fix(rustdb-storage): detect stale hint files using data file size metadata and add restart persistence regression tests

test/test.stale-sockets.ts

@@ -0,0 +1,82 @@
+import { expect, tap } from '@git.zone/tstest/tapbundle';
+import * as smartdb from '../ts/index.js';
+import * as fs from 'fs';
+import * as net from 'net';
+import * as path from 'path';
+import * as os from 'os';
+
+// ---------------------------------------------------------------------------
+// Test: Stale socket cleanup on startup
+// Covers: LocalSmartDb.cleanStaleSockets(), isSocketAlive()
+// ---------------------------------------------------------------------------
+
+function makeTmpDir(): string {
+  return fs.mkdtempSync(path.join(os.tmpdir(), 'smartdb-socket-test-'));
+}
+
+function cleanTmpDir(dir: string): void {
+  if (fs.existsSync(dir)) {
+    fs.rmSync(dir, { recursive: true, force: true });
+  }
+}
+
+// ============================================================================
+// Stale socket cleanup: active sockets are preserved
+// ============================================================================
+
+tap.test('stale-sockets: does not remove active sockets', async () => {
+  const tmpDir = makeTmpDir();
+  const activeSocketPath = path.join(os.tmpdir(), `smartdb-active-${Date.now()}.sock`);
+
+  // Create an active socket (server still listening)
+  const activeServer = net.createServer();
+  await new Promise<void>((resolve) => activeServer.listen(activeSocketPath, resolve));
+
+  expect(fs.existsSync(activeSocketPath)).toBeTrue();
+
+  // Start LocalSmartDb — should NOT remove the active socket
+  const localDb = new smartdb.LocalSmartDb({ folderPath: tmpDir });
+  await localDb.start();
+
+  expect(fs.existsSync(activeSocketPath)).toBeTrue();
+
+  // Cleanup
+  await localDb.stop();
+  await new Promise<void>((resolve) => activeServer.close(() => resolve()));
+  try { fs.unlinkSync(activeSocketPath); } catch {}
+  cleanTmpDir(tmpDir);
+});
+
+// ============================================================================
+// Stale socket cleanup: startup works with no stale sockets
+// ============================================================================
+
+tap.test('stale-sockets: startup works cleanly with no stale sockets', async () => {
+  const tmpDir = makeTmpDir();
+  const localDb = new smartdb.LocalSmartDb({ folderPath: tmpDir });
+  const info = await localDb.start();
+  expect(localDb.running).toBeTrue();
+  expect(info.socketPath).toBeTruthy();
+  await localDb.stop();
+  cleanTmpDir(tmpDir);
+});
+
+// ============================================================================
+// Stale socket cleanup: the socket file for the current instance is cleaned on stop
+// ============================================================================
+
+tap.test('stale-sockets: own socket file is removed on stop', async () => {
+  const tmpDir = makeTmpDir();
+  const localDb = new smartdb.LocalSmartDb({ folderPath: tmpDir });
+  const info = await localDb.start();
+
+  expect(fs.existsSync(info.socketPath)).toBeTrue();
+
+  await localDb.stop();
+
+  // Socket file should be gone after graceful stop
+  expect(fs.existsSync(info.socketPath)).toBeFalse();
+  cleanTmpDir(tmpDir);
+});
+
+export default tap.start();