Problems to generate googleapis gRPC source code about cpp-samples

[coryan]

Looks like you are using an old version of protoc. I cannot remember if the php stuff was introduced in 3.5 or 3.4, I would go with 3.5.

[jerrychang1243]

@coryan
My protoc version is 3.5.1

[coryan]

Sorry for the delay, I was busy with my full-time job. You are correct, googleapis does not compile with protobuf v3.5.1 or v3.5.2, which is the default version used by gRPC. googleapis recently introduced proto files that use the php_metadata_namespace, for example here:

https://github.com/googleapis/googleapis/blob/288ebfec039030c7dd9de05b73879634b72e0dc4/google/ads/googleads/v0/enums/day_of_week.proto#L29

while support for that option was added to protobuf here:

protocolbuffers/protobuf#4609

That pull request made it to protobuf-3.6.1.

We should change the documentation and code to require protobuf >= 3.6.1.

I am attaching a Dockerfile that can be used to reproduce the problem (with --build-arg=PBVER=3.5.2) and verify that it works with the newer version (with --build-arg=PBVER=3.6.1).

/cc: @SurferJeffAtGoogle

[coryan]

For what is worth, the gRPC folks recently upgraded to protobuf-3.6.1:

grpc/grpc@50b684a

I think that should have fixed this problem too.

[tmatsuo]

@jerrychang1243 I think we can close this issue, but feel free to reopen.