Android generate_guid leaks a JNI global reference on every call

Summary

generate_guid() creates a JNI global reference for java.util.UUID and stores it in a local variable. The function never calls DeleteGlobalRef, and nothing else owns that reference. Each call leaks one global ref.

This NewGlobalRef is also unnecessary: a FindClass local ref is enough for this one-shot use.

Location

Source/Shared/a/guid.cpp — generate_guid()

Details

jclass guidClass = jniEnv->FindClass("java/util/UUID");
if (guidClass == nullptr) {
    LOG_ERROR("Could not find UUID class");
    return "";
}
jclass m_guidClass = reinterpret_cast<jclass>(jniEnv->NewGlobalRef(guidClass));
jmethodID generateUuidMethodId = jniEnv->GetStaticMethodID(m_guidClass, "randomUUID", "()Ljava/util/UUID;");
jmethodID uuidToStringMethodId = jniEnv->GetMethodID(m_guidClass, "toString", "()Ljava/lang/String;");

jobject uuidObject = jniEnv->CallStaticObjectMethod(m_guidClass, generateUuidMethodId);
JString rawUuid{ jniEnv, static_cast<jstring>(jniEnv->CallObjectMethod(uuidObject, uuidToStringMethodId)) };

return Format("{%s}", rawUuid.c_str());

· m_guidClass is a function-local. It is not cached on java_interop or any other singleton.
· JNI_ATTACH_THREAD only detaches the thread (thread_holder); it does not delete global refs.
· JString only releases UTF chars; it does not delete m_guidClass.
· The project already has global_ref_holder in jni_utils.h, which calls DeleteGlobalRef in its destructor, but this path does not use it.

JNI global refs persist until DeleteGlobalRef. Repeated GUID generation can grow the global reference table and eventually overflow it.

Suggested fix
Prefer dropping NewGlobalRef and using guidClass directly:

jclass guidClass = jniEnv->FindClass("java/util/UUID");
// GetStaticMethodID / GetMethodID / Call* on guidClass

If a global ref is kept, wrap it with global_ref_holder, or call jniEnv->DeleteGlobalRef(m_guidClass) on every return path (including failures after NewGlobalRef).

Start in Source/Shared/a/guid.cpp at generate_guid() and inspect the JNI reference handling around FindClass and NewGlobalRef. Verify the chosen reference lifetime against jni_utils.h and global_ref_holder. Done means repeated GUID generation no longer retains an unowned JNI global reference, including failure paths.