#421 - Suppress results for suspended query methods returning kotlin.Unit.

We now discard results for suspended query methods if the return type is kotlin.Unit.

Related ticket: DATACMNS-1779

Original pull request: #422.

Author: mp911de

src/main/java/org/springframework/data/r2dbc/repository/query/AbstractR2dbcQuery.java

@@ -34,6 +34,7 @@
 import org.springframework.data.repository.query.RepositoryQuery;
 import org.springframework.data.repository.query.ResultProcessor;
 import org.springframework.data.repository.query.ReturnedType;
+import org.springframework.data.util.ReflectionUtils;
 import org.springframework.util.Assert;
 
 /**
@@ -136,7 +137,7 @@ private R2dbcQueryExecution getExecutionToWrap(ReturnedType returnedType) {
 				});
 			}
 
-			if (Void.class.isAssignableFrom(returnedType.getReturnedType())) {
+			if (ReflectionUtils.isVoid(returnedType.getReturnedType())) {
 				return (q, t, c) -> q.rowsUpdated().then();
 			}
 
@@ -152,7 +153,7 @@ private R2dbcQueryExecution getExecutionToWrap(ReturnedType returnedType) {
 
 	/**
 	 * Returns whether this query is a modifying one.
-	 * 
+	 *
 	 * @return
 	 * @since 1.1
 	 */

src/main/java/org/springframework/data/r2dbc/repository/query/R2dbcQueryExecution.java

@@ -30,6 +30,7 @@
 import org.springframework.data.relational.repository.query.DtoInstantiatingConverter;
 import org.springframework.data.repository.query.ResultProcessor;
 import org.springframework.data.repository.query.ReturnedType;
+import org.springframework.data.util.ReflectionUtils;
 import org.springframework.util.ClassUtils;
 
 /**
@@ -97,7 +98,7 @@ public Object convert(Object source) {
 				return source;
 			}
 
-			if (Void.class == returnedType.getReturnedType()) {
+			if (ReflectionUtils.isVoid(returnedType.getReturnedType())) {
 
 				if (source instanceof Mono) {
 					return ((Mono<?>) source).then();

src/test/kotlin/org/springframework/data/r2dbc/repository/CoroutineRepositoryUnitTests.kt

@@ -0,0 +1,74 @@
+/*
+ * Copyright 2020 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
+ *
+ *      https://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.data.r2dbc.repository
+
+import io.r2dbc.spi.test.MockResult
+import kotlinx.coroutines.runBlocking
+import org.junit.jupiter.api.BeforeEach
+import org.junit.jupiter.api.Test
+import org.springframework.data.annotation.Id
+import org.springframework.data.r2dbc.core.DatabaseClient
+import org.springframework.data.r2dbc.core.DefaultReactiveDataAccessStrategy
+import org.springframework.data.r2dbc.core.R2dbcEntityTemplate
+import org.springframework.data.r2dbc.dialect.PostgresDialect
+import org.springframework.data.r2dbc.repository.support.R2dbcRepositoryFactory
+import org.springframework.data.r2dbc.testing.StatementRecorder
+import org.springframework.data.repository.kotlin.CoroutineCrudRepository
+
+/**
+ * Unit tests for [CoroutineCrudRepository].
+ *
+ * @author Mark Paluch
+ */
+class CoroutineRepositoryUnitTests {
+
+	lateinit var client: DatabaseClient
+	lateinit var entityTemplate: R2dbcEntityTemplate
+	lateinit var recorder: StatementRecorder
+	lateinit var repositoryFactory: R2dbcRepositoryFactory
+
+	@BeforeEach
+	fun before() {
+		recorder = StatementRecorder.newInstance()
+		client = DatabaseClient.builder().connectionFactory(recorder)
+				.dataAccessStrategy(DefaultReactiveDataAccessStrategy(PostgresDialect.INSTANCE)).build()
+		entityTemplate = R2dbcEntityTemplate(client)
+		repositoryFactory = R2dbcRepositoryFactory(entityTemplate)
+	}
+
+	@Test
+	fun shouldIssueDeleteQuery() {
+
+		val result = MockResult.builder().rowsUpdated(2).build()
+		recorder.addStubbing({ s: String -> s.startsWith("DELETE") }, result)
+
+		val repository = repositoryFactory.getRepository(PersonRepository::class.java)
+
+		runBlocking {
+			repository.deleteUserAssociation(2)
+		}
+	}
+
+	interface PersonRepository : CoroutineCrudRepository<Person, Long> {
+
+		@Modifying
+		@Query("DELETE FROM person WHERE id = :id ")
+		suspend fun deleteUserAssociation(userId: Int)
+	}
+
+
+	data class Person(@Id var id: Long, var name: String)
+}