303 response missing Location header causes status 0 and loss of response headers

[NabiKAZ]

Description

Requests with HTTP 303 status code that do not include a Location header produce the following error:

{
  status: 0,
  headers: {},
  finalUrl: 'http://localhost:3000',
  data: '-\u003e \nPost "http://localhost:3000": 303 response missing Location header',
  json: [AsyncFunction: json],
  text: [AsyncFunction: text],
  arrayBuffer: [AsyncFunction: arrayBuffer],
  blob: [AsyncFunction: blob]
}

I tested with disableRedirect set to both true and false, but it didn't make any difference.

Here is an actual response from a real website, which uses a custom x-action-redirect header instead of Location:

HTTP/2 303 
date: Sun, 12 Oct 2025 14:21:48 GMT
content-type: text/html; charset=utf-8
cf-ray: ...
content-security-policy: default-src 'self' ...;    upgrade-insecure-requests;
vary: RSC, Next-Router-State-Tree, Next-Router-Prefetch, Next-Router-Segment-Prefetch, Accept-Encoding
cache-control: no-cache, no-store, max-age=0, must-revalidate
x-action-revalidated: [[],0,0]
x-action-redirect: /en-us/...;push
x-powered-by: Next.js
cf-cache-status: DYNAMIC
server: cloudflare
X-Firefox-Spdy: h2

Main issues:

• Status is set to 0
• Response headers are not returned (even if Location is missing, headers should always be visible)

Issue Type

Bug

Operating System

Windows 10

Node Version

Node 22.x

Golang Version

No response

Relevant Log Output

{
  status: 0,
  headers: {},
  finalUrl: 'http://localhost:3000',
  data: '-\u003e \nPost "http://localhost:3000": 303 response missing Location header',
  json: [AsyncFunction: json],
  text: [AsyncFunction: text],
  arrayBuffer: [AsyncFunction: arrayBuffer],
  blob: [AsyncFunction: blob]
}

HTTP/2 303 
date: Sun, 12 Oct 2025 14:21:48 GMT
content-type: text/html; charset=utf-8
cf-ray: ...
content-security-policy: default-src 'self' ...;    upgrade-insecure-requests;
vary: RSC, Next-Router-State-Tree, Next-Router-Prefetch, Next-Router-Segment-Prefetch, Accept-Encoding
cache-control: no-cache, no-store, max-age=0, must-revalidate
x-action-revalidated: [[],0,0]
x-action-redirect: /en-us/...;push
x-powered-by: Next.js
cf-cache-status: DYNAMIC
server: cloudflare
X-Firefox-Spdy: h2

[NabiKAZ]

If the redirect doesn't solve the problem, at least return the response header so we can handle it ourselves.