"Failed to parse body as FormData." with filename*=utf-8 content disposition

[FuJa0815]

Bug Description

When sending a multipart/form-data with a filename*=utf-8'' (as the MultipartFormDataContent class in C# does for example, or in this example in the RFC: https://datatracker.ietf.org/doc/html/rfc6266#section-5) content disposition it throws a "Failed to parse body as FormData." TypeError.

Reproducible By

const response = new Response([
    '--83d82e0d-9ced-44c0-ac79-4e66a827415b\r\n' +
    'Content-Type: text/plain\r\n' +
    'Content-Disposition: form-data; name="file"; filename*=utf-8\'\'file%20name.txt\r\n' +
    '\r\n' +
    'testabc\r\n' +
    '--83d82e0d-9ced-44c0-ac79-4e66a827415b--\r\n' +
    '\r\n',
  ].join(''), {
    headers: {
      'content-type': 'multipart/form-data; boundary="83d82e0d-9ced-44c0-ac79-4e66a827415b"'
    }
  });

await response.formData()

Expected Behavior

The existance of a filename*=utf-8 field shouldn't lead to parse failure, it should be used as the filename.

Logs & Screenshots

node:internal/deps/undici/undici:5619
                    throw new TypeError("Failed to parse body as FormData.");
                          ^

TypeError: Failed to parse body as FormData.
    at node:internal/deps/undici/undici:5619:27
    at successSteps (node:internal/deps/undici/undici:5663:27)
    at fullyReadBody (node:internal/deps/undici/undici:4561:9)
    at async consumeBody (node:internal/deps/undici/undici:5672:7)
    at async file:///index.js:15:1

Environment

This bug is NOT present in node v20.12.2, but IS present from node v20.13 and onward.

Additional context

Workaround: downgrade to node v20.12.2

[KhafraDev]

I will take a look in a few days. We switched formdata parsers, probably ended up between those two versions of node, and I guess I forgot to implement filename* parsing support.