`req.getHeaders()` does not return values set using "rawHeaders" array

[matthieusieben]

Version

v24.18.0

Platform

Darwin MBPM.local 25.5.0 Darwin Kernel Version 25.5.0: Tue Jun  9 22:28:29 PDT 2026; root:xnu-12377.121.10~1/RELEASE_ARM64_T6030 arm64

Subsystem

http

What steps will reproduce the bug?

Headers set using the message.rawHeaders format are not available on the request's getHeaders() method

import { get } from 'node:http'

const request = get(
  'http://localhost:3000',
  {
    headers: ['foo', 'bar', 'baz', 'qux']
  },
  (res) => {
    let data = ''

    res.on('data', (chunk) => {
      data += chunk
    })

    res.on('end', () => {
      console.log(data)
    })
  }
)

request.on('error', () => {})

console.log(request.getHeaders()) // [Object: null prototype] {}
console.log(request.getHeaderNames()) // []
console.log(request.getRawHeaderNames()) // []
console.log(request._header) // GET / HTTP/1.1\r\nfoo: bar\r\nbaz: qux\r\nConnection: keep-alive

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

Always

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

One would expect req.getHeaders() (and friends) to return a consistent value, whether an object or an array was passed as argument.

What do you see instead?

req.getHeaders() appears to be empty when request options are built using an array notation.

Additional information

No response

[Arpit483]

I traced the implementation and found that object headers go through setHeader() and populate kOutHeaders, while array headers are passed directly to _storeHeader() and never populate kOutHeaders. Since getHeaders() reads only from kOutHeaders, this explains the current behavior.

Before opening a PR, could you clarify whether the array form is expected to populate kOutHeaders as well, or if this behavior is intentional?

[efekrskl]

This seems to be a bit confusing indeed. Putting them in kOutHeaders might require us to normalize the headers first though, which might defeat the purpose of a raw array.

[Arpit483]

That makes sense. In that case, would you prefer getHeaders() (and related APIs) to continue reflecting only kOutHeaders, with the behavior documented, or would you be open to exposing the raw array through a different mechanism instead?

[matthieusieben]

What about lazily computing the headers map only if/when the getHeaders method is called?