Building docs takes >40 minutes on master

[effigies]

Can we reuse prior builds to avoid building all old versions every time?

[effigies]

Example run: https://app.circleci.com/pipelines/github/nipreps/niworkflows/398/workflows/1f3e62ab-c67d-4a13-bd70-7aa46fe1d5b0/jobs/1862

[oesteban]

Yeah, this is getting very bad. I believe sphinxcontrib-versioning should actually not build old releases if they are already built - however it is clearly not working.

[effigies]

Is there any advantage to keeping old commits around? I suspect it's gh-pages that's making clones take 1.7 minutes.

[oesteban]

I think that's one problem - probably solvable with a shallow clone that only fetches master and tags.

I don't think sphinxcontrib-versioning is building old commits, I think it is just building all tags.

[effigies]

But there's no real advantage to keeping history. I would suggest just squashing everything down to a single commit periodically (or even on every build) so that garbage collection can do its work.

[effigies]

History squashed with #622. Still need to build off of the last commit to save time.

[oesteban]

I just added the bug label because I think we are not reusing the existing documents in the gh-pages branch, and hence all the versions are built all the times.

I'm not confident the sphinxcontrib-versioning will reuse them (the package is pretty buggy), but, it will certainly will not if they are just not available :D