SystemError: extension module 'black' is already cached

[tyralla]

Unfortunately, I get this error only on AppVeyor and cannot reproduce it locally. It only happens under Python 3.13. According to their documentation, they recently switched from a release candidate to 3.13.1. I waited for this switch before filing this issue, but the problem remains.

Here is the complete traceback:

Traceback (most recent call last):
  File "C:\projects\hydpy-hep1s\prepare_build.py", line 258, in <module>
    main()  # pylint: disable=no-value-for-parameter
    ~~~~^^
  File "C:\Python313-x64\Lib\site-packages\click\core.py", line 1161, in __call__
    return self.main(*args, **kwargs)
           ~~~~~~~~~^^^^^^^^^^^^^^^^^
  File "C:\Python313-x64\Lib\site-packages\click\core.py", line 1082, in main
    rv = self.invoke(ctx)
  File "C:\Python313-x64\Lib\site-packages\click\core.py", line 1443, in invoke
    return ctx.invoke(self.callback, **ctx.params)
           ~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Python313-x64\Lib\site-packages\click\core.py", line 788, in invoke
    return __callback(*args, **kwargs)
  File "C:\projects\hydpy-hep1s\prepare_build.py", line 251, in main
    _convert_interfaces(fast_cython=fast_cython, profile_cython=profile_cython)
    ~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\projects\hydpy-hep1s\prepare_build.py", line 91, in _convert_interfaces
    from hydpy import config
  File "C:\projects\hydpy-hep1s\hydpy\__init__.py", line 21, in <module>
    from hydpy.core import pubtools
  File "C:\projects\hydpy-hep1s\hydpy\core\pubtools.py", line 10, in <module>
    from hydpy.core import exceptiontools
  File "C:\projects\hydpy-hep1s\hydpy\core\exceptiontools.py", line 10, in <module>
    from hydpy.core import objecttools
  File "C:\projects\hydpy-hep1s\hydpy\core\objecttools.py", line 18, in <module>
    import black
  File "<frozen importlib._bootstrap>", line 1360, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1331, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 921, in _load_unlocked
  File "<frozen importlib._bootstrap>", line 819, in module_from_spec
  File "<frozen importlib._bootstrap>", line 797, in _init_module_attrs
SystemError: extension module 'black' is already cached

pip-installed black version: 24.10.0

Any more information I can help with?

[hauntsaninja]

You maybe already know all of this, but just in case.... Black wheels are compiled with mypyc. I ran into this in a beta release of CPython 3.13 and it was fixed upstream, see python/mypy#17748. Could you confirm the Python version?

[tyralla]

Oh no, I should have checked more carefully before filing this issue. Despite the announced update to Python 3.13.1, AppVeyor's Visual Studio 2019 and 2022 images still contain version 3.13.0rc1 (tags/v3.13.0rc1:e4a3e78, Jul 31 2024, 20:58:38) [MSC v.1940 64 bit (AMD64)].

Thanks for the quick and helpful response!

In case anyone else encounters this problem, here is the link to the related AppVeyor discussion I just started: https://help.appveyor.com/discussions/problems/37742-python-3131