powerline fails to build with Python 3.14.0a3.

Running Sphinx v7.3.7

Traceback (most recent call last):
  File "/usr/lib/python3.14/site-packages/sphinx/config.py", line 509, in eval_config_file
    exec(code, namespace)  # NoQA: S102
    ~~~~^^^^^^^^^^^^^^^^^
  File "/builddir/build/BUILD/powerline-2.8.4-build/powerline-2.8.4/docs/source/conf.py", line 43, in <module>
    parser = get_argparser()
  File "/builddir/build/BUILD/powerline-2.8.4-build/powerline-2.8.4/powerline/commands/daemon.py", line 21, in get_argparser
    replace_group = exclusive_group.add_argument_group()
  File "/usr/lib64/python3.14/argparse.py", line 1712, in add_argument_group
    raise ValueError('argument groups cannot be nested')
ValueError: argument groups cannot be nested

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/usr/lib/python3.14/site-packages/sphinx/cmd/build.py", line 332, in build_main
    app = Sphinx(args.sourcedir, args.confdir, args.outputdir,
                 args.doctreedir, args.builder, args.confoverrides, args.status,
                 args.warning, args.freshenv, args.warningiserror,
                 args.tags, args.verbosity, args.jobs, args.keep_going,
                 args.pdb)
  File "/usr/lib/python3.14/site-packages/sphinx/application.py", line 211, in __init__
    self.config = Config.read(self.confdir, confoverrides or {}, self.tags)
                  ~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.14/site-packages/sphinx/config.py", line 309, in read
    namespace = eval_config_file(filename, tags)
  File "/usr/lib/python3.14/site-packages/sphinx/config.py", line 522, in eval_config_file
    raise ConfigError(msg % traceback.format_exc()) from exc
sphinx.errors.ConfigError: There is a programmable error in your configuration file:

Traceback (most recent call last):
  File "/usr/lib/python3.14/site-packages/sphinx/config.py", line 509, in eval_config_file
    exec(code, namespace)  # NoQA: S102
    ~~~~^^^^^^^^^^^^^^^^^
  File "/builddir/build/BUILD/powerline-2.8.4-build/powerline-2.8.4/docs/source/conf.py", line 43, in <module>
    parser = get_argparser()
  File "/builddir/build/BUILD/powerline-2.8.4-build/powerline-2.8.4/powerline/commands/daemon.py", line 21, in get_argparser
    replace_group = exclusive_group.add_argument_group()
  File "/usr/lib64/python3.14/argparse.py", line 1712, in add_argument_group
    raise ValueError('argument groups cannot be nested')
ValueError: argument groups cannot be nested


Configuration error:
There is a programmable error in your configuration file:

Traceback (most recent call last):
  File "/usr/lib/python3.14/site-packages/sphinx/config.py", line 509, in eval_config_file
    exec(code, namespace)  # NoQA: S102
    ~~~~^^^^^^^^^^^^^^^^^
  File "/builddir/build/BUILD/powerline-2.8.4-build/powerline-2.8.4/docs/source/conf.py", line 43, in <module>
    parser = get_argparser()
  File "/builddir/build/BUILD/powerline-2.8.4-build/powerline-2.8.4/powerline/commands/daemon.py", line 21, in get_argparser
    replace_group = exclusive_group.add_argument_group()
  File "/usr/lib64/python3.14/argparse.py", line 1712, in add_argument_group
    raise ValueError('argument groups cannot be nested')
ValueError: argument groups cannot be nested

https://docs.python.org/3.14/whatsnew/3.14.html

For the build logs, see:
https://copr-be.cloud.fedoraproject.org/results/@python/python3.14/fedora-rawhide-x86_64/08480159-powerline/

For all our attempts to build powerline with Python 3.14, see:
https://copr.fedorainfracloud.org/coprs/g/python/python3.14/package/powerline/

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 3.14:
https://copr.fedorainfracloud.org/coprs/g/python/python3.14/

Let us know here if you have any questions.

Python 3.14 is planned to be included in Fedora 43.
To make that update smoother, we're building Fedora packages with all pre-releases of Python 3.14.
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.