Autodoc - Class attributes required for bases with generic arguments to be resolved when using :show-inheritance:

[tanrbobanr]

Recently, I have been trying to document certain classes that inherit from pydantic.BaseModel, but have encountered a bit of an issue. Before I explain, here is some example code:

_T = TypeVar("_T")
_T2 = TypeVar("_T2")

class Base(pydantic.BaseModel, Generic[_T, _T2]):
    a: _T
    b: _T2

class Derived(Base[int, str]):
    pass

Here is what I would expect when Derived is documented: Bases: Base[int, str] where Base references our Base class, and int and str reference the python int and str classes (via intersphinx).

When not using pydantic.BaseModel (i.e. just inheriting from Generic), everything works as expected. But when using pydantic.BaseModel, a number of odd things happen. First, the reference to Base fails to be resolved - this is due to pydantic's odd handling of __name__ within __class_get_item__ (the full parametrized name is used, not just the name of the class). If we set __name__ to the actual class name, the reference to Base is successfully resolved. Unfortunately, this just shines light on another problem - the parameters are now completely ignored by sphinx (the bases are now shown as Bases: Base). Even though Base in Bases now correctly reference the Base class, its not really what I'm looking for.

This brings me to my question: Which class attributes (or something else) does sphinx use to determine the structure of Bases (particularly bases that are parametrized) when :show-inheritance: is used? My initial thought was __name__ and __args__, but manually assigning those to the correct values (in this case "Base" and (int, str) respectively) doesn't do the trick.

Although at the end of the day it is pydantic that is doing something odd with generics, I am still interesting in learning what exactly sphinx uses to hopefully help me implement a solution.

Thank you!