fix(wm): avoid obvious border manager thread crash

This commit adds an early exit from the border manager's event
processing loop whenever a window which still exists in the state but
has been destroyed is encountered. Instead of returning an error, the
'containers loop will now skip ahead to the next iteration.

This commit also makes an adjustment to the frequency with which the
reaper sends border manager notifications - a single notification is now
sent at the end of each iteration if necessary, rather than one
notification per workspace.

komorebi/src/border_manager/mod.rs

@@ -427,7 +427,7 @@ pub fn handle_notifications(wm: Arc<Mutex<WindowManager>>) -> color_eyre::Result
                             borders.remove(id);
                         }
 
-                        for (idx, c) in ws.containers().iter().enumerate() {
+                        'containers: for (idx, c) in ws.containers().iter().enumerate() {
                             // Get the border entry for this container from the map or create one
                             let mut new_border = false;
                             let border = match borders.entry(c.id().clone()) {
@@ -471,7 +471,17 @@ pub fn handle_notifications(wm: Arc<Mutex<WindowManager>>) -> color_eyre::Result
                             let reference_hwnd =
                                 c.focused_window().copied().unwrap_or_default().hwnd;
 
-                            let rect = WindowsApi::window_rect(reference_hwnd)?;
+                            // avoid getting into a thread restart loop if we try to look up
+                            // rect info for a window that has been destroyed by the time
+                            // we get here
+                            let rect = match WindowsApi::window_rect(reference_hwnd) {
+                                Ok(rect) => rect,
+                                Err(_) => {
+                                    let _ = border.destroy();
+                                    borders.remove(c.id());
+                                    continue 'containers;
+                                }
+                            };
 
                             let should_invalidate = match last_focus_state {
                                 None => true,

komorebi/src/reaper.rs

@@ -34,6 +34,8 @@ pub fn find_orphans(wm: Arc<Mutex<WindowManager>>) -> color_eyre::Result<()> {
         let mut wm = arc.lock();
         let offset = wm.work_area_offset;
 
+        let mut update_borders = false;
+
         for (i, monitor) in wm.monitors_mut().iter_mut().enumerate() {
             let work_area = *monitor.work_area_size();
             let window_based_work_area_offset = (
@@ -51,7 +53,7 @@ pub fn find_orphans(wm: Arc<Mutex<WindowManager>>) -> color_eyre::Result<()> {
                 let reaped_orphans = workspace.reap_orphans()?;
                 if reaped_orphans.0 > 0 || reaped_orphans.1 > 0 {
                     workspace.update(&work_area, offset, window_based_work_area_offset)?;
-                    border_manager::send_notification(None);
+                    update_borders = true;
                     tracing::info!(
                         "reaped {} orphan window(s) and {} orphaned container(s) on monitor: {}, workspace: {}",
                         reaped_orphans.0,
@@ -62,5 +64,9 @@ pub fn find_orphans(wm: Arc<Mutex<WindowManager>>) -> color_eyre::Result<()> {
                 }
             }
         }
+
+        if update_borders {
+            border_manager::send_notification(None);
+        }
     }
 }