[Distutils] Proposal: "Install and save"

[Jeremy Stanley]

On 2016-07-30 20:23:14 -0500 (-0500), Wes Turner wrote:
> pbr also supports "environment markers"
> which we would want to preserve when round-tripping (reading in, modifying,
> and writing out) requirements.txt files;
> though IDK if environment markers are part of any Python Packaging Spec?
> 
> from http://docs.openstack.org/developer/pbr/#environment-markers :
> 
> argparse; python_version=='2.6'

I'm assuming you didn't follow the "conditional dependencies" link
from the description in that first paragraph, as it would have taken
you to the corresponding section of one:

https://www.python.org/dev/peps/pep-0426/#environment-markers

You should probably also see:

https://www.python.org/dev/peps/pep-0496/
https://www.python.org/dev/peps/pep-0508/#environment-markers

Quickly skimming relevant changelogs, environment markers have been
supported by Setuptools since 0.7, and directly in requirements
lists since pip 6.0.
-- 
Jeremy Stanley