exposeHostPorts: connection to a closed host port causes an uncaught ECONNREFUSED in the test process #1607

Expected Behaviour

When a container connects to host.testcontainers.internal:<port> and nothing on the host listens on that port, the connection fails inside the container. The test process keeps running.

Actual Behaviour

The test process gets an uncaught exception:

Error: connect ECONNREFUSED 127.0.0.1:<port>
 ❯ TCPConnectWrap.afterConnect [as oncomplete] node:net:1864:16

Vitest reports this as an unhandled error and fails the run, even when every test passes.

The cause is in ssh-remote-port-forward, which PortForwarder uses for exposeHostPorts. Its tcp connection handler opens a socket and never listens for error on it:

.on("tcp connection", (info, accept) => {
  const stream = accept();
  stream.pause();
  const socket = net.connect(info.destPort, info.destIP, () => {
    stream.pipe(socket);
    socket.pipe(stream);
    stream.resume();
  });
})

If the host port is closed, net.connect emits error with no listener, so Node throws it. The SSH stream also stays open. A fix is to add socket.on("error", () => stream.close()), and probably stream.on("error", () => socket.destroy()) as well.

ssh-remote-port-forward@1.0.4 is the newest version and was last published in 2022. testcontainers@12.2.1 still depends on ^1.0.4.

Testcontainers Logs

The script below, run as plain Node with an uncaughtException handler that prints the error:

testcontainers [INFO] Exposing host port 35041...
testcontainers [INFO] Exposed host port 35041
testcontainers [DEBUG] [<id>] Executing command "sh -c nc -w 2 host.testcontainers.internal 35041 </dev/null; echo nc_exit=$?"...
UNCAUGHT: connect ECONNREFUSED 127.0.0.1:35041
testcontainers [DEBUG] [<id>] Executed command "sh -c nc -w 2 host.testcontainers.internal 35041 </dev/null; echo nc_exit=$?"...

Steps to Reproduce

1. Save this as repro.test.ts:

   import { createServer } from "node:net";
   import { once } from "node:events";
   import { GenericContainer, TestContainers } from "testcontainers";
   import { it } from "vitest";
   
   it("survives a connection to a closed exposed port", async () => {
     const server = createServer().listen(0, "127.0.0.1");
     await once(server, "listening");
     const address = server.address();
     if (address === null || typeof address === "string") throw new Error("no port");
     await TestContainers.exposeHostPorts(address.port);
     server.close();
   
     const container = await new GenericContainer("alpine:3.20")
       .withCommand(["sleep", "infinity"])
       .start();
     await container.exec(["sh", "-c", `nc -w 2 host.testcontainers.internal ${address.port} </dev/null || true`]);
     await container.stop();
   });

2. Run npx vitest run repro.test.ts.

3. The test passes, but Vitest reports Errors 1 error with ECONNREFUSED 127.0.0.1:<port>.

Environment Information

• Operating System: Ubuntu 22.04.5 LTS
• Container runtime and version: Docker Engine 29.7.2
• Node version: 24.19.0
• Test runner and version: Vitest 4.0.18, ESM
• Testcontainers version: 10.28.0 (the same dependency is in 12.2.1)
• Last Testcontainers version where this worked, if any: none known