HHH-7561 - Fix and test

hibernate-core/src/main/java/org/hibernate/tuple/entity/AbstractEntityTuplizer.java

@@ -328,6 +328,9 @@ public abstract class AbstractEntityTuplizer implements EntityTuplizer {
 		if ( entityMetamodel.getIdentifierProperty().isEmbedded() ) {
 			id = entity;
 		}
+		else if ( HibernateProxy.class.isInstance( entity ) ) {
+			id = ( (HibernateProxy) entity ).getHibernateLazyInitializer().getIdentifier();
+		}
 		else {
 			if ( idGetter == null ) {
 				if (identifierMapperType==null) {

hibernate-entitymanager/src/test/java/org/hibernate/jpa/test/util/Article.java

@@ -0,0 +1,44 @@
+package org.hibernate.jpa.test.util;
+
+import java.io.Serializable;
+import javax.persistence.Entity;
+import javax.persistence.FetchType;
+import javax.persistence.GeneratedValue;
+import javax.persistence.Id;
+import javax.persistence.ManyToOne;
+
+/**
+ * @author Lukasz Antoniak (lukasz dot antoniak at gmail dot com)
+ */
+@Entity
+public class Article implements Serializable {
+	@Id
+	@GeneratedValue
+	private Integer id;
+
+	@ManyToOne(fetch = FetchType.LAZY)
+	private Author author;
+
+	public Article() {
+	}
+
+	public Article(Author author) {
+		this.author = author;
+	}
+
+	public Integer getId() {
+		return id;
+	}
+
+	public void setId(Integer id) {
+		this.id = id;
+	}
+
+	public Author getAuthor() {
+		return author;
+	}
+
+	public void setAuthor(Author author) {
+		this.author = author;
+	}
+}

hibernate-entitymanager/src/test/java/org/hibernate/jpa/test/util/GetIdentifierTest.java

@@ -28,8 +28,11 @@ import javax.persistence.EntityManager;
 import org.junit.Test;
 
 import org.hibernate.jpa.test.BaseEntityManagerFunctionalTestCase;
+import org.hibernate.proxy.HibernateProxy;
+import org.hibernate.testing.TestForIssue;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
 
 /**
  * @author Emmanuel Bernard
@@ -47,6 +50,36 @@ public class GetIdentifierTest extends BaseEntityManagerFunctionalTestCase {
 		em.close();
 	}
 
+	@Test
+	@TestForIssue(jiraKey = "HHH-7561")
+	public void testProxyObject() {
+		EntityManager em = entityManagerFactory().createEntityManager();
+		em.getTransaction().begin();
+		Book book = new Book();
+		em.persist( book );
+		em.flush();
+		em.clear(); // Clear persistence context to receive proxy object below.
+		Book proxy = em.getReference( Book.class, book.getId() );
+		assertTrue( proxy instanceof HibernateProxy );
+		assertEquals( book.getId(), em.getEntityManagerFactory().getPersistenceUnitUtil().getIdentifier( proxy ) );
+		em.getTransaction().rollback();
+		em.close();
+
+		em = entityManagerFactory().createEntityManager();
+		em.getTransaction().begin();
+		Author author = new Author();
+		Article article = new Article( author );
+		em.persist( author );
+		em.persist( article );
+		em.flush();
+		em.clear(); // Clear persistence context to receive proxy relation below.
+		article = em.find( Article.class, article.getId() );
+		assertTrue( article.getAuthor() instanceof HibernateProxy );
+		assertEquals( author.getId(), em.getEntityManagerFactory().getPersistenceUnitUtil().getIdentifier( article.getAuthor() ) );
+		em.getTransaction().rollback();
+		em.close();
+	}
+
 	@Test
 	public void testEmbeddedId() {
 		EntityManager em = entityManagerFactory().createEntityManager();
@@ -86,7 +119,8 @@ public class GetIdentifierTest extends BaseEntityManagerFunctionalTestCase {
 				Book.class,
 				Umbrella.class,
 				Sickness.class,
-				Author.class
+				Author.class,
+				Article.class
 		};
 	}
 }