Added support for MyPy

[GameDungeon]

Overview: What does this pull request change?

I added mypy support, including the pre-commit hook, and also fixed some issues mypy brought up.

Many things are ignored, it is a task for future pulls to fix the issues.

Reviewer Checklist

• The PR title is descriptive enough for the changelog, and the PR is labeled correctly
• If applicable: newly added non-private functions and classes have a docstring including a short summary and a PARAMETERS section
• If applicable: newly added functions and classes are tested

[GameDungeon]

While we have been using mypy to fix issues in manim for a while, I think that it's important to be officially part of manim's developer tool kit.

[behackl]

I have no experience with MyPy at all, it would be great if someone else could look at the concrete changes here.

I don't particularly like the addition of 7 new dependencies.

[behackl]

Why can these types not be added to the actual code file?

[GameDungeon]

The capitalized colors are generated in runtime so it does not work.

[behackl]

This comment is not about color.pyi

[GameDungeon]

Ohh sorry. Mypy was interacting weirdly and this seemed to be the most direct solution.

[GameDungeon]

The new dependencies are Dev Dependecys, and you can't get much more maintained than under the python github account + microsoft

[hydrobeam]

What's the point of mypy? I'm not even sure why we need it.

[GameDungeon]

Static Type checking. It finds bugs in our documentation & code. If we mark functions for the wrong types it can mislead people. There have already been several prs fixing mypy errors.

[christopher-besch]

This looks like something we could really use.
Adding the type-hint dependencies shouldn't be an issue; they aren't that big and are required anyway if we want to make Manim type-safe. I don't think there is any way around MyPy once we move to the new dev-branch.

What I don't understand is why the .pyi files were changed.

[GameDungeon]

This pull is old enough that if we plan to merge it, it might be better to delete the pyi files.

[christopher-besch]

I gave it a run and this was the result:

Did I do something wrong?

[GameDungeon]

Try only running it on manim's folder. I did not do anything with the testing.

[christopher-besch]

Try only running it on manim's folder.

I still get this error:

[christopher-besch]

We should also add this to the .pre-commit-config.yaml.

[GameDungeon]

I've been away for a while, sorry for the really late response. I believe it's too early to add it to pre-commit. That one error was introduced since I made this.

[christopher-besch]

Could you also merge any new changes to Manim and check if MyPy runs?

[GameDungeon]

I think everything is up to data and functioning now :) I fixed the logger error as well.

[GameDungeon]

I also managed to get the mypy pre-commit hook working :)

[christopher-besch]

I ran it on my machine and everything seems to be working. With pre-commit it is also being run in CI.
I think we can merge this.

Thanks for the contribution!

[Darylgolden]

I think this looks good, thank you!