Bug 2356165

Summary: protobuf with Python 3.14: TypeError: Metaclasses with custom tp_new are not supported.
Product: [Fedora] Fedora Reporter: Karolina Surma <ksurma>
Component: protobufAssignee: Michel Lind <michel>
Status: CLOSED DUPLICATE QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: rawhideCC: adrian, code, igor.raits, jonathan, ksurma, mhroncok, michel, mizdebsk, msaulnier, orion, sander
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Last Closed: 2025-05-14 08:47:31 UTC Type: Bug
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Bug Blocks: 2322407    

Description Karolina Surma 2025-03-31 08:29:24 UTC
protobuf itself has built successfully with Python 3.14, but the dependent packages trying to import `from google.protobuf.pyext import _message` fail.

An example below:

______________ ERROR collecting lib/carbon/tests/test_service.py _______________
lib/carbon/tests/test_service.py:6: in <module>
    from carbon.service import CarbonRootService, setupPipeline
lib/carbon/service.py:40: in <module>
    import carbon.protobuf  # NOQA
lib/carbon/protobuf.py:6: in <module>
    from carbon.carbon_pb2 import Payload
lib/carbon/carbon_pb2.py:5: in <module>
    from google.protobuf import descriptor as _descriptor
/usr/lib64/python3.14/site-packages/google/protobuf/descriptor.py:47: in <module>
    from google.protobuf.pyext import _message
E   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/fedora-rawhide-x86_64/08837300-python-carbon/

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

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.

Comment 1 Karolina Surma 2025-05-14 08:47:31 UTC

*** This bug has been marked as a duplicate of bug 2343969 ***