fix: prevent macOS desktop unlock freeze after display sleep (#745)

* Restart the GPU process to recover from macOS compositor freezes

macOS display sleep can leave Chromium's GPU-process display link stuck
on a stale display, so the compositor stops producing frames and the
window looks frozen — unresponsive to clicks and keys — even though the
renderer stays alive.

setupDarwinCompositorWatchdog polls the renderer for frame production
and, on a sustained stall while the window is visible and unlocked,
restarts the GPU process so Chromium rebuilds the display link. This
replaces setupDarwinPaintRefresh, whose invalidate/resize nudges did
not address the dead display link.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* Give compositor watchdog a module home

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Co-authored-by: Mohamed Boudra <boudra.moha@gmail.com>

packages/desktop/src/main.ts

@@ -19,12 +19,12 @@ import {
   getMainWindowChromeOptions,
   getWindowBackgroundColor,
   resolveSystemWindowTheme,
-  setupDarwinPaintRefresh,
   setupWindowResizeEvents,
   setupDefaultContextMenu,
   setupDragDropPrevention,
   buildStandardContextMenuItems,
 } from "./window/window-manager.js";
+import { setupDarwinCompositorWatchdog } from "./window/compositor-watchdog/index.js";
 import { registerDialogHandlers } from "./features/dialogs.js";
 import {
   registerNotificationHandlers,
@@ -398,7 +398,7 @@ async function createMainWindow(): Promise<void> {
     app.dock?.setBadge(devWorktreeName);
   }
 
-  setupDarwinPaintRefresh(mainWindow);
+  setupDarwinCompositorWatchdog(mainWindow);
   setupWindowResizeEvents(mainWindow);
   setupDefaultContextMenu(mainWindow);
   setupDragDropPrevention(mainWindow);

packages/desktop/src/window/compositor-watchdog/index.test.ts

@@ -0,0 +1,36 @@
+import { describe, expect, it } from "vitest";
+
+import { shouldRecoverFromFrameStall } from ".";
+
+describe("compositor-watchdog", () => {
+  describe("shouldRecoverFromFrameStall", () => {
+    const recoverable = {
+      stalledChecks: 3,
+      recovering: false,
+      msSinceLastRecovery: 120_000,
+      consecutiveRecoveries: 0,
+    };
+
+    it("recovers once the stall threshold is reached", () => {
+      expect(shouldRecoverFromFrameStall(recoverable)).toBe(true);
+    });
+
+    it("waits until the stall threshold is reached", () => {
+      expect(shouldRecoverFromFrameStall({ ...recoverable, stalledChecks: 2 })).toBe(false);
+    });
+
+    it("does not recover while a recovery is already in progress", () => {
+      expect(shouldRecoverFromFrameStall({ ...recoverable, recovering: true })).toBe(false);
+    });
+
+    it("respects the cooldown between recoveries", () => {
+      expect(shouldRecoverFromFrameStall({ ...recoverable, msSinceLastRecovery: 30_000 })).toBe(
+        false,
+      );
+    });
+
+    it("stops recovering after the consecutive-recovery cap", () => {
+      expect(shouldRecoverFromFrameStall({ ...recoverable, consecutiveRecoveries: 3 })).toBe(false);
+    });
+  });
+});

packages/desktop/src/window/compositor-watchdog/index.ts

@@ -0,0 +1,158 @@
+import { app, type BrowserWindow, powerMonitor } from "electron";
+
+// COMPAT(darwinCompositorWatchdog): added in v0.1.78, target removal after
+// 2026-11-19. Workaround for Electron/Chromium macOS display-sleep compositor
+// stalls; re-test when Electron/Chromium is upgraded.
+
+// How often the main process probes the renderer for frame production.
+const FRAME_PROBE_INTERVAL_MS = 2000;
+// A probed frame must arrive within this window or the probe counts as stalled.
+const FRAME_PROBE_DEADLINE_MS = 300;
+// Consecutive stalled probes before the watchdog restarts the GPU process (~6 s).
+const FRAME_STALL_CHECKS_TO_RECOVER = 3;
+// Minimum gap between GPU-process restarts.
+const COMPOSITOR_RECOVERY_COOLDOWN_MS = 60_000;
+// Grace period for Chromium to relaunch the GPU process before probing resumes.
+const GPU_RELAUNCH_GRACE_MS = 5_000;
+// Stop restarting the GPU process after this many tries without frames returning.
+const MAX_CONSECUTIVE_RECOVERIES = 3;
+
+// Resolves { producedFrame, visibilityState } for the renderer. The frame is
+// requested with requestAnimationFrame; setTimeout (not vsync-driven) bounds the
+// wait so the probe always resolves even when frame production has stopped.
+const FRAME_PROBE_SOURCE = `new Promise((resolve) => {
+  let settled = false;
+  const finish = (producedFrame) => {
+    if (settled) return;
+    settled = true;
+    resolve({ producedFrame, visibilityState: document.visibilityState });
+  };
+  requestAnimationFrame(() => finish(true));
+  setTimeout(() => finish(false), ${FRAME_PROBE_DEADLINE_MS});
+})`;
+
+interface FrameStallState {
+  stalledChecks: number;
+  recovering: boolean;
+  msSinceLastRecovery: number;
+  consecutiveRecoveries: number;
+}
+
+export function shouldRecoverFromFrameStall(state: FrameStallState): boolean {
+  return (
+    state.stalledChecks >= FRAME_STALL_CHECKS_TO_RECOVER &&
+    !state.recovering &&
+    state.msSinceLastRecovery >= COMPOSITOR_RECOVERY_COOLDOWN_MS &&
+    state.consecutiveRecoveries < MAX_CONSECUTIVE_RECOVERIES
+  );
+}
+
+function findGpuProcessPid(): number | null {
+  for (const metric of app.getAppMetrics()) {
+    if (metric.type === "GPU") {
+      return metric.pid;
+    }
+  }
+  return null;
+}
+
+// macOS display sleep can leave Chromium's GPU-process display link (the vsync
+// source that drives frame production) stuck on a stale display. The compositor
+// then stops producing frames and the window looks frozen: unresponsive to
+// clicks and keys even though the renderer and every process stay alive. This
+// watchdog polls the renderer for frame production and, on a sustained stall,
+// restarts the GPU process so Chromium rebuilds the display link.
+export function setupDarwinCompositorWatchdog(win: BrowserWindow): void {
+  if (process.platform !== "darwin") {
+    return;
+  }
+
+  // Keep producing frames while occluded so the probe is not fooled by throttling.
+  win.webContents.setBackgroundThrottling(false);
+
+  let stalledChecks = 0;
+  let recovering = false;
+  let lastRecoveryAt = 0;
+  let consecutiveRecoveries = 0;
+  let screenLocked = false;
+
+  const recoverCompositor = async () => {
+    recovering = true;
+    lastRecoveryAt = Date.now();
+    consecutiveRecoveries += 1;
+    stalledChecks = 0;
+    const gpuPid = findGpuProcessPid();
+    console.warn(
+      `[compositor-watchdog] Desktop window stopped producing frames; restarting GPU process ` +
+        `(pid=${gpuPid ?? "unknown"}, attempt ${consecutiveRecoveries}) to recover`,
+    );
+    if (gpuPid !== null) {
+      try {
+        process.kill(gpuPid, "SIGKILL");
+      } catch (error) {
+        console.warn("[compositor-watchdog] Could not restart GPU process", error);
+      }
+    }
+    await new Promise((resolve) => setTimeout(resolve, GPU_RELAUNCH_GRACE_MS));
+    recovering = false;
+  };
+
+  const probeFrameProduction = async () => {
+    if (win.isDestroyed() || recovering) {
+      return;
+    }
+    // A freeze is only meaningful, and only distinguishable from a normal idle
+    // window, while the window is actually on screen. A locked screen, a
+    // minimized window, or a hidden one legitimately stops producing frames.
+    if (screenLocked || !win.isVisible() || win.isMinimized()) {
+      stalledChecks = 0;
+      return;
+    }
+
+    let result: { producedFrame?: unknown; visibilityState?: unknown } | null;
+    try {
+      result = await win.webContents.executeJavaScript(FRAME_PROBE_SOURCE);
+    } catch {
+      return;
+    }
+    if (!result || result.visibilityState !== "visible") {
+      stalledChecks = 0;
+      return;
+    }
+    if (result.producedFrame === true) {
+      stalledChecks = 0;
+      consecutiveRecoveries = 0;
+      return;
+    }
+
+    stalledChecks += 1;
+    if (
+      shouldRecoverFromFrameStall({
+        stalledChecks,
+        recovering,
+        msSinceLastRecovery: Date.now() - lastRecoveryAt,
+        consecutiveRecoveries,
+      })
+    ) {
+      void recoverCompositor();
+    }
+  };
+
+  const probeTimer = setInterval(() => void probeFrameProduction(), FRAME_PROBE_INTERVAL_MS);
+  const handleScreenLocked = () => {
+    screenLocked = true;
+    stalledChecks = 0;
+  };
+  const handleScreenUnlocked = () => {
+    screenLocked = false;
+    stalledChecks = 0;
+  };
+  powerMonitor.on("lock-screen", handleScreenLocked);
+  powerMonitor.on("unlock-screen", handleScreenUnlocked);
+
+  win.once("closed", () => {
+    clearInterval(probeTimer);
+    powerMonitor.off("lock-screen", handleScreenLocked);
+    powerMonitor.off("unlock-screen", handleScreenUnlocked);
+  });
+}

packages/desktop/src/window/window-manager.ts

@@ -229,59 +229,6 @@ export function setupWindowResizeEvents(win: BrowserWindow): void {
   });
 }
 
-function refreshChromiumSurface(win: BrowserWindow): void {
-  if (win.isDestroyed()) {
-    return;
-  }
-
-  win.webContents.invalidate();
-  if (win.isMaximized() || win.isFullScreen()) {
-    return;
-  }
-
-  const [width, height] = win.getSize();
-  win.setSize(width + 1, height);
-  setTimeout(() => {
-    if (!win.isDestroyed()) {
-      win.setSize(width, height);
-    }
-  }, 32);
-}
-
-export function setupDarwinPaintRefresh(win: BrowserWindow): void {
-  if (process.platform !== "darwin") {
-    return;
-  }
-
-  win.webContents.setBackgroundThrottling(false);
-
-  const requestSurfaceRefresh = () => {
-    if (!win.isDestroyed()) {
-      win.webContents.invalidate();
-    }
-  };
-  const handleChildProcessGone = (
-    _event: Electron.Event,
-    details: { type?: string; reason?: string },
-  ) => {
-    if (details.type !== "GPU") {
-      return;
-    }
-
-    console.warn("[window] GPU process gone:", details.reason);
-    refreshChromiumSurface(win);
-  };
-
-  win.on("restore", requestSurfaceRefresh);
-  win.on("show", requestSurfaceRefresh);
-  app.on("child-process-gone", handleChildProcessGone);
-  win.once("closed", () => {
-    win.off("restore", requestSurfaceRefresh);
-    win.off("show", requestSurfaceRefresh);
-    app.off("child-process-gone", handleChildProcessGone);
-  });
-}
-
 export function buildStandardContextMenuItems(
   contents: WebContents,
   params: Electron.ContextMenuParams,