(Somewhat of a small soapbox) So part of adding the new Options API was making sure we get the deduced property types right. No way to really test that in mypy. There's 3 tools in the wild that can help (https://pantsbuild.slack.com/archives/C0D7TNJHL/p1643838778597069) but they all invoke

mypy

in a subcprocess one way or another which doesn't work well in Pants' execution model. Turns out

pyright

(as of this year) and

pytype

have type assertions built-in, and it might make it into

typing_extensions

, but

mypy

is no-dice. So, I had some fun and decided to hack it in

mypy

through a plugin. Introducing my first and only PyPI package:

mypy-typing-asserts

https://github.com/thejcannon/mypy-typing-asserts And the resulting Pants PR (where the plugin found several issues 😈 ) https://github.com/pantsbuild/pants/pull/14527

"....where it found several issues..." Terrific! Thank you.

FWIW all the issues were introduced by me 🙂 But that's what happens when you can't test your code. You're asking for bugs.

gasp

Hahaha I could watch that on repeat all day. It's hypnotic.