https://xcancel.com/charliermarsh/status/1884651482009477368
We’re building a new static type checker for Python, from scratch, in Rust.
From a technical perspective, it’s probably our most ambitious project yet. We’re about 800 PRs deep!
Like Ruff and uv, there will be a significant focus on performance.
The entire system is designed to be highly incremental so that it can eventually power a language server (e.g., only re-analyze affected files on code change).
Performance is just one of many goals, though.
For example: we’re investing heavily in strong theoretical foundations and a consistent model of Python’s typing semantics.
(We’re lucky to have @carljm and @AlexWaygood on the team for many reasons, this is one of them.)
Another goal: minimizing false positives, especially on untyped code, to make it easier for projects to adopt a type checker and expand coverage gradually over time, without being swamped in bogus type errors from the start.
We haven’t publicized it to-date, but all of this work has been happening in the open, in the Ruff repository.
All driven by a uniquely great team: @carljm, @AlexWaygood, @sharkdp86, @MichaReiser, @DhruvManilawala, @ibraheemdev, @dcreager.
I’m learning so much from them.
Warning: this project is not ready for real-world user testing, and certainly not for production use (yet). The core architecture is there, but we’re still lacking support for some critical features.
Right now, I’d only recommend trying it out if you’re looking to contribute.
For now, we’re working towards an initial alpha release. When it’s ready, I’ll make sure you know :)
I use stub files and mypy, but have concerns about behavior.
Thought the point is to move the static type checking stuff into a separate file. This makes the code much easier to read.
When a particular stub file becomes out of date, contents don’t reflect what’s going on in the code, there is no warning.
inner functions are ignored.
a functions contents are ignored.
Reluctant to use a library running node (gh actions aside) or Rust. My opinion is speed and correctness are insufficient arguments to introduce another tech stack. If something breaks, suddenly the onus is on me to understand why. That’s complicated if the additional tech stack is in a coding language i’m unfamiliar with.
This takes out: ruff, uv, and pyright. And whatever else comes out.
Have seven published python packages.
Trying to be open minded. Please layout other arguments why should be open to utilizing other tech stacks.