Unhelpful error message when wrong version of protobuf

[WilliamTambellini]

Hi
Menoh fails to compile probably because my local protobuf is too old :

$ cmake
...
-- Found Protobuf: /usr/lib64/libprotobuf.so;-lpthread (found version "2.5.0")
-- Found Protobuf: /usr/lib64/libprotobuf.so;-lpthread;-lpthread (found version "2.5.0")
...
cmake exits successfully

$ make
Scanning dependencies of target gen_onnx_proto
[ 1%] Running gen_proto.py on onnx/onnx.in.proto
Processing /home/wtambellini/repos/menoh/external/onnx/onnx/onnx.in.proto
Writing /home/wtambellini/repos/menoh/Debug/external/onnx/onnx/onnx.proto
Writing /home/wtambellini/repos/menoh/Debug/external/onnx/onnx/onnx.proto3
generating /home/wtambellini/repos/menoh/Debug/external/onnx/onnx/onnx_pb.py
[ 2%] Running C++ protocol buffer compiler on /home/wtambellini/repos/menoh/Debug/external/onnx/onnx/onnx.proto
onnx/onnx.proto:393:5: Expected "required", "optional", or "repeated".
onnx/onnx.proto:393:17: Missing field number.
onnx/onnx.proto:420:3: Expected "required", "optional", or "repeated".
onnx/onnx.proto:420:15: Missing field number.
make[2]: *** [external/onnx/onnx/onnx.pb.cc] Error 1
make[1]: *** [external/onnx/CMakeFiles/gen_onnx_proto.dir/all] Error 2
make: *** [all] Error 2

Yes, I know the md doc state protobuf 2.6.1, but should nt cmake simply assert/check the version of protoc/protobuf ?

I see in the main cmake :
find_package(Protobuf ${PROTOBUF_VERSION} REQUIRED)

but PROTOBUF_VERSION is not set so empty so not imposing any minimum version.
I could prepare a PR if you re ok to check protobuf version at cmake time.
Kind

[okdshin]

Thank you for your report @WilliamTambellini and sorry for the trouble.
Checking at cmake time is suitable. We would like to take your PR.

[WilliamTambellini]

ok I ll prepare a PR.