How to turn warnings into errors when building sphinx documentation with setuptools?

Question

I am using setuptools to build my sphinx documentation of a python project (python setup.py build_sphinx).

As found on, e.g., this site, I have configured t

Answer 1

The only solution I can manage is both simple and sub-optimal.

Change from:

python setup.py build_sphinx

to:

python -W error setup.py build_sphinx

That will turn all warnings into errors, including errors from setuptools, etc., which isn't exactly what you want, but it will stop on sphinx errors.

If you're doing this to try and set up Continuous Integration or something, maybe this is good enough?

UPDATE: See stephenfin's answer if using Sphinx 1.5+