CoroutinesTimeout non-coroutines jobs dump

[cy6erGn0m]

It would be convenient to see non-coroutines incomplete Job instances in coroutines dumps as well. It will improve structured jobs analysis in the case when a Job (or CompletableDeferred) prevents a parent from completion.

The following example test hangs because of a job and a completable deferred, but the coroutines dump doesn't provide enough information, so it's not that easy to backtrace the reason.

class DumpTest {
    @get:Rule
    val timeout: CoroutinesTimeout = CoroutinesTimeout.seconds(1)

    private val parent = Job()

    @BeforeTest
    fun start() {
        Job(parent)
        CompletableDeferred<Unit>(parent)
    }

    @Test
    fun test(): Unit = runBlocking(CoroutineName("blocking")) {
        parent.complete()
        parent.join()
    }
}

[qwwdfsad]

I wonder how to represent that.
Do you expect to see a creation stacktraces of these jobs (implying corresponding overhead unless #1379 is here)? Because otherwise, it might not be that useful.
Do you want it to see only in tests or during the regular debugging/production uses as well?

How should things like this be represented both in the dump and programmatically?

launch {
    val job1 = Job(coroutineContext[Job])
    val job2 = Job(job2)
}

Should we nest stacktraces in that case? Or should we print them similarly to printJob, but for all the active jobs?

[elizarov]

IMO, capturing creation stack-trace for them in the debug mode seems to be Ok.

[cy6erGn0m]

I believe it is useful in both tests and debugging. Since there is no way to pass a coroutine name to Job() invocation, it seems that we need a stack-trace.

[cy6erGn0m]

Don't think we need to nest stack-traces since it will complicate reading. Jobs tree and stack-traces below could be a solution.