Proposal: Workaround for mypy's incorrect implementation of NotRequired

[untitaker]

We have a schema definition with two fields, foo_required and foo_optional.

{"properties": {"foo_required": {}, "foo_optional": {}}, "required": ["foo_required"]}

Now consider this code:

x["foo_optional"]

VSCode/pyright does error on the above line because it might crash. Unfortunately, mypy does not.

This issue is tracked in python/mypy#12094 -- unfortunately the issue is open for more than a year.

In a comment I came up with an idea for a workaround where we actually construct multiple TypedDicts and combine them with a Union. This contraption will also cause mypy to find the problem in the above code snippet.

class MyDict(TypedDict, total=False):
    foo_required: Required[int]
    foo_optional: NotRequired[int]


class MinimalDict(TypedDict, total=False):
    foo_required: Required[int]

MyDict2 = Union[MyDict, MinimalDict]

Do you think this would be reasonable to emit by default from jsonschema-gentypes? Or is it too hacky?

We are also considering running pyright in CI to catch those errors, but it would be a bigger project for us.