TypeError: Some type variables (...) are not listed in Generic[...]

[IkorJefocur]

Describe the bug

Using autodoc extension with autodoc_mock_imports configuration value, importing mocked module, then extending class from that module with generic on a new class causes exception when generating docs. Exception looks like this:

WARNING: [autosummary] failed to import main.
Possible hints:
* KeyError: 'main'
* ValueError: not enough values to unpack (expected 2, got 1)
* TypeError: Some type variables (pydantic.BaseModel) are not listed in Generic[T]

How to Reproduce

# conf.py
project = 'Test'
extensions = [
	'sphinx.ext.autodoc',
	'sphinx.ext.autosummary'
]

autosummary_generate = True
autodoc_mock_imports = ['pydantic']

# index.rst
Documentation
=============

.. autosummary::
   :toctree: generated
   :template: module.rst

   main

# main.py
from pydantic import BaseModel # can be any class from any mocked module

class MyModel[T](BaseModel):
	pass

Environment Information

Platform:              linux; (Linux-6.1.99-1-MANJARO-x86_64-with-glibc2.39)
Python version:        3.12.4 (main, Jun  7 2024, 06:33:07) [GCC 14.1.1 20240522])
Python implementation: CPython
Sphinx version:        8.0.2
Docutils version:      0.21.2
Jinja2 version:        3.1.4
Pygments version:      2.18.0

Sphinx extensions

['sphinx.ext.autodoc', 'sphinx.ext.autosummary']

Additional context

No response