I'm not sure what the best approach is here. I know we used outer_type because if it's list[int] it returns list.

What does _field.annotation give us?

For array field of strings _field.annotation is typing.Optional[typing.List[str]] but result is wrong

For array field of strings field_annotation["__args__"][0] is typing.List[str] which is correct

I don't know how to solve it otherwise, if you have any other idea feel free to write here.

Yeah, this was wrecking my brain.

I think I have a solution now - in Python 3.8 they added typing.get_origin and typing.get_args, which means if we have t.Optional[someType] we're able to extract someType.

Your solution probably would have been fine. I was just worried because for field_annotation["__args__"][0] to work we needed it to always be like (someType, None) and not (None, someType).

I just tried this and the _get_type function doesn't work as it should. The problem remains the same because the Array column does not display correct in the OpenAPI document filters. Now it's like this.

If I change the _get_type function to something like this

def _get_type(type_: t.Type) -> t.Type:
    """
    Extract the inner type from an optional if necessary, otherwise return
    the type as is.
    """
    args = t.get_args(type_)
    return args[0]

the result is correct and looks like this.

Can you check that in case I'm wrong or doing something wrong.

You're right - I can see the problem when trying to use the Director.years_nominated filter in the Swagger docs.

Will investigate.

It's a bit odd, but t.get_args returns this: (typing.List[int], <class 'NoneType'>) and I was expecting (typing.List[int], None).

I need to work out what NoneType is vs None.

So type(None) is NoneType. I've changed it to check for None and NoneType, and it should work.

Will add some tests.