fixes #1590 Ensure composite to be empty when unnecessary column is specified

Although more active solution (e.g. output a warning) might be better, there could be a use case that I am not aware of.

Author: harawata

src/main/java/org/apache/ibatis/builder/MapperBuilderAssistant.java

@@ -16,6 +16,7 @@
 package org.apache.ibatis.builder;
 
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
@@ -369,7 +370,12 @@ public ResultMapping buildResultMapping(
       boolean lazy) {
     Class<?> javaTypeClass = resolveResultJavaType(resultType, property, javaType);
     TypeHandler<?> typeHandlerInstance = resolveTypeHandler(javaTypeClass, typeHandler);
-    List<ResultMapping> composites = parseCompositeColumnName(column);
+    List<ResultMapping> composites;
+    if ((nestedSelect == null || nestedSelect.isEmpty()) && (foreignColumn == null || foreignColumn.isEmpty())) {
+      composites = Collections.emptyList();
+    } else {
+      composites = parseCompositeColumnName(column);
+    }
     return new ResultMapping.Builder(configuration, property, column, javaTypeClass)
         .jdbcType(jdbcType)
         .nestedQueryId(applyCurrentNamespace(nestedSelect, true))

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

@@ -26,7 +26,8 @@
     <id column="carid" property="id"/>
     <result column="cartype" property="type"/>
     <association property="engine" resultMap="engineResult"/>
-    <association property="brakes" resultMap="brakesResult"/>
+    <!-- the bogus 'column' below is to assert gh-1590 -->
+    <association property="brakes" resultMap="brakesResult" column="{carid=carid}" />
   </resultMap>
   <resultMap type="org.apache.ibatis.submitted.associationtest.Engine" id="engineResult">
     <result column="enginetype" property="type"/>