Obtain merged annotation for annotation validation.

We now validate declared annotations by pre-processing these through AnnotatedElementUtils to ensure a proper comparison. Previously, we compared annotation in their declared form (AnnotatedElement.getAnnotations()) with merged annotations which could fail due to aliasing effects of merged annotations.

Closes #2368.

src/main/java/org/springframework/data/mapping/model/AnnotationBasedPersistentProperty.java

@@ -120,13 +120,15 @@ public abstract class AnnotationBasedPersistentProperty<P extends PersistentProp
 
 				Class<? extends Annotation> annotationType = annotation.annotationType();
 
-				validateAnnotation(annotation,
+				Annotation mergedAnnotation = AnnotatedElementUtils.getMergedAnnotation(it, annotationType);
+
+				validateAnnotation(mergedAnnotation,
 						"Ambiguous mapping! Annotation %s configured "
 								+ "multiple times on accessor methods of property %s in class %s!",
 						annotationType.getSimpleName(), getName(), getOwner().getType().getSimpleName());
 
 				annotationCache.put(annotationType,
-						Optional.ofNullable(AnnotatedElementUtils.findMergedAnnotation(it, annotationType)));
+						Optional.of(mergedAnnotation));
 			}
 		});
 
@@ -135,13 +137,14 @@ public abstract class AnnotationBasedPersistentProperty<P extends PersistentProp
 			for (Annotation annotation : it.getAnnotations()) {
 
 				Class<? extends Annotation> annotationType = annotation.annotationType();
+				Annotation mergedAnnotation = AnnotatedElementUtils.getMergedAnnotation(it, annotationType);
 
-				validateAnnotation(annotation,
+				validateAnnotation(mergedAnnotation,
 						"Ambiguous mapping! Annotation %s configured " + "on field %s and one of its accessor methods in class %s!",
 						annotationType.getSimpleName(), it.getName(), getOwner().getType().getSimpleName());
 
 				annotationCache.put(annotationType,
-						Optional.ofNullable(AnnotatedElementUtils.findMergedAnnotation(it, annotationType)));
+						Optional.of(mergedAnnotation));
 			}
 		});
 	}

src/test/java/org/springframework/data/mapping/model/AnnotationBasedPersistentPropertyUnitTests.java

@@ -356,6 +356,7 @@ public class AnnotationBasedPersistentPropertyUnitTests<P extends AnnotationBase
 		}
 
 		@MyAnnotation
+		@RevisedAnnnotationWithAliasFor(value = "my-value")
 		public void setSetter(String setter) {
 			this.setter = setter;
 		}