Agreed; for something that managed to become the de-facto solution for Python package installation, pip always felt surprisingly unreliable to me. My solution

Agreed; for something that managed to become the de-facto solution for Python package installation, pip always felt surprisingly unreliable to me. My solution at a small company, where we couldn't waste time with this crap, was to vendor everything: when a developer updated the requirements.txt, they would also install the packages in a project directory (using "pip install -r requirements.txt -t ./dependencies") and commit that. That way, the rest of the process (CI, packaging, etc) could just checkout the repo, set PYTHONPATH=./dependencies and ignore pip completely.