v0.8.20

src/engine/commands.rs

@@ -170,15 +170,15 @@ async fn send_command_locked_inner(
 }
 
 fn record_device_transition_timestamps(state: &AppState, before: &Device, after: &Device) -> Result<(), AppError> {
-    if before.power == after.power && before.mode == after.mode { return Ok(()); }
-    let now = Utc::now();
-    for mut zone in state.db.list_zones()?.into_iter().filter(|zone| zone.device_id == after.id) {
-        if before.power != after.power { zone.last_power_change_at = Some(now); }
-        if before.mode != after.mode { zone.last_mode_change_at = Some(now); }
-        // Do not bump zone.updated_at here: an in-flight thermostat cycle uses that field
-        // as its optimistic snapshot guard. The cycle mirrors these timestamps into its own
-        // computed Zone after a successful automatic command.
-        state.db.save_zone(&zone)?;
+    let power_changed = before.power != after.power;
+    let mode_changed = before.mode != after.mode;
+    if !power_changed && !mode_changed { return Ok(()); }
+    // This function is often called while the device lock is held, so acquiring a zone lock
+    // here would invert the global zone -> device order. Merge only these timestamp fields
+    // with a DB compare-and-swap instead of saving a stale whole-zone snapshot.
+    for zone in state.db.merge_zone_device_transition_timestamps(
+        &after.id, power_changed, mode_changed, Utc::now(),
+    )? {
         state.broadcast("zone.updated", serde_json::to_value(&zone)?);
     }
     Ok(())