HHH-6813 @id @OnetoOne cause NullPointerException during query

Author: brmeyer

hibernate-core/src/main/java/org/hibernate/cfg/OneToOneSecondPass.java

@@ -32,6 +32,7 @@
 import org.hibernate.cfg.annotations.PropertyBinder;
 import org.hibernate.internal.util.StringHelper;
 import org.hibernate.mapping.Column;
+import org.hibernate.mapping.Component;
 import org.hibernate.mapping.DependantValue;
 import org.hibernate.mapping.Join;
 import org.hibernate.mapping.ManyToOne;
@@ -212,7 +213,23 @@ else if ( otherSideProperty.getValue() instanceof ManyToOne ) {
 					propertyHolder.addProperty( prop, inferredData.getDeclaringClass() );
 				}
 
-				value.setReferencedPropertyName( mappedBy );
+				// HHH-6813
+				// If otherSide's id is derived, do not set EntityType#uniqueKeyPropertyName.
+				// EntityType#isReferenceToPrimaryKey() assumes that, if it's set,
+				// a PK is not referenced.  Example:
+				//
+				// Foo: @Id long id, @OneToOne(mappedBy="foo") Bar bar
+				// Bar: @Id @OneToOne Foo foo
+				boolean referencesDerivedId = false;
+				try {
+					referencesDerivedId = otherSide.getIdentifier() instanceof Component
+							&& ( (Component) otherSide.getIdentifier() ).getProperty( mappedBy ) != null;
+				}
+				catch ( MappingException e ) {
+					// ignore
+				}
+				String referencedPropertyName = referencesDerivedId ? null : mappedBy;
+				value.setReferencedPropertyName( referencedPropertyName );
 
 				String propertyRef = value.getReferencedPropertyName();
 				if ( propertyRef != null ) {

hibernate-core/src/test/java/org/hibernate/test/annotations/derivedidentities/bidirectional/OneToOneWithDerivedIdentityTest.java

@@ -23,14 +23,14 @@
  */
 package org.hibernate.test.annotations.derivedidentities.bidirectional;
 
-import org.junit.Test;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
 
 import org.hibernate.Session;
 import org.hibernate.testing.FailureExpected;
+import org.hibernate.testing.TestForIssue;
 import org.hibernate.testing.junit4.BaseCoreFunctionalTestCase;
-
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
+import org.junit.Test;
 
 public class OneToOneWithDerivedIdentityTest extends BaseCoreFunctionalTestCase {
 	@Test
@@ -57,6 +57,29 @@ public void testInsertFooAndBarWithDerivedId() {
 		s.getTransaction().rollback();
 		s.close();
 	}
+	
+	@Test
+	@TestForIssue(jiraKey = "HHH-6813")
+	public void testSelectWithDerivedId() {
+		Session s = openSession();
+		s.beginTransaction();
+		Bar bar = new Bar();
+		bar.setDetails( "Some details" );
+		Foo foo = new Foo();
+		foo.setBar( bar );
+		bar.setFoo( foo );
+		s.persist( foo );
+		s.flush();
+		assertNotNull( foo.getId() );
+		assertEquals( foo.getId(), bar.getFoo().getId() );
+
+		s.clear();
+		Foo newFoo = (Foo) s.createQuery( "SELECT f FROM Foo f" ).uniqueResult();
+		assertNotNull( newFoo );
+		assertEquals( "Some details", newFoo.getBar().getDetails() );
+		s.getTransaction().rollback();
+		s.close();
+	}
 
 	@Override
 	protected Class<?>[] getAnnotatedClasses() {