> for some reason Optional[T] became deprecated, just as the ecosystem finally embraced types

Deprecated in favour of `T | None` exactly because of that embrace. It's cleaner, more consistent (you can `T | U` arbitrarily), and helps slim down the `from typing` imports.

> Also, for some reason Optional[T] became deprecated, just as the ecosystem finally embraced types ~3 years ago.

Optional[T] is now T | None. Means exactly the same thing but doesn't require an import. Support for the older syntax presumably won't be removed for a long while regardless.

(Note: I work on Python tooling.)

> for some reason we need 2-3 static analysis tools just for typechecking

I don’t follow: you need one type checker, of which you have several options. It’s arguably not ideal to have more than one option, but you should never need to run more than one.

- no tool understands each other's comment directives

In general, all type checkers in Python support the `type: ignore` directive, since it’s standardized.

> each tool reports a different error in your codebase

This is a real problem, but I think you can avoid it (like most people do) by not mixing different tools that do the same thing together.

To my understanding, you’d have the same problem if you combined (e.g.) biome and eslint in a JavaScript codebase.

UV, Ruff and Pyrefy and you're set. As someone who works with Python, Typescript and C/Zig quite a lot I don't disagree with you on Typescript, but I'm not sure why you'd pick Typescript over Python. Bun is kind of awesome, but it's also kind of unfinished, but if you go with the default Node I find that the setup for security compliance is next to impossible where Python can do most things with it's standard library, a pandas and pyarrow.

I personally prefer the fake typing in Python because it fits well with our defensive programming style with very low abstraction and little to no adherence to DRY. Since Python naturally force you to deal with runetime assertions rather than getting you to do compiletime checks that then don't actually offer any form of safety at runtime. Which is obviously not a very technical argument, but it just feels a lot cleaner rather than having to juggle the two.

I had a similar experience as you. We normally use Kotlin for everything, but last year we had to do a small project in Python. Setting up the tooling and choosing the tools is quite overwhelming, and the inconsistency between what the tools actually consider type errors is incredibly frustrating. I am actually happy that the project failed and that we don't have to work in that environment anymore.

I think Python is probably good for many things, including scripts and as a starter language, but I don't understand how anyone can stand writing large software systems in it.

In my (really large) typescript project we have like 6 static analysis tools running[1]. Steps to get the project running: install nodejs, install package manager, install dependencies, run project.

The main difference is that in the JS ecosystem it is all installed at the project level, you don't need anything globablly installed besides the runtime and package manager (and even the package manager can be auto-installed as well if you set it up that way).

[1]: eslint, biome, prettier, scass linter, graphql-codegen, tsc, tanstack-router codegen. That I remember, might be more (although codegen might not be considered static analysis, it is needed for static analysis).

Yes, changing a type checker tool is not done easily in larger projects, or on the fly, as they all have different edge cases, where they don't infer well enough, or are more lenient than another tool.

I have switched type checker recently in my own Python projects from zuban to ty. ty seems to work better, and is not a one man show/bus factor of 1, though I respect the work that has gone into zuban by its creator. But ty doesn't understand mypy configuration in pyproject.toml ...

I imagine switching a type checker in a bigger project and with more people involved to be a bit of a PITA, until everyone has adjusted their development environment/tooling. Best one can do is research beforehand which tool suits one best, test it, and then stick to it, unless it has unbearable failures.

I grew up on python and after working with Java I really came to appreciate types. However I do want to point out that big libraries like mpl pre-date most efforts for typing, so it is no wonder that they arent typed properly. A lot of these libraries are trying to improve this but it will just take some time.