How to fix grpc compilation error for protoc mismatch?

Question

What are you supposed to do to fix this grpc compilation error?

#10 629.8 [ 64%] Building CXX object CMakeFiles/grpc++_reflection.dir/gens/src/proto/grpc/reflection/v1alpha/reflection.pb.cc.o
#10 629.8 /usr/bin/x86_64-linux-gnu-g++  -DCARES_STATICLIB -D__CLANG_SUPPORT_DYN_ANNOTATION__ -I/home/src/third_party/zlib -I/home/src/include -I/home/src -I/home/src/third_party/address_sorting/include -I/home/src/third_party/boringssl-with-bazel/src/include -I/home/src/src/core/ext/upb-generated -I/home/i
nfinera/src/third_party/upb -I/home/src/build/x86_64/third_party/zlib -I/home/src/build/x86_64/gens -I/home/src/third_party/protobuf/src -I/home/src/build/x86_64/third_party/cares/cares -I/home/src/third_party/cares/cares -I/home/src/third_party/abseil-cpp  -fPIC   -std=c++11 -o CMakeFiles/grpc++_reflection
.dir/gens/src/proto/grpc/reflection/v1alpha/reflection.pb.cc.o -c /home/src/build/x86_64/gens/src/proto/grpc/reflection/v1alpha/reflection.pb.cc
#10 629.8 In file included from /home/src/build/x86_64/gens/src/proto/grpc/reflection/v1alpha/reflection.pb.cc:4:
#10 629.8 /home/src/build/x86_64/gens/src/proto/grpc/reflection/v1alpha/reflection.pb.h:12:2: error: #error This file was generated by a newer version of protoc which is
#10 629.8  #error This file was generated by a newer version of protoc which is
#10 629.8   ^~~~~
#10 629.8 /home/src/build/x86_64/gens/src/proto/grpc/reflection/v1alpha/reflection.pb.h:13:2: error: #error incompatible with your Protocol Buffer headers. Please update
#10 629.8  #error incompatible with your Protocol Buffer headers. Please update
#10 629.8   ^~~~~
#10 629.8 /home/src/build/x86_64/gens/src/proto/grpc/reflection/v1alpha/reflection.pb.h:14:2: error: #error your headers.
#10 629.8  #error your headers.
#10 629.8   ^~~~~

The timestamp prefixes are 'cuz this is running in a docker build.

I don't really understand what the pragma error is trying to tell me.

This file was generated by a newer version of protoc

Ok.

which is incompatible with your Protocol Buffer headers.

That sucks.

Please update your headers.

Umm...isn't the arrangement that I just run cmake and make to build your project? What exactly do I need to do to grpc's header files to "update" them?

How I build (paraphrased from a Dockerfile ):

mkdir -p /home/src && cd /home/src
git clone --branch v1.30.0 https://github.com/grpc/grpc.git ./
git submodule update --init --recursive
mkdir -p /home/src/build/x86_64 && cd /home/src/build/x86_64
cmake ../..
make

Answer 1

Just run make with the grpc project root Makefile .

https://chromium.googlesource.com/external/github.com/grpc/grpc/+/v1.14.0/BUILDING.md

Notably, among the combinations of build systems and OSes, the combination of cmake and Unix/Linux is not listed.

Not an answer for how to fix the CMake-based build, which is what I'd have liked ideally, but maybe sometimes just take the damn path of least resistance.