Compile error in cv2 python3 binding. multiple definition of caffe::... libopencv_dnn.a(caffe.pb.cc.o):caffe.pb.cc:(...): first defined here

[stablum]

System information (version)

• OpenCV => >3.2.0 (actually latest git snapshot)
• Operating System / Platform => Ubuntu 17.04
• Compiler => likely the Gnu/gcc/g++ compiler

Detailed description

[ 95%] Linking CXX shared module ../../lib/python3/cv2.cpython-36m-x86_64-linux-gnu.so
../../lib/libopencv_dnn_modern.a(caffe_converter.cpp.o): In function `caffe::BlobShape::SetCachedSize(int) const':
caffe_converter.cpp:(.text._ZNK5caffe9BlobShape13SetCachedSizeEi+0x0): multiple definition of `caffe::BlobShape::SetCachedSize(int) const'
../../lib/libopencv_dnn.a(caffe.pb.cc.o):caffe.pb.cc:(.text._ZNK5caffe9BlobShape13SetCachedSizeEi+0x0): first defined here
../../lib/libopencv_dnn_modern.a(caffe_converter.cpp.o): In function `caffe::BlobShape::IsInitialized() const':
caffe_converter.cpp:(.text._ZNK5caffe9BlobShape13IsInitializedEv+0x0): multiple definition of `caffe::BlobShape::IsInitialized() const'
../../lib/libopencv_dnn.a(caffe.pb.cc.o):caffe.pb.cc:(.text._ZNK5caffe14NormalizedBBox13IsInitializedEv+0x0): first defined here
../../lib/libopencv_dnn_modern.a(caffe_converter.cpp.o): In function `caffe::BlobProto::SetCachedSize(int) const':
caffe_converter.cpp:(.text._ZNK5caffe9BlobProto13SetCachedSizeEi+0x0): multiple definition of `caffe::BlobProto::SetCachedSize(int) const'
../../lib/libopencv_dnn.a(caffe.pb.cc.o):caffe.pb.cc:(.text._ZNK5caffe9BlobProto13SetCachedSizeEi+0x0): first defined here
../../lib/libopencv_dnn_modern.a(caffe_converter.cpp.o): In function `caffe::BlobProto::IsInitialized() const':

(it goes on with hundreds of similar messages)

../../lib/libopencv_dnn_modern.a(caffe_converter.cpp.o):(.rodata+0x4e94): multiple definition of `caffe::BlobShape::kDimFieldNumber'
../../lib/libopencv_dnn.a(caffe.pb.cc.o):(.rodata+0x5794): first defined here
../../lib/libopencv_dnn_modern.a(caffe_converter.cpp.o):(.bss+0x208): multiple definition of `caffe::static_descriptor_initializer_caffe_2eproto_'
../../lib/libopencv_dnn.a(caffe.pb.cc.o):(.bss+0x1a58): first defined here
collect2: error: ld returned 1 exit status
modules/python3/CMakeFiles/opencv_python3.dir/build.make:464: recipe for target 'lib/python3/cv2.cpython-36m-x86_64-linux-gnu.so' failed
make[2]: *** [lib/python3/cv2.cpython-36m-x86_64-linux-gnu.so] Error 1
CMakeFiles/Makefile2:5090: recipe for target 'modules/python3/CMakeFiles/opencv_python3.dir/all' failed
make[1]: *** [modules/python3/CMakeFiles/opencv_python3.dir/all] Error 2
Makefile:160: recipe for target 'all' failed
make: *** [all] Error 2

Steps to reproduce

export CPATH=$CPATH:/usr/include/x86_64-linux-gnu/
cmake \
    --with-ffmpeg \
    -D BUILD_opencv_python3=ON \
    -D HAVE_opencv_python3=ON \
    -D PYTHON3LIBS_VERSION_STRING=3.6m \
    -D PYTHON3_LIBRARIES=/usr/lib/x86_64-linux-gnu/libpython3.6m.so \
    -D PYTHON3_LIBRARY=/usr/lib/x86_64-linux-gnu/libpython3.6im.so \
    -D PYTHON3_INCLUDE_PATH=/usr/include/python3.6m \
    -D PYTHON3_INCLUDE_DIR=/usr/include/python3.6m \
    -D PYTHON3_INCLUDE_DIRS=/usr/include/python3.6m \
    -D PYTHON3_EXECUTABLE=/usr/bin/python3.6m \
    -D PYTHON_LIBRARIES=/usr/lib/x86_64-linux-gnu/libpython3.6m.so \
    -D PYTHON_LIBRARY=/usr/lib/x86_64-linux-gnu/libpython3.6im.so \
    -D PYTHON_INCLUDE_PATH=/usr/include/python3.6m \
    -D PYTHON_INCLUDE_DIR=/usr/include/python3.6m \
    -D PYTHON_INCLUDE_DIRS=/usr/include/python3.6m \
    -D CMAKE_BUILD_TYPE=RELEASE \
    -D CMAKE_INSTALL_PREFIX=/usr/local \
    -D BUILD_NEW_PYTHON_SUPPORT=OFF \
    -D INSTALL_C_EXAMPLES=OFF \
    -D INSTALL_PYTHON_EXAMPLES=ON \
    -D BUILD_EXAMPLES=OFF \
    -D ENABLE_PRECOMPILED_HEADERS=OFF \
    -D WITH_FFMPEG=ON \
    -D WITH_TBB=ON \
    -D BUILD_SHARED_LIBS=OFF \
    -D BUILD_TESTS=OFF \
    -D BUILD_PERF_TESTS=OFF \
    -D CUDA_NVCC_FLAGS="-ccbin gcc-5" \
    -D OPENCV_EXTRA_MODULES_PATH=$HOME/Downloads/opencv_contrib/modules \
    -D FFMPEG_INCLUDEDIR=/usr/include/x86_64-linux-gnu/ \
    -D FFMPEG_INCLUDE_DIRS="/usr/local/include;/usr/include/x86_64-linux-gnu/" \
    -D FFMPEG_CFLAGS="-I/usr/local/include -I/usr/include/x86_64-linux-gnu" \
    .. 2>&1 | tee my_cmake.log

[alalek]

Try to disable dnn_modern module:

cmake -DBUILD_opencv_dnn_modern=OFF ...

[stablum]

@alalek thank you for the suggestion! Will try and let you know if it worked.

[stablum]

@alalek it did indeed work! thanks! :)
Anyways, I feel that this issue should stay open because it should be detected by cmake instead of make.

[alalek]

#10092 #10139