HHH-12842 - Test that shows @OneToOne will be lazily loaded again

(cherry picked from commit bf6f105c41)

hibernate-core/src/test/java/org/hibernate/test/onetoone/lazy/LazyToOneTest.java

@@ -0,0 +1,164 @@
+/*
+ * Hibernate, Relational Persistence for Idiomatic Java
+ *
+ * License: GNU Lesser General Public License (LGPL), version 2.1 or later.
+ * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
+ */
+package org.hibernate.test.onetoone.lazy;
+
+import org.hibernate.testing.TestForIssue;
+import org.hibernate.testing.junit4.BaseCoreFunctionalTestCase;
+import org.junit.Before;
+import org.junit.Test;
+
+import javax.persistence.CascadeType;
+import javax.persistence.Column;
+import javax.persistence.Entity;
+import javax.persistence.FetchType;
+import javax.persistence.GeneratedValue;
+import javax.persistence.Id;
+import javax.persistence.MapsId;
+import javax.persistence.OneToOne;
+import javax.persistence.PrimaryKeyJoinColumn;
+import javax.persistence.Table;
+import java.util.Date;
+
+import static org.hibernate.Hibernate.isInitialized;
+import static org.hibernate.testing.transaction.TransactionUtil.doInHibernate;
+import static org.junit.Assert.assertFalse;
+
+@TestForIssue(jiraKey = "HHH-12842")
+public class LazyToOneTest extends BaseCoreFunctionalTestCase {
+
+    @Override
+    protected Class<?>[] getAnnotatedClasses() {
+        return new Class<?>[] { Post.class, PostDetails.class};
+    }
+
+    @Before
+    public void setUp() throws Exception {
+        doInHibernate( this::sessionFactory, s -> {
+            Post post = new Post();
+            post.setDetails(new PostDetails());
+            post.getDetails().setCreatedBy("ME");
+            post.getDetails().setCreatedOn(new Date());
+            post.setTitle("title");
+            s.persist(post);
+        } );
+    }
+
+    @Test
+    public void testOneToOneLazyLoading() {
+        doInHibernate( this::sessionFactory, s -> {
+            PostDetails post = (PostDetails) s.createQuery("select a from PostDetails a").getResultList().get(0);
+            assertFalse(isInitialized(post.post));
+        } );
+    }
+
+    @Entity(name = "PostDetails")
+    @Table(name = "post_details")
+    public static class PostDetails {
+
+        @Id
+        private Long id;
+
+        @Column(name = "created_on")
+        private Date createdOn;
+
+        @Column(name = "created_by")
+        private String createdBy;
+
+        @MapsId
+        @OneToOne(fetch = FetchType.LAZY, mappedBy = "details", optional = false)
+        private Post post;
+
+        public PostDetails() {}
+
+        public PostDetails(String createdBy) {
+            createdOn = new Date();
+            this.createdBy = createdBy;
+        }
+
+        public Long getId() {
+            return id;
+        }
+
+        public void setId(Long id) {
+            this.id = id;
+        }
+
+        public Date getCreatedOn() {
+            return createdOn;
+        }
+
+        public void setCreatedOn(Date createdOn) {
+            this.createdOn = createdOn;
+        }
+
+        public String getCreatedBy() {
+            return createdBy;
+        }
+
+        public void setCreatedBy(String createdBy) {
+            this.createdBy = createdBy;
+        }
+
+        public Post getPost() {
+            return post;
+        }
+
+        public void setPost(Post post) {
+            this.post = post;
+        }
+
+    }
+
+    @Entity(name = "Post")
+    @Table(name = "post")
+    public static class Post {
+
+        @Id
+        @GeneratedValue
+        private Long id;
+
+        private String title;
+
+        @PrimaryKeyJoinColumn
+        @OneToOne(cascade = CascadeType.ALL, fetch = FetchType.LAZY)
+        private PostDetails details;
+
+
+        public void setDetails(PostDetails details) {
+            if (details == null) {
+                if (this.details != null) {
+                    this.details.setPost(null);
+                }
+            }
+            else {
+                details.setPost(this);
+            }
+            this.details = details;
+        }
+
+        public Long getId() {
+            return id;
+        }
+
+        public void setId(Long id) {
+            this.id = id;
+        }
+
+        public String getTitle() {
+            return title;
+        }
+
+        public void setTitle(String title) {
+            this.title = title;
+        }
+
+        public PostDetails getDetails() {
+            return details;
+        }
+    }
+
+}