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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#539: Catching up with the Python Typing Council

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#539: Catching up with the Python Typing Council