XMLHttpRequest FormData / File upload never resolves

[ondrejsevcik]

Prerequisites

• I confirm my issue is not in the opened issues
• I confirm the Frequently Asked Questions didn't contain the answer to my issue

Environment check

• I'm using the latest msw version
• I'm using Node.js version 18 or higher

Node.js version

v20.14.0

Reproduction repository

https://github.com/ondrejsevcik/msw-xhr-upload-issues

Reproduction steps

The reproduction repository contains two tests. One is firing an XHR request, and the other one is firing an XHR request with a FormData body.

If you use v2.4.3, the tests will pass. When using version 2.4.4+ it fails.

1. npm install
2. npm run test

Current behavior

The XHR request with FormData never resolves. This has worked fine previously, but since version 2.4.4, it does not work anymore.

Expected behavior

It is possible to upload file / FormData with msw using XMLHttpRequest.

[kibertoad]

@kettanaito Most likely related to this change: Adopts a new, Socket-based request interception algorithm.

[roastnewt]

I am encountering the same issue

[LarsJK]

I am also encountering this, but only on linux. On my Mac it works fine. What OS are you using?

[roastnewt]

Windows. And also in our Ubuntu build/test pipeline

[RabbitShare]

Same issue on Mac and Debian. Node v22.11.0

[RabbitShare]

Also example from documentation not working https://mswjs.io/docs/recipes/file-uploads/