[kzrdude]

That's not really the debate in Python :)

Almost every Python user now has to "deal" with type annotations. It's tempting to gradually add type annotations, it's nice documentation.

But it also rubs me the wrong way to have annotations that are never checked(!). In many codebases, you might just have "casual" style type annotations in Python, and nothing ever asserts that they hold. That's nagging on me, a bit.

[inertiatic]

Never checked? They're statically checked.

Also, tooling like https://pydantic-docs.helpmanual.io/ can do runtime checking for important parts of your app or you can use this https://github.com/agronholm/typeguard to enforce all types at runtime (although I haven't measured the performance impact, probably something to do in a separate environment than production?).

[kzrdude]

They are statically checked, if you run a type checker. Which many don't.

[tehnub]

That's a good point. If they're never checked, then they're just like incorrect/outdated comments. They sort of get at this idea in the article, and sort of describe a compromise for it. They have a list of files that they've completely annotated, and only those files are checked by mypy. So in their case, they know which annotations to ignore, and which they can rely on.