onnx fails to build with Python 3.14.0b1.

The error comes from protobuf which doesn't work with Python 3.14 - it's reported in https://bugzilla.redhat.com/show_bug.cgi?id=2343969 but as we approach mass rebuild, I decided to raise this also with some of the dependent packages to increase visibility of the issue.

Traceback (most recent call last):
  File "/builddir/build/BUILD/onnx-1.17.0-build/onnx-1.17.0/redhat-linux-build/tools/protoc-gen-mypy.py", line 29, in <module>
    import google.protobuf.descriptor_pb2 as d_typed
  File "/usr/lib64/python3.14/site-packages/google/protobuf/descriptor_pb2.py", line 5, in <module>
    from google.protobuf import descriptor as _descriptor
  File "/usr/lib64/python3.14/site-packages/google/protobuf/descriptor.py", line 47, in <module>
    from google.protobuf.pyext import _message
TypeError: Metaclasses with custom tp_new are not supported.

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-b1/fedora-rawhide-x86_64/09037354-onnx/

For all our attempts to build onnx with Python 3.14, see:
https://copr.fedorainfracloud.org/coprs/g/python/python3.14-b1/package/onnx/

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-b1/

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.