Is there any possibility that `withTimeOut` constr...

# coroutines

[prasham.h.trivedi]

Is there any possibility that withTimeOut construct doesn’t throw TimeOutCancellationException?

In my android service I am using combination of timeout + channels to send data to specified duration using channels, and the sending operation should end after specified time. I have observed that channels kept sending the data well past timeout limit.

Here is my pseudocode

launch(<http://Dispatchers.IO|Dispatchers.IO>) {
                    val openChannel = openChannel(interval = interval)
                    try {
                        withTimeout(timeMillis = duration) {
                            openChannel.consumeEach {
                                doOnTick()
                            }
                        }
                    } catch (e: TimeoutCancellationException) {
                        openChannel.cancel()
                        stopService()
                    }
                }

In this code catch isn’t executed sometimes.

This code runs properly on kotlin playground, what is wrong above?

[elizarov]

I know of one thing that may be the culprit: in the current implementation Channel.send only checks for cancellation (and timeout) when it suspends. So, in the case when it never suspends (the other side is fast enough to always receive), then it will not timeout. You can add yield() inside your code — it always checks for cancellation and will throw the corresponding exception.

[elizarov]

If that is not your case, then there is some bug. It would be great if you can write a self-contained reproducer and report it to https://github.com/Kotlin/kotlinx.coroutines/issues

[Dico]

You can add
if (!isActive) yield()
In your consumeEach loop

[Dico]

isActive is coming from CoroutineScope receiver provided by launch