This one is fun. I'm going to skip directly to why.

When building docs encountering numpy/add_newdocs.py: The item should be a scalar value and `args`, autolink of sphinx ext kicks in. One of the things it does is attempting to import whatever is in between `...`, which happen to be args thus importing args , installed by clint, installed by twine which you might have installed to publish packages on PyPI.

The only available released versions of args is Python 2 only (uses basestring which is undefined on Py3), and has not seen an update in ~5 years even if seem to be fixed on args master.

So sphinx fails as it try to (indirectly) evaluate basestring. And no docs get produced.

Reproduced on Fresh ubuntu 17.04.

I'm not sure there is anything one can do (inject a fake args in sys modules via conf.py ?) but I want to at least make you aware, as I have little hope to see a fix in clint or args with the slow pace of release.