I have some suspending code running inside `withCo...

# coroutines

[rocketraman]

I have some suspending code running inside withContext that never completes. If I remove the withContext it does run to completion. The problem seems to be my use inside the withContext block of async(SupervisorJob(coroutineContext[Job])) { ... } as described in https://github.com/Kotlin/kotlinx.coroutines/issues/763 -- if I change the call to be a straight async call, then it works fine. Either this is a bug, or I'm not understanding something...

[rocketraman]

Using withContext(IO + SupervisorJob(coroutineContext[Job])) { ... } with regular async calls inside the block also hangs.

[rocketraman]

Using DebugProbes.printScope(this) shows a bunch of active SupervisorJobImpl. I'm not sure why these would be still be active... the underlying async calls have been awaited and values retrieved with no issues.

[louiscad]

@rocketraman Replace the supervisor with a local coroutineScope { ... } wrapping the async calls that may fail recoverably, and handle the throwables outside of the local coroutineScope { ... }

[rocketraman]

That's exactly what I ended up doing, but is there an explanation for the observed behavior?

[louiscad]

I think because of its context + its content withContext stays suspended as the job is likely staying active (since the parent job comes from outer context and supervisor is not cancelled by children)

[rocketraman]

Would you consider this a bug? Certainly seems so to me.

[louiscad]

I consider it a misusage, and you corrected it yourself. However you could request an IDE inspection on kotl.in/issue that detects this and suggests to use a local coroutineScope instead.