How to Build Protobuf Python Package 3.21.12 with upb Implementation

[Evan Lu]

Dear Protobuf Community,

I am trying to build the Protobuf Python package (version 3.21.12) from source with the upb implementation. Previously, I built it with the C++ implementation using:

python3.10 setup.py install --cpp_implementation

Running the following check:

from google.protobuf.internal import api_implementation print(api_implementation.Type())

returns "cpp", which is expected.

However, when I install without specifying --cpp_implementation:

python3.10 setup.py install

api_implementation.Type() returns "python" instead of "upb".

Could you please advise on how to correctly build the package with the upb implementation?

Thanks in advance for your help!

Best regards,
Evan