bun dev server fails with ConnectionClosed: The socket connection was closed unexpectedly

[evertonspader-tomtom]

What version of Bun is running?

1.0.1

What platform is your computer?

Darwin 23.0.0 arm64 arm

What steps can reproduce the bug?

I have a small project with NextJS and I am testing Bun. When starting the dev server with bun --bun run dev, I have a fetch() call to fetch some data on the home page that fails.

What is the expected behavior?

The dev server should start as it does with yarn and npm and load the home page with the data fetched populated in the fields.

What do you see instead?

ConnectionClosed: The socket connection was closed unexpectedly. For more information, pass `verbose: true` in the second argument to fetch()
 path: "http://localhost:62668/"

The port in the path is always different and fetch doesn't allow verbose: true in the second argument

Additional information

This is the snippet that is making the call to an API in the project that just returns a JSON with data. It works with npm and yarn

async function getHelperData() {
  const res = await fetch(`${BASE_URL}/api/helper-data`, {
    method: 'GET',
    headers: {
      'Content-Type': 'application/json'
    }
  });
  const data = await res.json();
  return data.data;
}

useEffect(() => {
    getHelperData()
      .then((data) => {
        setCategoriesData(data);
      })
      .catch((err) => {
        alert('Failed to fetch categories: ' + err);
      });
  }, []);

[nivoc]

I've the same issue. MacOS/M1 with Bun 1.0.1

What steps can reproduce the bug?

bun create next-app
bun --bun run dev

The unmodified next-app template fails.

Error

$ bun --bun run dev
- ready started server on localhost:3000, url: http://localhost:3000
- event compiled client and server successfully in 191 ms (20 modules)
- wait compiling...
- event compiled client and server successfully in 19 ms (20 modules)
- wait compiling /page (client and server)...
- event compiled client and server successfully in 1120 ms (417 modules)
- wait compiling...
- event compiled successfully in 70 ms (235 modules)
ConnectionClosed: The socket connection was closed unexpectedly. For more information, pass `verbose: true` in the second argument to fetch()
 path: "http://localhost:49324/"

- wait compiling /_error (client and server)...

[underclockd]

This was resolved for me today with the latest release, possibly fixed by #5126?

edit: I'm on MacOS Intel, not ARM, but I was experiencing this exact issue prior to updating.

I ran the dev server without the --bun flag before updating as well, which actually prompted me to give the process permission to use sockets. I'm not sure if that may have something to do with the fix, but I was still receiving the error up until I updated Bun and swapped to a fresh shell.

[cybermelons]

I ran into this error too on my nextjs project. Will check if it's fixed with latest release

EDIT: Ran this on bun 1.0.2.

When I run bun --bun run dev it throws me this error when I visit http://ocalhost:3000/

- error Failed to handle request for /
ConnectionClosed: The socket connection was closed unexpectedly. For more information, pass `verbose: true` in the second argument to fetch()
 path: "http://127.0.0.1:64086/"

[omrta-dev]

Can anyone running into this issue try to use: bun run dev instead of bun --bun run dev?

That seems to have fixed the issue for me, but i can't find documentation on the --bun flag that may be causing this issue.

[cybermelons]

Can anyone running into this issue try to use: bun run dev instead of bun --bun run dev?

That seems to have fixed the issue for me, but i can't find documentation on the --bun flag that may be causing this issue.

I use bun run dev and it works perfectly fine. My issue is with the --bun flag as well

[nivoc]

@omrta-dev, @cybermelons

Running bun run dev without the --bun flag says: Execute the script "next" with parameter "dev" as specified in package.json. But that script (node_modules/.bin/next) says in it's first line "#!/usr/bin/env node".
So in nextjs case, Node.js is the runtime, which is why there are no errors. Essentially, running without the flag is equivalent to running without Bun.

When you include the --bun flag, it means that #!/usr/bin/env node gets ignored and executed with bun as the runtime.

So, the --bun flag is essential to ensure Bun is the runtime for your environment.

https://bun.sh/docs/cli/run#bun

[nivoc]

Looks like it's not only a macos-Issue: #5494

[nivoc]

Update: I just tested with Bun1.0.2. It looks better but now I get a "error: Failed to construct 'Request': signal is not of type AbortSignal."

[PawelDuplaga]

Update: I just tested with Bun1.0.2. It looks better but now I get a "error: Failed to construct 'Request': signal is not of type AbortSignal."

Same here. I think it may be connected to using App Router, since i dont get that error using old "Pages"

[evertonspader-tomtom]

Update: I just tested with Bun1.0.2. It looks better but now I get a "error: Failed to construct 'Request': signal is not of type AbortSignal."

I just updated to 1.0.2 and the original error message is gone but I'm seeing the same error as mentioned above

[The-Code-Monkey]

Yeah getting this on M2 Mac Pro too.

[omrta-dev]

Getting this on both linux and WSL, so i don't think it's platform specific. @PawelDuplaga mentioned that it's related to the app router and I can confirm that I am also using the App router and facing this issue.

[StefanoVe]

I'm getting the same issue trying to spin up a proxy server using express with express-http-proxy inside a Docker (20.10.17) container running under CentOS 8 64 bit

[peacefulotter]

Still getting this issue with the --bun flag AND without, on Bun 1.0.22+b400b36ca. I am trying to send a big JSON through a POST request. Oddly, it works when the JSON is smaller, and, from my testings, it seems correlated.

[jellli]

I'm getting this error when I use hono.js on M1 Mac.

[mlitvinav]

I want to add that this error is in Bun version 1.0.28 and not only related to localhost or dev mode.
I have the same error in fetch, axios and superagent when using Bun against some targets. The request is sent to the server but the connection is cut for some reason.

Minimal example:

// test.js
fetch("https://www.saferpay.com/api/health/1", { verbose: true }).catch(console.error)

bun run --bun test.js

Stdout:

Request: GET /api/health/1
        Connection: keep-alive
        User-Agent: Bun/1.0.28
        Accept: */*
        Host: www.saferpay.com
        Accept-Encoding: gzip, deflate, br

ConnectionClosed: The socket connection was closed unexpectedly. For more information, pass `verbose: true` in the second argument to fetch()
 path: "https://www.saferpay.com/api/health/1"

[adhocore]

recently facing this same issue repeatedly. bun v1.0.29. after the error the server dies!

[adhocore]

rolled to 1.0.20 and issue is not there

[kevinm416]

I'm seeing this issue on bun 1.1.12 apple M2

[siarhei-semikau]

This issue is active for windows 11, bun 1.1.17!

[kirankunigiri]

Still seeing this issue on macOS M1, bun 1.1.20

[polRk]

presents in modern clouds

[Anyoks]

I have this issue too in bun v 1.1.20. using axios to make requests particularly via proxy

const config = {
    method: 'post',
    url: 'http://api.restful-api.dev/objects',
    data: {
      name: 'value1',
      data: 'value2',
    },
    proxy: {
      host: 'proxy.host',
      protocol: 'http',
      port: port,
      auth: {
        username: username,
        password: password
      }
    },
  
  };

  axios(config)
    .then((response) => {
      console.log(response.headers);
      console.log('Response:', response.data);
    })
    .catch((error) => {
      console.error('Error:', error.message);
    });

Error: The socket connection was closed unexpectedly. For more information, pass `verbose: true` in the second argument to fetch()

[devcaeg]

This error still occurs in the latest versions.

[Jarred-Sumner]

If you continue to run into this issue, please open a new issue and include a reproduction

Sockets closing can have many different unrelated causes (the server disconnected, received invalid data, sent invalid data, various edgecases involving TLS). This issue was originally closed after addressing an issue with TLS client renegotiation from #10166 and #5363 (comment):

fetch("https://www.saferpay.com/api/health/1", { verbose: true }).catch(console.error)