[bug] Remote terminal freezes after laptop sleep/wake (half-open WebSocket is never recovered) #5130

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1. yasyf commented on Jun 5, 2026

   

   yasyf

   on Jun 5, 2026

   Author

   More actions

   Full self-contained failing test, as offered above. Drop it in at apps/desktop/src/renderer/lib/terminal/terminal-ws-transport.sleep-repro.test.ts and run:

   bun test apps/desktop/src/renderer/lib/terminal/terminal-ws-transport.sleep-repro.test.ts
   

   It fails on main (Expected: 2 / Received: 1) and passes once the transport gains any time-based liveness recovery (I verified with a ~15-line setInterval watchdog in connect()).

   // Repro: a desktop workspace terminal freezes after laptop sleep/wake.
   //
   // On suspend the terminal WebSocket goes half-open: the connection is dead, but
   // readyState stays OPEN and no `close` event is ever delivered. The transport
   // only reconnects from its `close` handler, so nothing notices the dead pipe
   // and the pane stays frozen until it's killed and recreated.
   //
   // Fails on main (the dead socket is never replaced) and passes once the
   // transport gains any time-based liveness recovery.
   import {
   	afterEach,
   	beforeEach,
   	describe,
   	expect,
   	jest,
   	setSystemTime,
   	test,
   } from "bun:test";
   import type { Terminal as XTerm } from "@xterm/xterm";
   import { connect, createTransport } from "./terminal-ws-transport";
   
   type Listener = (event: { data?: unknown; code?: number; reason?: string }) => void;
   
   class MockWebSocket {
   	static readonly CONNECTING = 0;
   	static readonly OPEN = 1;
   	static readonly CLOSING = 2;
   	static readonly CLOSED = 3;
   	static instances: MockWebSocket[] = [];
   
   	readyState = MockWebSocket.CONNECTING;
   	binaryType: BinaryType = "blob";
   	private readonly listeners = new Map<string, Set<Listener>>();
   
   	constructor(readonly url: string) {
   		MockWebSocket.instances.push(this);
   	}
   
   	addEventListener(type: string, cb: Listener) {
   		let set = this.listeners.get(type);
   		if (!set) this.listeners.set(type, (set = new Set()));
   		set.add(cb);
   	}
   	send() {}
   	open() {
   		this.readyState = MockWebSocket.OPEN;
   		this.emit("open", {});
   	}
   	close() {
   		this.readyState = MockWebSocket.CLOSED;
   		this.emit("close", { code: 1000 });
   	}
   	message(data: unknown) {
   		this.emit("message", { data });
   	}
   	private emit(type: string, event: Parameters<Listener>[0]) {
   		for (const cb of this.listeners.get(type) ?? []) cb(event);
   	}
   }
   
   function createMockTerminal(): XTerm {
   	return {
   		cols: 80,
   		rows: 24,
   		onData: () => ({ dispose() {} }),
   		write() {},
   		writeln() {},
   	} as unknown as XTerm;
   }
   
   const realWebSocket = globalThis.WebSocket;
   
   beforeEach(() => {
   	MockWebSocket.instances = [];
   	globalThis.WebSocket = MockWebSocket as unknown as typeof WebSocket;
   });
   
   afterEach(() => {
   	globalThis.WebSocket = realWebSocket;
   	setSystemTime();
   	jest.useRealTimers();
   });
   
   describe("terminal-ws-transport — laptop sleep/wake", () => {
   	test("recovers a half-open socket after the machine resumes", () => {
   		jest.useFakeTimers();
   		setSystemTime(new Date("2026-01-01T00:00:00Z"));
   
   		const transport = createTransport();
   		connect(transport, createMockTerminal(), "ws://host/terminal/t1");
   
   		const socket = MockWebSocket.instances[0];
   		if (!socket) throw new Error("expected a websocket");
   		socket.open();
   		socket.message(JSON.stringify({ type: "attached", terminalId: "t1" }));
   		expect(transport.connectionState).toBe("open");
   
   		// Laptop sleeps. The connection dies, but the socket never observes it:
   		// readyState stays OPEN and no `close` event is delivered. We never call
   		// socket.close(); that silent death is the bug. Two minutes pass, then
   		// the machine wakes.
   		setSystemTime(new Date("2026-01-01T00:02:00Z"));
   		jest.advanceTimersByTime(120_000);
   
   		// Recovery means dropping the dead socket and opening a fresh one. On main
   		// there's no liveness check, so the transport stays wedged on the dead one.
   		expect(MockWebSocket.instances.length).toBe(2);
   	});
   });
2. github-actions

   added a commit that references this issue on Jun 5, 2026

   fix: solve #5130 — recover remote terminal after sleep/wake half-open…

   ...

   1779b3a
3. saddlepaddle commented on Jun 5, 2026

   

   saddlepaddle

   on Jun 5, 2026

   Collaborator

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   Fix opened in #5135 — adds a wall-clock-gap watchdog plus online/focus/visibilitychange recovery to terminal-ws-transport.ts. Your repro test is folded into terminal-ws-transport.test.ts (fails on main, passes with the fix). Thanks for the thorough writeup and the self-contained failing test.

   ❤️React with ❤️1Reacted by Yasyf Mohamedali
4. saddlepaddle commented on Jun 5, 2026

   

   saddlepaddle

   on Jun 5, 2026

   Collaborator

   More actions

   Thanks for reporting this!
5. saddlepaddle

   added a commit that references this issue on Jun 5, 2026

   fix(desktop): recover remote terminal after laptop sleep/wake (#5135)

   ...

   This issue will close once commit 38e6a2c is merged into the 'main' branch.

   38e6a2c
6. saddlepaddle

   closed this as completedin #5135on Jun 5, 2026