Remove explicit six dependency

[damccorm]

What happened?

Python tests have been failing on master for the last 18 hours - https://github.com/apache/beam/actions/workflows/python_tests.yml?query=branch%3Amaster - usually on the wordcount tests

Example link: https://github.com/apache/beam/actions/runs/3579807043

Looks like the first failure is https://github.com/apache/beam/actions/runs/3578786077

Issue Failure

Failure: Test is continually failing

Issue Priority

Priority: 1

Issue Component

Component: sdk-py-core

[damccorm]

Error is:

× python setup.py egg_info did not run successfully.
  │ exit code: 1
  ╰─> [18 lines of output]
      org/apache/beam/model/interactive/v1/beam_interactive_api.proto:36:1: warning: Import google/protobuf/timestamp.proto is unused.
      Traceback (most recent call last):
        File "/opt/hostedtoolcache/Python/3.10.8/x64/bin/protoc-gen-mypy", line 5, in <module>
          from mypy_protobuf import main
        File "/opt/hostedtoolcache/Python/3.10.8/x64/lib/python3.10/site-packages/mypy_protobuf.py", line 14, in <module>
          import six
      ModuleNotFoundError: No module named 'six'
      --mypy_out: protoc-gen-mypy: Plugin failed with status code 1.
      Traceback (most recent call last):
        File "<string>", line 2, in <module>
        File "<pip-setuptools-caller>", line [34](https://github.com/apache/beam/actions/runs/3585105935/jobs/6032653050#step:5:35), in <module>
        File "/home/runner/work/beam/beam/sdks/python/setup.py", line 180, in <module>
          generate_protos_first()
        File "/home/runner/work/beam/beam/sdks/python/setup.py", line 150, in generate_protos_first
          gen_protos.generate_proto_files()
        File "/home/runner/work/beam/beam/sdks/python/gen_protos.py", line 523, in generate_proto_files
          raise RuntimeError(
      RuntimeError: Protoc returned non-zero status (see logs for details): 1
      [end of output]

[damccorm]

Looks like its succeeding on mac, but failing on windows/linux

[AnandInguva]

This happens because of pip install -r build-requiremenets.txt.

Comparing passing build vs failing build, six is not getting installed in the failing build during this step. May be one of the dependencies might have removed six as transitive dep? I will dig more.

[AnandInguva]

For the passing build, grpcio was 1.50.0 and for the failing build, it picks up grpcio==1.51.1. The latest version removed six as its transitive dependency.

I will raise a PR to pin the grpcio version to 1.50.0 or better, we could install six without pinning version on grpcio

[damccorm]

Reopening since we should eventually remove this dependency entirely when the problem is fixed upstream per @AnandInguva

[tvalentyn]

was the issue reported upstream?

[AnandInguva]

mypy-protobuf 2.0 removed the dependency on six[1] but in our build we install mypy-protobuf==1.18 which depends on six.

six was installed as a transitive dependency of grpcio-tools==1.37.0 --> grpcio==1.50.0 --> six but yesterday grpcio new version has been released and it doesn't depend on six.

So, for a more concrete fix we should update mypy-protobuf>=2.0.0.

[1] https://github.com/nipunn1313/mypy-protobuf/blob/7692825cfcf7ef82f2428aaa40e78fb0ba449379/CHANGELOG.md?plain=1#L187

[AnandInguva]

This can be picked up during fixit week.