fix(coding-agent,mom): retry fs watchers on async errors closes #3564

packages/coding-agent/src/utils/fs-watch.ts

@@ -0,0 +1,30 @@
+import { type FSWatcher, type WatchListener, watch } from "node:fs";
+
+export const FS_WATCH_RETRY_DELAY_MS = 5000;
+
+export function closeWatcher(watcher: FSWatcher | null | undefined): void {
+	if (!watcher) {
+		return;
+	}
+
+	try {
+		watcher.close();
+	} catch {
+		// Ignore watcher close errors
+	}
+}
+
+export function watchWithErrorHandler(
+	path: string,
+	listener: WatchListener<string>,
+	onError: () => void,
+): FSWatcher | null {
+	try {
+		const watcher = watch(path, listener);
+		watcher.on("error", onError);
+		return watcher;
+	} catch {
+		onError();
+		return null;
+	}
+}