Destination does not exists if passing empty string in type safe arguments in jetpack compose navigation [339481310]

Fixed

Feature Request

Status Update

No update yet.

Description

st...@warting.se

created issue #1

May 9, 2024 12:59PM

Component used: Navigation
Version used: 2.8.0-alpha08

If passing an empty string as an safe argument the destination does not exists

@Serializable
object LoginSelector

@Serializable
data class RegisterUser(val email: String)

NavHost(
navController = navController,
startDestination = LoginSelector,
modifier = modifier
) {
composable<LoginSelector> {
Button(onClick = {
navController.navigate(RegisterUser("foo")) // Works!
}) {
Text(text = "Login1")
}

Button(onClick = {
navController.navigate(RegisterUser("")) // Doesn't work. Destination does not exists
}) {
Text(text = "Login2")
}

Button(onClick = {
navController.navigate(RegisterUser(null)) // works if making email nullable
}) {
Text(text = "Login3")
}
}

composable<RegisterUser> { backStackEntry ->
val emailLogin: RegisterUser = backStackEntry.toRoute()
Text(text =emailLogin.email)
}
}

Comments

jb...@google.com <jb...@google.com> May 9, 2024 02:11PM

Assigned to cl...@google.com.

do...@google.com <do...@google.com> #2May 10, 2024 07:29AM

We'll wait for your sample app.

cl...@google.com <cl...@google.com> #3May 14, 2024 10:11PM

Status: Won't Fix (Intended Behavior)

Seems like that this happens because in NavHost.kt, a last() function is called without handling the situation where this could be null

Message last modified on May 14, 2024 10:12PM

st...@warting.se <st...@warting.se> #4May 21, 2024 11:18AM

Re comment#3 - it should never, ever, ever be null, so last() is exactly what should be used.

Hence why we need a sample project to figure out how we're getting into this state.

cl...@google.com <cl...@google.com> #5Jun 7, 2024 06:43PM

Status: Assigned (reopened)

Issue is happening to me as well after library update when I switch between tabs quickly

Message last modified on Jun 10, 2024 04:38PM

st...@warting.se <st...@warting.se> #6Jun 10, 2024 11:45AM

Re comment#5 - do you have a sample project that reproduces your issue?

ap...@google.com <ap...@google.com> #7Jun 18, 2024 07:28PM

I made a sample project, which covers this bug:

https://github.com/Milchschlumpf/NavigationComposeBug

I can reproduce this bug with the Emulator and my physical devices. Just click very quickly between two items in the bottom nav bar until the app crashes.

cl...@google.com <cl...@google.com> #8Jun 18, 2024 08:29PM

Marked as fixed.

I could also reproduce the bug with your own sample:

https://github.com/android/compose-samples/tree/main/Jetsnack

Just update the dependency to androidx.navigation:navigation-compose:2.5.0-rc01 and do the same procedure I described in my previous comment.

pr...@google.com <pr...@google.com> #9Jun 26, 2024 05:43PM

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

commit 95d95a4c54474fc973eebd775ff953f1a2f54c4a
Author: Jeremy Woods <jbwoods@google.com>
Date: Wed Jun 08 14:06:02 2022

Fix crash in NavHost when fast switching between destinations

There is a currently an error when combining Crossfade with
visibleEntries and fast switching between bottom nav items, where when
going from item 1, to item 2, and back to item 1` before the transition
completes.

Crossfade currently disposes whenever the lastEntry changes, in this
case the old item 1 is not equal to the new item 1` and this causes the
visibleEntries which included item 2 to be disposed when the old item 1
to item 2 transition completes, but the item 2 to item 1` transition is
still going and when that attempts to retrieve item 2, it fails cause it
has already been marked as complete.

We need to make it so that visibleEntries are only marked as complete
when crossfade is being disposed.

RelNote: "Fixed a crash caused by fast switching between bottom
destinations when using the Navigation Compose `NavHost`."
Test: tested in sample app
Bug: 234054916

Change-Id: I3979acdda0b6715fcf96bb1948ad6f5e6ba87388

M navigation/navigation-compose/src/main/java/androidx/navigation/compose/NavHost.kt

https://android-review.googlesource.com/2120138