refactor: unify monitor abort lifecycle handling

src/discord/monitor/gateway-error-guard.test.ts

@@ -0,0 +1,33 @@
+import { EventEmitter } from "node:events";
+import { describe, expect, it, vi } from "vitest";
+import { attachEarlyGatewayErrorGuard } from "./gateway-error-guard.js";
+
+describe("attachEarlyGatewayErrorGuard", () => {
+  it("captures gateway errors until released", () => {
+    const emitter = new EventEmitter();
+    const fallbackErrorListener = vi.fn();
+    emitter.on("error", fallbackErrorListener);
+    const client = {
+      getPlugin: vi.fn(() => ({ emitter })),
+    };
+
+    const guard = attachEarlyGatewayErrorGuard(client as never);
+    emitter.emit("error", new Error("Fatal Gateway error: 4014"));
+    expect(guard.pendingErrors).toHaveLength(1);
+
+    guard.release();
+    emitter.emit("error", new Error("Fatal Gateway error: 4000"));
+    expect(guard.pendingErrors).toHaveLength(1);
+    expect(fallbackErrorListener).toHaveBeenCalledTimes(2);
+  });
+
+  it("returns noop guard when gateway emitter is unavailable", () => {
+    const client = {
+      getPlugin: vi.fn(() => undefined),
+    };
+
+    const guard = attachEarlyGatewayErrorGuard(client as never);
+    expect(guard.pendingErrors).toEqual([]);
+    expect(() => guard.release()).not.toThrow();
+  });
+});

src/discord/monitor/gateway-error-guard.ts

@@ -0,0 +1,36 @@
+import type { Client } from "@buape/carbon";
+import { getDiscordGatewayEmitter } from "../monitor.gateway.js";
+
+export type EarlyGatewayErrorGuard = {
+  pendingErrors: unknown[];
+  release: () => void;
+};
+
+export function attachEarlyGatewayErrorGuard(client: Client): EarlyGatewayErrorGuard {
+  const pendingErrors: unknown[] = [];
+  const gateway = client.getPlugin("gateway");
+  const emitter = getDiscordGatewayEmitter(gateway);
+  if (!emitter) {
+    return {
+      pendingErrors,
+      release: () => {},
+    };
+  }
+
+  let released = false;
+  const onGatewayError = (err: unknown) => {
+    pendingErrors.push(err);
+  };
+  emitter.on("error", onGatewayError);
+
+  return {
+    pendingErrors,
+    release: () => {
+      if (released) {
+        return;
+      }
+      released = true;
+      emitter.removeListener("error", onGatewayError);
+    },
+  };
+}

src/discord/monitor/provider.ts

@@ -34,7 +34,6 @@ import { createDiscordRetryRunner } from "../../infra/retry-policy.js";
 import { createSubsystemLogger } from "../../logging/subsystem.js";
 import { createNonExitingRuntime, type RuntimeEnv } from "../../runtime.js";
 import { resolveDiscordAccount } from "../accounts.js";
-import { getDiscordGatewayEmitter } from "../monitor.gateway.js";
 import { fetchDiscordApplicationId } from "../probe.js";
 import { normalizeDiscordToken } from "../token.js";
 import { createDiscordVoiceCommand } from "../voice/command.js";
@@ -52,6 +51,7 @@ import {
 } from "./agent-components.js";
 import { resolveDiscordSlashCommandConfig } from "./commands.js";
 import { createExecApprovalButton, DiscordExecApprovalHandler } from "./exec-approvals.js";
+import { attachEarlyGatewayErrorGuard } from "./gateway-error-guard.js";
 import { createDiscordGatewayPlugin } from "./gateway-plugin.js";
 import {
   DiscordMessageListener,
@@ -230,33 +230,6 @@ function isDiscordDisallowedIntentsError(err: unknown): boolean {
   return message.includes(String(DISCORD_DISALLOWED_INTENTS_CODE));
 }
 
-type EarlyGatewayErrorGuard = {
-  pendingErrors: unknown[];
-  release: () => void;
-};
-
-function attachEarlyGatewayErrorGuard(client: Client): EarlyGatewayErrorGuard {
-  const pendingErrors: unknown[] = [];
-  const gateway = client.getPlugin<GatewayPlugin>("gateway");
-  const emitter = getDiscordGatewayEmitter(gateway);
-  if (!emitter) {
-    return {
-      pendingErrors,
-      release: () => {},
-    };
-  }
-  const onGatewayError = (err: unknown) => {
-    pendingErrors.push(err);
-  };
-  emitter.on("error", onGatewayError);
-  return {
-    pendingErrors,
-    release: () => {
-      emitter.removeListener("error", onGatewayError);
-    },
-  };
-}
-
 export async function monitorDiscordProvider(opts: MonitorDiscordOpts = {}) {
   const cfg = opts.config ?? loadConfig();
   const account = resolveDiscordAccount({