https://stackoverflow.com/questions/44120045/something-is-breaking-my-packag... has full info on what i am seeing, but it suffices to say: I use setuptools in my setup.py I iterate a requirements.txt file to satisfy dependencies. I publish as sdist to pypi my package used to work fine as it currently is on pypi. however as of late i've been seeing the python setup.py invocation ( from pip install python-symphony ) fail with a couple different failure scenarios. one is it attempting to install what looks like a binary wheel ( that doesn't exist on pypi or anywhere ) that ends up being a bunch of blank stubs. the other is a situation where the package looks 100% correct in site-packages, but none of the module components are registered when you try to use the imported module. pip install --isolated --no-cache-dir python-symphony seems to avoid the issue. but it also tends to do weird stuff like break bpython by messing up the pygments install. curious if anyone was familiar with some sort of bug that i am stumbling into here. -Matt