RichHelpFormatter not working on Python 3.14.0b1

[tleonhardt]

I help maintain the cmd2 open-source library and for the next version we have been working on incorporating rich-argparse to make our help output more aesthetically pleasing.

We recently added testing for Python 3.14-dev to our GitHub Actions CI workflow and we are getting numerous unit test errors related to RichHelpFormatter. The errors all look like the following

/opt/hostedtoolcache/Python/3.14.0-beta.1/x64/lib/python3.14/argparse.py:2729: in _get_formatter
    return self.formatter_class(
E   TypeError: RichHelpFormatter.__init__() got an unexpected keyword argument 'prefix_chars'

Looking at the argparse documentation for Python 3.14, I highly suspect this deprecation notice may be of relevance here:

Deprecated since version 3.14: Passing prefix_chars to add_argument_group() is now deprecated.

[hamdanal]

This is a regression in the first beta of Python 3.14, it is already fixed on their main branch and the fix will be available for Python 3.14.0b2. To unblock CI now, please update rich-argparse to version 1.7.1 which I just uploaded to PyPI with the fix in #162.

[tleonhardt]

@hamdanal Thanks for your quick response and fix. Much appreciated. Feel free to close this from my perspective.