DATACMNS-1171 - Do not create PersistentEntity for unsupported Kotlin classes.

We now reject unsupported Kotlin classes from the MappingContext by default by not creating persistent entities.

Original pull request: #245.

src/main/java/org/springframework/data/mapping/context/AbstractMappingContext.java

@@ -471,15 +471,22 @@ public abstract class AbstractMappingContext<E extends MutablePersistentEntity<?
 
 	/**
 	 * Returns whether a {@link PersistentEntity} instance should be created for the given {@link TypeInformation}. By
-	 * default this will reject this for all types considered simple, but it might be necessary to tweak that in case you
-	 * have registered custom converters for top level types (which renders them to be considered simple) but still need
-	 * meta-information about them.
+	 * default this will reject all types considered simple and non-supported Kotlin classes, but it might be necessary to
+	 * tweak that in case you have registered custom converters for top level types (which renders them to be considered
+	 * simple) but still need meta-information about them.
+	 * <p/>
 	 *
 	 * @param type will never be {@literal null}.
 	 * @return
 	 */
 	protected boolean shouldCreatePersistentEntityFor(TypeInformation<?> type) {
-		return !simpleTypeHolder.isSimpleType(type.getType());
+
+		if (simpleTypeHolder.isSimpleType(type.getType())) {
+			return false;
+		}
+
+		return !org.springframework.data.util.ReflectionUtils.isKotlinClass(type.getType())
+				|| org.springframework.data.util.ReflectionUtils.isSupportedKotlinClass(type.getType());
 	}
 
 	/**

src/test/java/org/springframework/data/mapping/context/AbstractMappingContextUnitTests.java

@@ -45,6 +45,7 @@ import org.springframework.util.StringUtils;
  *
  * @author Oliver Gierke
  * @author Thomas Darimont
+ * @author Mark Paluch
  */
 public class AbstractMappingContextUnitTests {
 
@@ -210,6 +211,16 @@ public class AbstractMappingContextUnitTests {
 		assertHasEntityFor(TreeMap.class, context, false);
 	}
 
+	@Test // DATACMNS-1171
+	public void shouldCreateEntityForKotlinDataClass() {
+		assertThat(context.getPersistentEntity(SimpleDataClass.class)).isNotNull();
+	}
+
+	@Test // DATACMNS-1171
+	public void shouldNotCreateEntityForSyntheticKotlinClass() {
+		assertThat(context.getPersistentEntity(TypeCreatingSyntheticClass.class)).isNotNull();
+	}
+
 	@Test // DATACMNS-695
 	public void persistentPropertyPathTraversesGenericTypesCorrectly() {
 		assertThat(context.getPersistentPropertyPath("field.wrapped.field", Outer.class)).hasSize(3);

src/test/kotlin/org/springframework/data/mapping/context/SimpleDataClass.kt

@@ -0,0 +1,22 @@
+/*
+ * Copyright 2017 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.data.mapping.context
+
+/**
+ * @author Mark Paluch
+ */
+data class SimpleDataClass(val firstname: String) {
+}

src/test/kotlin/org/springframework/data/mapping/context/TypeCreatingSyntheticClass.kt

@@ -0,0 +1,25 @@
+/*
+ * Copyright 2017 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.data.mapping.context
+
+/**
+ * @author Mark Paluch
+ */
+class TypeCreatingSyntheticClass {
+}
+
+fun foobar(args: Array<String>) {
+}