Module event_task 

PH7.8c — the per-plugin event-delivery actor + bus wiring.

Design fragment: docs/dev/architecture/plugin-host.md §5 events + §3 (Store-per-plugin, task-per-Store). Slice plan: PH7.8c.

The shape

Event delivery is host→guest, fire-and-forget — the opposite direction of the picker/completion bridges (which are host-calls-guest-for-a-reply). The host owns an mpsc; the native EventBus pushes each matched [Event] into it via a SubscriptionTarget::Plugin sink (with the bus lock dropped, so a slow handler never stalls the publisher or another subscriber, audit M1); the EventActor drains that channel on the plugin’s own task and drives the guest on-event export. There is no reply — a hook observes, it does not return a value (the bus is observation-only in v1, §5.10).

So this actor is simpler than picker_task: no oneshot, no Client with call methods. Its input channel IS the sink the bus pushes into; the loop projects each event to WIT and calls on-event. Async delivery keeps plugin event work off the keystroke path entirely (paramount #4), bounded per-delivery by PluginBudget::event.

Runtime ownership + lifecycle

The lib owns no runtime: PluginHost::spawn_event_plugin returns the (Vec<SubscriptionId>, EventActor) pair; the caller drives EventActor::run on its multi-thread runtime and holds the subscription ids to EventBus::unsubscribe on teardown. When every subscription is removed (teardown / lazy prune of a closed sink), the sink Arcs drop, the channel closes, and the actor loop ends — dropping the Store (the teardown seam; full crash-quarantine is PH7.12).

Structs

EventActor

The per-plugin actor: owns the Store + events bindings for the plugin’s life and drives on-event for each delivery the bus pushes onto its channel. Construct via PluginHost::spawn_event_plugin; drive by spawning run on a multi-thread runtime.