Sphinx automodule: class method not documented when decorated with mocked function

[GutiCW]

Describe the bug

I have a class with decorated methods. The function used as a decorator is provided by a module not available when building the documentation, hence this module is mocked in conf.py using autodoc_mock_imports = ['module_with_decorator'].

.. automodule:: my_class
    :members:

from module_with_decorator import my_decorator


class MyClass:
    """
    My test class.
    """

    @staticmethod
    def my_undecorated_static_method():
        """This is my_undecorated_static_method."""

    @staticmethod
    @my_decorator(param0, param1)
    def my_decorated_static_method():
        """This is my_decorated_static_method."""

    @classmethod
    def my_undecorated_class_method(cls):
        """This is my_undecorated_class_method."""

    @classmethod
    @my_decorator(param0, param1)
    def my_decorated_class_method(cls):
        """This is my_decorated_class_method."""

    def my_undecorated_instance_method(self):
        """This is my_undecorated_instance_method."""

    @my_decorator(param0, param1)
    def my_decorated_instance_method(self):
        """This is my_decorated_instance_method."""

The decorated class methods are not shown in the documentation - others are shown correctly.

Any suggestions regarding this issue?

How to Reproduce

Decorate a class method with a function from a mocked module.
PowerShell:
$builder_name = "html" ; $doc_source = "...\test\doc\tp_testcase_docstring" ; $dest = "$doc_source_build$builder_name" ; conda activate $conda_env ; sphinx-build "$doc_source" "$dest" -b $builder_name

Expected behavior

The class methods should be visible in the documentation.

Your project

test.zip

Screenshots

No response

OS

Windows

Python version

3.9.7

Sphinx version

4.4.0

Sphinx extensions

sphinx.ext.autodoc

Extra tools

No response

Additional context

Related to stackoverflow.com.

[tk0miya]

At present, decorators on the mocked module are not working because they return mocked objects instead of functions or methods. I don't have good ideas to generate documents for them. So I marked this as "help wanted".

Please post your idea or send a PR to implement it. Thanks,