Hey there! What are my options if I want to retain parent-child relationship in terms of making pare...

# coroutines

[Sergey]

Hey there! What are my options if I want to retain parent-child relationship in terms of making parent wait for children completion when parent.join() is invoked but prevent propagation of a cancellations from parent to children i.e. let children complete on it’s own without interruptions when parent.cancel() / parent.cancelAndJoin() is invoked? I create children using async {} blocks i.e.

val parent = CoroutineScope(dispatcher).launch { 
...
    val childRes0 = async { ... }
    val childRes1 = async { ... }
...
}

...

parent.cancelAndJoin()

[kevin.cianfarini]

Wrap the children in NonCancellable?

[Sergey]

Thanks Kevin, I’m reading what internet has on NonCancellable right now. I believe I have to adapt my code to something like

val parent = CoroutineScope(dispatcher).launch { 
...
withConttext(NonCancellable) {
    val childRes0 = async { ... }
    val childRes1 = async { ... }
}
...
}

...

parent.cancelAndJoin()

what if my children are created in dedicated coroutineScope like

fun runManyChildren() = coroutineScope {
    vals.map { x -> async { .... } }
}

val parent = CoroutineScope(dispatcher).launch { 
...
withConttext(NonCancellable) {
    runManyChildren()
}
...
}

...

parent.cancelAndJoin()

Will runManyChildren be uncancellable in this case?

[kevin.cianfarini]

yup

[Sergey]

Got it, thanks for your help!

[kevin.cianfarini]

No problem!

[uli]

be aware though, that even the canceled parent will only terminate after all children completed

[Sergey]

Thanks Uli, that’s the desired behaviour in my case.