models values_list unexpected type warning

[A-Iskakov]

using values_list() on django models gets unexpected type(s) warning

[mkurnikov]

More details?

[mkurnikov]

cc @syastrov

[A-Iskakov]

[mkurnikov]

What about mypy, does it show any errors? mypy output is a reference for this project, pycharm can have it's own bugs.

[syastrov]

I think it is due to use of Literal types, which is a mypy extension and also highly experimental according to their docs.
In the interest of compatibility, and because we will probably make values_list smarter in the future, I will make a PR to implement the different return types dependent on parameters in the plugin instead.

[syastrov]

There are Literal types used in a few other places in the stubs, so not sure if we should do something about that. It would be nice to keep the stubs clean of mypy-specific stuff, so they are as generally-useful as possible.

If we don't want to make special-cases in the plugin, then we could solve these cases by making a condition in the stubs, something like:

if MYPY:
    class _SupportsValuesList(Generic[_T]):
        ... # mypy-specific values_list function overloads using Literal types
else:
    class _SupportsValuesList(Generic[_T]):
        ... # values_list function that would be used by other type-checkers (e.g. PyCharm) and would return a QuerySet[_T, Any]

class QuerySet(..., _SupportsValuesList[_T]):
    ...