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kotlinlang

Trying to understand some strange behavior with the K/N compiler. I have a case where, as I’m trying to debug through a confusing crash, adding a line of `somePointer.rawValue` corrects the issue. I’m not using the value, just putting that line as a statement. Are there some side-effects anyone is aware of to calling `.rawValue` on a pointer (implemented as a getter of `value.toNativePtr()` internally) that might explain what I’m seeing? I have a number of other things to debug into, but seeing this leads me to believe there’s more going on here that I need to understand first.

Don’t know about the call. what’s the crash?

I think the root cause is something I’m doing wrong with JNI. Using it to call a Kotlin class in a JVM (strange use case, I realize), and getting a null result back from JNI (with no exception) where the method cannot return null.

This `.rawValue` call I alluded to above is in the implementation for another method which the JVM class calls via JNI on that side. It’s actually just a debug print message method used on both ends. I noticed that when I remove the call from the Kotlin/JVM source, this NPE situation happens. Introducing the call, even when the K/N implementation does nothing but take the `jstring` pointer and call `.rawValue` , causes everything to work properly. So something’s behaving strangely; I’m still hunting down stuff in the JNI bits I’m using, as I suspect it will end up being a GlobalRef vs LocalRef situation where the JVM has moved things out from under me. We’ll see.

Follow-up: pretty sure I have the root cause addressed (it did end up being JNI GlobalRef shenanigans). Still a bit mystified why the call to `.rawValue` in K/N was fixing/masking the issues, but I at least have a path forward.