DATACMNS-1780 - PersistentEntities allows in flight metadata creation if the associated mapping context can be identified.

Use a more lenient approach, that allows metadata creation, when looking up persistent entities. This allows eg. a configured AuditingHandler to kick in without having to register an initial entity set in first place.

Original pull request: #462.

src/test/java/org/springframework/data/auditing/IsNewAwareAuditingHandlerUnitTests.java

@@ -16,6 +16,7 @@
 package org.springframework.data.auditing;
 
 import static org.assertj.core.api.Assertions.*;
+import static org.mockito.Mockito.*;
 
 import java.util.Optional;
 
@@ -103,6 +104,19 @@ class IsNewAwareAuditingHandlerUnitTests extends AuditingHandlerUnitTests {
 		getHandler().markAudited(Optional.of(new EntityWithoutId()));
 	}
 
+	@Test // DATACMNS-1780
+	void singleContextAllowsInFlightMetadataCreationForUnknownPersistentEntities() {
+
+		SampleMappingContext mappingContext = spy(new SampleMappingContext());
+		mappingContext.afterPropertiesSet();
+
+		AuditedUser user = new AuditedUser();
+		user.id = 1L;
+
+		new IsNewAwareAuditingHandler(PersistentEntities.of(mappingContext)).markAudited(user);
+		verify(mappingContext).getPersistentEntity(AuditedUser.class);
+	}
+
 	static class Domain {
 
 		@Id Long id;