by zahlman | 2025-12-19 17:58:04+00:00
> I just always feel frustrated, that during the great breakup from 2-3, they didn't try to fix more of the known issues

Absolutely agreed. I would rather they left 2.x in someone else's hands entirely. Instead they were ultimately forced to produce 2.7, wheedle and bargain to not have to produce 2.8, and give 2.7 an extended support window instead; and they still got complaints and abuse from people upset about making changes that were generally quite easy to make.

I would still have completely switched to 3.x (at least when it appeared ready) simply based on it coming from the same team and advertising the main features and fixes that it ended up with.

> Reference counting instead of using a real garbage collector

This is not explicitly part of the design. You are free to use other implementations.

But before the `with` block was added (in 2.5), reference counting was useful for deterministic cleanup.

> The absolutely weak support for functional programming, which then was patched by list comprehensions and co later

I'll give you this one. GvR actually didn't like this stuff very much, which is how `reduce` lost its builtin status. The basics can take you really far, though. The important thing is that functions are first-class objects.

> venv and other solutions to isolate dependencies for a project

There is nothing fundamentally wrong with venvs. 99% of the complaints I hear about venvs are not actually the venv's fault. (They're usually pip's fault. Pip is bad.)

A venv is literally just a place to put packages (organized roughly the same way the system packages are) and a simple scheme for enabling Python to understand where that place is (so that `sys.path` can be modified at startup). Every other possibility has the same problem: either you have to learn one or more options for telling Python to use that package location, or it works by magic (which means eventually you have to understand the magic, and anyway "Explicit is better than implicit").

> The pyproject.toml format is under-specified, comes decades too late for a problem that has been solved good enough by Apache Maven more than 2 decades ago

pom.xml is not at all "good enough". The pyproject.toml format is actually quite detailed (https://packaging.python.org/en/latest/specifications/pyproj...). It also has explicit design goals of a) allowing arbitrary tools to store their config and b) being human-readable and -writable.

More importantly, Python didn't have something like Maven in 2004 alongside Maven because Maven only has to worry about Java code; the Python packaging system has to worry about potentially every programming language, and very commonly C, C++, FORTRAN and now Rust. In 2003 (with Python 2.2) it got `distutils`. That was designed (and Setuptools picked up the torch) to use code in `setup.py` for everything, because nobody had any concept of a real "ecosystem" yet (see if you can find some archives of the Cheeseshop from its first year, if you dare) and it was simple and seemed Pythonic at the time.

And now we're in a thread where OP is upset that Python code doesn't work for 30 years, which seems like a pretty common take. It turns out that when you accommodate backwards compatibility, it gets in the way of actually fixing old problems quite a bit. There are still projects out there that are just Python code that could be perfectly well built using Flit, that are using (slow!) legacy setup.py-based build setups. Not because there's anything wrong with pyproject.toml for their purposes (there absolutely isn't), but because nobody is forcing them.

People don't even keep their setup.py contents up to date, let alone pay attention to any kind of deprecation warnings. Literally the only thing that gets anyone to do anything is to break their setup, and then for most of them their action is to complain and make the Setuptools team put things back how they were.

I'm not just talking about random developers on tiny forgettable projects, either. I'm talking about PSF-managed projects like Requests that:

* are pure Python code

* are among the most popular packages on PyPI (Requests is top ten)

* had their "source builds" break this year (https://github.com/psf/requests/issues/6775) because of a removed import in setup.py for something that nobody has actually used for years (a legacy testing setup that has been completely abandoned since the project uses tox)

* already had a `pyproject.toml` file but weren't actually using it to store even basic build configuration (still in `setup.cfg`, so they had all three files for really no reason).

(Thankfully, something is actually getting done in Requests. Supposedly. The work for this was apparently "already done" in May 2024 and is supposed to appear "in the next minor version release". The last release as a patch release this August. The main branch of the repo doesn't reflect this work.)