I have a question about

SupervisorJob

. This code

CoroutineScope(SupervisorJob()).launch {
    launch { 
        println("Launched Child 1")
        delay(500)
        println("Child 1 crashed")
        throw SillyException()
    }

    launch {
        println("Launched Child 2")
        delay(1000)
        println("Child 2 is still running")
        delay(500)
    }

    delay(1000)
    println("Parent is still running")
}

Thread.sleep(2000)

prints out this:

Launched Child 1
Launched Child 2
Child 1 crashed
Exception in thread "DefaultDispatcher-worker-2 @coroutine#3" launch_exceptions.SillyException: Silly
	at launch_exceptions.FileKt$main$1$1.invokeSuspend(File.kt:20)
        ...

I expected only “Child 1” to crash/stop, due to the parent being a Supervisor-Job . However, I expected “Child 2" launch and the parent to continue running… especially since

MainScope()

is defined in a similar way…

inner

launch

is start as child for outer

launch

, which is not a

SupervisorJob

. Only childs of

CoroutineScope(SupervisorJob())

fails independently from each other

I see. Thank you, @Evgeniy Zaharov ! You say that this would work:

val scope = CoroutineScope(SupervisorJob())
scope.launch { 
    println("Launched Child 1")
    delay(500)
    println("Child 1 crashed")
    throw SillyException()
}

scope.launch {
    println("Launched Child 2")
    delay(1000)
    println("Child 2 is still running")
    delay(500)
}

You could use

supervisorScope { … }

also, and launch all the coroutines here.

Thanks! But not always, though. The function

supervisorScope

is a

suspend

fun and can’t be called from a regular non-suspending function.

Perhaps it would work if you used the coroutine context parameter instead of the scope