fix: add dispose method to prevent abort listener leak (#12269)

* fix: add dispose method to prevent abort listener leak

Add dispose() method to StreamAbortController that explicitly removes
the abort event listener when stream ends normally. Previously, the
listener would only be removed when abort was triggered ({ once: true }),
but if the stream completed normally without abort, the listener would
remain attached until garbage collection.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

* chore: format code

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

---------

Co-authored-by: Claude <noreply@anthropic.com>

src/main/apiServer/routes/agents/handlers/messages.ts

@@ -1,6 +1,10 @@
 import { loggerService } from '@logger'
 import { MESSAGE_STREAM_TIMEOUT_MS } from '@main/apiServer/config/timeouts'
-import { createStreamAbortController, STREAM_TIMEOUT_REASON } from '@main/apiServer/utils/createStreamAbortController'
+import {
+  createStreamAbortController,
+  STREAM_TIMEOUT_REASON,
+  type StreamAbortController
+} from '@main/apiServer/utils/createStreamAbortController'
 import { agentService, sessionMessageService, sessionService } from '@main/services/agents'
 import type { Request, Response } from 'express'
 
@@ -26,7 +30,7 @@ const verifyAgentAndSession = async (agentId: string, sessionId: string) => {
 }
 
 export const createMessage = async (req: Request, res: Response): Promise<void> => {
-  let clearAbortTimeout: (() => void) | undefined
+  let streamController: StreamAbortController | undefined
 
   try {
     const { agentId, sessionId } = req.params
@@ -45,14 +49,10 @@ export const createMessage = async (req: Request, res: Response): Promise<void>
     res.setHeader('Access-Control-Allow-Origin', '*')
     res.setHeader('Access-Control-Allow-Headers', 'Cache-Control')
 
-    const {
-      abortController,
-      registerAbortHandler,
-      clearAbortTimeout: helperClearAbortTimeout
-    } = createStreamAbortController({
+    streamController = createStreamAbortController({
       timeoutMs: MESSAGE_STREAM_TIMEOUT_MS
     })
-    clearAbortTimeout = helperClearAbortTimeout
+    const { abortController, registerAbortHandler, dispose } = streamController
     const { stream, completion } = await sessionMessageService.createSessionMessage(
       session,
       messageData,
@@ -64,8 +64,8 @@ export const createMessage = async (req: Request, res: Response): Promise<void>
     let responseEnded = false
     let streamFinished = false
 
-    const cleanupAbortTimeout = () => {
-      clearAbortTimeout?.()
+    const cleanup = () => {
+      dispose()
     }
 
     const finalizeResponse = () => {
@@ -78,7 +78,7 @@ export const createMessage = async (req: Request, res: Response): Promise<void>
       }
 
       responseEnded = true
-      cleanupAbortTimeout()
+      cleanup()
       try {
         // res.write('data: {"type":"finish"}\n\n')
         res.write('data: [DONE]\n\n')
@@ -108,7 +108,7 @@ export const createMessage = async (req: Request, res: Response): Promise<void>
      * - Mark the response as ended to prevent further writes
      */
     registerAbortHandler((abortReason) => {
-      cleanupAbortTimeout()
+      cleanup()
 
       if (responseEnded) return
 
@@ -189,7 +189,7 @@ export const createMessage = async (req: Request, res: Response): Promise<void>
           logger.error('Error writing stream error to SSE', { error: writeError })
         }
         responseEnded = true
-        cleanupAbortTimeout()
+        cleanup()
         res.end()
       }
     }
@@ -221,14 +221,14 @@ export const createMessage = async (req: Request, res: Response): Promise<void>
           logger.error('Error writing completion error to SSE stream', { error: writeError })
         }
         responseEnded = true
-        cleanupAbortTimeout()
+        cleanup()
         res.end()
       })
     // Clear timeout when response ends
-    res.on('close', cleanupAbortTimeout)
-    res.on('finish', cleanupAbortTimeout)
+    res.on('close', cleanup)
+    res.on('finish', cleanup)
   } catch (error: any) {
-    clearAbortTimeout?.()
+    streamController?.dispose()
     logger.error('Error in streaming message handler', {
       error,
       agentId: req.params.agentId,

src/main/apiServer/utils/createStreamAbortController.ts

@@ -4,6 +4,7 @@ export interface StreamAbortController {
   abortController: AbortController
   registerAbortHandler: (handler: StreamAbortHandler) => void
   clearAbortTimeout: () => void
+  dispose: () => void
 }
 
 export const STREAM_TIMEOUT_REASON = 'stream timeout'
@@ -40,6 +41,15 @@ export const createStreamAbortController = (options: CreateStreamAbortController
 
   signal.addEventListener('abort', handleAbort, { once: true })
 
+  let disposed = false
+
+  const dispose = () => {
+    if (disposed) return
+    disposed = true
+    clearAbortTimeout()
+    signal.removeEventListener('abort', handleAbort)
+  }
+
   const registerAbortHandler = (handler: StreamAbortHandler) => {
     abortHandler = handler
 
@@ -59,6 +69,7 @@ export const createStreamAbortController = (options: CreateStreamAbortController
   return {
     abortController,
     registerAbortHandler,
-    clearAbortTimeout
+    clearAbortTimeout,
+    dispose
   }
 }