Direct deployment via GitHub Actions

[simonbyrne]

GitHub Pages are now deployed via GitHub Actions, see https://github.blog/2022-08-10-github-pages-now-uses-actions-by-default/ for more details. You can see the current Action which does this for Documenter.jl here:
https://github.com/JuliaDocs/Documenter.jl/actions/workflows/pages/pages-build-deployment

This means that instead of Documenter pushing to the gh-pages branch, it should be possible to deploy directly via GitHub Actions. It's not clear how this would work for keeping versioned docs around (would it still need a branch to keep track of this? could they be stored as artifacts?)

[simonbyrne]

It's a bit buried in the docs, but there are some more details here: https://docs.github.com/en/pages/getting-started-with-github-pages/configuring-a-publishing-source-for-your-github-pages-site#creating-a-custom-github-actions-workflow-to-publish-your-site

[mortenpi]

This is interesting. But I agree that the uploaded artifact replacing the whole Pages contents (like GitLab) is a problem. And I didn't see any way to access the existing files? I suppose we could store things as artifacts, but I think that can have issues too -- how do you know which one is the latest? And also, they expire and get deleted after a while.

This is probably less of an issue, but you'll also lose the history on the gh-pages branch, which can be useful when debugging, or restoring things of something goes very wrong.

[simonbyrne]

Yeah, in that case I'm not sure it's worth it? To be honest, I only reason I noticed this at all is because I was updating MPI.jl which has a huge CI matrix, and that was blocking the deployment jobs from being run. One thing we could do is move the deployment to be an extra explicit step in the documenter action though (without changing the current workflow)