Throw Exception when adding @AutomapConstructor to multiple constructors

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

@@ -710,12 +710,14 @@ private Optional<Constructor<?>> findConstructorForAutomapping(final Class<?> re
     if (constructors.length == 1) {
       return Optional.of(constructors[0]);
     }
-    for (final Constructor<?> constructor : constructors) {
-      if (constructor.isAnnotationPresent(AutomapConstructor.class)) {
-        return Optional.of(constructor);
-      }
-    }
-    if (configuration.isArgNameBasedConstructorAutoMapping()) {
+    Optional<Constructor<?>> annotated = Arrays.stream(constructors)
+        .filter(x -> x.isAnnotationPresent(AutomapConstructor.class))
+        .reduce((x, y) -> {
+          throw new ExecutorException("@AutomapConstructor should be used in only one constructor.");
+        });
+    if (annotated.isPresent()) {
+      return annotated;
+    } else if (configuration.isArgNameBasedConstructorAutoMapping()) {
       // Finding-best-match type implementation is possible,
       // but using @AutomapConstructor seems sufficient.
       throw new ExecutorException(MessageFormat.format(

src/test/java/org/apache/ibatis/autoconstructor/AutoConstructorMapper.java

@@ -1,5 +1,5 @@
 /*
- *    Copyright 2009-2021 the original author or authors.
+ *    Copyright 2009-2022 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.
@@ -29,6 +29,9 @@ public interface AutoConstructorMapper {
   @Select("SELECT * FROM subject")
   List<AnnotatedSubject> getAnnotatedSubjects();
 
+  @Select("SELECT * FROM subject")
+  List<BadAnnotatedSubject> getBadAnnotatedSubjects();
+
   @Select("SELECT * FROM subject")
   List<BadSubject> getBadSubjects();
 

src/test/java/org/apache/ibatis/autoconstructor/AutoConstructorTest.java

@@ -1,5 +1,5 @@
 /*
- *    Copyright 2009-2021 the original author or authors.
+ *    Copyright 2009-2022 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.
@@ -15,6 +15,7 @@
  */
 package org.apache.ibatis.autoconstructor;
 
+import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
@@ -23,6 +24,7 @@
 
 import org.apache.ibatis.BaseDataTest;
 import org.apache.ibatis.exceptions.PersistenceException;
+import org.apache.ibatis.executor.ExecutorException;
 import org.apache.ibatis.io.Resources;
 import org.apache.ibatis.session.SqlSession;
 import org.apache.ibatis.session.SqlSessionFactory;
@@ -71,6 +73,16 @@ void annotatedSubject() {
     }
   }
 
+  @Test
+  void badMultipleAnnotatedSubject() {
+    try (SqlSession sqlSession = sqlSessionFactory.openSession()) {
+      final AutoConstructorMapper mapper = sqlSession.getMapper(AutoConstructorMapper.class);
+      final PersistenceException ex = assertThrows(PersistenceException.class, mapper::getBadAnnotatedSubjects);
+      final ExecutorException cause = (ExecutorException)  ex.getCause();
+      assertEquals("@AutomapConstructor should be used in only one constructor.", cause.getMessage());
+    }
+  }
+
   @Test
   void badSubject() {
     try (SqlSession sqlSession = sqlSessionFactory.openSession()) {

src/test/java/org/apache/ibatis/autoconstructor/BadAnnotatedSubject.java

@@ -0,0 +1,44 @@
+/*
+ *    Copyright 2009-2022 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.apache.ibatis.autoconstructor;
+
+import org.apache.ibatis.annotations.AutomapConstructor;
+
+public class BadAnnotatedSubject {
+  private final int id;
+  private final String name;
+  private final int age;
+  private final int height;
+  private final int weight;
+
+  @AutomapConstructor
+  public BadAnnotatedSubject(final int id, final String name, final int age, final int height, final int weight) {
+    this.id = id;
+    this.name = name;
+    this.age = age;
+    this.height = height;
+    this.weight = weight;
+  }
+
+  @AutomapConstructor
+  public BadAnnotatedSubject(final int id, final String name, final int age) {
+    this.id = id;
+    this.name = name;
+    this.age = age;
+    this.height = 0;
+    this.weight = 0;
+  }
+}