fix: MaxListenersExceededWarning memory leak (#782)

Author: charlesvien

apps/twig/src/main/lib/typed-event-emitter.ts

@@ -1,6 +1,11 @@
 import { EventEmitter, on } from "node:events";
 
 export class TypedEventEmitter<TEvents> extends EventEmitter {
+  constructor() {
+    super();
+    this.setMaxListeners(50);
+  }
+
   emit<K extends keyof TEvents & string>(
     event: K,
     payload: TEvents[K],

apps/twig/src/main/services/agent/service.ts

@@ -26,7 +26,7 @@ import { MAIN_TOKENS } from "../../di/tokens.js";
 import { logger } from "../../lib/logger.js";
 import { TypedEventEmitter } from "../../lib/typed-event-emitter.js";
 import type { ProcessTrackingService } from "../process-tracking/service.js";
-import { SleepService } from "../sleep/service.js";
+import type { SleepService } from "../sleep/service.js";
 import {
   AgentServiceEvent,
   type AgentServiceEvents,
@@ -873,6 +873,14 @@ For git operations while detached:
       sessionCount: sessionIds.length,
     });
 
+    for (const session of this.sessions.values()) {
+      try {
+        await session.agent.flushAllLogs();
+      } catch {
+        log.debug("Failed to flush session logs during shutdown");
+      }
+    }
+
     for (const taskRunId of sessionIds) {
       await this.cleanupSession(taskRunId);
     }

packages/agent/src/agent.ts

@@ -99,7 +99,14 @@ export class Agent {
     });
   }
 
+  async flushAllLogs(): Promise<void> {
+    await this.sessionLogWriter?.flushAll();
+  }
+
   async cleanup(): Promise<void> {
+    if (this.sessionLogWriter && this.taskRunId) {
+      await this.sessionLogWriter.flush(this.taskRunId);
+    }
     await this.acpConnection?.cleanup();
   }
 }

packages/agent/src/session-log-writer.ts

@@ -18,25 +18,14 @@ export class SessionLogWriter {
     this.posthogAPI = posthogAPI;
     this.logger =
       logger ?? new Logger({ debug: false, prefix: "[SessionLogWriter]" });
+  }
 
-    const flushAllAndExit = async () => {
-      const flushPromises: Promise<void>[] = [];
-      for (const sessionId of this.configs.keys()) {
-        flushPromises.push(this.flush(sessionId));
-      }
-      await Promise.all(flushPromises);
-      process.exit(0);
-    };
-
-    process.on("beforeExit", () => {
-      flushAllAndExit().catch((e) => this.logger.error("Flush failed:", e));
-    });
-    process.on("SIGINT", () => {
-      flushAllAndExit().catch((e) => this.logger.error("Flush failed:", e));
-    });
-    process.on("SIGTERM", () => {
-      flushAllAndExit().catch((e) => this.logger.error("Flush failed:", e));
-    });
+  async flushAll(): Promise<void> {
+    const flushPromises: Promise<void>[] = [];
+    for (const sessionId of this.configs.keys()) {
+      flushPromises.push(this.flush(sessionId));
+    }
+    await Promise.all(flushPromises);
   }
 
   register(sessionId: string, config: SessionLogConfig): void {