Pyproject.toml

[neworderofjamie]

I have been putting this off for several years as I hate build systems but, installing Python projects using python setup.py develop or python setup.py install has been deprecated for some time now and warnings have become increasingly aggressive. The final straw is that the latest pip seems to default to building packages (like GeNN) which only provide a setup.py in an isolated environment (this is why mlGeNN builds have been failing) and the main issue with setup.py is that there's no (sensible) way of handling build dependencies meaning there's no way to setup this isolated environment (see https://peps.python.org/pep-0518/ for a more complete story)!

The modern approach centres around a file called pyproject.toml (this format is somewhere between yaml and a classic config file). Projects with a pyproject.toml can be built using a whole bunch of different frontends e.g. pip or build and, as a minimum, it provides the information to select a backend e.g. setuptools and install whatever dependencies are required for the build process. In python-only projects, it can fully replace setup.py by also providing meta-data.

Because it's still not clear to me how you pass build options right through the frontend and backend all the way to setup.py (which we need to do to generate debug and coverage-recording GeNN builds), we want to be able to still build the old way so, in this PR, I have followed the minimum pathway outlined in https://packaging.python.org/en/latest/guides/modernize-setup-py-project/ and:

• Left the metadata in setup.py so, for now at least, you can still create coverage or debug builds for development as before
• Added a very minimal pyproject.toml that bootstraps the setuptools build system.
• Made a few very minor fixes to setup.py to make all the paths that go into setuptools relative
• Add the python wrapper around pkg-config as a dependency and use this to correctly link/include pkg-config on Linux and Mac
• Updated Jenkins to build its final wheels using the build frontend

I have done the following testing in clean venvs/conda environemnts using pip install git+https://github.com/genn-team/genn.git@pyproject to test pip (having run pip install -U pip first and python setup.py install to test the legacy route:

OS	Python version	pip	legacy
Windows	3.14	✔️	✔️
Windows	3.13	✔️	✔️
Windows	3.12	✔️	✔️
Windows	3.9	✔️	✔️
Ubuntu 20	3.11	✔️	✔️
Ubuntu 20	3.9	✔️	✔️
Ubuntu 20	3.8	✔️	✔️

Using all this magic, installing GeNN is now pretty easy so I've taken the opportunity to simplify the README (and remembered to add references to HIP where appropriate).

TODO @tnowotny , it would be great if you could try and install both ways from this branch on Mac! Once you're happy with the readme, I'll copy-paste into the documentation

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 88.55%. Comparing base (f5f53be) to head (6864a47).
⚠️ Report is 21 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #720      +/-   ##
==========================================
+ Coverage   88.47%   88.55%   +0.08%     
==========================================
  Files         107      107              
  Lines       14262    14836     +574     
==========================================
+ Hits        12618    13138     +520     
- Misses       1644     1698      +54     

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