> That's still doable with contextvars. You just need a custom mock-like object (or library) that stores its settings/state in a context variable.

contextvars only work with asyncio, what about the iterator case?

In addition, you can't possibly expect authors to re-implement a library just because it may or may not be used with asyncio. In my example, re-implementing mock/patch is quite a task just to get such basic functionality.

In other words, contextvars don't solve this issue, it just creates new issues to solve and causes code duplication.