HHH-6177: fixing a bug with mapping null references introduced by the last pull request

hibernate-envers/src/main/java/org/hibernate/envers/entities/mapper/id/AbstractCompositeIdMapper.java

@@ -58,7 +58,9 @@ public abstract class AbstractCompositeIdMapper extends AbstractIdMapper impleme
         }
 
         for (SingleIdMapper mapper : ids.values()) {
-            mapper.mapToEntityFromMap(ret, data);
+            if (!mapper.mapToEntityFromMap(ret, data)) {
+                return null;
+            }
         }
 
         return ret;

hibernate-envers/src/main/java/org/hibernate/envers/entities/mapper/id/EmbeddedIdMapper.java

@@ -61,9 +61,9 @@ public class EmbeddedIdMapper extends AbstractCompositeIdMapper implements Simpl
         mapToMapFromId(data, getter.get(obj));
     }
 
-    public void mapToEntityFromMap(Object obj, Map data) {
+    public boolean mapToEntityFromMap(Object obj, Map data) {
         if (data == null || obj == null) {
-            return;
+            return false;
         }
 
         Getter getter = ReflectionTools.getGetter(obj.getClass(), idPropertyData);
@@ -71,11 +71,17 @@ public class EmbeddedIdMapper extends AbstractCompositeIdMapper implements Simpl
 
         try {
             Object subObj = ReflectHelper.getDefaultConstructor( getter.getReturnType() ).newInstance();
-            setter.set(obj, subObj, null);
 
+            boolean ret = true;
             for (IdMapper idMapper : ids.values()) {
-                idMapper.mapToEntityFromMap(subObj, data);
+                ret &= idMapper.mapToEntityFromMap(subObj, data);
             }
+
+            if (ret) {
+                setter.set(obj, subObj, null);
+            }
+
+            return ret;
         } catch (Exception e) {
             throw new AuditException(e);
         }

hibernate-envers/src/main/java/org/hibernate/envers/entities/mapper/id/IdMapper.java

@@ -34,7 +34,12 @@ public interface IdMapper {
 
     void mapToMapFromEntity(Map<String, Object> data, Object obj);
 
-    void mapToEntityFromMap(Object obj, Map data);
+    /**
+     * @param obj Object to map to.
+     * @param data Data to map.
+     * @return True if data was mapped; false otherwise (when the id is {@code null}).
+     */
+    boolean mapToEntityFromMap(Object obj, Map data);
 
     Object mapToIdFromEntity(Object data);
 

hibernate-envers/src/main/java/org/hibernate/envers/entities/mapper/id/MultipleIdMapper.java

@@ -47,10 +47,13 @@ public class MultipleIdMapper extends AbstractCompositeIdMapper implements Simpl
         mapToMapFromId(data, obj);
     }
 
-    public void mapToEntityFromMap(Object obj, Map data) {
+    public boolean mapToEntityFromMap(Object obj, Map data) {
+        boolean ret = true;
         for (IdMapper idMapper : ids.values()) {
-            idMapper.mapToEntityFromMap(obj, data);
+            ret &= idMapper.mapToEntityFromMap(obj, data);
         }
+
+        return ret;
     }
 
     public IdMapper prefixMappedProperties(String prefix) {

hibernate-envers/src/main/java/org/hibernate/envers/entities/mapper/id/SingleIdMapper.java

@@ -53,13 +53,20 @@ public class SingleIdMapper extends AbstractIdMapper implements SimpleIdMapperBu
         this.propertyData = propertyData;
     }
 
-    public void mapToEntityFromMap(Object obj, Map data) {
+    public boolean mapToEntityFromMap(Object obj, Map data) {
         if (data == null || obj == null) {
-            return;
+            return false;
+        }
+
+        Object value = data.get(propertyData.getName());
+        if (value == null) {
+            return false;
         }
 
         Setter setter = ReflectionTools.getSetter(obj.getClass(), propertyData);
-        setter.set(obj, data.get(propertyData.getName()), null);
+        setter.set(obj, value, null);
+
+        return true;
     }
 
     public Object mapToIdFromMap(Map data) {

hibernate-envers/src/test/java/org/hibernate/envers/test/integration/onetoone/unidirectional/UnidirectionalMulIdWithNulls.java

@@ -9,6 +9,8 @@ import org.junit.Test;
 
 import javax.persistence.EntityManager;
 
+import static org.junit.Assert.*;
+
 /**
  * @author Lukasz Antoniak (lukasz dot antoniak at gmail dot com)
  */
@@ -42,14 +44,14 @@ public class UnidirectionalMulIdWithNulls extends AbstractEntityTest {
     @Test
     public void testNullReference() {
         UniRefIngMulIdEntity nullRef = getAuditReader().find(UniRefIngMulIdEntity.class, 2, 1);
-        assert nullRef.getReference() == null;
+        assertNull(nullRef.getReference());
     }
 
     @Test
     public void testNotNullReference() {
         EmbIdTestEntity eite = getAuditReader().find(EmbIdTestEntity.class, ei, 1);
         UniRefIngMulIdEntity notNullRef = getAuditReader().find(UniRefIngMulIdEntity.class, 1, 1);
-        assert notNullRef.getReference() != null;
-        assert notNullRef.getReference().equals(eite);
+        assertNotNull(notNullRef.getReference());
+        assertEquals(notNullRef.getReference(), eite);
     }
 }