Get github-metadata gem working on Netlify about jkan

[timwis]

I've written a Netlify Build plugin (98a812b) to generate a _config_override.yml file, but issue 1 and 4 above still remain for some reason. I'll see if I can reproduce them locally by setting JEKYLL_ENV=production on my laptop's build.

[timwis]

Okay, I've dug in a lot deeper to the github-metadata gem, and I think I understand what's behind the two main issues:

• It's setting site.github.source.branch to the default branch of the upstream repository, not the fork. This probably isn't an issue in practice, but could be (whether for debugging, or if an admin wants to change the default branch of their repo, since they're not actually using github pages)
• It's setting baseurl according to the fact that the repository is a "user repository" rather than an "org repository". The plugin's designed to get the site working on github pages, and not for compatibility elsewhere. I've solved this one by explicitly declaring baseurl: "" in _config_override.yml

Very nearly there!

[timwis]

All right, I've reported the branch issue on the github-metadata repo, and implemented a workaround: the Netlify Build Plugin now saves the name of the branch being deployed to site.branch. When we configure the Editor UI in /editor/index.html, it now says branch: {{ site.branch | default: site.github.source.branch }}, using the value from the config if it's available, and defaulting back to whatever's generated by the github-metadata gem.

So, just to recap, we've essentially made the github-metadata gem "get out of the way" when deploying to Netlify. We do this by generating a supplemental _config.ci.yml file during the build process — but only in a Netlify build (via a Netlify build plugin). Jekyll loads this _config.ci.yml first, then loads the normal _config.yml, so an admin can override anything that's generated, if they prefer.

I think once we switch the GitHub Pages approach to using Actions, we should explore moving away from the github-metadata gem (because we can have the Action generate a _config.ci.yml file as well).