python3.9 - TypeError: __new__() missing 2 required positional arguments: 'bases' and 'classdict'

[bachradsusi]

Fedora Python team started to build tools with Python3.9. SETools builds find with it, but it can't be used due to the following backtrace:

# seinfo
Traceback (most recent call last):
  File "/usr/bin/seinfo", line 21, in <module>
    import setools
  File "/usr/lib64/python3.9/site-packages/setools/__init__.py", line 79, in <module>
    from .diff import PolicyDifference
  File "/usr/lib64/python3.9/site-packages/setools/diff/__init__.py", line 37, in <module>
    from .terules import TERulesDifference
  File "/usr/lib64/python3.9/site-packages/setools/diff/terules.py", line 201, in <module>
    class TERulesDifference(Difference):
  File "/usr/lib64/python3.9/site-packages/setools/diff/terules.py", line 208, in TERulesDifference
    diff_allows = av_diff_template("allow")
  File "/usr/lib64/python3.9/site-packages/setools/diff/terules.py", line 71, in av_diff_template
    ruletype = TERuletype.lookup(ruletype)
  File "setools/policyrep/util.pxi", line 59, in setools.policyrep.PolicyEnum.lookup
TypeError: __new__() missing 2 required positional arguments: 'bases' and 'classdict'

Originally reported in Fedora bug - https://bugzilla.redhat.com/show_bug.cgi?id=1813076#c2

[pebenito]

Seems like it is a cython issue, as setools.policyrep.PolicyEnum.lookup is a @classmethod. There is no explicit __new__ method in the SETools code.

[bachradsusi]

Reported on cython https://bugzilla.redhat.com/show_bug.cgi?id=1788506 cython/cython#3349