Clean up CDP proxy client listeners

src/main/browser/cdp-ws-proxy.test.ts

@@ -330,6 +330,28 @@ describe('CdpWsProxy', () => {
     })
   })
 
+  it('detaches client websocket listeners after client close', async () => {
+    const client = await connect()
+    const serverClient = (proxy as unknown as { client: WebSocket | null }).client
+    expect(serverClient).toBeTruthy()
+    const offSpy = vi.spyOn(serverClient!, 'off')
+
+    client.close()
+
+    const start = Date.now()
+    while (
+      (proxy as unknown as { client: WebSocket | null }).client &&
+      Date.now() - start < 2_000
+    ) {
+      await new Promise((resolve) => setTimeout(resolve, 20))
+    }
+
+    expect((proxy as unknown as { client: WebSocket | null }).client).toBeNull()
+    const removedEvents = offSpy.mock.calls.map(([event]) => event)
+    expect(removedEvents).toEqual(expect.arrayContaining(['message', 'close']))
+    offSpy.mockRestore()
+  })
+
   it('rejects inflight requests on stop', async () => {
     let resolveCommand: (v: unknown) => void
     mock.webContents.debugger.sendCommand.mockImplementation(

src/main/browser/cdp-ws-proxy.ts

@@ -1,3 +1,4 @@
+/* eslint-disable max-lines -- Why: this proxy owns HTTP discovery, websocket client lifecycle, and CDP debugger forwarding together. */
 import { WebSocketServer, WebSocket } from 'ws'
 import { createServer, type Server, type IncomingMessage, type ServerResponse } from 'http'
 import type { WebContents } from 'electron'
@@ -9,6 +10,7 @@ export class CdpWsProxy {
   private httpServer: Server | null = null
   private wss: WebSocketServer | null = null
   private client: WebSocket | null = null
+  private detachClientListeners: (() => void) | null = null
   private port = 0
   private debuggerMessageHandler: ((...args: unknown[]) => void) | null = null
   private debuggerDetachHandler: ((...args: unknown[]) => void) | null = null
@@ -39,16 +41,27 @@ export class CdpWsProxy {
         failStart(error)
       }
       this.wss.on('connection', (ws) => {
-        if (this.client) {
-          this.client.close()
-        }
+        this.closeClient()
         this.client = ws
-        ws.on('message', (data) => this.handleClientMessage(ws, data.toString()))
-        ws.on('close', () => {
+        const onMessage = (data: WebSocket.RawData): void => {
+          this.handleClientMessage(ws, data.toString())
+        }
+        const onClose = (): void => {
+          detach()
           if (this.client === ws) {
             this.client = null
           }
-        })
+        }
+        const detach = (): void => {
+          ws.off('message', onMessage)
+          ws.off('close', onClose)
+          if (this.detachClientListeners === detach) {
+            this.detachClientListeners = null
+          }
+        }
+        this.detachClientListeners = detach
+        ws.on('message', onMessage)
+        ws.on('close', onClose)
       })
       this.httpServer.listen(0, '127.0.0.1', () => {
         this.httpServer?.removeListener('error', onListenError)
@@ -66,10 +79,7 @@ export class CdpWsProxy {
 
   async stop(): Promise<void> {
     this.detachDebugger()
-    if (this.client) {
-      this.client.close()
-      this.client = null
-    }
+    this.closeClient()
     if (this.wss) {
       this.wss.close()
       this.wss = null
@@ -84,6 +94,14 @@ export class CdpWsProxy {
     return this.port
   }
 
+  private closeClient(): void {
+    const client = this.client
+    this.detachClientListeners?.()
+    this.detachClientListeners = null
+    this.client = null
+    client?.close()
+  }
+
   private send(payload: unknown, client = this.client): void {
     if (client?.readyState === WebSocket.OPEN) {
       client.send(JSON.stringify(payload))