build VS installer

If it's pure Python, the only packaging file you need is `pyproject.toml`. You can fill that file with packaging metadata per PEP 518 and PEP 621, including using modern build tooling like flit[1] for the build backend and build[2] for the frontend.

With that, you entire package build (for all distribution types) should be reducible to `python -m build`. Here's an example of a full project doing everything with just `pyproject.toml`[3] (FD: my project).

[1]: https://github.com/pypa/flit

[2]: https://github.com/pypa/build

[3]: https://github.com/pypa/pip-audit

RE the dislike of a "third-party tool", what do you mean by this? All the major tools for packaging in Python are under the PyPA, e.g. - twine - build - hatch

building wheels/sdists to upload or install: build

python3 setup.py sdist bdist_wheel - no need for an sdist when building wheels, also I'd recommend using pypa/build instead.

The first step is to turn the internal package into a wheel (a *.whl file). We can use the build tool for this purpose. After installing build with pip we can run it as follows:

Shouldn't https://github.com/pypa/build help? I don't think it has enough features yet but I was under the impression that was the distro solution.

And probably https://github.com/pradyunsg/installer https://pypi.org/project/installer/ too, but that one isn't under the pypa org yet, given the author, it probably will be.

All that being said, the deprecations and removals are being done way before the replacements are in place and tested and features/rough edges rounded out, which I guess is python tradition at this point.

IMHO, the repos maintained by pypa should all be part of the core teams responsibility (e.g. pip is maintained by pypa, not core, but its installed as part of the python installer you download from the foundation's website...), along with solving building/installing/packaging/distributing as a whole. But the core team decided their volunteers didn't want to work on that (ok fair) and pypa stepped up to do it, but never really had enough manpower to tackle it well (ok also fair). And none of the tech companies ever thought "gee we rely so heavily on this awesome tool, maybe we should send them some money to keep the lights on..." So instead its just been a giant mess.

python -m installer --destdir="$pkgdir" once pradyunsg/installer#66 is finally merged