From 821481a2fd6fa89a84af70bfa888a7b064c27503 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Konrad=20Kami=C5=84ski?= Date: Wed, 13 Dec 2017 16:16:05 +0100 Subject: [PATCH] Return correct return type for Kotlin suspending functions in MethodParameter. Return type for Kotlin suspending functions (as returned by MethodParameter#getParameterType and MethodParameter#getgenericReturnType methods) is incorrect. The true return type is the generic parameter of the last parameter of the method. This change modifies the behaviour of the aforementioned methods so that they work correctly for all cases. Issue: SPR-16515 --- .../springframework/core/MethodParameter.java | 52 ++++++++++++- .../core/KotlinGenericTypeResolverTests.kt | 61 +++++++++++++++ .../core/KotlinMethodParameterTests.kt | 78 ++++++++++++++++++- 3 files changed, 184 insertions(+), 7 deletions(-) create mode 100644 spring-core/src/test/kotlin/org/springframework/core/KotlinGenericTypeResolverTests.kt diff --git a/spring-core/src/main/java/org/springframework/core/MethodParameter.java b/spring-core/src/main/java/org/springframework/core/MethodParameter.java index ad3b190f629c..e54cf0bf6a77 100644 --- a/spring-core/src/main/java/org/springframework/core/MethodParameter.java +++ b/spring-core/src/main/java/org/springframework/core/MethodParameter.java @@ -25,6 +25,7 @@ import java.lang.reflect.Parameter; import java.lang.reflect.ParameterizedType; import java.lang.reflect.Type; +import java.lang.reflect.WildcardType; import java.util.HashMap; import java.util.List; import java.util.Map; @@ -396,7 +397,9 @@ public Class getParameterType() { if (paramType == null) { if (this.parameterIndex < 0) { Method method = getMethod(); - paramType = (method != null ? method.getReturnType() : void.class); + paramType = (method != null ? + (KotlinDetector.isKotlinType(getContainingClass()) ? + KotlinDelegate.getReturnType(method) : method.getReturnType()) : void.class); } else { paramType = this.executable.getParameterTypes()[this.parameterIndex]; @@ -416,7 +419,9 @@ public Type getGenericParameterType() { if (paramType == null) { if (this.parameterIndex < 0) { Method method = getMethod(); - paramType = (method != null ? method.getGenericReturnType() : void.class); + paramType = (method != null ? + (KotlinDetector.isKotlinType(getContainingClass()) ? + KotlinDelegate.getGenericReturnType(method) : method.getGenericReturnType()) : void.class); } else { Type[] genericParameterTypes = this.executable.getGenericParameterTypes(); @@ -777,6 +782,47 @@ else if (ctor != null) { } return false; } - } + /** + * Returns a return type of a method using Kotlin Reflection API. + * Introduced to support suspending functions. + */ + static private Class getReturnType(Method method) { + if (isSuspend(method)) { + final Class returnType = getSuspendReturnType(method).resolve(); + Assert.notNull(returnType, "returnType cannot be null"); + return returnType; + } else { + return method.getReturnType(); + } + } + + /** + * Returns a generic return type of a method using Kotlin Reflection API. + * Introduced to support suspending functions. + */ + static private Type getGenericReturnType(Method method) { + if (isSuspend(method)) { + return getSuspendReturnType(method).getType(); + } else { + return method.getGenericReturnType(); + } + } + + static private boolean isSuspend(Method method) { + KFunction function = ReflectJvmMapping.getKotlinFunction(method); + return (function != null && function.isSuspend()); + } + + static private ResolvableType getSuspendReturnType(Method method) { + ResolvableType cgeneric = ResolvableType.forMethodParameter(method, method.getParameterCount() - 1) + .getGeneric(0); + + if (cgeneric.getType() instanceof WildcardType) { + return ResolvableType.forType(((WildcardType) cgeneric.getType()).getLowerBounds()[0]); + } else { + return cgeneric; + } + } + } } diff --git a/spring-core/src/test/kotlin/org/springframework/core/KotlinGenericTypeResolverTests.kt b/spring-core/src/test/kotlin/org/springframework/core/KotlinGenericTypeResolverTests.kt new file mode 100644 index 000000000000..affaad869b0f --- /dev/null +++ b/spring-core/src/test/kotlin/org/springframework/core/KotlinGenericTypeResolverTests.kt @@ -0,0 +1,61 @@ +/* + * Copyright 2002-2018 the original author or authors. + * + * 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 org.springframework.core + +import org.junit.Assert.assertEquals +import org.junit.Test +import org.springframework.core.GenericTypeResolver.resolveReturnTypeArgument +import java.lang.reflect.Method + +/** + * Tests for Kotlin support in [MethodParameter.getGenericParameterType]. + * + * @author Konrad Kaminski + */ + +class KotlinGenericTypeResolverTests { + + @Test + fun methodReturnTypes() { + assertEquals(Integer::class.java, + resolveReturnTypeArgument(findMethod(MyTypeWithMethods::class.java, "integer")!!, MyInterfaceType::class.java)) + assertEquals(String::class.java, + resolveReturnTypeArgument(findMethod(MyTypeWithMethods::class.java, "string")!!, MyInterfaceType::class.java)) + assertEquals(null, resolveReturnTypeArgument(findMethod(MyTypeWithMethods::class.java, "raw")!!, MyInterfaceType::class.java)) + assertEquals(null, + resolveReturnTypeArgument(findMethod(MyTypeWithMethods::class.java, "object")!!, MyInterfaceType::class.java)) + } + + private fun findMethod(clazz: Class<*>, name: String): Method? = + clazz.methods.firstOrNull { it.name == name } + + open class MyTypeWithMethods { + suspend fun integer(): MyInterfaceType? = null + + suspend fun string(): MySimpleInterfaceType? = null + + suspend fun `object`(): Any? = null + + suspend fun raw(): MyInterfaceType<*>? = null + } + + interface MyInterfaceType + + interface MySimpleInterfaceType: MyInterfaceType + + open class MySimpleTypeWithMethods: MyTypeWithMethods() +} \ No newline at end of file diff --git a/spring-core/src/test/kotlin/org/springframework/core/KotlinMethodParameterTests.kt b/spring-core/src/test/kotlin/org/springframework/core/KotlinMethodParameterTests.kt index 2157099a4ce8..dacf65471f33 100644 --- a/spring-core/src/test/kotlin/org/springframework/core/KotlinMethodParameterTests.kt +++ b/spring-core/src/test/kotlin/org/springframework/core/KotlinMethodParameterTests.kt @@ -16,12 +16,15 @@ package org.springframework.core -import java.lang.reflect.Method - +import org.junit.Assert.assertEquals +import org.junit.Assert.assertFalse +import org.junit.Assert.assertTrue import org.junit.Before import org.junit.Test - -import org.junit.Assert.* +import java.lang.reflect.Method +import java.lang.reflect.TypeVariable +import kotlin.reflect.full.declaredFunctions +import kotlin.reflect.jvm.javaMethod /** * Tests for Kotlin support in [MethodParameter]. @@ -29,6 +32,7 @@ import org.junit.Assert.* * @author Raman Gupta * @author Sebastien Deleuze * @author Juergen Hoeller + * @author Konrad Kaminski */ class KotlinMethodParameterTests { @@ -57,6 +61,43 @@ class KotlinMethodParameterTests { assertFalse(MethodParameter(nonNullableMethod, -1).isOptional()) } + @Test + fun `Suspending function return type`() { + assertEquals(Number::class.java, returnParameterType("suspendFun")) + assertEquals(Number::class.java, returnGenericParameterType("suspendFun")) + + assertEquals(Producer::class.java, returnParameterType("suspendFun2")) + assertEquals("org.springframework.core.Producer", returnGenericParameterTypeName("suspendFun2")) + + assertEquals(Wrapper::class.java, returnParameterType("suspendFun3")) + assertEquals("org.springframework.core.Wrapper", returnGenericParameterTypeName("suspendFun3")) + + assertEquals(Consumer::class.java, returnParameterType("suspendFun4")) + assertEquals("org.springframework.core.Consumer", returnGenericParameterTypeName("suspendFun4")) + + assertEquals(Producer::class.java, returnParameterType("suspendFun5")) + assertTrue(returnGenericParameterType("suspendFun5") is TypeVariable<*>) + assertEquals("org.springframework.core.Producer", returnGenericParameterTypeBoundName("suspendFun5")) + + assertEquals(Wrapper::class.java, returnParameterType("suspendFun6")) + assertTrue(returnGenericParameterType("suspendFun6") is TypeVariable<*>) + assertEquals("org.springframework.core.Wrapper", returnGenericParameterTypeBoundName("suspendFun6")) + + assertEquals(Consumer::class.java, returnParameterType("suspendFun7")) + assertTrue(returnGenericParameterType("suspendFun7") is TypeVariable<*>) + assertEquals("org.springframework.core.Consumer", returnGenericParameterTypeBoundName("suspendFun7")) + + assertEquals(Object::class.java, returnParameterType("suspendFun8")) + assertEquals(Object::class.java, returnGenericParameterType("suspendFun8")) + } + + private fun returnParameterType(funName: String) = returnMethodParameter(funName).parameterType + private fun returnGenericParameterType(funName: String) = returnMethodParameter(funName).genericParameterType + private fun returnGenericParameterTypeName(funName: String) = returnGenericParameterType(funName).typeName + private fun returnGenericParameterTypeBoundName(funName: String) = (returnGenericParameterType(funName) as TypeVariable<*>).bounds[0].typeName + + private fun returnMethodParameter(funName: String) = + MethodParameter(this::class.declaredFunctions.first { it.name == funName }.javaMethod!!, -1) @Suppress("unused", "unused_parameter") fun nullable(p1: String?): Int? = 42 @@ -64,4 +105,33 @@ class KotlinMethodParameterTests { @Suppress("unused", "unused_parameter") fun nonNullable(p1: String): Int = 42 + @Suppress("unused", "unused_parameter") + suspend fun suspendFun(p1: String): Number = TODO() + + @Suppress("unused", "unused_parameter") + suspend fun suspendFun2(p1: String): Producer = TODO() + + @Suppress("unused", "unused_parameter") + suspend fun suspendFun3(p1: String): Wrapper = TODO() + + @Suppress("unused", "unused_parameter") + suspend fun suspendFun4(p1: String): Consumer = TODO() + + @Suppress("unused", "unused_parameter") + suspend fun > suspendFun5(p1: String): T = TODO() + + @Suppress("unused", "unused_parameter") + suspend fun > suspendFun6(p1: String): T = TODO() + + @Suppress("unused", "unused_parameter") + suspend fun > suspendFun7(p1: String): T = TODO() + + @Suppress("unused", "unused_parameter") + suspend fun suspendFun8(p1: String): Any? = TODO() } + +interface Producer + +interface Wrapper + +interface Consumer