Fix undefined name sre_constants in Python 3.11

[cclauss]

#546 (comment)

@gopackgo90 Your review, please.

Description

Related Issue

Motivation and Context

How Has This Been Tested?

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• My change requires a change to the dependencies
• I have updated the dependencies accordingly
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

[Pierre-Sassoulas]

There's still a warning in 3.11:

tests/execution/test_execution.py::test_non_subpath
  module 'sre_constants' is deprecated

[cclauss]

Good catch. Thanks.

[Pierre-Sassoulas]

👍

[gopackgo90]

I'm a little surprised this works on Python < 3.11, because on my own system, doing this sort of import doesn't work for me on Python 3.8:

$ python
Python 3.8.13 (default, Aug 16 2022, 12:16:29) 
[GCC 9.3.1 20200408 (Red Hat 9.3.1-2)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import re._constants
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ModuleNotFoundError: No module named 're._constants'; 're' is not a package

I had anticipated a fix would be to do conditional imports like either jwilk/pydiatra@b69f3fc or The-Compiler/hypothesis@66ca462.

[cclauss]

Interesting because the CPython change that you highlighted was from 2008 (Python 3.0.0) which proceeds by a decade

• https://devguide.python.org/versions

The changes made work like this...

>>> import re
>>> re._constants
<module 're._constants' from '/opt/homebrew/Cellar/python@3.11/3.11.0/Frameworks/Python.framework/Versions/3.11/lib/python3.11/re/_constants.py'>

[gopackgo90]

Doing the import that way on Python 3.8 I get:

$ python
Python 3.8.13 (default, Aug 16 2022, 12:16:29) 
[GCC 9.3.1 20200408 (Red Hat 9.3.1-2)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import re
>>> re._constants
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: module 're' has no attribute '_constants'

[Pierre-Sassoulas]

The tests are green, but maybe this file isn't even imported ?

[cclauss]

Or the two exceptions are never triggered.