HHH-13815 - org.hibernate.TransientObjectException when merging a bidirectional one-to-many relation

documentation/src/test/java/org/hibernate/userguide/associations/BidirectionalOneToManyMergeTest.java

@@ -0,0 +1,174 @@
+package org.hibernate.userguide.associations;
+
+import org.hibernate.jpa.test.BaseEntityManagerFunctionalTestCase;
+import org.hibernate.testing.TestForIssue;
+import org.junit.Before;
+import org.junit.Test;
+
+import javax.persistence.CascadeType;
+import javax.persistence.Entity;
+import javax.persistence.FetchType;
+import javax.persistence.GeneratedValue;
+import javax.persistence.GenerationType;
+import javax.persistence.Id;
+import javax.persistence.JoinColumn;
+import javax.persistence.ManyToOne;
+import javax.persistence.OneToMany;
+import java.util.ArrayList;
+import java.util.List;
+
+import static org.hibernate.testing.transaction.TransactionUtil.doInJPA;
+
+/**
+ * @author Lisandro Fernandez (kelechul at gmail dot com)
+ */
+@TestForIssue(jiraKey = "HHH-13815")
+public class BidirectionalOneToManyMergeTest extends BaseEntityManagerFunctionalTestCase {
+
+    @Override
+    protected Class<?>[] getAnnotatedClasses() {
+        return new Class<?>[]{
+                Post.class,
+                PostComment.class,
+        };
+    }
+
+    @Before
+    public void setUp() {
+        doInJPA(this::entityManagerFactory, entityManager -> {
+            entityManager.persist(
+                    new Post("High-Performance Java Persistence").setId(1L)
+            );
+        });
+    }
+
+    @Test
+    public void testFailMerge() {
+        doInJPA(this::entityManagerFactory, entityManager -> {
+            Post post = entityManager.find(Post.class, 1L);
+            post.addComment(new PostComment("This post rocks!"));
+            post.getComments().isEmpty(); // this fails
+            entityManager.merge(post);
+        });
+    }
+
+    @Entity
+    public static class Post {
+
+        @Id
+        private Long id;
+
+        private String title;
+
+        @OneToMany(mappedBy = "post", cascade = CascadeType.ALL, orphanRemoval = true)
+        private List<PostComment> comments = new ArrayList<>();
+
+        public Post() {
+        }
+
+        public Post(String title) {
+            this.title = title;
+        }
+
+        public Long getId() {
+            return id;
+        }
+
+        public Post setId(Long id) {
+            this.id = id;
+            return this;
+        }
+
+        public String getTitle() {
+            return title;
+        }
+
+        public Post setTitle(String title) {
+            this.title = title;
+            return this;
+        }
+
+        public List<PostComment> getComments() {
+            return comments;
+        }
+
+        private Post setComments(List<PostComment> comments) {
+            this.comments = comments;
+            return this;
+        }
+
+        public Post addComment(PostComment comment) {
+            comments.add(comment);
+            comment.setPost(this);
+
+            return this;
+        }
+
+        public Post removeComment(PostComment comment) {
+            comments.remove(comment);
+            comment.setPost(null);
+
+            return this;
+        }
+    }
+
+    @Entity
+    public static class PostComment {
+
+        @Id
+        @GeneratedValue(strategy = GenerationType.IDENTITY)
+        private Long id;
+
+        private String review;
+
+        @ManyToOne(fetch = FetchType.LAZY)
+        @JoinColumn(name = "post_id")
+        private Post post;
+
+        public PostComment() {
+        }
+
+        public PostComment(String review) {
+            this.review = review;
+        }
+
+        public Long getId() {
+            return id;
+        }
+
+        public PostComment setId(Long id) {
+            this.id = id;
+            return this;
+        }
+
+        public String getReview() {
+            return review;
+        }
+
+        public PostComment setReview(String review) {
+            this.review = review;
+            return this;
+        }
+
+        public Post getPost() {
+            return post;
+        }
+
+        public PostComment setPost(Post post) {
+            this.post = post;
+            return this;
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) return true;
+            if (!(o instanceof PostComment)) return false;
+            return id != null && id.equals(((PostComment) o).getId());
+        }
+
+        @Override
+        public int hashCode() {
+            return 31;
+        }
+    }
+}