fun main(args: Array<String>) = runBlocking<Unit> {
    try {
        failedConcurrentSum()
    } catch(e: ArithmeticException) {
        println("Computation failed with ArithmeticException")
    }
}

suspend fun failedConcurrentSum(): Int = coroutineScope {
    val one = async<Int> { 
        try {
            delay(Long.MAX_VALUE) // Emulates very long computation
            42
        } finally {
            println("First child was cancelled")
        }
    }
    val two = async<Int> { 
        println("Second child throws an exception")
        throw ArithmeticException()
    }
        one.await() + two.await()
}

it doesnt seem to work for me. The parent coroutine still blocks waiting for the first

async

after the second threw the exception

Have you updated your coroutines version to 0.30.1?

The reason is that the

two

coroutine doesn't throw its exception until you call

two.await()

which doesn't occur until

one.await()

returns.

@Dico this behaviour was changed in the latest realese