Make a friendlier development install

[jhamrick]

This makes it possible to install with python setup.py develop regardless of whether you're running python 2 or python 3. It may not always work exactly the same way as it does with setuptools since this uses flit on the backend, but for basic usage it should be consistent, at least.

cc @jklymak

[jdfreder]

@ellisonbg did you see this? Do you still have trouble, even with the changes introduced by this PR?

[ellisonbg]

Yes, I did. Sorry I wasn't clear. I think we need to have a proper
setup.py that just uses distutils/setuptools be default. Otherwise you
can't:

• pip install -e .
• pip install git+https://github.com/jupyter/nbgrader.git#egg=nbgrader

IOW, everything needs to work without flit being present ever.

I am fine with flit being used optionally in any way.

On Tue, Jan 5, 2016 at 9:34 AM, Jonathan Frederic notifications@github.com
wrote:

@ellisonbg https://github.com/ellisonbg did you see this? Do you still
have trouble, even with the changes introduced by this PR?

—
Reply to this email directly or view it on GitHub
#409 (comment).

Brian E. Granger
Associate Professor of Physics and Data Science
Cal Poly State University, San Luis Obispo
@ellisonbg on Twitter and GitHub
bgranger@calpoly.edu and ellisonbg@gmail.com

[takluyver]

For reference, the equivalent of pip install -e . is flit install --symlink.

I'm not sure what the significance of having things work without flit being present is - flit is very simple to install.

[ellisonbg]

A bit more background:

• Right now I am spending most of my time using our tools rather than
  developing them. By that I mean standing up in front of 50 students for 12
  hours a week. In a context like this, I have to have as few uncertainties
  as possible. I am willing to live "on the edge" in a few very narrow areas
  that I know super well (jupyter, jupyterhub, etc.). But for everything
  else, this means using the most standardized and well supported tools
  possible - especially in the world of installation - that means using tools
  that have millions of users beating on them every day.
• The history of packaging in python shows that it is extremely difficult
  to really get right. Even when you get it right, it is still probably
  broken for someone else. I hope you don't take this personally @takluyver
  but I have too much scar tissue about new packaging tools to quickly accept
  and start using new ones. This is a statement about the difficulty of
  packaging, not the skills or knowledge of the people writing tools.
• I have a medium-complexity deployment of jupyterhub that is, in part,
  based on my ability to quickly deploy hot fixes as follows:

pip3 install git+https://github.com/org/repo.git#egg=package

I have installed jupyter/notebook and jupyter/jupyterhub from branches
using this approach dozens of times using this approach. So far, I have
been able to run a released version of ngrader, but soon I will need to
start deploying custom branches of it.

On Wed, Jan 6, 2016 at 1:46 PM, Thomas Kluyver notifications@github.com
wrote:

For reference, the equivalent of pip install -e . is flit install
--symlink.

I'm not sure what the significance of having things work without flit
being present is - flit is very simple to install.

—
Reply to this email directly or view it on GitHub
#409 (comment).

Brian E. Granger
Associate Professor of Physics and Data Science
Cal Poly State University, San Luis Obispo
@ellisonbg on Twitter and GitHub
bgranger@calpoly.edu and ellisonbg@gmail.com