DNN module build failed with PROTOBUF_UPDATE_FILES

[smartnet-club]

• OpenCV => 4.2.0
• Operating System / Platform => Linux acer 4.15.0-74-generic fixed android warnings #83~16.04.1-Ubuntu SMP Wed Dec 18 04:56:23 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux
• Compiler => gcc (Ubuntu 6.5.0-2ubuntu1~16.04) 6.5.0 20181026

Detailed description

error: opencv-caffe.pb.h not found

Steps to reproduce

build with:
-DWITH_PROTOBUF:BOOL=ON
-DBUILD_PROTOBUF:BOOL=FALSE
-DPROTOBUF_UPDATE_FILES:BOOL=ON
-DOPENCV_DNN_EXTERNAL_PROTOBUF:BOOL=ON

to fix
in dnn/CMakeLists.txt

file(GLOB proto_files "${CMAKE_CURRENT_LIST_DIR}/src/tensorflow/*.proto" "${CMAKE_CURRENT_LIST_DIR}/src/caffe/opencv-caffe.proto" "${CMAKE_CURRENT_LIST_DIR}/src/onnx/opencv-onnx.proto")
set(PROTOBUF_GENERATE_CPP_APPEND_PATH ON) # required for tensorflow
protobuf_generate_cpp(fw_srcs fw_hdrs ${proto_files})
set(fw_inc "${CMAKE_CURRENT_BINARY_DIR}/src/caffe" "${CMAKE_CURRENT_BINARY_DIR}/src/tensorflow" "${CMAKE_CURRENT_BINARY_DIR}/src/onnx")

[alalek]

-DBUILD_PROTOBUF:BOOL=FALSE
-DPROTOBUF_UPDATE_FILES:BOOL=ON

Not compatible set of values (misused).

Valid parameters values are (should work always):

• default: -DBUILD_PROTOBUF=ON -DPROTOBUF_UPDATE_FILES=OFF
• or upgrade mode: -DBUILD_PROTOBUF=OFF -DPROTOBUF_UPDATE_FILES=ON

This set of values is non reliable (you must have the same protobuf version as builtin OpenCV - unlikely)

• -DBUILD_PROTOBUF=OFF -DPROTOBUF_UPDATE_FILES=OFF

BTW, always cleanup your build folder if you are playing with CMake build options - build from scratch.

---

duplicate of opencv/opencv#16312

[smartnet-club]

default Protobuf versions of latest OpenCV and latest Tensorflow are incompatible.

[alalek]

So, which error message is observed?

[smartnet-club]

opencv-caffe.pb.h not found
It needs to specify include path to generated files

[alalek]

default
opencv-caffe.pb.h not found

Please recheck that this code has been executed in "default" configuration (PROTOBUF_UPDATE_FILES=OFF).

If so, then dump complete failed compiler command line parameters and its output (make VERBOSE=1 should help).

[smartnet-club]

If I set PROTOBUF_UPDATE_FILES=OFF the error will be This file was generated by an older version of protoc because I use external newer version of Protobuf (v3.11.2)
I've already patched code by set(fw_inc "${CMAKE_CURRENT_BINARY_DIR}/src/caffe" "${CMAKE_CURRENT_BINARY_DIR}/src/tensorflow" "${CMAKE_CURRENT_BINARY_DIR}/src/onnx") and finished work. So can't make complete dump.

[smartnet-club]

The error also in protobuf-config.cmake

They set list(APPEND _generated_srcs "${protobuf_generate_PROTOC_OUT_DIR}/${_rel_dir}/${_basename}${_ext}")
but generate into ARGS --${protobuf_generate_LANGUAGE}_out ${_dll_export_decl}${protobuf_generate_PROTOC_OUT_DIR} ${_protobuf_include_path} ${_abs_file}

See this