Setuptools build shim doesn't actually install script

I’m trying to upgrade the Arch Linux AUR package to 53.0 and something isn’t right. Because it’s still basically the only Python ecosystem that manages installs to alternate roots correctly almost all package builds use setuptools. The package as downloaded from PyPi does have a flit generated setup.py file. To my eye it even looks right, it has the packages and entry_points that I would expect to see. However when running python setup.py install --root=... I do not get any /usr/bin/weasyprint script as everything up through 52.x has been doing and I would expect to see now.

[alerque]

Wow, just wow. So much missing the point! Nobody is down on the tooling rewrites, we just need a tool. To quote something buried in those threads:

It’s downright depressing to see this hostile attitude toward distros that are literally asking for one thing and one thing only: do not drop support for the old way of doing things until after a new way is implemented.

That was two years ago and the issues is still not addressed. The new tooling handles the user-space and venv style installations nicely, but does not meet this use case. The installer and other work-arounds have huge drawbacks and are clearly written as if the thing they are doing shouldn’t be done.

For anybody else hitting this issue for this package, this problem can be fixed by monkey patching the Flit generated script. It is loading the even more legacy distutils as a shim but passing it data meant for setuputils! It works fine and the binary is installed if you just swap out the library for the one that Flit should be importing all along. The upstream rational for leaving this clear mistake is just weird (and probably more political than technical but I don’t feel like going deeper down the rabbit hole).

sed -i -e 's/distutils.core/setuptools/' setup.py

[liZe]

I have to admit that this was not that hard due to the fantastic work of Fedora’s Python wranglers.

Wow. ❤️. Thanks a lot for sharing.

The macros in pyproject-rpm-macros could be really useful for other distributions. But, of course, it would be actually hard to use the same scripts everywhere because of differences between distributions. That’s where the distributions and the Python team will have to work closely together, but it won’t be easy: distributions have different points of view about a lot of things (filesystem paths, package formats…), and they definitely have different points of view about Python packaging too.

Fedora’s workflow uses pip wheel and pip install, with some adjustments made for Fedora’s needs. Most of this code is actually useless for WeasyPrint (as it handles specific setup.py and setup.cfg hacks too), and we can assume that it will become more and more simple with time, now that the format is specified.

I really hope that other distributions will follow this path. Fedora won’t have to change anything when Flit will remove setup.py, because the wheel+install steps will be exactly the same. Distributions relying on another workflow may have to make new adjustments again, just as they did for years with setuptools workarounds. I’m really sorry for them 😢 and hope that they’ll find a clean solution soon.

If you’re a distribution packager, we’re really open to discussion: come talk on our Gitter room, or open a dedicated issue in this repository. We’re closing this issue for now, as a workaround has been given for setuptools users, and some hints have been given for a more reliable packaging.