[The_Colonel]

I remember mypy being slow and buggy. I remember one mypy upgrade broke all our builds because they changed some type of resolution thing. IIRC after some outcry they backtracked and started providing some migration path.

The other thing which rubbed me the wrong way was that the python was happy to run the code with completely wrong type hints.

I guess I went into it with wrong expectations, even though it says right in the name - it's "type hints". The whole experience felt more like a formalized documentation with partially working optional verification (which can't really be relied upon).

[depressedpanda]

I've also had a mixed experience with mypy. Take a look at using pyright for static type checking instead, it's worked quite well for me.

But do write type hints. I recently got thrown into a large-ish project where neither types nor docs where used. Trying to figure out wth a parameter was supposed to be wasn't a pleasant experience for a newcomer. In addition to improving DX, I also believe it's alot more effective in the long run.

I saw how these guys were developing: write code, run code, deal with the runtime crashes they encounter, then run code some more and deal with other unexpected runtime crashes. It would have been a lot faster and more stable if they'd just used type hints and static type checking, as their IDE could've easily found many of these bugs for them immediately.

[icedchai]

Type hints are basically for documentation and metadata. You also find a bunch of third party libraries and frameworks, like pydantic, fastapi, etc. that makes use of them.

[dragonwriter]

> Type hints are basically for documentation and metadata.

They are also for static checking.

If you choose to run the code despite that failing (which you can, because there is no execution dependency on type-checking) that’s a choice, but its kind of odd to complain that Python lets you do that.

[icedchai]

I'm not the original poster and not complaining about it. I once worked at a shop that ran mypy checks as a precommit hook and never really found it terribly useful, but to each their own.