Requests with Transfer-Encoding: chunked seems to be broken in Bun but not in Node

[shadone]

What version of Bun is running?

1.1.12

What platform is your computer?

Darwin 23.5.0 arm64 arm

What steps can reproduce the bug?

1. create index.js

const express = require('express')
const bodyParser = require('body-parser')
const multer = require('multer')

const app = express()
app.use(bodyParser.json())

const upload = multer({ storage: multer.memoryStorage() })

function handleRegistrations(req, res, next) {
	const product_id = req.body.product_id
	console.log(`### handleRegistrations: product_id=${product_id}`)
	res.status(200).json({ product_id })
}

app.post(
  "/registrations",
  upload.single("image"),
  handleRegistrations,
)

app.post("*", (req, res, next) => {
	console.log("Unhandled endpoint", req)
	res.status(404).send()
})

console.log("Listening on port 8080")
app.listen(8080)

2. run the server with bun ./index.js

3. make the request with Transfer-Encoding: chunked like this: curl -XPOST http://localhost:8080/registrations -F product_id=1234foobar567 -H 'Transfer-Encoding: chunked'

The server spits the following error:

Error: Unexpected end of form
    at _final (/Users/denis/tmp/node-multipart-form-data/node_modules/busboy/lib/types/multipart.js:588:13)
    at callFinal (node:stream:2778:23)
    at prefinish (node:stream:2801:23)
    at finishMaybe (node:stream:2808:25)
    at <anonymous> (node:stream:2741:76)
    at onend (node:stream:2088:21)
    at emit (native)
    at endReadableNT (node:stream:2396:27)
    at processTicksAndRejections (:12:39)

What is the expected behavior?

Run the same server with node instead of bun, no errors occur.

What do you see instead?

No response

Additional information

No response

[shadone]

I believe this could be the same or related issue as the following:
#4139
#9100
#4234
#8638

[shadone]

What happens when Bun.listen() is used to handle Transfer-Encoding: chunked?

I am not sure what you would like me to test with Bun.listen() - that seems to give raw tcp socket data which I wouldn't know how to read from Bun/TS code

However I tried Bun.serve() instead, maybe that will be helpful?

async function streamToString(stream) {
  const chunks = [];

  for await (const chunk of stream) {
    chunks.push(Buffer.from(chunk));
  }

  return Buffer.concat(chunks).toString("utf-8");
}

Bun.serve({
  port: 8080,
  async fetch(req) {
    console.log("req:")
    console.log(req);

    const result = await streamToString(req.body)
    console.log("body:")
    console.log(result);

    return new Response("Bun!");
  },
});

I sent this request with curl: curl -XPOST http://localhost:8080/registrations -F product_id=1234foobar567 -H 'Transfer-Encoding: chunked'

server logs:

$ bun ./index.js
req:
Request (0 KB) {
  method: "POST",
  url: "http://localhost:8080/registrations",
  headers: Headers {
    "host": "localhost:8080",
    "user-agent": "curl/8.6.0",
    "accept": "*/*",
    "transfer-encoding": "chunked",
    "content-type": "multipart/form-data; boundary=------------------------VA4meCsV7czVKCTz7jQ3NZ",
  }
}
body:
--------------------------VA4meCsV7czVKCTz7jQ3NZ
Content-Disposition: form-data; name="product_id"

1234foobar567
--------------------------VA4meCsV7czVKCTz7jQ3NZ--