[shrumm]

Thanks Astral team! We use Pydantic heavily, and it looks like first class support from Ty is slated for the stable release, we'd love to try it.

While we wait... what's everyone's type checking setup? We run both Pyright and Mypy... they catch different errors so we've kept both, but it feels redundant.

https://htmlpreview.github.io/?https://github.com/python/typ... suggests that Pyright is a superset, which hasn't matched our experience.

Though our analysis was ~2 years ago. Anyone with a large Python codebase successfully consolidated to just Pyright?

[gwking]

I appreciate the even tempered question. I’ve been using mypy since its early days, and when pyright was added to vs code I was forced to reckon with their differences. For the most part I found mypy was able to infer more accurately and flexibly. At various times I had to turn pyright off entirely because of false positives. But perhaps someone else would say that I’m leaning on weaknesses of mypy; I think I’m pretty strict but who knows. And like yourself, mine is a rather dated opinion. It used to be that every mypy release was an event, where I’d have a bunch of new errors to fix, but that lessened over the years.

I suspect pyright has caught up a lot but I turned it off again rather recently.

For what it’s worth I did give up on cursor mostly because basedpyright was very counterproductive for me.

I will say that I’ve seen a lot more vehement trash talking about mypy and gushing about pyright than vice versa for quite a few years. It doesn’t quite add up in my mind.

[hauntsaninja]

I’ve added ecosystem regression checks to every Python type checker and typeshed via https://github.com/hauntsaninja/mypy_primer. This helped a tonne with preventing unintended or overly burdensome regressions in mypy, so glad to hear upgrades are less of an Event for you

[shrumm]

> I will say that I’ve seen a lot more vehement trash talking about mypy and gushing about pyright than vice versa for quite a few years. It doesn’t quite add up in my mind.

agreed! mypy's been good to us over the years.

The biggest problem we're looking to solve now is raw speed, type checking is by far the slowest part of our precommit stack which is what got us interested in Ty.

[hauntsaninja]

Mentioned this in another comment, but the spec conformance suite is not representative of the things users care about (nor is it meant to be).

The spec mostly concerns itself with the semantics of annotations, not diagnostics or inference. I don't really recommend using it as the basis for choosing a type checker.

(I was on the Python Typing Council and helped put together the spec, the conformance test suite, etc)