Couldn't build the project: Execution failed for task ':app:externalNativeBuildDebug'

[Suhail]

Hey there, I get an immediate failure. Stack trace is here: https://gist.github.com/Suhail/d16154b6e09420b278ab0bf21da1b0a2

Here are the important sections though:

org.gradle.api.tasks.TaskExecutionException: Execution failed for task ':app:externalNativeBuildDebug'.
	at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:103)
	at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.execute(ExecuteActionsTaskExecuter.java:73)
	at org.gradle.api.internal.tasks.execution.OutputDirectoryCreatingTaskExecuter.execute(OutputDirectoryCreatingTaskExecuter.java:51)
	at org.gradle.api.internal.tasks.execution.SkipUpToDateTaskExecuter.execute(SkipUpToDateTaskExecuter.java:59)
....
Caused by: org.gradle.internal.UncheckedException: Build command failed.
Error while executing process /Users/suhail/Library/Android/sdk/cmake/3.6.4111459/bin/cmake with arguments {--build /Users/suhail/Desktop/AI/AICamera/app/.externalNativeBuild/cmake/debug/armeabi-v7a --target native-lib}
[1/4] Building C object CMakeFiles/cpufeatures.dir/Users/suhail/Library/Android/sdk/ndk-bundle/sources/android/cpufeatures/cpu-features.c.o
[2/4] Linking C static library libcpufeatures.a
[3/4] Building CXX object CMakeFiles/native-lib.dir/src/main/cpp/native-lib.cpp.o
[4/4] Linking CXX shared library ../../../../build/intermediates/cmake/debug/obj/armeabi-v7a/libnative-lib.so
FAILED: : && /Users/suhail/Library/Android/sdk/ndk-bundle/toolchains/llvm/prebuilt/darwin-x86_64/bin/clang++  --target=armv7-none-linux-androideabi22 --gcc-toolchain=/Users/suhail/Library/Android/sdk/ndk-bundle/toolchains/arm-linux-androideabi-4.9/prebuilt/darwin-x86_64 --sysroot=/Users/suhail/Library/Android/sdk/ndk-bundle/sysroot -fPIC -isystem /Users/suhail/Library/Android/sdk/ndk-bundle/sysroot/usr/include/arm-linux-androideabi -g -DANDROID -ffunction-sections -funwind-tables -fstack-protector-strong -no-canonical-prefixes -march=armv7-a -mfloat-abi=softfp -mfpu=vfpv3-d16 -mthumb -Wa,--noexecstack -Wformat -Werror=format-security -std=c++11 -frtti -fexceptions -std=c++11 -O0 -fno-limit-debug-info  -Wl,--exclude-libs,libgcc.a -Wl,--exclude-libs,libatomic.a -nostdlib++ --sysroot /Users/suhail/Library/Android/sdk/ndk-bundle/platforms/android-22/arch-arm -Wl,--build-id -Wl,--warn-shared-textrel -Wl,--fatal-warnings -Wl,--fix-cortex-a8 -Wl,--exclude-libs,libunwind.a -L/Users/suhail/Library/Android/sdk/ndk-bundle/sources/cxx-stl/llvm-libc++/libs/armeabi-v7a -Wl,--no-undefined -Wl,-z,noexecstack -Qunused-arguments -Wl,-z,relro -Wl,-z,now -shared -Wl,-soname,libnative-lib.so -o ../../../../build/intermediates/cmake/debug/obj/armeabi-v7a/libnative-lib.so CMakeFiles/native-lib.dir/src/main/cpp/native-lib.cpp.o  -Wl,--whole-archive ../../../../src/main/jniLibs/armeabi-v7a/libCaffe2_CPU.a -Wl,--no-whole-archive ../../../../src/main/jniLibs/armeabi-v7a/libCAFFE2_NNPACK.a ../../../../src/main/jniLibs/armeabi-v7a/libCAFFE2_PTHREADPOOL.a ../../../../src/main/jniLibs/armeabi-v7a/libglog.so ../../../../src/main/jniLibs/armeabi-v7a/libprotobuf.a libcpufeatures.a -llog -landroid -ldl -latomic -lm "/Users/suhail/Library/Android/sdk/ndk-bundle/sources/cxx-stl/llvm-libc++/libs/armeabi-v7a/libc++_static.a" "/Users/suhail/Library/Android/sdk/ndk-bundle/sources/cxx-stl/llvm-libc++/libs/armeabi-v7a/libc++abi.a" "/Users/suhail/Library/Android/sdk/ndk-bundle/sources/cxx-stl/llvm-libc++/libs/armeabi-v7a/libunwind.a" "-ldl" && :
../../../../src/main/jniLibs/armeabi-v7a/libCaffe2_CPU.a(nnpack_ops.cc.o):nnpack_ops.cc:function std::_Sp_counted_deleter<void*, void (*)(void*), std::allocator<void>, (__gnu_cxx::_Lock_policy)2>::_M_get_deleter(std::type_info const&): error: undefined reference to 'std::type_info::operator==(std::type_info const&) const'

....

../../../../src/main/jniLibs/armeabi-v7a/libprotobuf.a(descriptor_database.cc.o):descriptor_database.cc:function google::protobuf::SimpleDescriptorDatabase::DescriptorIndex<std::pair<void const*, int> >::AddFile(google::protobuf::FileDescriptorProto const&, std::pair<void const*, int>): error: undefined reference to 'std::string::operator+=(char)'
clang++: error: linker command failed with exit code 1 (use -v to see invocation)
ninja: build stopped: subcommand failed.

	at com.android.build.gradle.tasks.ExternalNativeBuildTaskUtils.executeBuildProcessAndLogError(ExternalNativeBuildTaskUtils.java:245)
	at com.android.build.gradle.tasks.ExternalNativeBuildTask.executeProcessBatch(ExternalNativeBuildTask.java:307)
	at com.android.build.gradle.tasks.ExternalNativeBuildTask.build(ExternalNativeBuildTask.java:185)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.gradle.internal.reflect.JavaMethod.invoke(JavaMethod.java:73)
	... 120 more

Important info:

Collecting environment information...
PyTorch version: 1.0.0a0+f34c848
Is debug build: No
CUDA used to build PyTorch: None

OS: Mac OSX 10.14
GCC version: Could not collect
CMake version: version 3.12.2

Python version: 3.6
Is CUDA available: No
CUDA runtime version: No CUDA
GPU models and configuration: No CUDA
Nvidia driver version: No CUDA
cuDNN version: No CUDA

Versions of relevant libraries:
[pip] Could not collect
[conda] pytorch                   0.4.1           py36_cuda0.0_cudnn0.0_1    pytorch
[conda] pytorch-nightly           1.0.0.dev20181029         py3.6_0    pytorch
[conda] pytorch-nightly-cpu       1.0.0.dev20181014         py3.6_0    pytorch
[conda] torch                     1.0.0a0+f34c848           <pip>
[conda] torch                     0.4.0                     <pip>
[conda] torch                     0.3.1                     <pip>
[conda] torchtext                 0.2.3                     <pip>
[conda] torchvision               0.2.1                     <pip>
[conda] torchvision               0.2.1                    py36_1    pytorch
[conda] torchvision-nightly       0.2.1                     <pip>
[conda] torchvision-nightly-cpu   0.2.1              pyh19dea27_0    fastai

In order to stop complaining about "Expected NDK STL shared object file libgnustl_shared.so" I commented out:

externalNativeBuild {
            cmake {
                cppFlags "-frtti -fexceptions -std=c++11"
                //arguments "-DANDROID_STL=gnustl_shared"
            }
        }

If I uncomment it, it'll just say:
Expected NDK STL shared object file at /Users/<username>/Library/Android/sdk/ndk-bundle/sources/cxx-stl/gnu-libstdc++/4.9/libs/armeabi-v7a/libgnustl_shared.so

Seems like the demo requires a pre-built that might not work on mac os x?