[Distutils] setup_requires for dev environments

[Daniel Holth]

If that's what you want then we could say the spec was to put the
requirements in setup_requires.txt, in the requirements.txt format,
which pip would eventually look for and install before running
setup.py

On Thu, Mar 19, 2015 at 9:32 AM, Leonardo Rochael Almeida
<leorochael at gmail.com> wrote:
>
> On 18 March 2015 at 14:37, Daniel Holth <dholth at gmail.com> wrote:
>>
>> [...]
>>
>> The behavior we're aiming for would be:
>>
>> "installer run setup.py" - installs things
>> "python setup.py" - does not install things
>
>
> Besides that, I'd add that we're also looking for: "python setup.py" (by
> itself) should not raise ImportError, even if setup.py needs extra things
> installed for certain operations (egg_info, build, sdist, develop, install).
>
> IMO, the biggest pain point is not people putting crazy stuff in setup.py to
> get version numbers. For me, the biggest pain point is when setup.py needs
> to import other packages in order to even know how to build:
>
> So I'd like to suggest the following series of small improvements to both
> pip and setuptools:
>
>  * setuptools: `python setup.py setup_requires` dumps its setup_requires
> keyword in 'requirements.txt' format
>
> It's is already in this format, so should be trivial, but allows one to do
> something like:
>
>     $ python setup.py setup_requires > setup_requires.txt
>     $ pip install -r setup_requires.txt
>
> Or in one bash line:
>
>     $ pip install -r <( python setup.py setup_requires )
>
>  * setuptools: setup.py gains the ability to accept callables in most (all?)
> of its parameters.
>
> This will allow people to move all top level setup.py imports into
> functions, so that we can turn code like this:
>
>     from setuptools import setup, Extension
>     import numpy
>
>     setup(ext_modules=[
>         Extension("_cos_doubles",
>             sources=["cos_doubles.c", "cos_doubles.i"],
>             include_dirs=[numpy.get_include()])])
>
> Into this:
>
>     from setuptools import setup, Extension
>
>     def ext_modules():
>         import numpy
>         return [
>             Extension("_cos_doubles",
>                 sources=["cos_doubles.c", "cos_doubles.i"],
>                 include_dirs=[numpy.get_include()])
>         ]
>
>     setup(ext_modules=ext_modules
>               setup_requires=['setuptools'])
>
>  * pip: When working with an sdist, before running "setup.py egg_info" in a
> sandbox, pip would run "setup.py setup_requires", install those packages in
> the sandbox (not in the main environment), then run "egg_info", "wheel",
> etc.
>
> Notice that the changes proposed above are all backward compatible, create
> no additional pain, and allow developers to move all top level setup.py
> craziness inside functions.
>
> After that, we can consider making setup.py not call the easy_install
> functionality when it finds a setup_requires keyword while running other
> commands, but just report if those packages are not available.
>
>
> PS: Yes, I've already proposed something similar recently:
> https://mail.python.org/pipermail/distutils-sig/2015-January/025682.html