python-m2r fails to build with Python 3.10.0a3.

Traceback (most recent call last):
  File "/builddir/build/BUILD/m2r-66f4a5a500cdd9fc59085106bff082c9cadafaf3/setup.py", line 15, in <module>
    readme = parse_from_file(readme_file)
  File "/builddir/build/BUILD/m2r-66f4a5a500cdd9fc59085106bff082c9cadafaf3/m2r.py", line 674, in parse_from_file
    output = convert(src, **kwargs)
  File "/builddir/build/BUILD/m2r-66f4a5a500cdd9fc59085106bff082c9cadafaf3/m2r.py", line 666, in convert
    return M2R(**kwargs)(text)
  File "mistune.py", line 970, in mistune.Markdown.__call__
    return self.parse(text)
  File "/builddir/build/BUILD/m2r-66f4a5a500cdd9fc59085106bff082c9cadafaf3/m2r.py", line 524, in parse
    output = super(M2R, self).parse(text)
  File "mistune.py", line 980, in mistune.Markdown.parse
    out = self.output(preprocessing(text))
  File "mistune.py", line 1022, in mistune.Markdown.output
    self.tokens = self.block(text, rules)
  File "mistune.py", line 205, in mistune.BlockLexer.__call__
    return self.parse(text, rules)
  File "mistune.py", line 224, in mistune.BlockLexer.parse
    m = manipulate(text)
  File "mistune.py", line 216, in mistune.BlockLexer.parse.manipulate
    m = rule.match(text)
SystemError: /builddir/build/BUILD/Python-3.10.0a3/Python/getargs.c:2035: bad argument to internal function

For the build logs, see:
https://copr-be.cloud.fedoraproject.org/results/@python/python3.10/fedora-rawhide-x86_64/01827124-python-m2r/

For all our attempts to build python-m2r with Python 3.10, see:
https://copr.fedorainfracloud.org/coprs/g/python/python3.10/package/python-m2r/

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.