fix: App hanging on shutdown (#676)

- Updated agent logger
- Added ace shutdown against timeout to prevent app from hanging forever
- Fixed ACP shutdown deadlock

Author: charlesvien

apps/twig/src/main/lib/async.ts

@@ -0,0 +1,18 @@
+/**
+ * Races an operation against a timeout.
+ * Returns success with the value if the operation completes in time,
+ * or timeout if the operation takes longer than the specified duration.
+ */
+export async function withTimeout<T>(
+  operation: Promise<T>,
+  timeoutMs: number,
+): Promise<{ result: "success"; value: T } | { result: "timeout" }> {
+  const timeoutPromise = new Promise<{ result: "timeout" }>((resolve) =>
+    setTimeout(() => resolve({ result: "timeout" }), timeoutMs),
+  );
+  const operationPromise = operation.then((value) => ({
+    result: "success" as const,
+    value,
+  }));
+  return Promise.race([operationPromise, timeoutPromise]);
+}

apps/twig/src/main/services/app-lifecycle/service.ts

@@ -2,6 +2,7 @@ import { app } from "electron";
 import { injectable } from "inversify";
 import { ANALYTICS_EVENTS } from "../../../types/analytics.js";
 import { container } from "../../di/container.js";
+import { withTimeout } from "../../lib/async.js";
 import { logger } from "../../lib/logger.js";
 import { shutdownPostHog, trackAppEvent } from "../posthog-analytics.js";
 
@@ -10,6 +11,7 @@ const log = logger.scope("app-lifecycle");
 @injectable()
 export class AppLifecycleService {
   private _isQuittingForUpdate = false;
+  private static readonly SHUTDOWN_TIMEOUT_MS = 3000;
 
   get isQuittingForUpdate(): boolean {
     return this._isQuittingForUpdate;
@@ -20,23 +22,33 @@ export class AppLifecycleService {
   }
 
   async shutdown(): Promise<void> {
-    log.info("Performing graceful shutdown...");
+    // Race shutdown against timeout to prevent app from hanging forever
+    const result = await withTimeout(
+      this.doShutdown(),
+      AppLifecycleService.SHUTDOWN_TIMEOUT_MS,
+    );
+
+    if (result.result === "timeout") {
+      log.warn("Shutdown timeout reached, proceeding anyway", {
+        timeoutMs: AppLifecycleService.SHUTDOWN_TIMEOUT_MS,
+      });
+    }
+  }
 
+  private async doShutdown(): Promise<void> {
     try {
       await container.unbindAll();
     } catch (error) {
-      log.error("Error during container unbind", error);
+      log.error("Failed to unbind container", error);
     }
 
     trackAppEvent(ANALYTICS_EVENTS.APP_QUIT);
 
     try {
       await shutdownPostHog();
     } catch (error) {
-      log.error("Error shutting down PostHog", error);
+      log.error("Failed to shutdown PostHog", error);
     }
-
-    log.info("Graceful shutdown complete");
   }
 
   async shutdownAndExit(): Promise<void> {

packages/agent/src/adapters/acp-connection.ts

@@ -15,6 +15,7 @@ export type AcpConnectionConfig = {
   logWriter?: SessionLogWriter;
   sessionId?: string;
   taskId?: string;
+  logger?: Logger;
 };
 
 export type InProcessAcpConnection = {
@@ -32,7 +33,9 @@ export type InProcessAcpConnection = {
 export function createAcpConnection(
   config: AcpConnectionConfig = {},
 ): InProcessAcpConnection {
-  const logger = new Logger({ debug: true, prefix: "[AcpConnection]" });
+  const logger =
+    config.logger?.child("AcpConnection") ??
+    new Logger({ debug: true, prefix: "[AcpConnection]" });
   const streams = createBidirectionalStreams();
 
   const { logWriter } = config;

packages/agent/src/adapters/base-acp-agent.ts

@@ -62,8 +62,11 @@ export abstract class BaseAcpAgent implements Agent {
 
   async closeSession(): Promise<void> {
     try {
-      await this.cancel({ sessionId: this.sessionId });
+      // Abort first so in-flight HTTP requests are cancelled,
+      // otherwise interrupt() deadlocks waiting for the query to stop
+      // while the query waits on an API call that will never abort.
       this.session.abortController.abort();
+      await this.cancel({ sessionId: this.sessionId });
       this.logger.info("Closed session", { sessionId: this.sessionId });
     } catch (err) {
       this.logger.warn("Failed to close session", {

packages/agent/src/agent.ts

@@ -62,6 +62,7 @@ export class Agent {
       logWriter: this.sessionLogWriter,
       sessionId: taskRunId,
       taskId,
+      logger: this.logger,
     });
 
     return this.acpConnection;