How would you decide if a message received for being subscribed to pubsub is meant to be forwarded to the live component? Those messages are in arbitrary shape and don’t include any hint if the source for the subscription might be a child live component or the live view itself. It could even be that both are subscribed to the same pubsub.

Tbh I think the issue here is that you use a LiveComponent to subscribe to PubSub in the first place. Given LiveComponents are indeed not processes you’re essentially leaking a subscription onto the parent LiveView as a sideeffect, which then materializes by the fact that you cannot clean that up anymore. I agree that this is a limitation to what a LiveComponent can encapsulate, but imo the solution isn’t an unmount callback. Even with that there would still be no handle_info callback as well, so you’re still dependant on the parent LV.

I very much agree on this!

I have another suggestion to allow PubSub to send events directly to the LiveComponent since this is the same way LiveComponent allready gets its message when using send_update.
Then the LiveComponent could be able to use PubSub without involving the parent LiveView.

This could then call update/2 in the same way send_update allready does this

The way I solve the handle_info in the parent today is to use Phoenix.LiveView.attach_hook/4 function and then use send_update to forward it to the component
I attach the hook by defining a hook/1 function in my component that is called from the LiveView.mount function