macOS File Permission Issue at Runtime

[suyashcjoshi]

While following the directions to compile and run the gradle demo app, I ran into strage macOS Catalina issue. This happens after executing the following command.
pop up dialog.

.gradle run command

Please see the attached screenshots of the OS

StackTrace of the Build Fail exception:

~/Code/Java/LibTorch-PyTorch/java-demo-master $ ./gradlew run

Task :run FAILED
Exception in thread "main" java.lang.UnsatisfiedLinkError: /Users/sj/Code/Java/LibTorch-PyTorch/libtorch/lib/libpytorch_jni.dylib: dlopen(/Users/sj/Code/Java/LibTorch-PyTorch/libtorch/lib/libpytorch_jni.dylib, 1): Library not loaded: @rpath/libtorch_cpu.dylib
Referenced from: /Users/sj/Code/Java/LibTorch-PyTorch/libtorch/lib/libpytorch_jni.dylib
Reason: no suitable image found. Did find:
/Users/sj/Code/Java/LibTorch-PyTorch/libtorch/lib/libtorch_cpu.dylib: code signature in (/Users/sj/Code/Java/LibTorch-PyTorch/libtorch/lib/libtorch_cpu.dylib) not valid for use in process using Library Validation: library load disallowed by system policy
at java.base/java.lang.ClassLoader$NativeLibrary.load0(Native Method)
at java.base/java.lang.ClassLoader$NativeLibrary.load(ClassLoader.java:2430)
at java.base/java.lang.ClassLoader$NativeLibrary.loadLibrary(ClassLoader.java:2487)
at java.base/java.lang.ClassLoader.loadLibrary0(ClassLoader.java:2684)
at java.base/java.lang.ClassLoader.loadLibrary(ClassLoader.java:2649)
at java.base/java.lang.Runtime.loadLibrary0(Runtime.java:829)
at java.base/java.lang.System.loadLibrary(System.java:1870)
at com.facebook.soloader.nativeloader.SystemDelegate.loadLibrary(SystemDelegate.java:22)
at com.facebook.soloader.nativeloader.NativeLoader.loadLibrary(NativeLoader.java:43)
at org.pytorch.NativePeer.(NativePeer.java:11)
at org.pytorch.Module.load(Module.java:23)
at demo.App.main(App.java:12)

FAILURE: Build failed with an exception.

• What went wrong:
  Execution failed for task ':run'.

Process 'command '/Library/Java/JavaVirtualMachines/jdk-11.0.5.jdk/Contents/Home/bin/java'' finished with non-zero exit value 1

[suyashcjoshi]

Here is the fix that I found and submitting a documentation update PR for the same so it can help other macOS users.

Run the following commands after the warning popup occurs so as to delete the macOS quarantine flag from all the files inside of /path/to/libtorch/lib folder

xattr -r -d com.apple.quarantine /path/to/libtorch/lib
./gradlew run