Express.js middlewares are reused when creating a second Express app

[1cedsoda]

What version of Bun is running?

1.0.11+f7f6233ea

What platform is your computer?

Darwin 23.0.0 arm64 arm

What steps can reproduce the bug?

// bun version 1.0.11+f7f6233ea
// node version v18.18.2

import express from "express";

async function newServer() {
  const app = express();
  const x = Math.random();
  app.use((req, res, next) => {
    console.log("middleware x", x);
    res.send("Hello World");
  });
  return new Promise((resolve, reject) => {
    const listener = app.listen(9999, () => {
      resolve(listener);
    });
  });
}

async function main() {
  const listener = await newServer();
  await fetch("http://localhost:9999");
  await listener.close();

  const listener2 = await newServer();
  await fetch("http://localhost:9999");
  await listener2.close();
}

main();

Running bun x.js

middleware x 0.6306528523654233
middleware x 0.6306528523654233

Expected: numbers to be different Got: numbers are same

Running node x.js

middleware x 0.63468082718277
middleware x 0.16123682051243216

Expected: numbers to be different Got: numbers are different

What is the expected behavior?

Bun: numbers should be different (middlewares are redeclared) Express: numbers should be different (middlewares are redeclared)

What do you see instead?

Bun: numbers are the same (middlewares are reused) Express: numbers should be different (middlewares are redeclared

Findings

In Bun the express middlewares seem to be reused.

Additional information

node version v18.18.2 express version 4.18.2

[Electroid]

This is likely a difference in behaviour for when listening to the same port twice. We will fix it.

[1cedsoda]

Can confirm, it only happens if the same port is used multiple times.

[liz3]

I can confirm that calling server.stop(true) instead of server.stop() here: https://github.com/oven-sh/bun/blob/main/src/js/node/http.ts#L446 does fix the issue, @Electroid is this something which would be okay to do?

[Electroid]

I can confirm that calling server.stop(true) instead of server.stop() here: https://github.com/oven-sh/bun/blob/main/src/js/node/http.ts#L446 does fix the issue, @Electroid is this something which would be okay to do?

Yep, that should be a good fix.

[1cedsoda]

Still appears in 1.1.0+5903a6141