With the advent of pip’s solver, the quality of metadata will be much more heavily tested. Pip currently warns (?) but allows creation of inconsistent environments, where one or more constraints don’t agree. There’s two topics here that might need to be considered separately:
- Can/should pip be disallowing installation of packages that break consistency by default?
- How can PyPI deal with bad metadata? From Conda’s experience, once it is in the index, things will be badly disrupted until either the offending package is removed, or the metadata is altered. Conda alters the index metadata, but with the distributed ownership of packages of PyPI, I’m not sure that’s an option.