Hi! Why is this coroutine here that uses Thread.sl...

# coroutines

[Lukas Lechner]

Hi! Why is this coroutine here that uses Thread.sleep() not cancelled?

fun main() = runBlocking {

    val job = launch {
        repeat(5) { index ->
            println("operation number $index")
            ensureActive()
            Thread.sleep(100)
        }
    }
    delay(150)
    job.cancel()

}

[Lukas Lechner]

all 5 lines are printed out, although actually only one should be printed out?

[octylFractal]

you never suspend, and runBlocking is a single thread, so job.cancel() never runs until it's already finished

[Tijl]

add a yield

[octylFractal]

yes, either replace ensureActive() with yield(), or delay instead of Thread.sleep, or use <http://Dispatcher.IO|Dispatcher.IO> -- any of these will solve the issue, and may be appropriate depending on what you're actually doing

[Lukas Lechner]

Ahh, ensureActive is a not a supend function, whereas yield() is one 🤔

[Lukas Lechner]

Thanks guys