python-pydantic fails to build with Python 3.10.0a5.

Traceback (most recent call last):
  File "/builddir/build/BUILD/pydantic-1.6.1/setup.py", line 94, in <module>
    setup(
  File "/usr/lib/python3.10/site-packages/setuptools/__init__.py", line 153, in setup
    return distutils.core.setup(**attrs)
  File "/usr/lib64/python3.10/distutils/core.py", line 148, in setup
    dist.run_commands()
  File "/usr/lib64/python3.10/distutils/dist.py", line 966, in run_commands
    self.run_command(cmd)
  File "/usr/lib64/python3.10/distutils/dist.py", line 985, in run_command
    cmd_obj.run()
  File "/usr/lib/python3.10/site-packages/setuptools/command/test.py", line 232, in run
    self.run_tests()
  File "/usr/lib/python3.10/site-packages/setuptools/command/test.py", line 250, in run_tests
    test = unittest.main(
  File "/usr/lib64/python3.10/unittest/main.py", line 100, in __init__
    self.parseArgs(argv)
  File "/usr/lib64/python3.10/unittest/main.py", line 124, in parseArgs
    self._do_discovery(argv[2:])
  File "/usr/lib64/python3.10/unittest/main.py", line 244, in _do_discovery
    self.createTests(from_discovery=True, Loader=Loader)
  File "/usr/lib64/python3.10/unittest/main.py", line 154, in createTests
    self.test = loader.discover(self.start, self.pattern, self.top)
  File "/usr/lib64/python3.10/unittest/loader.py", line 349, in discover
    tests = list(self._find_tests(start_dir, pattern))
  File "/usr/lib64/python3.10/unittest/loader.py", line 405, in _find_tests
    tests, should_recurse = self._find_test_path(
  File "/usr/lib64/python3.10/unittest/loader.py", line 483, in _find_test_path
    tests = self.loadTestsFromModule(package, pattern=pattern)
  File "/usr/lib/python3.10/site-packages/setuptools/command/test.py", line 50, in loadTestsFromModule
    tests.append(self.loadTestsFromName(submodule))
  File "/usr/lib64/python3.10/unittest/loader.py", line 154, in loadTestsFromName
    module = __import__(module_name)
  File "/builddir/build/BUILD/pydantic-1.6.1/tests/try_assert.py", line 4, in <module>
    from pydantic import BaseModel, ValidationError, validator
  File "/builddir/build/BUILD/pydantic-1.6.1/pydantic/__init__.py", line 2, in <module>
    from . import dataclasses
  File "/builddir/build/BUILD/pydantic-1.6.1/pydantic/dataclasses.py", line 7, in <module>
    from .main import create_model, validate_model
  File "/builddir/build/BUILD/pydantic-1.6.1/pydantic/main.py", line 315, in <module>
    class BaseModel(Representation, metaclass=ModelMetaclass):
  File "/builddir/build/BUILD/pydantic-1.6.1/pydantic/main.py", line 311, in __new__
    cls.__signature__ = ClassAttribute('__signature__', generate_model_signature(cls.__init__, fields, config))
  File "/builddir/build/BUILD/pydantic-1.6.1/pydantic/utils.py", line 183, in generate_model_signature
    if config.extra is config.extra.allow:
  File "/usr/lib64/python3.10/enum.py", line 146, in __get__
    raise AttributeError(
AttributeError: Extra: no attribute 'allow'

For the build logs, see:
https://copr-be.cloud.fedoraproject.org/results/@python/python3.10/fedora-rawhide-x86_64/01966388-python-pydantic/

For all our attempts to build python-pydantic with Python 3.10, see:
https://copr.fedorainfracloud.org/coprs/g/python/python3.10/package/python-pydantic/

Testing and mass rebuild of packages is happening in copr. You can follow these instructions to test locally in mock if your package builds with Python 3.10:
https://copr.fedorainfracloud.org/coprs/g/python/python3.10/

Let us know here if you have any questions.

Python 3.10 will be included in Fedora 35. To make that update smoother, we're building Fedora packages with early pre-releases of Python 3.10.
A build failure prevents us from testing all dependent packages (transitive [Build]Requires), so if this package is required a lot, it's important for us to get it fixed soon.
We'd appreciate help from the people who know this package best, but if you don't want to work on this now, let us know so we can try to work around it on our side.