Workaround circular dependency of KProperty1 and KClassImpl

This appeared after introduction of KProperty in delegated property convention
methods. If a KProperty1 instance is created while constructing a KClassImpl
instance before assigning the 'jClass' field, an NPE is thrown because the
constructor of that KProperty1 instance tries to lookup the declaring class of
the property, which in some case happens to be the exact KClassImpl we're
constructing. No test added because I was not able to reproduce the behavior in
an isolated environment

core/reflection.jvm/src/kotlin/reflect/jvm/internal/KClassImpl.kt

@@ -38,7 +38,7 @@ import kotlin.reflect.KFunction
 import kotlin.reflect.KotlinReflectionInternalError
 
 internal class KClassImpl<T : Any>(override val jClass: Class<T>) : KDeclarationContainerImpl(), KClass<T>, KAnnotatedElementImpl {
-    val descriptor by ReflectProperties.lazySoft {
+    private val descriptor_ = ReflectProperties.lazySoft {
         val classId = classId
 
         val descriptor =
@@ -48,6 +48,9 @@ internal class KClassImpl<T : Any>(override val jClass: Class<T>) : KDeclaration
         descriptor ?: throw KotlinReflectionInternalError("Class not resolved: $jClass")
     }
 
+    val descriptor: ClassDescriptor
+        get() = descriptor_()
+
     override val annotated: Annotated get() = descriptor
 
     private val classId: ClassId get() = RuntimeTypeMapper.mapJvmClassToKotlinClassId(jClass)
@@ -138,7 +141,7 @@ internal class KClassImpl<T : Any>(override val jClass: Class<T>) : KDeclaration
         }.filterNotNull().map { KClassImpl(it) }
 
     @Suppress("UNCHECKED_CAST")
-    override val objectInstance: T? by ReflectProperties.lazy {
+    private val objectInstance_ = ReflectProperties.lazy {
         val descriptor = descriptor
         if (descriptor.kind != ClassKind.OBJECT) return@lazy null
 
@@ -151,6 +154,9 @@ internal class KClassImpl<T : Any>(override val jClass: Class<T>) : KDeclaration
         field.get(null) as T
     }
 
+    override val objectInstance: T?
+        get() = objectInstance_()
+
     override fun equals(other: Any?): Boolean =
             other is KClassImpl<*> && jClass == other.jClass
 

core/reflection.jvm/src/kotlin/reflect/jvm/internal/KDeclarationContainerImpl.kt

@@ -22,6 +22,7 @@ import org.jetbrains.kotlin.load.java.JvmAbi
 import org.jetbrains.kotlin.load.java.structure.reflect.classId
 import org.jetbrains.kotlin.load.java.structure.reflect.createArrayType
 import org.jetbrains.kotlin.load.java.structure.reflect.safeClassLoader
+import org.jetbrains.kotlin.load.kotlin.reflect.RuntimeModuleData
 import org.jetbrains.kotlin.name.ClassId
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.resolve.scopes.JetScope
@@ -36,11 +37,16 @@ import kotlin.reflect.KCallable
 import kotlin.reflect.KotlinReflectionInternalError
 
 internal abstract class KDeclarationContainerImpl : ClassBasedDeclarationContainer {
+    // NB: be careful not to introduce delegated properties in this class and subclasses, there are problems with circular dependencies
+
     // Note: this is stored here on a soft reference to prevent GC from destroying the weak reference to it in the moduleByClassLoader cache
-    val moduleData by ReflectProperties.lazySoft {
+    private val moduleData_ = ReflectProperties.lazySoft {
         jClass.getOrCreateModule()
     }
 
+    val moduleData: RuntimeModuleData
+        get() = moduleData_()
+
     abstract val constructorDescriptors: Collection<ConstructorDescriptor>
 
     abstract fun getProperties(name: Name): Collection<PropertyDescriptor>

core/reflection.jvm/src/kotlin/reflect/jvm/internal/KPackageImpl.kt

@@ -28,13 +28,14 @@ import kotlin.reflect.KCallable
 import kotlin.reflect.KPackage
 
 internal class KPackageImpl(override val jClass: Class<*>, val moduleName: String) : KDeclarationContainerImpl(), KPackage {
-    val descriptor by ReflectProperties.lazySoft {
+    private val descriptor = ReflectProperties.lazySoft {
-        val moduleData = moduleData
+        with(moduleData) {
-        moduleData.packageFacadeProvider.registerModule(moduleName)
+            packageFacadeProvider.registerModule(moduleName)
-        moduleData.module.getPackage(jClass.classId.packageFqName)
+            module.getPackage(jClass.classId.packageFqName)
+        }
     }
 
-    internal val scope: JetScope get() = descriptor.memberScope
+    internal val scope: JetScope get() = descriptor().memberScope
 
     override val members: Collection<KCallable<*>>
         get() = getMembers(scope, declaredOnly = false, nonExtensions = true, extensions = true).toList()

core/reflection.jvm/src/kotlin/reflect/jvm/internal/ReflectProperties.java

@@ -23,15 +23,16 @@ import org.jetbrains.annotations.Nullable;
 import java.lang.ref.SoftReference;
 import java.lang.ref.WeakReference;
 
-/**
- * The fact that this is a Java class is used in reflection implementation classes: otherwise if it were a Kotlin class, KClassImpl()
- * instance would have been invoked in its static initializer (to create and cache $kotlinClass field), resulting in infinite recursion.
- */
 /* package */ class ReflectProperties {
     public static abstract class Val<T> {
         private static final Object NULL_VALUE = new Object() {};
 
-        public abstract T get(Object instance, Object metadata);
+        @SuppressWarnings("UnusedParameters")
+        public T get(Object instance, Object metadata) {
+            return invoke();
+        }
+
+        public abstract T invoke();
 
         protected Object escape(T value) {
             return value == null ? NULL_VALUE : value;
@@ -53,7 +54,7 @@ import java.lang.ref.WeakReference;
         }
 
         @Override
-        public T get(Object instance, Object metadata) {
+        public T invoke() {
             Object cached = value;
             if (cached != null) {
                 return unescape(cached);
@@ -80,7 +81,7 @@ import java.lang.ref.WeakReference;
         }
 
         @Override
-        public T get(Object instance, Object metadata) {
+        public T invoke() {
             SoftReference<Object> cached = value;
             if (cached != null) {
                 Object result = cached.get();
@@ -107,7 +108,7 @@ import java.lang.ref.WeakReference;
         }
 
         @Override
-        public T get(Object instance, Object metadata) {
+        public T invoke() {
             WeakReference<Object> cached = value;
             if (cached != null) {
                 Object result = cached.get();