If I make modifications (`add`, `remove`) on `Muta...

# coroutines

[zokipirlo]

If I make modifications (add, remove) on MutableList only in actor which runs in Dispatcher.MAIN, is it safe to call contains in other context (<http://Dispatcher.IO|Dispatcher.IO>) or should rather check that in withContext(Main) before sending to actor?

[bdawg.io]

It's shared mutable state any time you access or modify a mutable structure from multiple locations. In your case, you should have a message sent to your actor that requests if that structure contains an element

[zokipirlo]

Oh, ok... so even iteration over list is problematic. Thank you.

[uli]

Even if it was safe to call.... what do you do with the result fo contains? On your next line of code the result might not be valid any more.

[zokipirlo]

Yes, but only one thread (actor) can modify it, so it won't be a big problem I guess with list consistency. I'm just checking for contains in background thread because it's processing a lot of messages and it need to handle it only once normally and don't want to "wake" actor in 99% of cases when not necessary.