`supervisorScope` kdoc states that `A failure of the scope itself (exception thrown in the block or ...

# coroutines

[Patrick Steiger]

supervisorScope kdoc states that A failure of the scope itself (exception thrown in the block or external cancellation) … does not cancel parent job
Is that really the case though ? I’m finding it hard to provide a code example where a failure of the supervisorScope job itself does not cancel the parent.

[gildor]

Yes, it's the case, for example if your async failed without supervisor scope parent will be cancelled, with supervisor scope it will cache fail as deferred result without cancelling parent

[Patrick Steiger]

@gildor but that’s about a failure of the child of the supervisor scope. Docs mention about a failure of the scope itself and specifically mentions an exception thrown in block. How can the block throw an exception and not cancel the parent?

[gildor]

I think the doc says about supervisorScope itself as parent scope, not about parent of supervisorScope (which may have no scope at all, it called from suspend function)

[gildor]

Or maybe it's indeed a mistake (or a bad explanation of way how supervisorScope semantics) of the doc, because fail or coroutineScope wouldn't cancel parent on error either, it would just throw exception which can be caught

[Patrick Steiger]

^ this

Docs are unclear IMO, I could not see any difference from coroutineScope WRT cancellation of parent when the scope own job fails — they both fail the parent (unless parent itself is a supervisor?)

So I’d love to see an explanation of semantics here or just a code snippet demonstrating what docs mean

[gildor]

Probably worth creating an issue about this doc

[Patrick Steiger]

github.com/Kotlin/kotlinx.coroutines/issues/3725