unittest import loop with pre-release Python #4376
Description
Filing this so it's recorded - at the moment a bit stumped.
In the last two Python 3.12 betas, the Platform unit tests fail on Windows with an import loop.
An unsubstantiated theory is that it's no longer possible to have a local module file named "posix". Standard library module names should be considered reserved. The case of posix is strange, it's a submodule of os with instructions never to import it directly:
This module provides access to operating system functionality that is standardized by the C Standard and the POSIX standard (a thinly disguised Unix interface).
Do not import this module directly Instead, import the module
os, which provides a portable version of this interface. On Unix, theosmodule provides a superset of theposixinterface. On non-Unix operating systems theposixmodule is not available, but a subset is always available through theosinterface.
Is it possible that changes to the import system and internal Python checks based on whether posix is available are now being fooled by us having imported our own posix module?
Anyway, here are the two fails showing the broken import chain:
15/1279 (1.17%) C:\Users\mats\AppData\Local\Programs\Python\Python312\python.exe SCons\Platform\PlatformTests.py
Traceback (most recent call last):
File "C:\Users\mats\Documents\github\scons\SCons\Platform\PlatformTests.py", line 25, in <module>
import unittest
File "C:\Users\mats\AppData\Local\Programs\Python\Python312\Lib\unittest\__init__.py", line 65, in <module>
from .loader import TestLoader, defaultTestLoader
File "C:\Users\mats\AppData\Local\Programs\Python\Python312\Lib\unittest\loader.py", line 10, in <module>
from fnmatch import fnmatch, fnmatchcase
File "C:\Users\mats\AppData\Local\Programs\Python\Python312\Lib\fnmatch.py", line 13, in <module>
import posixpath
File "<frozen importlib._bootstrap>", line 1266, in _find_and_load
File "<frozen importlib._bootstrap>", line 1237, in _find_and_load_unlocked
File "<frozen importlib._bootstrap>", line 841, in _load_unlocked
File "<frozen importlib._bootstrap>", line 1082, in exec_module
File "<frozen posixpath>", line 374, in <module>
File "C:\Users\mats\Documents\github\scons\SCons\Platform\posix.py", line 34, in <module>
from SCons.Platform import TempFileMunge
File "C:\Users\mats\Documents\github\scons\SCons\Platform\__init__.py", line 52, in <module>
import SCons.Tool
File "C:\Users\mats\Documents\github\scons\SCons\Tool\__init__.py", line 51, in <module>
from SCons.Tool.linkCommon import LibSymlinksActionFunction, LibSymlinksStrFun
File "C:\Users\mats\Documents\github\scons\SCons\Tool\linkCommon\__init__.py", line 30, in <module>
from SCons.Tool.DCommon import isD
File "C:\Users\mats\Documents\github\scons\SCons\Tool\DCommon.py", line 32, in <module>
from pathlib import Path
File "C:\Users\mats\AppData\Local\Programs\Python\Python312\Lib\pathlib.py", line 73, in <module>
_FNMATCH_PREFIX, _FNMATCH_SUFFIX = fnmatch.translate('_').split('_')
^^^^^^^^^^^^^^^^^
AttributeError: partially initialized module 'fnmatch' has no attribute 'translate' (most likely due to a circular import)
Test execution time: 0.8 seconds
16/1279 (1.25%) C:\Users\mats\AppData\Local\Programs\Python\Python312\python.exe SCons\Platform\virtualenvTests.py
Traceback (most recent call last):
File "C:\Users\mats\Documents\github\scons\SCons\Platform\virtualenvTests.py", line 25, in <module>
import unittest
File "C:\Users\mats\AppData\Local\Programs\Python\Python312\Lib\unittest\__init__.py", line 65, in <module>
from .loader import TestLoader, defaultTestLoader
File "C:\Users\mats\AppData\Local\Programs\Python\Python312\Lib\unittest\loader.py", line 10, in <module>
from fnmatch import fnmatch, fnmatchcase
File "C:\Users\mats\AppData\Local\Programs\Python\Python312\Lib\fnmatch.py", line 13, in <module>
import posixpath
File "<frozen importlib._bootstrap>", line 1266, in _find_and_load
File "<frozen importlib._bootstrap>", line 1237, in _find_and_load_unlocked
File "<frozen importlib._bootstrap>", line 841, in _load_unlocked
File "<frozen importlib._bootstrap>", line 1082, in exec_module
File "<frozen posixpath>", line 374, in <module>
File "C:\Users\mats\Documents\github\scons\SCons\Platform\posix.py", line 34, in <module>
from SCons.Platform import TempFileMunge
File "C:\Users\mats\Documents\github\scons\SCons\Platform\__init__.py", line 52, in <module>
import SCons.Tool
File "C:\Users\mats\Documents\github\scons\SCons\Tool\__init__.py", line 51, in <module>
from SCons.Tool.linkCommon import LibSymlinksActionFunction, LibSymlinksStrFun
File "C:\Users\mats\Documents\github\scons\SCons\Tool\linkCommon\__init__.py", line 30, in <module>
from SCons.Tool.DCommon import isD
File "C:\Users\mats\Documents\github\scons\SCons\Tool\DCommon.py", line 32, in <module>
from pathlib import Path
File "C:\Users\mats\AppData\Local\Programs\Python\Python312\Lib\pathlib.py", line 73, in <module>
_FNMATCH_PREFIX, _FNMATCH_SUFFIX = fnmatch.translate('_').split('_')
^^^^^^^^^^^^^^^^^
AttributeError: partially initialized module 'fnmatch' has no attribute 'translate' (most likely due to a circular import)