Improved error message that might save an exhausted developer dealing with a monstrous constructor

Author: harawata

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

@@ -156,7 +156,7 @@ private boolean verifyPropertyNaming(Set<String> constructorArgsByName) {
     // either specify all names and (optional random order), or type info.
     if (!allMappingsHavePropertyNames && !constructorArgsByName.isEmpty()) {
       throw new BuilderException("Error in result map '" + resultMapId
-          + "'. We do not support partially specifying a property name. Either specify all property names, or none.");
+          + "'. We do not support partially specifying a property name nor duplicates. Either specify all property names, or none.");
     }
 
     return allMappingsHavePropertyNames;

src/test/java/org/apache/ibatis/builder/ResultMappingConstructorResolverTest.java

@@ -189,6 +189,19 @@ void testThrowExceptionWithPartialPropertyNameSpecified() {
         .hasMessageContaining("Either specify all property names, or none.");
   }
 
+  @Test
+  void testThrowExceptionWithDuplicatedPropertyNames() {
+    ResultMapping mappingA = createConstructorMappingFor(Object.class, "a", "a");
+    ResultMapping mappingB = createConstructorMappingFor(Object.class, "a", "b");
+    ResultMapping mappingC = createConstructorMappingFor(LocalDate.class, "c", "c");
+
+    final ResultMappingConstructorResolver resolver = createResolverFor(ResultType1.class, TEST_ID, mappingA, mappingB,
+        mappingC);
+
+    assertThatThrownBy(resolver::resolveWithConstructor).isInstanceOf(BuilderException.class)
+        .hasMessageContaining("Either specify all property names, or none.");
+  }
+
   @Test
   void testCanResolveWithMissingPropertyNameAndAllTypeInfo() {
     ResultMapping mappingA = createConstructorMappingFor(long.class, null, "a");