The fix is to use `start = CoroutineStart.UNDISPAT...

# coroutines

[Martin Devillers]

The fix is to use start = CoroutineStart.UNDISPATCHED, but that feels a bit weird

[elizarov]

The proper fix is to use send instead of offer

[Martin Devillers]

The thing is, I’m sending a command to the actor, but I’d purposely like for the actor to drop this command if it’s busy. I don’t think I can accomplish this with send.

[elizarov]

In your case the actor was busy starting up 🙂

[elizarov]

You can create a buffered channel, though. Use actor(capacity) { ... }.

[Martin Devillers]

Thanks for your response. I’ll explain my use-case a bit more. I’m handling some user actions, but sometimes the system sends a bunch of click events really fast. In that case, I’d like for the first one to be processed, but the following calls should be dropped since the first process is still running. If I use a buffered channel, I’ll end up processing the event multiple times because the events will become queued up.

[elizarov]

That’s what conflated channels for

[elizarov]

Use actor(Channel.CONFLATED) { ... }

[Martin Devillers]

But conflated still essentially has a capacity of 1. So if I re-send a command while one is already running, then it’ll re-run it after the first one is done.

[elizarov]

If you resend, yes. But it conflates repeated into just one.

[Martin Devillers]

I understand, but I’m looking for a behavior where sent events are simply ignored if the previous one is still being processed

[elizarov]

I am not sure what exact behavior do you want. Just drop any commands while its running? That’s what default rendezvous done (and you are obviously not happy with it)

[elizarov]

You can use default with undispatched start then.

[Martin Devillers]

I am very happy with it actually 🙂 I’m just surprised that I had to use UNDISPATCHED for the initial command in order to make sure that it wasn’t dropped

[elizarov]

(just exactly as you did)

[Martin Devillers]

So we agree 😆

[elizarov]

Because it has to start

[elizarov]

(it is not receiving anything while it is starting, so that is why it gets dropped)

[Martin Devillers]

Yes I guess I actually understand it now, but it just felt strange seeing that there was this “initialisation” which required special care. Thanks for taking the time to explain. I guess just have to wrap my head around the fact that even though actor returns a channel, it’s still just a couroutine builder, so it follows the same principles of asynchronously launching the coroutine which receives from the channel.

[elizarov]

Yes. It is