route = "home?arg={arg}") { backStackEntry ->
            val arg = backStackEntry.arguments?.getString("arg") ?: "Empty"
            Column {
                Text("Argument: $arg")
                Button(
                    onClick = {
                        navController.navigate("home?arg=value2") {
                            launchSingleTop = true
                        }
                    }
                ) {
                    Text("Click to navigate!")
                }
            }
        }
    }
}

In NavController#currentBackStackEntryAsState, the State's value won't be changed because the reference stays the same and the NavBackStackEntry held by the state has already been mutated, so the NavHost won't recompose after that change. Maybe the NeverEqualPolicy could be used as a quick fix.

Let me know if you need more info, cheers!

Comments

il...@google.com <il...@google.com> Jun 8, 2021 08:02PM

Assigned to jb...@google.com.

wa...@reaktor.fi <wa...@reaktor.fi> #2Jun 28, 2021 09:21AM

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.

Screen Recording 2021-06-28 at 12.08.31.mov

1.5 MB

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th...@gmail.com <th...@gmail.com> #3Aug 11, 2021 05:48AM

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

ap...@google.com <ap...@google.com> #4Aug 12, 2021 12:30AM

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:

Navigate from Second Fragment to Child nav graph (with non-nullable parameters).
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.

jb...@google.com <jb...@google.com> #5Aug 12, 2021 03:02AM

Marked as fixed.

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.

ro...@gmail.com <ro...@gmail.com> #6Aug 12, 2021 04:02AM

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

jb...@google.com <jb...@google.com> #7Aug 12, 2021 02:47PM

Project: platform/frameworks/support
Branch: androidx-main

commit 6b358154b794a0456b089ac8e548bfb830dd6c22
Author: Clara Fok <clarafok@google.com>
Date: Tue Mar 14 17:56:12 2023

Fix missing non-nullable arg when rebuilding hierarchy

When navigating with NavDirections, args is populated with an empty bundle. This causes issue when we rebuild parent hierarchy while adding a new entry to NavBackStack. If the Entry being rebuilt contains a non-nullalbe arg, i.e. Long, this empty bundle will cause an exception.

Test: ./gradlew navigation:navigation-runtime:cC
Bug: 249988437
Change-Id: I5c8ce739ad9a3428c8a8de13eae391bfff0db5df

M navigation/navigation-runtime/src/androidTest/java/androidx/navigation/NavControllerTest.kt
M navigation/navigation-runtime/src/main/java/androidx/navigation/NavController.kt

https://android-review.googlesource.com/2488855

ro...@gmail.com <ro...@gmail.com> #8Aug 12, 2021 04:29PM

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

ro...@gmail.com <ro...@gmail.com> #9Aug 12, 2021 04:33PM

The issue in #comment2 is also still happening. For example, in the code from #comment1, notice how tapping the button does not update the value as expected: it always stays Empty. But if you leave the app open and toggle the system dark mode, now the app will get recomposed with the new value2.

If it helps, I can share the project, but it's really just the code from #comment1 put in an "Empty Compose Activity" project.

th...@gmail.com <th...@gmail.com> #10Aug 12, 2021 04:56PM

Comment has been deleted.

Message last modified on Aug 12, 2021 04:56PM

th...@gmail.com <th...@gmail.com> #11Aug 12, 2021 04:57PM

This is still reproducible with the latest snapshot version. Since this is marked as fixed, I've created another issue with the sample code and screen record(

https://issuetracker.google.com/issues/196244667)

Also, IMO, this is a core issue and should be marked as a high priority.

jb...@google.com <jb...@google.com> #12Aug 12, 2021 09:47PM

Status: Assigned (reopened)

Yeah, sorry looks like we still haven't fixed this. Somehow our test, which is very similar to the code in #1 passes, but in practice we still aren't recomposing.

ap...@google.com <ap...@google.com> #13Aug 24, 2021 10:43PM

Project: platform/frameworks/support
Branch: androidx-main

commit 5f1bdbbffc8c06355b22fdfe72ef1cf666b0d904
Author: Jeremy Woods <jbwoods@google.com>
Date: Wed Aug 18 03:45:03 2021

Ensure changing arguments causes recompose

Now that NavBackStackEntries are immutable and we don't just change
arguements, we change entire entries, we should make sure NavigatorState
properly handles launchSingleTop.

The only thing we need to do is to update both the navController and
navigator state back stacks with the proper entry.

RelNote: "Navigation Compose now properly recomposes when changing back
stack arguments and using launchSingleTop=true."
Test: all tests pass, and tested in samples from bug
Bug: 186392337
Fixes: 196390311

Change-Id: Iebd698c9e310ad84ce65238c8a5a33db86a9f1f7

M navigation/navigation-common/api/current.txt
M navigation/navigation-common/api/public_plus_experimental_current.txt
M navigation/navigation-common/api/restricted_current.txt
M navigation/navigation-common/src/main/java/androidx/navigation/Navigator.kt
M navigation/navigation-common/src/main/java/androidx/navigation/NavigatorState.kt
M navigation/navigation-runtime/src/androidTest/java/androidx/navigation/NavControllerTest.kt
M navigation/navigation-runtime/src/main/java/androidx/navigation/NavController.kt

https://android-review.googlesource.com/1799948

jb...@google.com <jb...@google.com> #14Aug 26, 2021 11:24PM

Marked as fixed.

We were able to get a fix for this in Navigation 2.4.0-alpha08.

You can try this out by following the snapshot instructions and using Build Id #7677699.

ma...@gmail.com <ma...@gmail.com> #15Jun 1, 2022 11:21AM

This still doesn't work in 2.4.2

jb...@google.com <jb...@google.com> #16Jun 1, 2022 04:39PM

Please file a new bug with a minimal sample project that reproduces the issue.

so...@gmail.com <so...@gmail.com> #17Nov 24, 2023 02:08PM

The same issue still exists.

il...@google.com <il...@google.com> #18Nov 27, 2023 06:23PM

Re comment#17 - you'll want to file a new bug with a sample project that reproduces the issue you're still experiencing.