IssueTracker

Desugaring of libraries breaks native method signatures. For example, if a library has defined a method whose signature involves a class that is desugared (parameter or return value) and it's implementation is in native, after desugaring it will be broken as the method signature is not what it was when native library was built.

For example, if library has this method:

public static native int test(ConcurrentHashMap<String, String> map);

If it is registered using RegisterNatives method, it would have a signature of test(Ljava/util/concurrent/ConcurrentHashMap;)I. You would also use signature like this to find the method in native code.

If an application enables desugaring, then it will without any errors/warnings change this method signature to test(Lj$/util/concurrent/ConcurrentHashMap;)I.

I understand that not changing is not an option and not all cases can be covered. For example simply trying to find method/field that was desugared from native code will result in field/method/class not being found and there could be no indication in Java that it could be used from native.
So at minimum I would like to see some warning that a method that is declared as native is referencing desugared class and signature will be changed. Though I believe this should be an error.

Another issue is that even in case where no desugared method is actually used, class is still desugared. ConcurrentHashMap is a good example. If user is not actually using any of desugared methods (only using put and get), then no desugaring is actually needed.

Attached is an example app, which when built will crash with Failed to register native method com.example.goodlib.ClassWithRegisterNatives.test(Ljava/util/concurrent/ConcurrentHashMap;)I