1417338 - fetch sets wrong Content-Type header on redirects

Status: UNCONFIRMED

(Core :: DOM: Core & HTML, defect, P3)

Description

[tozz]

Attachment: har.json

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:58.0) Gecko/20100101 Firefox/58.0
Build ID: 20171103003834

Steps to reproduce:

Create a fetch request that submits FormData to a backend that sends a 303 and a Location header.

fetch(url, {
  method: 'POST',
  credentials: 'same-origin',
  body: new FormData(document.getElementById('#form'))
})


Actual results:

The FormData is sent correctly to the server, the Location header is parsed and followed as a GET, but the Content-Type header gets set as "multipart/form-data".

HAR log of the two requests attached.


Expected results:

The GET should not have header Content-Type "multipart/form-data".

Comment 1

[tozz]

Attachment: Test case with markup and node server

This shows the behavior, surprisingly this also makes Chrome set the content-type on redirect but it doesn't do it on the site production code.