fix(daemon): preserve replacement socket ownership

src/daemon/host.ts

@@ -452,18 +452,24 @@ async function prepareSocket(socketPath: string): Promise<void> {
 }
 
 async function cleanupArtifacts(options: DaemonHostOptions): Promise<void> {
+  await cleanupDaemonArtifactsIfOwned(options, process.pid);
+}
+
+export async function cleanupDaemonArtifactsIfOwned(
+  paths: Pick<DaemonHostOptions, 'metadataPath' | 'socketPath'>,
+  ownerPid: number
+): Promise<void> {
+  // A superseded daemon may finish shutting down after its replacement has
+  // already rebound the same paths. Never let that old process unlink the
+  // replacement daemon's live socket and metadata.
+  const metadata = await readJsonFile<{ pid?: number; socketPath?: string }>(paths.metadataPath).catch(() => undefined);
+  if (metadata?.pid !== ownerPid || metadata.socketPath !== paths.socketPath) {
+    return;
+  }
   if (process.platform !== 'win32') {
-    try {
-      await fs.unlink(options.socketPath);
-    } catch {
-      // ignore
-    }
-  }
-  try {
-    await fs.unlink(options.metadataPath);
-  } catch {
-    // ignore
+    await fs.unlink(paths.socketPath).catch(() => {});
   }
+  await fs.unlink(paths.metadataPath).catch(() => {});
 }
 
 async function handleSocketRequest(

tests/daemon-host.test.ts

@@ -5,7 +5,12 @@ import os from 'node:os';
 import path from 'node:path';
 import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
 import type { ServerDefinition } from '../src/config.js';
-import { __testProcessRequest, isDaemonResponding, metadataMatches } from '../src/daemon/host.js';
+import {
+  __testProcessRequest,
+  cleanupDaemonArtifactsIfOwned,
+  isDaemonResponding,
+  metadataMatches,
+} from '../src/daemon/host.js';
 import type { DaemonRequest } from '../src/daemon/protocol.js';
 import type { Runtime } from '../src/runtime.js';
 
@@ -246,6 +251,41 @@ describe('metadataMatches', () => {
   });
 });
 
+describe('daemon artifact cleanup', () => {
+  let dir: string;
+  let metadataPath: string;
+  let socketPath: string;
+
+  beforeEach(async () => {
+    dir = await fs.mkdtemp(path.join(os.tmpdir(), 'mcporter-cleanup-'));
+    metadataPath = path.join(dir, 'daemon.json');
+    socketPath = path.join(dir, 'daemon.sock');
+    await fs.writeFile(socketPath, 'socket', 'utf8');
+  });
+
+  afterEach(async () => {
+    await fs.rm(dir, { recursive: true, force: true });
+  });
+
+  it('removes artifacts still owned by the stopping daemon', async () => {
+    await fs.writeFile(metadataPath, JSON.stringify({ pid: 4321, socketPath }), 'utf8');
+
+    await cleanupDaemonArtifactsIfOwned({ metadataPath, socketPath }, 4321);
+
+    await expect(fs.access(metadataPath)).rejects.toThrow();
+    await expect(fs.access(socketPath)).rejects.toThrow();
+  });
+
+  it('preserves artifacts replaced by a newer daemon', async () => {
+    await fs.writeFile(metadataPath, JSON.stringify({ pid: 9876, socketPath }), 'utf8');
+
+    await cleanupDaemonArtifactsIfOwned({ metadataPath, socketPath }, 4321);
+
+    await expect(fs.access(metadataPath)).resolves.toBeUndefined();
+    await expect(fs.access(socketPath)).resolves.toBeUndefined();
+  });
+});
+
 function createRuntimeDouble(): Pick<Runtime, 'callTool' | 'listTools'> {
   return {
     callTool: vi.fn().mockResolvedValue({ ok: true }),