DATAJPA-1261 - Revert DATAJPA-931.

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.

Author: schauder

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

@@ -488,11 +488,9 @@ public <S extends T> S save(S entity) {
 		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

@@ -145,15 +145,15 @@ public void mergeGetsCalledWhenDetached() {
 		verify(em).merge(detachedUser);
 	}
 
-	@Test // DATAJPA-931
-	public void mergeGetsNotCalledWhenAttached() {
+	@Test // DATAJPA-931, DATAJPA-1261
+	public void mergeGetsCalledWhenAttached() {
 
 		User attachedUser = new User();
 
 		when(em.contains(attachedUser)).thenReturn(true);
 
 		repo.save(attachedUser);
 
-		verify(em, never()).merge(attachedUser);
+		verify(em).merge(attachedUser);
 	}
 }