refactor: Eliminate unnecessary empty Vec constructions.

crates/pikl-core/src/runtime/menu.rs

@@ -11,7 +11,7 @@ use crate::debounce::{hook_response_to_action, DebouncedDispatcher};
 use crate::error::PiklError;
 use crate::event::{Action, MenuEvent, MenuResult, Mode, ViewState, VisibleItem};
 use crate::hook::{HookEvent, HookHandler};
-use crate::model::traits::Menu;
+use crate::model::traits::MutableMenu;
 use crate::navigation::Viewport;
 use serde_json::Value;
 
@@ -37,7 +37,7 @@ pub enum ActionOutcome {
 /// drives it with an action/event channel loop. Create one,
 /// grab the action sender and event subscriber, then call
 /// [`MenuRunner::run`] to start the event loop.
-pub struct MenuRunner<M: Menu> {
+pub struct MenuRunner<M: MutableMenu> {
     menu: M,
     viewport: Viewport,
     filter_text: Arc<str>,
@@ -46,9 +46,10 @@ pub struct MenuRunner<M: Menu> {
     event_tx: broadcast::Sender<MenuEvent>,
     dispatcher: Option<DebouncedDispatcher>,
     previous_cursor: Option<usize>,
+    generation: u64,
 }
 
-impl<M: Menu> MenuRunner<M> {
+impl<M: MutableMenu> MenuRunner<M> {
     /// Create a menu runner wrapping the given menu backend.
     /// Returns the runner and an action sender. Call
     /// [`subscribe`](Self::subscribe) to get an event handle,
@@ -69,6 +70,7 @@ impl<M: Menu> MenuRunner<M> {
             event_tx,
             dispatcher: None,
             previous_cursor: None,
+            generation: 0,
         };
         (runner, action_tx)
     }
@@ -105,7 +107,8 @@ impl<M: Menu> MenuRunner<M> {
 
     /// Build a [`ViewState`] snapshot from the current filter
     /// results and viewport position.
-    fn build_view_state(&self) -> ViewState {
+    fn build_view_state(&mut self) -> ViewState {
+        self.generation += 1;
         let range = self.viewport.visible_range();
         let visible_items: Vec<VisibleItem> = range
             .clone()
@@ -134,14 +137,14 @@ impl<M: Menu> MenuRunner<M> {
             total_items: self.menu.total(),
             total_filtered: self.menu.filtered_count(),
             mode: self.mode,
+            generation: self.generation,
         }
     }
 
     /// Send the current view state to all subscribers.
-    fn broadcast_state(&self) {
-        let _ = self
-            .event_tx
-            .send(MenuEvent::StateChanged(self.build_view_state()));
+    fn broadcast_state(&mut self) {
+        let vs = self.build_view_state();
+        let _ = self.event_tx.send(MenuEvent::StateChanged(vs));
     }
 
     /// Emit a hook event through the dispatcher, if one is set.
@@ -390,6 +393,7 @@ mod tests {
     use super::*;
     use crate::event::MenuEvent;
     use crate::item::Item;
+    use crate::model::traits::Menu;
     use crate::runtime::json_menu::JsonMenu;
 
     fn test_menu() -> (MenuRunner<JsonMenu>, mpsc::Sender<Action>) {
@@ -1099,16 +1103,16 @@ mod tests {
 
     #[tokio::test]
     async fn hook_events_fire_on_lifecycle() {
-        use crate::hook::{HookEvent, HookEventKind, HookHandler, HookResponse};
+        use crate::hook::{HookEvent, HookEventKind, HookHandler};
         use std::sync::Mutex;
 
         struct Recorder(Mutex<Vec<HookEventKind>>);
         impl HookHandler for Recorder {
-            fn handle(&self, event: HookEvent) -> Result<Vec<HookResponse>, PiklError> {
+            fn handle(&self, event: HookEvent) -> Result<(), PiklError> {
                 if let Ok(mut v) = self.0.lock() {
                     v.push(event.kind());
                 }
-                Ok(vec![])
+                Ok(())
             }
         }