report error in case of constructor-arg index ambiguity (SPR-6329)

org.springframework.beans/src/main/java/org/springframework/beans/factory/config/ConstructorArgumentValues.java

@@ -131,6 +131,14 @@ public class ConstructorArgumentValues {
 		this.indexedArgumentValues.put(key, newValue);
 	}
 
+	/**
+	 * Check whether an argument value has been registered for the given index.
+	 * @param index the index in the constructor argument list
+	 */
+	public boolean hasIndexedArgumentValue(int index) {
+		return this.indexedArgumentValues.containsKey(index);
+	}
+
 	/**
 	 * Get argument value for the given index in the constructor argument list.
 	 * @param index the index in the constructor argument list

org.springframework.beans/src/main/java/org/springframework/beans/factory/xml/BeanDefinitionParserDelegate.java

@@ -778,7 +778,12 @@ public class BeanDefinitionParserDelegate {
 							valueHolder.setName(nameAttr);
 						}
 						valueHolder.setSource(extractSource(ele));
-						bd.getConstructorArgumentValues().addIndexedArgumentValue(index, valueHolder);
+						if (bd.getConstructorArgumentValues().hasIndexedArgumentValue(index)) {
+							error("Ambiguous constructor-arg entries for index " + index, ele);
+						}
+						else {
+							bd.getConstructorArgumentValues().addIndexedArgumentValue(index, valueHolder);
+						}
 					}
 					finally {
 						this.parseState.pop();