MonkeyType VS darker

MonkeyType collects runtime types of function arguments and return values, and can automatically generate stub files or add type annotations directly to your Python code based on the types collected at runtime.

To alleviate the burden of manual annotation, MonkeyType offers a clever solution. It dynamically observes the types entering and leaving functions during code execution. Based on this observation, it generates a preliminary draft of type annotations. This significantly reduces the effort needed to add type hints to legacy code.

https://github.com/instagram/MonkeyType can perform the call logging, and can export a static typing file which is used by mypy, but also e.g. PyCharm. It doesn't expose such fine grained types, but you could build that based on the logged data.

Which introduces MonkeyType, a python library that generatics static type annotations by collecting runtime types.

Not sure if you're joking but there is something similar for python developed by a rather well known company https://github.com/Instagram/MonkeyType

Thanks for your suggestions. I have gone through the GitHub issue that you have mentioned. From there I got to know about this plugin https://github.com/akaihola/darker

For Python, Darker does that by applying Black only to changed areas of the code. Maybe the same approach could be used for rustfmt by creating a separate tool?

Not an answer to your question but in the specific case of black you can instead use: https://github.com/akaihola/darker

For instance, we have a number of interesting features planned for the 1.5.0 release of Darker, a tool for running Black/isort/pylint/flake8 but limiting to only lines modified between two given Git commits.

I knew one library using "composite". - Darker: https://github.com/akaihola/darker/blob/master/action.yml - More details here: https://docs.github.com/en/actions/creating-actions/creating-a-composite-action

There's also Darker for only reformatting (using Black) the lines modified by commits.

Assuming the range you're interested in is a range with your changes, you should look at darker.

Yeah that's how we've used it. The results need manual checking, but together with darker https://github.com/akaihola/darker that's how we've been slowly ratcheting our Django monolith into a typed codebase.