fix(tui): unref'd desktop notifier subprocess so it cannot delay process exit

Bun keeps spawned subprocesses referenced by the event loop until they exit, regardless of stdio: "ignore". A slow notify-send or a hung gdbus call (e.g. stalled session-bus activation) could therefore keep omp alive past renderer shutdown after a completion or ask notification. Call .unref() on the spawned child so the event loop can exit immediately.

Test updated to assert .unref() is invoked on the spawned subprocess.

Re #3685

packages/tui/src/desktop-notify.ts

@@ -178,12 +178,19 @@ export function sendDesktopNotification(message: string | TerminalNotification):
 	const notifier = resolveDesktopNotifier();
 	if (!notifier) return;
 	try {
-		Bun.spawn({
+		// `.unref()` lets the event loop exit while the notifier is still running.
+		// Without it, an unresponsive D-Bus activation (slow `notify-send`, hung
+		// `gdbus` waiting on a stalled session bus) would keep `omp` alive past
+		// the renderer's shutdown — a completion toast must never delay process
+		// exit. Ignored stdio alone does not detach the child from the parent's
+		// reference count.
+		const child = Bun.spawn({
 			cmd: buildDesktopNotifyCommand(notifier, message),
 			stdin: "ignore",
 			stdout: "ignore",
 			stderr: "ignore",
 		});
+		child.unref();
 	} catch {
 		// Best-effort: a failed spawn is silent.
 	}

packages/tui/test/desktop-notify.test.ts

@@ -173,9 +173,10 @@ describe("sendDesktopNotification", () => {
 		resetDesktopNotifierCache();
 	});
 
-	it("fires Bun.spawn with the resolved notify-send argv and detached stdio", () => {
+	it("fires Bun.spawn with the resolved notify-send argv and unref's the child so it never blocks process exit", () => {
 		vi.spyOn(utils, "$which").mockImplementation(name => (name === "notify-send" ? "/usr/bin/notify-send" : null));
-		const spawn = vi.spyOn(Bun, "spawn").mockImplementation((..._args: unknown[]) => ({}) as never);
+		const unref = vi.fn();
+		const spawn = vi.spyOn(Bun, "spawn").mockImplementation((..._args: unknown[]) => ({ unref }) as never);
 
 		sendDesktopNotification({ title: "Session", body: "Complete" });
 
@@ -198,11 +199,15 @@ describe("sendDesktopNotification", () => {
 		expect(opts.stdin).toBe("ignore");
 		expect(opts.stdout).toBe("ignore");
 		expect(opts.stderr).toBe("ignore");
+		// `.unref()` is what actually decouples a slow notifier from process exit;
+		// without it Bun keeps the event loop pinned to the child even with
+		// stdio: "ignore".
+		expect(unref).toHaveBeenCalledTimes(1);
 	});
 
 	it("is a silent no-op when no notifier binary is installed", () => {
 		vi.spyOn(utils, "$which").mockReturnValue(null);
-		const spawn = vi.spyOn(Bun, "spawn").mockImplementation((..._args: unknown[]) => ({}) as never);
+		const spawn = vi.spyOn(Bun, "spawn").mockImplementation((..._args: unknown[]) => ({ unref: vi.fn() }) as never);
 
 		sendDesktopNotification("ping");