IllegalStateException when popping nested graph [190265699]

Fixed

Bug

Status Update

No update yet.

Description

jo...@olavstoppen.no

created issue #1

Jun 7, 2021 10:19AM

Component used: Navigation

Version used: 2.4.0-beta02

Devices/Android versions reproduced on: Pixel 3, Huawei P20 Pro, emulator, Android 11, 12

I have a main graph and a login graph. When login is done, I want to pop the entire login graph, and return to the main graph.

This action in the login graph used to work in version 2.3.0, but throws an exception in 2.4.0-beta01/2:

<action
    android:id="@+id/to_main_screen"
    app:destination="@id/main_nav_graph"
    app:popUpTo="@id/login_nav_graph"
    app:popUpToInclusive="true" />

The stack trace:

java.lang.IllegalStateException: popBackStack was called with androidx.navigation.NavBackStackEntry@c554768 which does not exist in back stack []
        at androidx.navigation.Navigator.popBackStack(Navigator.kt:185)
        at androidx.navigation.NavController.popBackStackInternal(NavController.kt:202)
        at androidx.navigation.NavController.popBackStackInternal(NavController.kt:455)
        at androidx.navigation.NavController.popBackStackInternal$default(NavController.kt:413)
        at androidx.navigation.NavController.addEntryToBackStack(NavController.kt:1533)
        at androidx.navigation.NavController.addEntryToBackStack$default(NavController.kt:1466)
        at androidx.navigation.NavController$navigate$7.invoke(NavController.kt:1437)
        at androidx.navigation.NavController$navigate$7.invoke(NavController.kt:1435)
        at androidx.navigation.NavController$NavControllerNavigatorState.add(NavController.kt:215)
        at androidx.navigation.fragment.FragmentNavigator.navigate(FragmentNavigator.kt:246)
        at androidx.navigation.fragment.FragmentNavigator.navigate(FragmentNavigator.kt:162)
        at androidx.navigation.NavGraphNavigator.navigate(NavGraphNavigator.kt:83)
        at androidx.navigation.NavGraphNavigator.navigate(NavGraphNavigator.kt:49)
        at androidx.navigation.NavController.navigateInternal(NavController.kt:188)
        at androidx.navigation.NavController.navigate(NavController.kt:1435)
        at androidx.navigation.NavController.navigate(NavController.kt:1221)
        at androidx.navigation.NavController.navigate(NavController.kt:1149)
        at androidx.navigation.NavController.navigate(NavController.kt:1575)
        at my.app.features.login.login.LoginUIKt$LoginScreen$2.invoke(LoginUI.kt:65)
        at my.app.features.login.login.LoginUIKt$LoginScreen$2.invoke(LoginUI.kt:64)
        at my.app.features.login.LoginResultHandlerKt$LoginResultHandler$1.invoke(LoginResultHandler.kt:38)
        at my.app.features.login.LoginResultHandlerKt$LoginResultHandler$1.invoke(LoginResultHandler.kt:34)
        at androidx.compose.runtime.CompositionImpl$RememberEventDispatcher.dispatchSideEffects(Composition.kt:789)
        at androidx.compose.runtime.CompositionImpl.applyChanges(Composition.kt:640)
        at androidx.compose.runtime.Recomposer$runRecomposeAndApplyChanges$2$2.invoke(Recomposer.kt:478)
        at androidx.compose.runtime.Recomposer$runRecomposeAndApplyChanges$2$2.invoke(Recomposer.kt:415)
        at androidx.compose.ui.platform.AndroidUiFrameClock$withFrameNanos$2$callback$1.doFrame(AndroidUiFrameClock.android.kt:34)
        at androidx.compose.ui.platform.AndroidUiDispatcher.performFrameDispatch(AndroidUiDispatcher.android.kt:109)
        at androidx.compose.ui.platform.AndroidUiDispatcher.access$performFrameDispatch(AndroidUiDispatcher.android.kt:41)
        at androidx.compose.ui.platform.AndroidUiDispatcher$dispatchCallback$1.doFrame(AndroidUiDispatcher.android.kt:69)
        at android.view.Choreographer$CallbackRecord.run(Choreographer.java:1003)
        at android.view.Choreographer.doCallbacks(Choreographer.java:826)
        at android.view.Choreographer.doFrame(Choreographer.java:757)
        at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:990)
        at android.os.Handler.handleCallback(Handler.java:938)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loopOnce(Looper.java:201)
        at android.os.Looper.loop(Looper.java:288)
        at android.app.ActivityThread.main(ActivityThread.java:7727)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:548)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:975)

Comments

il...@google.com <il...@google.com> #2Jun 7, 2021 05:16PM

Can you include a sample project that reproduces your issue?

Note that if you want to just return to your main graph (which I assume launched your login_nav_graph), you would want to leave out the app:destination="@id/main_nav_graph" line entirely as that will create a second instance of your main_nav_graph.

jo...@olavstoppen.no <jo...@olavstoppen.no> #3Jun 8, 2021 09:37AM

Thank you! While working on a minimal repro and keeping your comment in mind, I solved my problem.

My problem was partly that I had an app:destination in my pop action, but also that the action leading to login_nav_graph was popping:

<action
    android:id="@+id/logout"
    app:destination="@id/login_nav_graph"
    app:popUpTo="@id/main_nav_graph"
    app:popUpToInclusive="true" />

Here is a working sample of what I wanted to achieve:

main_nav_graph.xml

<?xml version="1.0" encoding="utf-8"?>
<navigation xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/main_nav_graph"
    app:startDestination="@id/mainFragment">

    <fragment
        android:id="@+id/mainFragment"
        android:name="app.reitan.navigationrepro.MainFragment"
        android:label="fragment_main"
        tools:layout="@layout/fragment_main">
        <action
            android:id="@+id/to_login_nav_graph"
            app:destination="@id/login_nav_graph"/>
    </fragment>

    <include app:graph="@navigation/login_nav_graph" />
</navigation>

login_nav_graph.xml

<?xml version="1.0" encoding="utf-8"?>
<navigation xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/login_nav_graph"
    app:startDestination="@id/loginFragment">

    <fragment
        android:id="@+id/loginFragment"
        android:name="app.reitan.navigationrepro.LoginFragment"
        android:label="fragment_login"
        tools:layout="@layout/fragment_login">
        <action
            android:id="@+id/pop_login_nav_graph"
            app:popUpTo="@id/main_nav_graph"
            app:popUpToInclusive="true" />
    </fragment>
</navigation>

jo...@olavstoppen.no <jo...@olavstoppen.no> #4Jun 8, 2021 09:39AM

Even though the error was probably in my code, this is still a change of behavior, as this used to work fine in 2.3.0. Just so you know :)

jo...@gmail.com <jo...@gmail.com> #5Jun 8, 2021 02:51PM

Trying to recreate this issue in a sample project as well, but I am seeing the same thing. However I am navigating by id instead of action.

an...@gmail.com <an...@gmail.com> #6Jun 8, 2021 08:07PM

Have the same issue with Navigation Component v2.4.0-alpha02, and no issue with 2.3.0
Here is the sample project that reproduces the issue:

https://github.com/eugene-kirzhanov/nav-test

il...@google.com <il...@google.com> #7Jun 9, 2021 12:44AM

Assigned to il...@google.com.

While the project in comment#6 is absolutely the wrong way to do conditional navigation (instead, you should follow the guide for login, it does reproduce the issue reliably enough for us to pinpoint what the problem is.

il...@google.com <il...@google.com> Jun 9, 2021 03:40AM

Accepted by il...@google.com.

ap...@google.com <ap...@google.com> #8Jun 9, 2021 05:21PM

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

commit 91744799f42b2b5bc42c727a17cd3618eb232c01
Author: Ian Lake <ilake@google.com>
Date: Tue Jun 08 19:02:25 2021

Ensure that NavGraphNavigator stack order remains correct

When popping the root graph, the root graph
needs to be added to the front of the
hierarchy to ensure that the
navigatorBackStack for the NavGraphNavigator
is rebuilt in the correct order.

This ensures that future popBackStack() calls
will find that the NavController's back stack
ordering matches the NavigatorState of the
NavGraphNavigator, avoiding an
IllegalStateException.

Test: new NavControllerTest test passes
BUG: 190265699
Relnote: "Fixed an IllegalStateException when
calling popBackStack() after previously popping
the root graph of the NavController."

Change-Id: I2a330acdd339aece36455aa0da37d0609767552c

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

https://android-review.googlesource.com/1731130

il...@google.com <il...@google.com> #9Jun 9, 2021 05:26PM

Marked as fixed.

We've fixed the underlying issue (related to popping the root graph, then navigating to another nested graph) internally and it will be available in Navigation 2.4.0-alpha03.