How do I debug this? - It crashes only on Android,...

# multiplatform

[Samuel]

How do I debug this? - It crashes only on Android, not desktop, iOS or web:

FATAL EXCEPTION: main
                                                                                                    Process: dev.upvote.debug, PID: 22296

There's no other traceback; I've tried running with debugger also.

[Pablichjenkov]

Real device or emulator?

[Gabe Kauffman]

You should provide more information about when it is crashing. For example, does it crash on app start up or after you perform a specific action? Also, I suspect there would be more information or logs about what's going on in Logcat

[Pablichjenkov]

Usually incomplete logs is a sign or process being abruptly killed. Could be exhausted use of memory, some permission issues. Things of that nature

[Pablichjenkov]

Emulators some times run out of memory that's why I asked

[Samuel]

Emulator yes, but I have plenty of memory remaining.

Open-sourcing everything but it's nowhere near ready for outside contribution: https://github.com/upvote-dev/UpvoteApp/blob/465e37d/composeApp/src/commonMain/kotlin/dev/upvote/presentation/profile/ProfileScreen.kt#L59

To replicate open the app on Android and click "Profile" in bottom left.

(notably I have figured out neither Decompose nor a nice way of sharing data between `Composable`s yet so have a lot of ugly/verbose hacks… so feel free to ignore that part and just see if you can replicate the crash)

[Samuel]

Any clue how to debug this?

[Pablichjenkov]

Not really, I don't see anything dramatic in code.
It only crashes when you visit this screen?
Can you debug until the line of code that causes the crash?

[Gabe Kauffman]

There's tons of stuff you can try:
• Copy pasting this code into ChatGPT and telling it very specifically what's happening, how it's crashing for one platform but not another
• Systematically comment out any potentially problematic pieces of code until the crash stops, use that to determine which specific bit of code is causing the crash

[Samuel]

Yeah I traced it all the way through and it seems to be the viewModel.getProfile() line. When that's removed it doesn't crash. But there's nothing fancy going on there; so a bit confused.

[Gabe Kauffman]

Have you tried asking ChatGPT why that line might cause a crash on Android specifically?

Next you could comment out specific parts of getProfile() to narrow down exactly what's going wrong there.

In general having lifecycle listeners in Composables strikes me as a weird and potentially dangerous pattern

OnLifecycleEvent { _, event ->
        when (event) {
            Lifecycle.Event.ON_RESUME -> {
                viewModel.getProfile()
            }
            else -> {}
        }
    }

[Pablichjenkov]

What is inside that function? Do the same procedure there and find the last piece of the puzzle

[Gabe Kauffman]

Also noting that this code is also super dangerous

val profile = profileContentRepository.getProfile().first()
                profile.also {
                    setProfile(profile = profile!!)
                }

• .first() will cause a crash if the flow does not have a value, prefer to use .firstOrNull()
• profile!! will cause a crash if profile is null, prefer to do something like

profile?.let {
   setProfile(profile = it)
}

[Samuel]

In general having lifecycle listeners in Composables strikes me as a weird and potentially dangerous pattern

Agreed, only added them as a debug measure

Oh I thought profile.also did that. Ok changed to your syntax.

As for first, it's

override fun getProfile() = flow {
        emit(profileApi.getProfile())
    }

Where profileApi.getProfile is either going to error [404] or have one value [.first guaranteed to succeed]