Maybe a dumb question (EDIT: certainly dumb question 🙃) but how can I force app crash (Android) when child of

SupervisorJob

(viewModelScope) throws exception? My use case is that when debugging I want my app to crash whenever there is unhandled exception anywhere in my business logic but because

viewModelScope

is

SupervisorJob

, the coroutine is only getting cancelled. This behavior can be achieved by using

Dispatchers.Main

as context (presumably because it calls android

UncaughtExceptionHandler

) but I how can I achieve this when using

.Default

or

.IO

dispatchers?

You can kill the app by calling System.exit from your handler

Sigh...sometimes things are too obvious to think of. Thanks Zach, you saved my day 🤦‍♂️

It’s easy to forget, you don’t see System much in Android 😅

I think the app should crash automatically if you're using

launch

(but not

async

which should be part of a child non supervisor scope.

I think, even async will crash. But only when you await, which will rethrow.

I thought so too but it doesn't crash and I don't know what I'm doing wrong. There is async call but it's wrappen in

coroutineScope

and it only crashes when I'm using

Dispatchers.Main

. Any tips on where should I look to resolve this? My coroutine structure:

viewModelScope.launch(<http://Dispatchers.IO|Dispatchers.IO>)
  withContext(Dispatchers.Default)
    coroutineScope
      async
      await - exception is thrown

OR

viewModelScope.launch(<http://Dispatchers.IO|Dispatchers.IO>)
  withContext(Dispatchers.Default)
    exception is thrown

Neither of those crash the app

Are you 100% certain the app doesn't crash? On recent Android versions, the force close popup can not be shown and the process be silently restarted. An easy way to check it is attach a debugger and let the app crash. If the app actually crashes, the debugger wil be disconnected @Filip Wiesner

I can just continue using it and I don't see any closing animations. And yes, the debugger is still connected. And even if it would crash silently, why would there be a different behavior when using

.Main

dispatcher?

Does it happen with

lifecycleScope

in an Activity or only in

viewmModelScope

? Which AndroidX ViewModel KTX version are you using?

I am using version 2.2.0 and I'll test the

lifecycleScope

. Gimme a sec

This code crashes as expected for me:

viewModelScope.launch(<http://Dispatchers.IO|Dispatchers.IO>) {
    withContext(Dispatchers.Default) {
        throw RuntimeException("TEST")
    }
}

Are you sure that the thrown exception is not

CancellationException

or its subclass? 🙂

Yeah, if I create new project and try the same structure, it does crash for me too 😞 I'll post here if I make any progress on this issue

Might be related to a crash reporting library or something that deals with

Thread.setUncaughtExceptionHandler

in your project.

It's definetly a project issue. I can call

GlobalScope.launch {
    error("")
}

inside a ViewModel and it still does not crash...

Solely because of Crashlytics? Which version? I'm a bit surprised because I use Crashlytics and if I crash the app, well, it crashes anyway.

My colleague found the "bug" and apparently it's because we didn't have enabled Crashlytics for debug (only for alpha, beta and prod). So maybe some Crashlytics handler was consuming the exceptions but not propagating them to default handler (maybe it was crashing? I am not sure) I am still not 100% sure it's only because of Crashlytics becasue it's....weird but when my colleague enabled Crashlytics on debug, my unchanged code started crashing the app. But we are still investigating...

Same version of CrashLytics?

Same project - version 17.0.0

Looks like a random bug in that version of CrashLytics