fix(core): Prevent SSH tunnel cleanup timer from keeping the process alive (no-changelog) (#32146)

packages/core/src/execution-engine/__tests__/ssh-clients-manager.test.ts

@@ -40,6 +40,12 @@ afterEach(() => {
 	sshClientsManager.onShutdown();
 });
 
+it('should not keep the process alive for the stale-connection cleanup timer', () => {
+	const { cleanupTimer } = sshClientsManager as unknown as { cleanupTimer: NodeJS.Timeout };
+
+	expect(cleanupTimer.hasRef()).toBe(false);
+});
+
 describe('getClient', () => {
 	it('should create a new SSH client', async () => {
 		const client = await sshClientsManager.getClient(credentials);

packages/core/src/execution-engine/ssh-clients-manager.ts

@@ -65,8 +65,12 @@ export class SSHClientsManager {
 		// Close all SSH connections when the process exits
 		process.on('exit', () => this.onShutdown());
 
-		// Regularly close stale SSH connections
-		this.cleanupTimer = setInterval(() => this.cleanupStaleConnections(), 60 * 1000);
+		// Regularly close stale SSH connections. Unref'd so this housekeeping
+		// timer never keeps the process alive on its own: the manager is created
+		// by every workflow execution, and a referenced interval would block
+		// process exit until SIGKILL (e.g. single-file integration test runs
+		// hang after the run completes).
+		this.cleanupTimer = setInterval(() => this.cleanupStaleConnections(), 60 * 1000).unref();
 
 		this.logger = logger.scoped('ssh-client');
 	}