The registration order of http server listen depends on the Node.js version

[yamachu]

Version

v20.13.1

Platform

Darwin 23.5.0 Darwin Kernel Version 23.5.0: Wed May 1 20:16:51 PDT 2024; root:xnu-10063.121.3~5/RELEASE_ARM64_T8103 arm64

Subsystem

No response

What steps will reproduce the bug?

The behavior of Server.listen on the same port has changed between node 20.12 and 20.13.

If you execute code like the following,
In node 20.12, 127.0.0.1:8888 (or 0.0.0.0:8888, localhost:8888) is listened to and the Hello World string is returned.
However, in node 20.13, only 192.168.10.104:8888 is listened to, and the rest, such as 127.0.0.1:8888, are not listened to.

import { createServer } from "node:http";

const server = createServer((_, res) => {
  res.writeHead(200, { "Content-Type": "text/plain" });
  res.end("Hello World\n");
});

// listen order dependents on the version of node.js...
server.listen(8888, "127.0.0.1"); // 20.13 < , this one is used.
server.listen(8888, "192.168.10.104" /* replace your local ip address */); // 20.13 >= , this one is used.

How often does it reproduce? Is there a required condition?

always

What is the expected behavior? Why is that the expected behavior?

Both will be LISTENED to, or if there is a specification for the order, that document will be clearly noted.

What do you see instead?

no outputs

Additional information

For example, this is how it is used.
https://github.com/Azure/static-web-apps-cli/blob/352be8f4ce2d01e1dac17797a80f9f414d612bc0/src/msha/server.ts#L173-L174

[avivkeller]

@nodejs/http

[avivkeller]

Reference: Azure/static-web-apps-cli#829

Looking at the changelogs between 20.12.2 and 20.13.0, I don't see anything that directly says it changed this functionality, but the following commit might be of interest: #52492 . I'm not sure, but it's involving DNS ordering, so it might be worth a look.

Changelog: https://nodejs.org/en/blog/release/v20.13.0

[theanarkh]

I think this is related to this, this PR makes the last listen is valid. Before this PR, the follow code just listen to 127.0.0.1(I think that's not right it should listen to 192.168.10.104) instead of both. Maybe we should update the docs.

server.listen(8888, "127.0.0.1"); // 20.13 < , this one is used.
server.listen(8888, "192.168.10.104" /* replace your local ip address */); // 20.13 >= , this one is used.

[avivkeller]

I think this is related to this. this PR makes the last listen is valid. Before this PR, the follow code just listen to 127.0.0.1 instead of both. I think that's not right, maybe we should update the docs.

server.listen(8888, "127.0.0.1"); // 20.13 < , this one is used.

server.listen(8888, "192.168.10.104" /* replace your local ip address */); // 20.13 >= , this one is used.

Ahh that makes more sense

[mcollina]

I didn't even know multiple .listen() was possible. I think we should just error in this case, or add support for multiple interfaces. In Fastify, we handle it with having multiple server instances.