I have two completely independent `CorouteScopes`. Then I `launch` a coroutine in one of these scope...

# coroutines

[Norbi]

I have two completely independent CorouteScopes.
Then I launch a coroutine in one of these scopes.
How to make this launched coroutine to be automatically cancelled if any of the two scopes is cancelled?
Thanks.

[Joffrey]

The cancellation from the scope it is launched in is obviously already in place. For the second scope, you could register an invokeOnCompletion callback on its Job, and cancel your own coroutine from it manually if it's a cancellation.

[Sam]

scope2.launch(start = ATOMIC) {
  try {
    awaitCancellation()
  } finally {
    jobFromScope1.cancel()
  }
}

[Joffrey]

Sam's approach also should work. This is the one I meant:

val jobFromScope1 = scope1.launch { ... }

scope2.job.invokeOnCompletion { cause ->
    if (cause != null) {
        jobFromScope1.cancel()
    }
}

[Awkin]

It's a long-standing issue: https://github.com/Kotlin/kotlinx.coroutines/issues/1001

[kevin.cianfarini]

While these both work, the more natural approach would be to have a third scope that's a parent of the two scopes you mention. Is that possible?

[Sam]

Mine assumes scope2 never terminates normally, only via cancellation/failure. That’s normally the case for custom scopes, but not for e.g. the coroutineScope function

[Norbi]

Thanks for the lightning fast answers 🙂