It is not uncommon for packages to depend on
pkg_resources which is provided by
setuptools. Typically, packages don’t add
install_requires when they need
pkg_resources. I think they should, because even though
setuptools may be a build-time dependency as its often the build system, that says nothing about whether it will be available during runtime. What do you think? Where can we clarify this? In Nixpkgs we are now patching our recipes to add
setuptools in case they have a runtime dependency.
This is somewhat related to https://discuss.python.org/t/support-for-build-and-run-time-dependencies.