Native Node.js fetch fails with attempting DELETE requests

[rdmurphy]

Hello! This possibly overlaps with @octokit/endpoint — we noticed today after updating to the latest version of @octokit/rest (v19) that any API requests that we make that result in a DELETE request (in our case it's delete a label) now fail when they are ran using Node v18. We think we tracked it down to how @octokit/request now opts into using the native Fetch API.

It appears that node-fetch and undici-fetch (AKA native Node.js fetch) feel differently about DELETE requests that set content-length: 0 (which happens via @octokit/endpoint) without adding a body. node-fetch allows it to happen, undici-fetch throws an error with the UND_ERR_REQ_CONTENT_LENGTH_MISMATCH code.

[gr2m]

DELETE requests that set content-length: 0

I don't recall the exact reason, but I remember that there was a weird problem with some of GitHub's REST APIs when the content-length: 0 header is not set, I'd have to dig for that one a little, or we could run some tests if it's still necessary at all.

[rdmurphy]

Forgot to add — I did attempt to hit that DELETE endpoint with native Node.js fetch with a bare fetch() call (with all the proper headers and authentication) and it did work without the passing of content-length: 0 or a body. Unfortunately did not also attempt to hit PATCH and PUT endpoints — I saw that@octokit/endpoint notes the REST API does have unique expectations with those.

[timrogers]

It looks like this is affecting other places too - see octokit/rest.js#190.

Would it be practical to just set the body to an empty string?

[gr2m]

@rdmurphy can you confirm that the problems is resolved for you via @octokit/endpoint@7.0.2? Make sure to do a fresh install to get the latest version of @octokit/endpoint (rm -rf package-lock.json node_modules && npm install)