How Clever Is the Caching on the Docs Rebuild?

Sphinx uses Travis or Circle CI to build documents. It's actually extremely hard to do it correctly because a lot of times Sphinx projects will use some auto API that's referencing code. So we, we just decided at some point, this is too hard. We'll just waste resources and have our builds be correct. And interestingly enough, I think a lot of the CI services went the same route.