chore: fix CI setup for unit tests

[benmccann]

@Conduitry with his eagle eyes noticed that the CI jobs aren't running on the specified Node versions: #8528 (comment)

[vercel]

@benmccann is attempting to deploy a commit to the Svelte Team on Vercel.

A member of the Team first needs to authorize it.

[Conduitry]

👍

I'm wondering now, though, why we're not seeing the error with pnpm in Node 20 that I was seeing locally and that a bunch of other people saw too and was fixed in pnpm 8.3.1.

[benmccann]

Because the CI uses pnpm 7:

svelte/package.json

Line 164 in df2f656

"packageManager": "pnpm@7.32.0",

[Conduitry]

I'm getting the same ERR_INVALID_THIS errors on pnpm 7.32.0 when I try to install dependencies from the version-4 branch locally with Node 20. Can you confirm whether you're seeing this locally on your end? Could this be a result of a cache in GH actions, so it doesn't actually need to install the new dependencies?

[benmccann]

Hmm. Interesting. I've never seen the error locally. I've got pnpm 8.3.1 installed. Perhaps I just skipped over the broken version or there were no new dependencies added while I was on it, so it was just grabbing stuff from the local cache.

[Conduitry]

If you're using Corepack locally (or if you manually install pnpm 7.32.0) and are on Node 20 and you clear node_modules and the pnpm cache, what happens for you on the version-4 branch when you run pnpm install?

[benmccann]

8.3.1 is the working version I believe so I imagine it would work. I don't have corepack installed, so can't easily switch pnpm versions

This PR we should merge regardless. The only question is what to do on the other PR. Maybe we should have that discussion there to avoid things getting lost, but I think I'd lean towards dropping Node 14 support and using the latest version of pnpm 8 everywhere which would avoid the issue you'd seen