fix(discord): avoid false heartbeat ACK timeouts

Fix the Discord Gateway heartbeat scheduler so ACK timeout checks are measured from the actual heartbeat send, not from the fixed HELLO-time interval. This prevents late randomized first heartbeats from causing false reconnect loops while the Discord channel is still awaiting readiness.\n\nVerification:\n- pnpm test extensions/discord/src/internal/gateway-lifecycle.test.ts extensions/discord/src/internal/gateway.test.ts\n- pnpm exec oxfmt --check --threads=1 CHANGELOG.md extensions/discord/src/internal/gateway-lifecycle.ts extensions/discord/src/internal/gateway-lifecycle.test.ts extensions/discord/src/internal/gateway.test.ts\n- git diff --check\n- Real behavior proof check passed on PR head bf239b886020c11d55af33f16674e953535f9b4c\n\nFixes #77668.\nSupersedes #77956.\nThanks @bryce-d-greybeard and @NikolaFC.

CHANGELOG.md

@@ -101,6 +101,7 @@ Docs: https://docs.openclaw.ai
 
 ### Fixes
 
+- Discord/gateway: measure heartbeat ACK timeouts from the actual heartbeat send, preventing late initial heartbeats from triggering false reconnect loops while the channel is still awaiting readiness. Fixes #77668. (#78087) Thanks @bryce-d-greybeard and @NikolaFC.
 - Control UI/Sessions: make the compaction count a compact `N Checkpoint(s)` disclosure and show expanded session-level details with modern checkpoint history cards across responsive table layouts. Thanks @BunsDev.
 - Control UI/performance: keep chat and channel tabs responsive while history payloads and channel probes are slow, label partial channel status, and record slow chat/config render timings in the event log. Thanks @BunsDev.
 - Control UI/sessions: fire the documented `/new` command and lifecycle hooks only for explicit Control UI session creation, restoring session-memory and custom hook capture without changing SDK parent-session creates. Fixes #76957. Thanks @BunsDev.

extensions/discord/src/internal/gateway-lifecycle.test.ts

@@ -0,0 +1,114 @@
+import { afterEach, describe, expect, it, vi } from "vitest";
+import { GatewayHeartbeatTimers } from "./gateway-lifecycle.js";
+
+describe("GatewayHeartbeatTimers", () => {
+  afterEach(() => {
+    vi.restoreAllMocks();
+    vi.useRealTimers();
+  });
+
+  it("does not false-timeout when the first heartbeat fires near the interval boundary", () => {
+    vi.useFakeTimers();
+
+    const onHeartbeat = vi.fn();
+    const onAckTimeout = vi.fn();
+    const isAcked = vi.fn().mockReturnValue(false);
+    const timers = new GatewayHeartbeatTimers();
+
+    timers.start({
+      intervalMs: 45_000,
+      isAcked,
+      onAckTimeout,
+      onHeartbeat,
+      random: () => 0.95,
+    });
+
+    vi.advanceTimersByTime(42_750);
+    expect(onHeartbeat).toHaveBeenCalledTimes(1);
+    expect(onAckTimeout).not.toHaveBeenCalled();
+
+    vi.advanceTimersByTime(2_250);
+    expect(onAckTimeout).not.toHaveBeenCalled();
+
+    isAcked.mockReturnValue(true);
+    vi.advanceTimersByTime(42_750);
+    expect(onHeartbeat).toHaveBeenCalledTimes(2);
+    expect(onAckTimeout).not.toHaveBeenCalled();
+
+    timers.stop();
+  });
+
+  it("fires an ACK timeout when a heartbeat is genuinely not acknowledged", () => {
+    vi.useFakeTimers();
+
+    const timers = new GatewayHeartbeatTimers();
+    const onHeartbeat = vi.fn();
+    const onAckTimeout = vi.fn();
+
+    timers.start({
+      intervalMs: 45_000,
+      isAcked: () => false,
+      onAckTimeout,
+      onHeartbeat,
+      random: () => 0,
+    });
+
+    vi.advanceTimersByTime(0);
+    expect(onHeartbeat).toHaveBeenCalledTimes(1);
+
+    vi.advanceTimersByTime(45_000);
+    expect(onAckTimeout).toHaveBeenCalledTimes(1);
+
+    timers.stop();
+  });
+
+  it("sends heartbeats at regular intervals after the initial random delay", () => {
+    vi.useFakeTimers();
+
+    const timers = new GatewayHeartbeatTimers();
+    const onHeartbeat = vi.fn();
+    const onAckTimeout = vi.fn();
+
+    timers.start({
+      intervalMs: 10_000,
+      isAcked: () => true,
+      onAckTimeout,
+      onHeartbeat,
+      random: () => 0.5,
+    });
+
+    vi.advanceTimersByTime(5_000);
+    expect(onHeartbeat).toHaveBeenCalledTimes(1);
+
+    vi.advanceTimersByTime(10_000);
+    expect(onHeartbeat).toHaveBeenCalledTimes(2);
+
+    vi.advanceTimersByTime(10_000);
+    expect(onHeartbeat).toHaveBeenCalledTimes(3);
+    expect(onAckTimeout).not.toHaveBeenCalled();
+
+    timers.stop();
+  });
+
+  it("stop cancels all pending timers", () => {
+    vi.useFakeTimers();
+
+    const timers = new GatewayHeartbeatTimers();
+    const onHeartbeat = vi.fn();
+    const onAckTimeout = vi.fn();
+
+    timers.start({
+      intervalMs: 10_000,
+      isAcked: () => true,
+      onAckTimeout,
+      onHeartbeat,
+      random: () => 0.5,
+    });
+
+    timers.stop();
+    vi.advanceTimersByTime(100_000);
+
+    expect(onHeartbeat).not.toHaveBeenCalled();
+    expect(onAckTimeout).not.toHaveBeenCalled();
+  });
+});

extensions/discord/src/internal/gateway-lifecycle.ts

@@ -4,6 +4,24 @@ export class GatewayHeartbeatTimers {
   heartbeatInterval?: GatewayTimer;
   firstHeartbeatTimeout?: GatewayTimer;
 
+  private scheduleHeartbeatCycle(params: {
+    intervalMs: number;
+    isAcked: () => boolean;
+    onAckTimeout: () => void;
+    onHeartbeat: () => void;
+  }): void {
+    this.heartbeatInterval = setTimeout(() => {
+      this.heartbeatInterval = undefined;
+      if (!params.isAcked()) {
+        params.onAckTimeout();
+        return;
+      }
+      params.onHeartbeat();
+      this.scheduleHeartbeatCycle(params);
+    }, params.intervalMs);
+    this.heartbeatInterval.unref?.();
+  }
+
   start(params: {
     intervalMs: number;
     isAcked: () => boolean;
@@ -14,23 +32,19 @@ export class GatewayHeartbeatTimers {
     this.stop();
     const random = params.random ?? Math.random;
     this.firstHeartbeatTimeout = setTimeout(
-      params.onHeartbeat,
+      () => {
+        this.firstHeartbeatTimeout = undefined;
+        params.onHeartbeat();
+        this.scheduleHeartbeatCycle(params);
+      },
       Math.max(0, params.intervalMs * random()),
     );
     this.firstHeartbeatTimeout.unref?.();
-    this.heartbeatInterval = setInterval(() => {
-      if (!params.isAcked()) {
-        params.onAckTimeout();
-        return;
-      }
-      params.onHeartbeat();
-    }, params.intervalMs);
-    this.heartbeatInterval.unref?.();
   }
 
   stop(): void {
     if (this.heartbeatInterval) {
-      clearInterval(this.heartbeatInterval);
+      clearTimeout(this.heartbeatInterval);
       this.heartbeatInterval = undefined;
     }
     if (this.firstHeartbeatTimeout) {