I think we're about to hear about this: setuptools 78.0.0, released yesterday, no longer allows dashes in keys in setup.cfg: https://setuptools.pypa.io/en/stable/history.html#v78-0-0
The pyspark packaging has 'description-file' instead of 'description_file' in its setup.cfg, and so will not install. This was addressed for Spark 4.0 in https://issues.apache.org/jira/browse/SPARK-45994 I think this just needs to be backported, but, it'll be kind of unfortunate because older releases won't install, I think.
