#539: Catching up with the Python Typing Council

You're adding type hints to your Python code, your editor is happy, autocomplete is working great. But then you switch tools and suddenly there are red squiggles everywhere. Who decides what a float annotation actually means? Or whether passing None where an int is expected should be an error? It turns out there's a five-person council dedicated to exactly these questions -- and two brand-new Rust-based type checkers are raising the bar. On this episode, I sit down with three members of the Python Typing Council -- Jelle Zijlstra, Rebecca Chen, and Carl Meyer -- to learn how the type system is governed, where the spec and the type checkers agree and disagree, and get the council's official advice on how much typing is just enough.

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Links from the show Guests

Carl Meyer: github.com

Jelle Zijlstra: jellezijlstra.github.io

Rebecca Chen: github.com

Typing Council: github.com

typing.python.org: typing.python.org

details here: github.com

ty: docs.astral.sh

pyrefly: pyrefly.org

conformance test suite project: github.com

typeshed: github.com

Stub files: mypy.readthedocs.io

Pydantic: pydantic.dev

Beartype: github.com

TOAD AI: github.com

PEP 747 – Annotating Type Forms: peps.python.org

PEP 724 – Stricter Type Guards: peps.python.org

Python Typing Repo (PRs and Issues): github.com

Watch this episode on YouTube: youtube.com

Episode #539 deep-dive: talkpython.fm/539

Episode transcripts: talkpython.fm

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