DATAJPA-1261 - Revert optimizations made for existing entities in implementation of CrudRepository.save(…).

This reverts the functional change made by DATAJPA-931. This means merge will be called again, even if the entity for which save was called is already attached to the session. Tests stay in place to verify the new old behavior.

Related ticket: DATAJPA-931.
Original pull request: #249.

src/main/java/org/springframework/data/jpa/repository/support/SimpleJpaRepository.java

@@ -489,11 +489,9 @@ public class SimpleJpaRepository<T, ID> implements JpaRepository<T, ID>, JpaSpec
 		if (entityInformation.isNew(entity)) {
 			em.persist(entity);
 			return entity;
-		} else if (!em.contains(entity)) {
+		} else {
 			return em.merge(entity);
 		}
-
-		return entity;
 	}
 
 	/*

src/test/java/org/springframework/data/jpa/repository/support/SimpleJpaRepositoryUnitTests.java

@@ -145,8 +145,8 @@ public class SimpleJpaRepositoryUnitTests {
 		verify(em).merge(detachedUser);
 	}
 
-	@Test // DATAJPA-931
-	public void mergeGetsNotCalledWhenAttached() {
+	@Test // DATAJPA-931, DATAJPA-1261
+	public void mergeGetsCalledWhenAttached() {
 
 		User attachedUser = new User();
 
@@ -154,6 +154,6 @@ public class SimpleJpaRepositoryUnitTests {
 
 		repo.save(attachedUser);
 
-		verify(em, never()).merge(attachedUser);
+		verify(em).merge(attachedUser);
 	}
 }