`:members:` option on `automodule::` is ignored when `members` is set in `autodoc_default_options`

Describe the bug

Given a conf.py containing the following:

extensions = [
    "sphinx.ext.autodoc",
]

autodoc_default_options = {
    "members": True,
    #"undoc-members": True,  # Doesn't matter whether this is commented out or not
}

and a reStructuredText file like the following:

.. automodule:: somemodule
    :members: func1

All of the members of the module, not just func1, will appear in the documentation.

How to Reproduce

git clone https://github.com/jwodder/sphinx-bug-20211006
tox -e docs
# Open docs/_build/html/index.html and observe that both `show_in_documentation()`
# and `dont_show_documentation()` appear in the documentation

Expected behavior

Only the members listed in the automodule:: directive's :members: option should have been documented, as the settings in autodoc_default_options are, as the name suggests, defaults and thus should be overridden by explicit :members: options.

Your project

https://github.com/jwodder/sphinx-bug-20211006

Screenshots

OS

macOS 11.6

Python version

3.9.7

Sphinx version

4.2.0

Sphinx extensions

sphinx.ext.autodoc

Extra tools

No response

Additional context

No response

Reproduce the issue with the referenced conf.py and reStructuredText automodule example by running tox -e docs, then inspect sphinx.ext.autodoc handling of :members: and autodoc_default_options. Done means an explicit :members: func1 option documents only func1, rather than every module member, while the generated docs in docs/_build/html/index.html match the expected behavior.