fix: increase minimum protobuf version to 6.31.1

[khneal]

What

Increase the minimum version of package "protobuf" to 6.31.1

Why

Using an older (lower) version of protobuf causes a runtime error.

To reproduce:

$ uv venv
...
$ uv pip install "pynumaflow @ git+https://github.com/numaproj/numaflow-python.git@v0.12.1#subdirectory=packages/pynumaflow"
...
$ uv pip install protobuf==6.31.0
...
$ uv run python -c "import pynumaflow.sinker"
Traceback (most recent call last):
  File "<string>", line 1, in <module>
    import pynumaflow.sinker
  File "/.../.venv/lib/python3.14/site-packages/pynumaflow/sinker/__init__.py", line 1, in <module>
    from pynumaflow.sinker.async_server import SinkAsyncServer
  File "/.../.venv/lib/python3.14/site-packages/pynumaflow/sinker/async_server.py", line 7, in <module>
    from pynumaflow.sinker.servicer.async_servicer import AsyncSinkServicer
  File "/.../.venv/lib/python3.14/site-packages/pynumaflow/sinker/servicer/async_servicer.py", line 5, in <module>
    from pynumaflow.shared.asynciter import NonBlockingIterator
  File "/.../.venv/lib/python3.14/site-packages/pynumaflow/shared/__init__.py", line 1, in <module>
    from pynumaflow.shared.server import NumaflowServer
  File "/.../.venv/lib/python3.14/site-packages/pynumaflow/shared/server.py", line 32, in <module>
    from pynumaflow.proto.mapper import map_pb2_grpc
  File "/.../.venv/lib/python3.14/site-packages/pynumaflow/proto/mapper/map_pb2_grpc.py", line 7, in <module>
    from pynumaflow.proto.mapper import map_pb2 as pynumaflow_dot_proto_dot_mapper_dot_map__pb2
  File "/.../.venv/lib/python3.14/site-packages/pynumaflow/proto/mapper/map_pb2.py", line 12, in <module>
    _runtime_version.ValidateProtobufRuntimeVersion(
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^
        _runtime_version.Domain.PUBLIC,
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    ...<4 lines>...
        'pynumaflow/proto/mapper/map.proto'
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
  File "/.../.venv/lib/python3.14/site-packages/google/protobuf/runtime_version.py", line 113, in ValidateProtobufRuntimeVersion
    _ReportVersionError(
    ~~~~~~~~~~~~~~~~~~~^
        'Detected incompatible Protobuf Gencode/Runtime versions when loading'
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        f' {location}: gencode {gen_version} runtime {version}. Runtime version'
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        f' cannot be older than the linked gencode version. {error_prompt}'
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
  File "/.../.venv/lib/python3.14/site-packages/google/protobuf/runtime_version.py", line 50, in _ReportVersionError
    raise VersionError(msg)
google.protobuf.runtime_version.VersionError: Detected incompatible Protobuf Gencode/Runtime versions when loading pynumaflow/proto/mapper/map.proto: gencode 6.31.1 runtime 6.31.0. Runtime version cannot be older than the linked gencode version. See Protobuf version guarantees at https://protobuf.dev/support/cross-version-runtime-guarantee.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 94.00%. Comparing base (5877fa8) to head (e0be6bf).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #318   +/-   ##
=======================================
  Coverage   94.00%   94.00%           
=======================================
  Files          66       66           
  Lines        3087     3087           
  Branches      156      156           
=======================================
  Hits         2902     2902           
  Misses        138      138           
  Partials       47       47           

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[vigith]

i am not sure why our grpc server fails with 6.31.0 while 6.31.1 works; as per https://protobuf.dev/support/cross-version-runtime-guarantee/ (except for cpp and rust) they are compatible across minor versions

@BulkBeing, could you please take a look into this?

[khneal]

It appears you used 6.31.1 to generate the code, so it requires at least that version of runtime.
From the page you linked:

New Gencode + Old Runtime = Never Allowed

We may add new runtime APIs in any kind of release (Major, Minor, or Patch). Gencode in that release is allowed to use those new APIs. The consequence is that gencode should never be paired with a runtime that predates the protoc and plugin that was used to generate those bindings.

[vigith]

We use python grpc_tools.protoc to compile proto. We haven't updated those packages (grpcio and grpcio-tools) in a while.

[khneal]

I see several files were updated in this PR from "Protobuf Python Version: 4.25.1" to "Protobuf Python Version: 6.31.1":
https://github.com/numaproj/numaflow-python/pull/250/changes#diff-e63ec56ffe8112f354bb57291ab232155bea9ec15e62c6db29aa697c08a092ab

[vigith]

@kohlisid/@BulkBeing, should we rollback our proto files or go ahead with bumping up protobuf?

[kohlisid]

I think we should bump the proto up @vigith
With newer versions of other libs using grpc, we will see more mistmatches later

[vigith]

thank you @khneal, i opened an issue (#319) to catch these in CI