align with python and remove unused abost controller.

Author: mattzcarey

src/__fixtures__/serverThatHangs.ts

@@ -1,4 +1,4 @@
-import { setTimeout } from 'node:timers';
+import { setInterval } from 'node:timers';
 import process from 'node:process';
 import { McpServer } from '../server/mcp.js';
 import { StdioServerTransport } from '../server/stdio.js';
@@ -20,12 +20,22 @@ const server = new McpServer(
 
 await server.connect(transport);
 
+// Keep process alive even after stdin closes
+const keepAlive = setInterval(() => {}, 60_000);
+
+// Prevent transport close from exiting
+transport.onclose = () => {
+    // Intentionally ignore - we want to test the signal handling
+};
+
 const doNotExitImmediately = async (signal: NodeJS.Signals) => {
     await server.sendLoggingMessage({
         level: 'debug',
         data: `received signal ${signal}`
     });
-    setTimeout(() => process.exit(0), 30 * 1000);
+    // Clear keepalive but delay exit to simulate slow shutdown
+    clearInterval(keepAlive);
+    setInterval(() => {}, 30_000);
 };
 
 process.on('SIGINT', doNotExitImmediately);

src/client/stdio.ts

@@ -91,7 +91,6 @@ export function getDefaultEnvironment(): Record<string, string> {
  */
 export class StdioClientTransport implements Transport {
     private _process?: ChildProcess;
-    private _abortController: AbortController = new AbortController();
     private _readBuffer: ReadBuffer = new ReadBuffer();
     private _serverParams: StdioServerParameters;
     private _stderrStream: PassThrough | null = null;
@@ -126,17 +125,11 @@ export class StdioClientTransport implements Transport {
                 },
                 stdio: ['pipe', 'pipe', this._serverParams.stderr ?? 'inherit'],
                 shell: false,
-                signal: this._abortController.signal,
                 windowsHide: process.platform === 'win32' && isElectron(),
                 cwd: this._serverParams.cwd
             });
 
             this._process.on('error', error => {
-                if (error.name === 'AbortError') {
-                    // Expected when close() is called.
-                    return;
-                }
-
                 reject(error);
                 this.onerror?.(error);
             });
@@ -225,10 +218,18 @@ export class StdioClientTransport implements Transport {
                 // ignore
             }
 
-            this._abortController.abort();
-
             await Promise.race([closePromise, new Promise(resolve => setTimeout(resolve, 2_000).unref())]);
 
+            if (processToClose.exitCode === null) {
+                try {
+                    processToClose.kill('SIGTERM');
+                } catch {
+                    // ignore
+                }
+
+                await Promise.race([closePromise, new Promise(resolve => setTimeout(resolve, 2_000).unref())]);
+            }
+
             if (processToClose.exitCode === null) {
                 try {
                     processToClose.kill('SIGKILL');