python-httpcore fails to build with Python 3.14.0a6.

____________________ ERROR collecting tests/test_models.py _____________________
tests/test_models.py:5: in <module>
    import httpcore
httpcore/__init__.py:140: in <module>
    setattr(__locals[__name], "__module__", "httpcore")  # noqa
E   AttributeError: 'typing.Union' object has no attribute '__module__' and no __dict__ for setting new attributes. Did you mean: '__reduce__'?

https://docs.python.org/3.14/whatsnew/3.14.html:
The internal class typing._UnionGenericAlias is no longer used to implement typing.Union. To preserve compatibility with users using this private class, a compatibility shim will be provided until at least Python 3.17. (Contributed by Jelle Zijlstra in gh-105499.)

For the build logs, see:
https://copr-be.cloud.fedoraproject.org/results/@python/python3.14/fedora-rawhide-x86_64/08783420-python-httpcore/

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

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.