Sphinx 3.x broken on Python 3.10

[humitos]

Describe the bug

It seems that Sphinx 3.x is broken when using Python 3.10 because of this line: https://github.com/sphinx-doc/sphinx/blob/v3.5.4/sphinx/util/typing.py#L33

$ python3.10
Python 3.10.0 (default, Nov  3 2021, 12:30:55) [GCC 11.1.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import sys
>>> sys.version_info > (3, 10)
True
>>> from types import Union as types_Union
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: cannot import name 'Union' from 'types' (/home/humitos/.asdf/installs/python/3.10.0/lib/python3.10/types.py)
>>>

Am I correct?

How to Reproduce

$ pip install "sphinx<4"
$ python3.10
Python 3.10.0 (default, Nov  3 2021, 12:30:55) [GCC 11.1.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from sphinx.testing import util
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/humitos/rtfd/code/sphinx-notfound-page/.direnv/python-3.10.0/lib/python3.10/site-packages/sphinx/testing/util.py", line 23, in <module>
    from sphinx import application, locale
  File "/home/humitos/rtfd/code/sphinx-notfound-page/.direnv/python-3.10.0/lib/python3.10/site-packages/sphinx/application.py", line 32, in <module>
    from sphinx.config import Config
  File "/home/humitos/rtfd/code/sphinx-notfound-page/.direnv/python-3.10.0/lib/python3.10/site-packages/sphinx/config.py", line 23, in <module>
    from sphinx.util import logging
  File "/home/humitos/rtfd/code/sphinx-notfound-page/.direnv/python-3.10.0/lib/python3.10/site-packages/sphinx/util/__init__.py", line 35, in <module>
    from sphinx.util import smartypants  # noqa
  File "/home/humitos/rtfd/code/sphinx-notfound-page/.direnv/python-3.10.0/lib/python3.10/site-packages/sphinx/util/smartypants.py", line 33, in <module>
    from sphinx.util.docutils import __version_info__ as docutils_version
  File "/home/humitos/rtfd/code/sphinx-notfound-page/.direnv/python-3.10.0/lib/python3.10/site-packages/sphinx/util/docutils.py", line 31, in <module>
    from sphinx.util.typing import RoleFunction
  File "/home/humitos/rtfd/code/sphinx-notfound-page/.direnv/python-3.10.0/lib/python3.10/site-packages/sphinx/util/typing.py", line 34, in <module>
    from types import Union as types_Union
ImportError: cannot import name 'Union' from 'types' (/home/humitos/.asdf/installs/python/3.10.0/lib/python3.10/types.py)

Expected behavior

It should not enter to that if because Python 3.10 version is not greater than (3, 10). It should probably check for

>>> (sys.version_info.major, sys.version_info.minor) > (3, 10)
False

Your project

https://github.com/humitos/sphinx-notfound-page

Screenshots

No response

OS

ArchLinux

Python version

3.10

Sphinx version

3.x

Sphinx extensions

No response

Extra tools

No response

Additional context

No response

[tk0miya]

Why do you use such an old version? Please use 4.2.0.

[humitos]

Hi @tk0miya! I don't personally use that version. I'm author and maintainer of an extension and I found this problem while running the extension's tests over different Python and Sphinx versions.

I expect users of the extension to use 3.x and I wanted to have them covered by the test suite. I didn't know you considered 3.x really old since it's the previous version of the current latest.

I'm skipping this combination for now in my tests to workaround the issue.

Feel free to close the issue. Thanks!

[jaraco]

Sphinx 4.1.2 has the same issue, and I can't use 4.2.0 due to a bug in that release that I'll report shortly. I was only able to run using sphinx<4.2 and python<3.10.

[tk0miya]

Now we don't have enough resources to maintain old versions. At present, we've supported the latest version only. So I'm closing this now.
Thanks,