Migrate setup configuration to setup.cfg

[DragaDoncila]

• Moved configuration options into setup.cfg.
• For editable installs, kept use_scm in setup.py.
• setup.cfg doesn't support a file: option for the install_requires keyword, and it doesn't look like that'll be coming anytime soon, based on the discussion in this issue. So for our purposes I've kept the requirements reading in setup.py

I built a plugin locally and it worked as expected. I tried running tests locally but running the created plugin's tests failed with

E           TypeError: Failed expected string as 'msg' parameter, got 'CalledProcessError' instead.
E           Perhaps you meant to use a mark?

I saw the same behaviour on master though so I think it must be something I'm doing wrong.

Addresses #26.

[tlambert03]

setup.cfg doesn't support a file: option for the install_requires keyword, and it doesn't look like that'll be coming anytime soon, based on the discussion in this issue. So for our purposes I've kept the requirements reading in setup.py

let's move away from reading requirements.txt into the setup.cfg... and do it the other way around instead:

# requirements.txt

-e .

[DragaDoncila]

Umm, I'm confused how that would work.
I thought we needed to read from requirements.txt because we don't know what the minimal installation requirements are, and if we don't move them into setup.py then users would have to install using pip install -r.

But are you saying that there's a relationship between the editable install and the requirements file? What does adding -e . to the requirements file do? And, does that mean users would have to add their dependencies into setup.cfg themselves, rather than in requirements.txt where we're telling them to put them now?

[tlambert03]

highly recommend this article: https://caremad.io/posts/2013/07/setup-vs-requirement/

requirements.txt is only there for the ability to do pip install -r requirements.txt which (to my understanding) has come to be an expected way to set up an environment, particular for non-redistributable things... like "i go this set of things to work, and here are the requirements". install_requires (in setup.py, setup.cfg), on the other hand, is the canonical way of specifying what an installable package/library needs to run.

does that mean users would have to add their dependencies into setup.cfg themselves, rather than in requirements.txt where we're telling them to put them now?

exactly. that's the "right" place for a package to declare it's dependencies... and the "right" way to install a package after cloning it is probably pip install -e . ... so, adding -e . to requirements.txt is just a "courtesy" that lets people used to doing pip install -r requirements.txt keep their muscle memory. (but... we could also just get rid of it entirely)

[DragaDoncila]

@tlambert03 thanks for the details - I know they're very newbie questions. If I've understood you correctly, then these latest two commits should do it.