Wrong fix for http://code.google.com/p/mybatis/issues/detail?id=433 and a test that shows why it does not work

Author: emacarron

src/main/java/org/apache/ibatis/executor/resultset/NestedResultSetHandler.java

@@ -153,10 +153,6 @@ private boolean applyNestedResultMappings(ResultSet rs, ResultMap resultMap, Met
                   final MetaObject targetMetaObject = configuration.newMetaObject(collectionProperty);
                   targetMetaObject.add(rowValue);
                 } else {
-                  if (!newObject) { 
-                    throw new ExecutorException("Trying to overwrite a previous set value for the association '" + resultMapping.getProperty() 
-                        + "'. Check your id/result elements to ensure they identify uniquely an record.");
-                  }
                   metaObject.setValue(resultMapping.getProperty(), rowValue);
                 }
                 foundValues = true;

src/test/java/org/apache/ibatis/submitted/associationtest/AssociationTest.java

@@ -19,7 +19,6 @@
 import java.sql.Connection;
 import java.util.List;
 
-import org.apache.ibatis.exceptions.PersistenceException;
 import org.apache.ibatis.io.Resources;
 import org.apache.ibatis.jdbc.ScriptRunner;
 import org.apache.ibatis.session.SqlSession;
@@ -58,25 +57,43 @@ public void shouldGetAllCars() {
       Mapper mapper = sqlSession.getMapper(Mapper.class);
       List<Car> cars = mapper.getCars();
       Assert.assertEquals(4, cars.size());
+      Assert.assertEquals("VW", cars.get(0).getType());
+      Assert.assertNotNull(cars.get(0).getEngine());
+      Assert.assertNull(cars.get(0).getBrakes());
+      Assert.assertEquals("Opel", cars.get(1).getType());
+      Assert.assertNull(cars.get(1).getEngine());
+      Assert.assertNotNull(cars.get(1).getBrakes());
     } finally {
       sqlSession.close();
     }
   }
 
-  @Test(expected=PersistenceException.class)
+  @Test
+  public void shouldGetOneCarWithOneEngineAndBrakes() {
+    SqlSession sqlSession = sqlSessionFactory.openSession();
+    try {
+      Mapper mapper = sqlSession.getMapper(Mapper.class);
+      List<Car> cars = mapper.getCars2();      
+      Assert.assertEquals(1, cars.size());
+      Assert.assertNotNull(cars.get(0).getEngine());
+      Assert.assertNotNull(cars.get(0).getBrakes());      
+    } finally {
+      sqlSession.close();
+    }
+  }
+
+  @Test
   public void shouldGetAllCarsNonUnique() {
     // this is a little weird - we might expect 4 objects back, but there are only
-    // 2 unique combinations of Car attributes, so we get two back.
-    
-    // update, this was reported as an error, see Issue #433
-    // in this case there is data loss, so now it fails
+    // 1 distinct carid, so we get one back.
     SqlSession sqlSession = sqlSessionFactory.openSession();
     try {
       Mapper mapper = sqlSession.getMapper(Mapper.class);
-      List<Car> cars = mapper.getCarsNonUnique();
-      Assert.assertEquals(2, cars.size());
+      List<Car> cars = mapper.getCars2();
+      Assert.assertEquals(1, cars.size());
     } finally {
       sqlSession.close();
     }
   }
+
 }

src/test/java/org/apache/ibatis/submitted/associationtest/Brakes.java

@@ -0,0 +1,30 @@
+/*
+ *    Copyright 2009-2013 The MyBatis Team
+ *
+ *    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.apache.ibatis.submitted.associationtest;
+
+public class Brakes {
+  
+  private String type;
+
+  public String getType() {
+    return type;
+  }
+
+  public void setType(String type) {
+    this.type = type;
+  }
+
+}

src/test/java/org/apache/ibatis/submitted/associationtest/Car.java

@@ -1,9 +1,26 @@
+/*
+ *    Copyright 2009-2013 The MyBatis Team
+ *
+ *    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.apache.ibatis.submitted.associationtest;
 
 public class Car {
   private int id;
   private String type;
   private Engine engine;
+  private Brakes brakes;
+  
   public int getId() {
     return id;
   }
@@ -22,5 +39,11 @@ public Engine getEngine() {
   public void setEngine(Engine engine) {
     this.engine = engine;
   }
+  public Brakes getBrakes() {
+    return brakes;
+  }
+  public void setBrakes(Brakes brakes) {
+    this.brakes = brakes;
+  }
 
 }

src/test/java/org/apache/ibatis/submitted/associationtest/CreateDB.sql

@@ -20,10 +20,11 @@ create table cars (
   carid integer,
   cartype varchar(20),
   enginetype varchar(20),
-  enginecylinders integer
+  enginecylinders integer,
+  brakestype varchar(20)
 );
 
-insert into cars (carid, cartype, enginetype, enginecylinders) values(1, 'VW', 'Diesel', 4);
-insert into cars (carid, cartype, enginetype, enginecylinders) values(2, 'VW', 'Gas', 6);
-insert into cars (carid, cartype, enginetype, enginecylinders) values(3, 'Audi', 'Diesel', 6);
-insert into cars (carid, cartype, enginetype, enginecylinders) values(4, 'Audi', 'Gas', 8);
+insert into cars (carid, cartype, enginetype, enginecylinders, brakestype) values(1, 'VW',   'Diesel', 4,    null);
+insert into cars (carid, cartype, enginetype, enginecylinders, brakestype) values(2, 'Opel',    null,    null, 'drum');
+insert into cars (carid, cartype, enginetype, enginecylinders, brakestype) values(3, 'Audi', 'Diesel', 4,    'disk');
+insert into cars (carid, cartype, enginetype, enginecylinders, brakestype) values(4, 'Ford', 'Gas',    8,    'drum');

src/test/java/org/apache/ibatis/submitted/associationtest/Mapper.java

@@ -20,6 +20,7 @@
 public interface Mapper {
 
   List<Car> getCars();
-  List<Car> getCarsNonUnique();
+  List<Car> getCars2();
+  List<Car> getCars3();
 
 }

src/test/java/org/apache/ibatis/submitted/associationtest/Mapper.xml

@@ -21,20 +21,29 @@
 <mapper namespace="org.apache.ibatis.submitted.associationtest.Mapper">
 
   <resultMap type="org.apache.ibatis.submitted.associationtest.Car" id="carResult">
-    <result column="carid" property="id"/>
+    <id column="carid" property="id"/>
     <result column="cartype" property="type"/>
     <association property="engine" resultMap="engineResult"/>
+    <association property="brakes" resultMap="brakesResult"/>
   </resultMap>
   <resultMap type="org.apache.ibatis.submitted.associationtest.Engine" id="engineResult">
     <result column="enginetype" property="type"/>
     <result column="enginecylinders" property="cylinders"/>
   </resultMap>
+  <resultMap type="org.apache.ibatis.submitted.associationtest.Brakes" id="brakesResult">
+    <result column="brakesType" property="type"/>
+  </resultMap>
 
   <select id="getCars" resultMap="carResult">
     select * from cars
   </select>
 
   <select id="getCarsNonUnique" resultMap="carResult">
-    select 1 as carid, cartype, enginetype, enginecylinders from cars
+    select 1 as carid, cartype, enginetype, enginecylinders, brakestype from cars
+  </select>
+  
+  <select id="getCars2" resultMap="carResult">
+    select 1 as carid, cartype, enginetype, enginecylinders, brakestype from cars where carid in (1,2)
   </select>
+  
 </mapper>