Zahlblog

Meta-automation

Karl Knechtel — Wed, 25 Feb 2026 05:00:00 GMT

One of the really fun things about switching to Linux is realizing just how much you can accomplish with a few lines of Bash. Especially when those lines are taking advantage of, not just built-in programs, but other things you made before.

Today I published a couple of tiny tools I use to make my life easier, and I'd like to talk about them a little bit.

Python Packaging 外伝１: Oxidation and Radiation - The Rise of uv in 2025

Karl Knechtel — Wed, 31 Dec 2025 05:00:00 GMT

Today I'm offering a sort of "side story" to my main series on Python packaging. The main thrust of the series has been that everything is broken or historically has been broken; but I've also been trying to fight some common misconceptions and defend some things that people don't seem to like but which are actually quite reasonable in context.

But I've been doing this in the shadow of uv existing, and uv's momentum has been unstoppable this year. Of course there were many adopters in 2024 as well, but we're now seeing more and more evidence in PyPI stats, surveys, CI pipelines etc. that people are switching away from pip (and other tools) to uv.

Which is unsurprising, given how positive the coverage has been overall. There have been many popular posts about it on Hacker News this year (I wouldn't mind adding to the pile!) and everyone is touting its features and praising their experience with it.

So before the year is out, I really wanted to write down some thoughts about uv's success so far and the impact it's had on me — which as it turns out is mostly not about actually using it. This will mostly be gathering things that I've already said repeatedly in the aforementioned threads, but I think there's value to that.

Python packaging: Why we can't have nice things - Part 3: Premature Compilation

Karl Knechtel — Fri, 28 Feb 2025 05:00:00 GMT

Pip 25.0 has been out for a bit over a month now; and we now also have an official blog post about the release, as well as a 25.0.1 patch for a regression.

Pip 25.0 has what I consider a very serious security vulnerability. In the Python ecosystem, it's normal and expected that third-party packages provide their own, arbitrary "setup" code for installation (for example, to run C compilers in project-specific ways, when the code uses a C extension). But Pip will run such code in many more situations than you might naively expect. I think it's obvious that running arbitrary code when you aren't expecting it and prepared for it is a much bigger problem. The user should have a chance to decide whether to trust the code, first.

I believe that warnings are more important than baiting people to read the post, so here's the PSA up front:

Never use Pip to download, test, "dry-run" etc. an untrusted source distribution (sdist). It will try to build the package, potentially running arbitrary code (as building an sdist always entails). Instead, use the PyPI website directly, or the API it provides.
Never use sudo to run Pip (nor run it with administrative privileges on Windows). Aside from the potential problems caused by conflicting with the system package manager, Pip will not drop privileges when it runs as root and attempts to build an sdist - which again, potentially runs arbitrary code.
If you expect wheels to be available for the packages you want to install with Pip, strongly consider adding --only-binary=:all: to the Pip command to ensure that only wheels are used. If you really need to use sdists, it's wise to inspect them first, which by definition isn't possible with a fully automated installation.
If you release Python packages, please try to provide wheels for them, even if - no, especially if your package includes only Python code and doesn't require explicitly "compiling" anything. An sdist is much slower to install than a wheel even in these cases, and making a wheel available allows your users to demand wheels from Pip - raising the overall baseline for trust and safety in the Python ecosystem.

Okay, I did clickbait a bit. This security issue isn't some new discovery. In fact, it has plagued Pip for its entire history.

Please enjoy my detailed analysis below.

Leaning IN to my U/X

Karl Knechtel — Fri, 24 Jan 2025 05:00:00 GMT

$ stat / | grep Birth | cut -d ' ' -f 3
2022-01-24

Today (although this won't go live until the 25th in my time zone) is three years since the day I finally kicked Windows to the curb and installed Linux on my home desktop. I'd used Linux before, but all my life I'd had a habit of just using whatever OS was provided to me, without really giving it much thought.

In late 2021, Windows Update told me - entirely unprompted - that my system didn't meet minimum specs to run Windows 11. (Perhaps it would now - I understand that the declared requirements have been relaxed, even if nothing has been optimized or stripped down - but I don't care to check. I'm also told that people still on Windows 10 are under increasing pressure to switch, even though they're still comfortably in the majority - unless something has radically changed in the last few months.)

I found this impolite - as I hadn't asked, and didn't consider anything wrong or inadequate about my computer - and a bit absurd (whatever they're offering now that requires more computing power, I'm not interested; especially not if it's anything to do with Cortana). So I took that as my queue to switch. I bought a new SSD (figuring I would need the space anyway) and attempted to set up a dual boot - GRUB never worked properly for me, but I could still use the BIOS screen to boot Windows from the old SSD.

And I never looked back.

Today, I'd like to relate a few anecdotes about that experience.

A Brief Annotation

Karl Knechtel — Sat, 11 Jan 2025 05:00:00 GMT

I've been quite busy working on both the next article in my packaging series and on the overall appearance of the blog (I wasn't able to keep that confined to the weekend, apparently).

So, today, just a quick note, on the occasion of the 4th anniversary of the creation of PEP 649 "Deferred Evaluation Of Annotations Using Descriptors".

Yes, that's a mouthful, but in short: starting in Python 3.14, if you use annotations, you'll be able to defer the evaluation of the annotation code. (The feature was supposed to be added for 3.13, but didn't make it in.) That means you don't have to rely on strings for forward references in your type annotations, but you can still make full use of annotations at runtime (you'll have a proper object for the annotation itself, rather than just a string). Thank you to core Python developer Mr. Larry Hastings for putting a tremendous amount of effort into refining this proposal.

Now, I don't personally use type annotations very much - I don't use a type checker at all; I only write annotations as a form of documentation. But as it happened, when I was new to the Python Discourse forum, I came across Mr. Hastings' post, puzzling over the best way to name what will soon become the __annotate__ attribute of annotated objects.

The name __annotate__ was my suggestion.

I was not credited in the PEP, and I was ignored when I tried to point this out. So it falls to me to draw attention to my contribution.

This is all very niche stuff, of course - but I'm happy to have been able to leave this mark on the Python language itself, as opposed to just making useful things with it.

Python Packaging: Why we can't have nice things - Part 2: Stupid Pipx Tricks

Karl Knechtel — Tue, 07 Jan 2025 05:00:00 GMT

Pip has a lot of problems (that I'll be discussing in future posts in this series), but the good news is that you don't have to resort to heavyweight third-party tools to improve your experience with Python packaging. Pipx (now under the Python Packaging Authority (PyPA) umbrella) is a focused wrapper around Pip that handles the major pain points without trying to take over your entire workflow.

In this post I'll talk about Pipx's major use cases, its limitations, and how to get more mileage out of it with a few simple tweaks.

New year, new blog

Karl Knechtel — Wed, 01 Jan 2025 05:00:00 GMT

You're not imagining things - the blog has a whole new look, in large part as a result of switching to the Nikola site generator.

fixup! added list - The rest of the TODOwl

Karl Knechtel — Tue, 31 Dec 2024 05:00:00 GMT

Happy new year to all.

Today's post is about a folder on my desktop named dev. It's where I've kept (for many years, well into my Windows-using days, even into the era when I used SVN rather than Git) all my working copies for my own projects (and forks of others'), mostly Python code of course. (I'm not sure how I organized things at the time, but there are projects in there dating back to 2006.)

Python packaging: Why we can't have nice things - Part 1: The Old Refrain

Karl Knechtel — Tue, 24 Dec 2024 05:00:00 GMT

This post is a start of a series I've planned about how packaging currently works in Python, what's wrong with it, and how to cope with the problems. But before I get into the meat of it, I want to talk about common complaints that don't resonate with me.

# TODO: finish todo list

Karl Knechtel — Fri, 20 Dec 2024 05:00:00 GMT

This is a difficult post to write, largely because of the self-critique involved. Which is part of why I've been putting it off. For months, if I'm honest with myself.

But putting it off has only made it harder to write. I also seem to have reached a point where it psychologically feels impossible to publish anything else here first. So, I'm finally forcing myself to write it now - during the holiday season, to prove to myself that I can.

It's no secret that the history of this blog so far has been dominantly one of false starts. Please allow me a moment to explain how that came to be.