pip wheel conditional dependencies

Question

While working on a virtualenv for developing a python package, I use to issue a "pip wheel ." to generate all wheel archives needed for the package. I start using conditional dependencies by listing them in the setup tools extras_require parameter. Is it possible to generate the wheel archives of a specific conditional dependency?

I am looking for something like: pip wheel ".[conditional_feature]" is not supported. (at least on python-2.7) Note that I can install these dependencies in the virtualenv with: pip install -e ".[conditional_feature]"

Answer 1

With the latest version (2017) of the pypa trio (pip,setuptools, wheel) you can now use conditional requirements directly. Here is an example with extra_requires that install various versions of lxml on different OSes:

extras_require={
        ':platform_system == "Windows"': ['lxml == 3.6.0'],
        ':platform_system == "Linux"': ['lxml == 3.6.4'],
        ':platform_system == "Darwin"': ['lxml == 3.6.4'],

},
You can do a lot more than this of course with even more complex expressions.