Support introspection of parameter names and indices in reflection

compiler/testData/codegen/boxWithStdlib/reflection/parameters/functionParameterNameAndIndex.kt

@@ -0,0 +1,27 @@
+import kotlin.reflect.*
+import kotlin.test.assertEquals
+
+fun foo(bar: String): Int = bar.length()
+
+class A(val c: String) {
+    fun foz(baz: Int) {}
+}
+
+fun Int.qux(zux: String) {}
+
+fun checkParameters(f: KFunction<*>, names: List<String?>) {
+    val params = f.parameters
+    assertEquals(names, params.map { it.name })
+    assertEquals((0..params.size() - 1).toList(), params.mapIndexed { index, element -> index })
+}
+
+fun box(): String {
+    checkParameters(::box, listOf())
+    checkParameters(::foo, listOf("bar"))
+    checkParameters(A::foz, listOf(null, "baz"))
+    checkParameters(Int::qux, listOf(null, "zux"))
+
+    checkParameters(::A, listOf("c"))
+
+    return "OK"
+}

compiler/testData/codegen/boxWithStdlib/reflection/parameters/propertySetter.kt

@@ -0,0 +1,24 @@
+import kotlin.reflect.*
+import kotlin.test.assertEquals
+
+var default: Int = 0
+
+var defaultAnnotated: Int = 0
+    public set
+
+var custom: Int = 0
+    set(myName: Int) {}
+
+fun checkPropertySetterParam(property: KMutableProperty<*>, name: String?) {
+    val parameter = property.setter.parameters.single()
+    assertEquals(0, parameter.index)
+    assertEquals(name, parameter.name)
+}
+
+fun box(): String {
+    checkPropertySetterParam(::default, null)
+    checkPropertySetterParam(::defaultAnnotated, null)
+    checkPropertySetterParam(::custom, "myName")
+
+    return "OK"
+}

compiler/tests/org/jetbrains/kotlin/codegen/generated/BlackBoxWithStdlibCodegenTestGenerated.java

@@ -3196,6 +3196,27 @@ public class BlackBoxWithStdlibCodegenTestGenerated extends AbstractBlackBoxCode
             }
         }
 
+        @TestMetadata("compiler/testData/codegen/boxWithStdlib/reflection/parameters")
+        @TestDataPath("$PROJECT_ROOT")
+        @RunWith(JUnit3RunnerWithInners.class)
+        public static class Parameters extends AbstractBlackBoxCodegenTest {
+            public void testAllFilesPresentInParameters() throws Exception {
+                JetTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("compiler/testData/codegen/boxWithStdlib/reflection/parameters"), Pattern.compile("^(.+)\\.kt$"), true);
+            }
+
+            @TestMetadata("functionParameterNameAndIndex.kt")
+            public void testFunctionParameterNameAndIndex() throws Exception {
+                String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/boxWithStdlib/reflection/parameters/functionParameterNameAndIndex.kt");
+                doTestWithStdlib(fileName);
+            }
+
+            @TestMetadata("propertySetter.kt")
+            public void testPropertySetter() throws Exception {
+                String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/boxWithStdlib/reflection/parameters/propertySetter.kt");
+                doTestWithStdlib(fileName);
+            }
+        }
+
         @TestMetadata("compiler/testData/codegen/boxWithStdlib/reflection/properties")
         @TestDataPath("$PROJECT_ROOT")
         @RunWith(JUnit3RunnerWithInners.class)

core/builtins/src/kotlin/reflect/KCallable.kt

@@ -31,4 +31,9 @@ public interface KCallable<out R> {
      *   the setter, similarly, will have the name "<set-foo>".
      */
     public val name: String
+
+    /**
+     * Parameters required to make a call to this callable.
+     */
+    public val parameters: List<KParameter>
 }

core/builtins/src/kotlin/reflect/KParameter.kt

@@ -0,0 +1,37 @@
+/*
+ * Copyright 2010-2015 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package kotlin.reflect
+
+/**
+ * Represents a parameter passed to a function or a property getter/setter,
+ * including `this` and extension receiver parameters.
+ */
+public interface KParameter {
+    /**
+     * 0-based index of this parameter in the parameter list of its containing callable.
+     */
+    public val index: Int
+
+    /**
+     * Name of this parameter as it was declared in the source code,
+     * or `null` if the parameter has no name or its name is not available at runtime.
+     * Examples of nameless parameters include `this` instance for member functions,
+     * extension receiver for extension functions or properties, parameters of Java methods
+     * compiled without the debug information, and others.
+     */
+    public val name: String?
+}

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

@@ -18,7 +18,6 @@ package kotlin.reflect.jvm.internal
 
 import org.jetbrains.kotlin.descriptors.PropertyDescriptor
 import org.jetbrains.kotlin.descriptors.Visibilities
-import org.jetbrains.kotlin.load.java.structure.reflect.desc
 import org.jetbrains.kotlin.resolve.DescriptorUtils
 import org.jetbrains.kotlin.serialization.ProtoBuf
 import org.jetbrains.kotlin.serialization.deserialization.NameResolver
@@ -27,12 +26,12 @@ import org.jetbrains.kotlin.serialization.jvm.JvmProtoBuf
 import java.lang.reflect.Field
 import java.lang.reflect.Method
 
-abstract class DescriptorBasedProperty protected constructor(
+abstract class DescriptorBasedProperty<out R> protected constructor(
         container: KCallableContainerImpl,
         name: String,
         signature: String,
         descriptorInitialValue: PropertyDescriptor?
-) {
+) : KCallableImpl<R> {
     constructor(container: KCallableContainerImpl, name: String, signature: String) : this(
             container, name, signature, null
     )
@@ -50,7 +49,7 @@ abstract class DescriptorBasedProperty protected constructor(
             val signature: JvmProtoBuf.JvmPropertySignature
     )
 
-    protected val descriptor: PropertyDescriptor by ReflectProperties.lazySoft<PropertyDescriptor>(descriptorInitialValue) {
+    override val descriptor: PropertyDescriptor by ReflectProperties.lazySoft<PropertyDescriptor>(descriptorInitialValue) {
         container.findPropertyDescriptor(name, signature)
     }
 
@@ -88,7 +87,7 @@ abstract class DescriptorBasedProperty protected constructor(
     }
 
     override fun equals(other: Any?): Boolean =
-            other is DescriptorBasedProperty && descriptor == other.descriptor
+            other is DescriptorBasedProperty<*> && descriptor == other.descriptor
 
     override fun hashCode(): Int =
             descriptor.hashCode()

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

@@ -16,6 +16,32 @@
 
 package kotlin.reflect.jvm.internal
 
+import org.jetbrains.kotlin.descriptors.CallableMemberDescriptor
+import java.util.ArrayList
 import kotlin.reflect.KCallable
+import kotlin.reflect.KParameter
 
-interface KCallableImpl<out R> : KCallable<R>
+interface KCallableImpl<out R> : KCallable<R> {
+    val descriptor: CallableMemberDescriptor
+
+    override val parameters: List<KParameter>
+        get() {
+            val result = ArrayList<KParameter>()
+            var index = 0
+
+            if (descriptor.dispatchReceiverParameter != null) {
+                result.add(KParameterImpl(index++) { descriptor.dispatchReceiverParameter!! })
+            }
+
+            if (descriptor.extensionReceiverParameter != null) {
+                result.add(KParameterImpl(index++) { descriptor.extensionReceiverParameter!! })
+            }
+
+            for (i in descriptor.valueParameters.indices) {
+                result.add(KParameterImpl(index++) { descriptor.valueParameters[i] })
+            }
+
+            result.trimToSize()
+            return result
+        }
+}

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

@@ -14,6 +14,7 @@
  * limitations under the License.
  */
 
+@file:suppress("DEPRECATED_SYMBOL_WITH_MESSAGE")
 package kotlin.reflect.jvm.internal
 
 import org.jetbrains.kotlin.descriptors.FunctionDescriptor
@@ -25,7 +26,7 @@ open class KFunctionImpl protected constructor(
         name: String,
         signature: String,
         descriptorInitialValue: FunctionDescriptor?
-) : KFunction<Any?>, FunctionImpl(),
+) : KFunction<Any?>, KCallableImpl<Any?>, FunctionImpl(),
         KLocalFunction<Any?>, KMemberFunction<Any, Any?>, KTopLevelExtensionFunction<Any?, Any?>, KTopLevelFunction<Any?> {
     constructor(container: KCallableContainerImpl, name: String, signature: String) : this(container, name, signature, null)
 
@@ -33,7 +34,7 @@ open class KFunctionImpl protected constructor(
             container, descriptor.getName().asString(), RuntimeTypeMapper.mapSignature(descriptor), descriptor
     )
 
-    protected val descriptor: FunctionDescriptor by ReflectProperties.lazySoft<FunctionDescriptor>(descriptorInitialValue) {
+    override val descriptor: FunctionDescriptor by ReflectProperties.lazySoft<FunctionDescriptor>(descriptorInitialValue) {
         container.findFunctionDescriptor(name, signature)
     }
 

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

@@ -0,0 +1,35 @@
+/*
+ * Copyright 2010-2015 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package kotlin.reflect.jvm.internal
+
+import org.jetbrains.kotlin.descriptors.ParameterDescriptor
+import org.jetbrains.kotlin.descriptors.ValueParameterDescriptor
+import kotlin.reflect.KParameter
+
+class KParameterImpl(
+        override val index: Int,
+        private val computeDescriptor: () -> ParameterDescriptor
+) : KParameter {
+    private val descriptor: ParameterDescriptor by ReflectProperties.lazySoft(computeDescriptor)
+
+    override val name: String? get() {
+        val valueParameter = descriptor as? ValueParameterDescriptor ?: return null
+        if (valueParameter.containingDeclaration.hasSynthesizedParameterNames()) return null
+        val name = valueParameter.name
+        return if (name.isSpecial) null else name.asString()
+    }
+}

core/reflection.jvm/src/kotlin/reflect/jvm/internal/KProperty0Impl.kt

@@ -23,7 +23,7 @@ import kotlin.reflect.IllegalPropertyAccessException
 import kotlin.reflect.KMutableProperty0
 import kotlin.reflect.KProperty0
 
-open class KProperty0Impl<out R> : DescriptorBasedProperty, KProperty0<R>, KPropertyImpl<R> {
+open class KProperty0Impl<out R> : DescriptorBasedProperty<R>, KProperty0<R>, KPropertyImpl<R> {
     constructor(container: KCallableContainerImpl, name: String, signature: String) : super(container, name, signature)
 
     override val name: String get() = descriptor.getName().asString()
@@ -42,7 +42,7 @@ open class KProperty0Impl<out R> : DescriptorBasedProperty, KProperty0<R>, KProp
         }
     }
 
-    class Getter<out R>(override val property: KProperty0Impl<R>) : KPropertyImpl.Getter<R>, KProperty0.Getter<R> {
+    class Getter<out R>(override val property: KProperty0Impl<R>) : KPropertyImpl.Getter<R>(), KProperty0.Getter<R> {
         override fun invoke(): R = property.get()
     }
 }
@@ -63,7 +63,7 @@ open class KMutableProperty0Impl<R> : KProperty0Impl<R>, KMutableProperty0<R>, K
         }
     }
 
-    class Setter<R>(override val property: KMutableProperty0Impl<R>) : KMutablePropertyImpl.Setter<R>, KMutableProperty0.Setter<R> {
+    class Setter<R>(override val property: KMutableProperty0Impl<R>) : KMutablePropertyImpl.Setter<R>(), KMutableProperty0.Setter<R> {
         override fun invoke(value: R): Unit = property.set(value)
     }
 }

core/reflection.jvm/src/kotlin/reflect/jvm/internal/KProperty1Impl.kt

@@ -24,7 +24,7 @@ import kotlin.reflect.IllegalPropertyAccessException
 import kotlin.reflect.KMutableProperty1
 import kotlin.reflect.KProperty1
 
-open class KProperty1Impl<T, out R> : DescriptorBasedProperty, KProperty1<T, R>, KPropertyImpl<R> {
+open class KProperty1Impl<T, out R> : DescriptorBasedProperty<R>, KProperty1<T, R>, KPropertyImpl<R> {
     constructor(container: KCallableContainerImpl, name: String, signature: String) : super(container, name, signature)
 
     constructor(container: KCallableContainerImpl, descriptor: PropertyDescriptor) : super(container, descriptor)
@@ -56,7 +56,7 @@ open class KProperty1Impl<T, out R> : DescriptorBasedProperty, KProperty1<T, R>,
         }
     }
 
-    class Getter<T, out R>(override val property: KProperty1Impl<T, R>) : KPropertyImpl.Getter<R>, KProperty1.Getter<T, R> {
+    class Getter<T, out R>(override val property: KProperty1Impl<T, R>) : KPropertyImpl.Getter<R>(), KProperty1.Getter<T, R> {
         override fun invoke(receiver: T): R = property.get(receiver)
     }
 }
@@ -92,7 +92,7 @@ open class KMutableProperty1Impl<T, R> : KProperty1Impl<T, R>, KMutableProperty1
         }
     }
 
-    class Setter<T, R>(override val property: KMutableProperty1Impl<T, R>) : KMutablePropertyImpl.Setter<R>, KMutableProperty1.Setter<T, R> {
+    class Setter<T, R>(override val property: KMutableProperty1Impl<T, R>) : KMutablePropertyImpl.Setter<R>(), KMutableProperty1.Setter<T, R> {
         override fun invoke(receiver: T, value: R): Unit = property.set(receiver, value)
     }
 }

core/reflection.jvm/src/kotlin/reflect/jvm/internal/KProperty2Impl.kt

@@ -23,7 +23,7 @@ import kotlin.reflect.IllegalPropertyAccessException
 import kotlin.reflect.KMutableProperty2
 import kotlin.reflect.KProperty2
 
-open class KProperty2Impl<D, E, out R> : DescriptorBasedProperty, KProperty2<D, E, R>, KPropertyImpl<R> {
+open class KProperty2Impl<D, E, out R> : DescriptorBasedProperty<R>, KProperty2<D, E, R>, KPropertyImpl<R> {
     constructor(container: KClassImpl<D>, name: String, signature: String) : super(container, name, signature)
 
     constructor(container: KClassImpl<D>, descriptor: PropertyDescriptor) : super(container, descriptor)
@@ -46,7 +46,7 @@ open class KProperty2Impl<D, E, out R> : DescriptorBasedProperty, KProperty2<D,
         }
     }
 
-    class Getter<D, E, out R>(override val property: KProperty2Impl<D, E, R>) : KPropertyImpl.Getter<R>, KProperty2.Getter<D, E, R> {
+    class Getter<D, E, out R>(override val property: KProperty2Impl<D, E, R>) : KPropertyImpl.Getter<R>(), KProperty2.Getter<D, E, R> {
         override fun invoke(receiver1: D, receiver2: E): R = property.get(receiver1, receiver2)
     }
 }
@@ -70,7 +70,7 @@ class KMutableProperty2Impl<D, E, R> : KProperty2Impl<D, E, R>, KMutableProperty
         }
     }
 
-    class Setter<D, E, R>(override val property: KMutableProperty2Impl<D, E, R>) : KMutablePropertyImpl.Setter<R>, KMutableProperty2.Setter<D, E, R> {
+    class Setter<D, E, R>(override val property: KMutableProperty2Impl<D, E, R>) : KMutablePropertyImpl.Setter<R>(), KMutableProperty2.Setter<D, E, R> {
         override fun invoke(receiver1: D, receiver2: E, value: R): Unit = property.set(receiver1, receiver2, value)
     }
 }

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

@@ -16,8 +16,14 @@
 
 package kotlin.reflect.jvm.internal
 
-import java.lang.reflect.*
+import org.jetbrains.kotlin.descriptors.PropertyDescriptor
-import kotlin.reflect.*
+import org.jetbrains.kotlin.descriptors.PropertyGetterDescriptor
+import org.jetbrains.kotlin.descriptors.PropertySetterDescriptor
+import org.jetbrains.kotlin.resolve.DescriptorFactory
+import java.lang.reflect.Field
+import java.lang.reflect.Method
+import kotlin.reflect.KMutableProperty
+import kotlin.reflect.KProperty
 
 interface KPropertyImpl<out R> : KProperty<R>, KCallableImpl<R> {
     val javaField: Field?
@@ -26,12 +32,19 @@ interface KPropertyImpl<out R> : KProperty<R>, KCallableImpl<R> {
 
     override val getter: Getter<R>
 
+    override val descriptor: PropertyDescriptor
+
     interface Accessor<out R> : KProperty.Accessor<R> {
         override val property: KPropertyImpl<R>
     }
 
-    interface Getter<out R> : KProperty.Getter<R>, KCallableImpl<R> {
+    abstract class Getter<out R> : KProperty.Getter<R>, Accessor<R>, KCallableImpl<R> {
         override val name: String get() = "<get-${property.name}>"
+
+        override val descriptor: PropertyGetterDescriptor by ReflectProperties.lazySoft {
+            // TODO: default getter created this way won't have any source information
+            property.descriptor.getGetter() ?: DescriptorFactory.createDefaultGetter(property.descriptor)
+        }
     }
 }
 
@@ -41,7 +54,12 @@ interface KMutablePropertyImpl<R> : KMutableProperty<R>, KPropertyImpl<R> {
 
     override val setter: Setter<R>
 
-    interface Setter<R> : KMutableProperty.Setter<R>, KPropertyImpl.Accessor<R>, KCallableImpl<Unit> {
+    abstract class Setter<R> : KMutableProperty.Setter<R>, KPropertyImpl.Accessor<R>, KCallableImpl<Unit> {
         override val name: String get() = "<set-${property.name}>"
+
+        override val descriptor: PropertySetterDescriptor by ReflectProperties.lazySoft {
+            // TODO: default setter created this way won't have any source information
+            property.descriptor.getSetter() ?: DescriptorFactory.createDefaultSetter(property.descriptor)
+        }
     }
 }

core/runtime.jvm/src/kotlin/jvm/internal/CallableReference.java

@@ -19,6 +19,9 @@ package kotlin.jvm.internal;
 import kotlin.jvm.KotlinReflectionNotSupportedError;
 import kotlin.reflect.KCallable;
 import kotlin.reflect.KDeclarationContainer;
+import kotlin.reflect.KParameter;
+
+import java.util.List;
 
 /**
  * A superclass for all classes generated by Kotlin compiler for callable references.
@@ -60,7 +63,10 @@ public abstract class CallableReference implements KCallable {
     // The following methods are the stub implementations of reflection functions.
     // They are called when you're using reflection on a property reference without the reflection implementation in the classpath.
 
-    // (nothing here yet)
+    @Override
+    public List<KParameter> getParameters() {
+        throw error();
+    }
 
     protected static Error error() {
         throw new KotlinReflectionNotSupportedError();

core/runtime.jvm/src/kotlin/jvm/internal/FunctionReference.java

@@ -19,6 +19,8 @@ package kotlin.jvm.internal;
 import kotlin.jvm.KotlinReflectionNotSupportedError;
 import kotlin.reflect.*;
 
+import java.util.List;
+
 @SuppressWarnings("deprecation")
 public class FunctionReference
         extends FunctionImpl
@@ -58,6 +60,11 @@ public class FunctionReference
         throw error();
     }
 
+    @Override
+    public List<KParameter> getParameters() {
+        throw error();
+    }
+
     protected static Error error() {
         throw new KotlinReflectionNotSupportedError();
     }