I came across this trying to run mypy benchmarks. The version I had contained

class AugmentedHelpFormatter(argparse.RawDescriptionHelpFormatter):
    def __init__(self, prog: str) -> None:
        super().__init__(prog=prog, max_help_position=30)

Which was rewritten in a newer version to:

class AugmentedHelpFormatter(argparse.RawDescriptionHelpFormatter):
    def __init__(self, prog: str, **kwargs: Any) -> None:
        super().__init__(prog=prog, max_help_position=30, **kwargs)

The changes in #124456 and #132323 can be made without breaking user code, if they accept the new args as **kwargs, extract their values from kwargs if they are there, and continue working as before if not. Is there a good reason not to do this?

Do these changes currently comply with Python's backwards compatibility policy?

Linked PRs

• gh-133653: Fix subclassing HelpFormatter #133668
• gh-133653: Fix argparse.ArgumentParser with the formatter_class argument #133813
• [3.14] gh-133653: Fix argparse.ArgumentParser with the formatter_class argument (GH-133813) #133941