HHH-18389 Add test for issue

hibernate-core/src/test/java/org/hibernate/orm/test/collection/dereferenced/UnversionedCascadeDereferencedCollectionTest.java

@@ -36,6 +36,7 @@ import org.hibernate.testing.orm.junit.SessionFactory;
 import org.hibernate.testing.orm.junit.SessionFactoryScope;
 import org.junit.jupiter.api.Test;
 
+import static org.assertj.core.api.AssertionsForClassTypes.assertThat;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertNull;
@@ -76,12 +77,9 @@ public class UnversionedCascadeDereferencedCollectionTest extends AbstractDerefe
 
 		scope.inTransaction(
 				session -> {
-					UnversionedCascadeOne one = (UnversionedCascadeOne) session.merge( unversionedCascadeOne );
+					UnversionedCascadeOne one = session.merge( unversionedCascadeOne );
 
-					// after merging, one.getManies() should still be null;
-					// the EntityEntry loaded state should contain a PersistentCollection though.
-
-					assertNull( one.getManies() );
+					assertThat( one.getManies().size() ).isEqualTo( 0 );
 					EntityEntry eeOne = getEntityEntry( session, one );
 					AbstractPersistentCollection maniesEEOneStateOrig = (AbstractPersistentCollection) eeOne.getLoadedValue(
 							"manies" );
@@ -109,27 +107,7 @@ public class UnversionedCascadeDereferencedCollectionTest extends AbstractDerefe
 					// Ensure the same EntityEntry is being used.
 					assertSame( eeOne, getEntityEntry( session, one ) );
 
-					// Ensure one.getManies() is still null.
-					assertNull( one.getManies() );
-
-					// Ensure CollectionEntry for maniesEEOneStateOrig is no longer in the PersistenceContext.
-					assertNull( getCollectionEntry( session, maniesEEOneStateOrig ) );
-
-					// Ensure the original CollectionEntry has role, persister, and key set to null.
-					assertNull( ceManiesOrig.getRole() );
-					assertNull( ceManiesOrig.getLoadedPersister() );
-					assertNull( ceManiesOrig.getKey() );
-
-					// Ensure the PersistentCollection (that was previously returned by eeOne.getLoadedState())
-					// has key and role set to null.
-					assertNull( maniesEEOneStateOrig.getKey() );
-					assertNull( maniesEEOneStateOrig.getRole() );
-
-					// Ensure eeOne.getLoadedState() returns null for collection after flush.
-					assertNull( eeOne.getLoadedValue( "manies" ) );
-
-					// Ensure the session in maniesEEOneStateOrig has been unset.
-					assertNull( maniesEEOneStateOrig.getSession() );
+					assertThat( one.getManies().size() ).isEqualTo( 0 );
 				}
 		);
 	}

hibernate-core/src/test/java/org/hibernate/orm/test/collection/dereferenced/UnversionedNoCascadeDereferencedCollectionTest.java

@@ -36,6 +36,7 @@ import org.hibernate.testing.orm.junit.SessionFactory;
 import org.hibernate.testing.orm.junit.SessionFactoryScope;
 import org.junit.jupiter.api.Test;
 
+import static org.assertj.core.api.AssertionsForClassTypes.assertThat;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertNull;
@@ -74,12 +75,10 @@ public class UnversionedNoCascadeDereferencedCollectionTest extends AbstractDere
 
 		scope.inTransaction(
 				session -> {
-					UnversionedNoCascadeOne one = (UnversionedNoCascadeOne) session.merge( unversionedNoCascadeOne );
+					UnversionedNoCascadeOne one = session.merge( unversionedNoCascadeOne );
 
-					// after merging, one.getManies() should still be null;
-					// the EntityEntry loaded state should contain a PersistentCollection though.
+					assertThat( one.getManies().size() ).isEqualTo( 0 );
 
-					assertNull( one.getManies() );
 					EntityEntry eeOne = getEntityEntry( session, one );
 					AbstractPersistentCollection maniesEEOneStateOrig = (AbstractPersistentCollection) eeOne.getLoadedValue(
 							"manies" );
@@ -107,27 +106,8 @@ public class UnversionedNoCascadeDereferencedCollectionTest extends AbstractDere
 					// Ensure the same EntityEntry is being used.
 					assertSame( eeOne, getEntityEntry( session, one ) );
 
-					// Ensure one.getManies() is still null.
-					assertNull( one.getManies() );
+					assertThat( one.getManies().size() ).isEqualTo( 0 );
 
-					// Ensure CollectionEntry for maniesEEOneStateOrig is no longer in the PersistenceContext.
-					assertNull( getCollectionEntry( session, maniesEEOneStateOrig ) );
-
-					// Ensure the original CollectionEntry has role, persister, and key set to null.
-					assertNull( ceManiesOrig.getRole() );
-					assertNull( ceManiesOrig.getLoadedPersister() );
-					assertNull( ceManiesOrig.getKey() );
-
-					// Ensure the PersistentCollection (that was previously returned by eeOne.getLoadedState())
-					// has key and role set to null.
-					assertNull( maniesEEOneStateOrig.getKey() );
-					assertNull( maniesEEOneStateOrig.getRole() );
-
-					// Ensure eeOne.getLoadedState() returns null for collection after flush.
-					assertNull( eeOne.getLoadedValue( "manies" ) );
-
-					// Ensure the session in maniesEEOneStateOrig has been unset.
-					assertNull( maniesEEOneStateOrig.getSession() );
 				}
 		);
 	}

hibernate-core/src/test/java/org/hibernate/orm/test/collection/dereferenced/VersionedCascadeDereferencedCollectionTest.java

@@ -36,6 +36,7 @@ import org.hibernate.testing.orm.junit.SessionFactory;
 import org.hibernate.testing.orm.junit.SessionFactoryScope;
 import org.junit.jupiter.api.Test;
 
+import static org.assertj.core.api.AssertionsForClassTypes.assertThat;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertNull;
@@ -76,12 +77,9 @@ public class VersionedCascadeDereferencedCollectionTest extends AbstractDerefere
 
 		scope.inTransaction(
 				session -> {
-					VersionedCascadeOne one = (VersionedCascadeOne) session.merge( versionedCascadeOne );
+					VersionedCascadeOne one = session.merge( versionedCascadeOne );
 
-					// after merging, one.getManies() should still be null;
-					// the EntityEntry loaded state should contain a PersistentCollection though.
-
-					assertNull( one.getManies() );
+					assertThat( one.getManies().size() ).isEqualTo( 0 );
 					EntityEntry eeOne = getEntityEntry( session, one );
 					AbstractPersistentCollection maniesEEOneStateOrig = (AbstractPersistentCollection) eeOne.getLoadedValue(
 							"manies" );
@@ -109,28 +107,7 @@ public class VersionedCascadeDereferencedCollectionTest extends AbstractDerefere
 					// Ensure the same EntityEntry is being used.
 					assertSame( eeOne, getEntityEntry( session, one ) );
 
-					// Ensure one.getManies() is still null.
-					assertNull( one.getManies() );
-
-					// Ensure CollectionEntry for maniesEEOneStateOrig is no longer in the PersistenceContext.
-					assertNull( getCollectionEntry( session, maniesEEOneStateOrig ) );
-
-					// Ensure the original CollectionEntry has role, persister, and key set to null.
-					assertNull( ceManiesOrig.getRole() );
-					assertNull( ceManiesOrig.getLoadedPersister() );
-					assertNull( ceManiesOrig.getKey() );
-
-					// Ensure the PersistentCollection (that was previously returned by eeOne.getLoadedState())
-					// has key and role set to null.
-					assertNull( maniesEEOneStateOrig.getKey() );
-					assertNull( maniesEEOneStateOrig.getRole() );
-
-					// Ensure eeOne.getLoadedState() returns null for collection after flush.
-					assertNull( eeOne.getLoadedValue( "manies" ) );
-
-					// Ensure the session in maniesEEOneStateOrig has been unset.
-					assertNull( maniesEEOneStateOrig.getSession() );
-
+					assertThat( one.getManies().size() ).isEqualTo( 0 );
 				}
 		);
 	}

hibernate-core/src/test/java/org/hibernate/orm/test/collection/dereferenced/VersionedNoCascadeDereferencedCollectionTest.java

@@ -36,6 +36,7 @@ import org.hibernate.testing.orm.junit.SessionFactory;
 import org.hibernate.testing.orm.junit.SessionFactoryScope;
 import org.junit.jupiter.api.Test;
 
+import static org.assertj.core.api.AssertionsForClassTypes.assertThat;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertNull;
@@ -76,12 +77,9 @@ public class VersionedNoCascadeDereferencedCollectionTest extends AbstractDerefe
 
 		scope.inTransaction(
 				session -> {
-					VersionedNoCascadeOne one = (VersionedNoCascadeOne) session.merge( versionedNoCascadeOne );
+					VersionedNoCascadeOne one = session.merge( versionedNoCascadeOne );
 
-					// after merging, one.getManies() should still be null;
-					// the EntityEntry loaded state should contain a PersistentCollection though.
-
-					assertNull( one.getManies() );
+					assertThat( one.getManies().size() ).isEqualTo( 0 );
 					EntityEntry eeOne = getEntityEntry( session, one );
 					AbstractPersistentCollection maniesEEOneStateOrig = (AbstractPersistentCollection) eeOne.getLoadedValue(
 							"manies" );
@@ -109,27 +107,7 @@ public class VersionedNoCascadeDereferencedCollectionTest extends AbstractDerefe
 					// Ensure the same EntityEntry is being used.
 					assertSame( eeOne, getEntityEntry( session, one ) );
 
-					// Ensure one.getManies() is still null.
-					assertNull( one.getManies() );
-
-					// Ensure CollectionEntry for maniesEEOneStateOrig is no longer in the PersistenceContext.
-					assertNull( getCollectionEntry( session, maniesEEOneStateOrig ) );
-
-					// Ensure the original CollectionEntry has role, persister, and key set to null.
-					assertNull( ceManiesOrig.getRole() );
-					assertNull( ceManiesOrig.getLoadedPersister() );
-					assertNull( ceManiesOrig.getKey() );
-
-					// Ensure the PersistentCollection (that was previously returned by eeOne.getLoadedState())
-					// has key and role set to null.
-					assertNull( maniesEEOneStateOrig.getKey() );
-					assertNull( maniesEEOneStateOrig.getRole() );
-
-					// Ensure eeOne.getLoadedState() returns null for collection after flush.
-					assertNull( eeOne.getLoadedValue( "manies" ) );
-
-					// Ensure the session in maniesEEOneStateOrig has been unset.
-					assertNull( maniesEEOneStateOrig.getSession() );
+					assertThat( one.getManies().size() ).isEqualTo( 0 );
 				}
 		);
 	}

hibernate-core/src/test/java/org/hibernate/orm/test/jpa/orphan/onetomany/merge/MergeBidirectionalCascadeTest.java

@@ -0,0 +1,218 @@
+/*
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ * Copyright Red Hat Inc. and Hibernate Authors
+ */
+package org.hibernate.orm.test.jpa.orphan.onetomany.merge;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.hibernate.testing.orm.junit.DomainModel;
+import org.hibernate.testing.orm.junit.JiraKey;
+import org.hibernate.testing.orm.junit.SessionFactory;
+import org.hibernate.testing.orm.junit.SessionFactoryScope;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import jakarta.persistence.CascadeType;
+import jakarta.persistence.Entity;
+import jakarta.persistence.Id;
+import jakarta.persistence.JoinColumn;
+import jakarta.persistence.ManyToOne;
+import jakarta.persistence.OneToMany;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+@DomainModel(
+		annotatedClasses = {
+				MergeBidirectionalCascadeTest.Parent.class,
+				MergeBidirectionalCascadeTest.Child.class,
+		}
+)
+@SessionFactory
+@JiraKey("HHH-18389")
+public class MergeBidirectionalCascadeTest {
+
+	private static final Long ID_PARENT_WITHOUT_CHILDREN = 1L;
+	private static final Long ID_PARENT_WITH_CHILDREN = 2L;
+
+	@BeforeEach
+	public void setUp(SessionFactoryScope scope) {
+		scope.inTransaction(
+				session -> {
+					Parent parent = new Parent( ID_PARENT_WITHOUT_CHILDREN, "old name" );
+					session.persist( parent );
+
+					Parent parent2 = new Parent( ID_PARENT_WITH_CHILDREN, "old name" );
+					Child child = new Child( 2l, "Child" );
+					parent2.addChild( child );
+
+					session.persist( child );
+					session.persist( parent2 );
+				}
+		);
+	}
+
+	@AfterEach
+	private void tearDown(SessionFactoryScope scope) {
+		scope.inTransaction(
+				session -> {
+					session.createMutationQuery( "delete from Child" ).executeUpdate();
+					session.createMutationQuery( "delete from Parent" ).executeUpdate();
+				}
+		);
+	}
+
+	@Test
+	public void testMergeParentWihoutChildren(SessionFactoryScope scope) {
+		scope.inTransaction(
+				session -> {
+					Parent parent = new Parent( ID_PARENT_WITHOUT_CHILDREN, "new name" );
+					Parent merged = session.merge( parent );
+					assertThat( merged.getName() ).isEqualTo( "new name" );
+
+				}
+		);
+	}
+
+	@Test
+	public void testMergeParentWithChildren(SessionFactoryScope scope) {
+		scope.inTransaction(
+				session -> {
+					Parent parent = new Parent( ID_PARENT_WITH_CHILDREN, "new name" );
+					Child child = new Child( 2l, "Child" );
+					parent.addChild( child );
+					Parent merged = session.merge( parent );
+					assertThat( merged.getName() ).isEqualTo( "new name" );
+
+				}
+		);
+		scope.inTransaction(
+				session -> {
+					Parent parent = session.get( Parent.class, ID_PARENT_WITH_CHILDREN );
+					assertThat( parent.getChildren().size() ).isEqualTo( 1 );
+
+				}
+		);
+	}
+
+	@Test
+	public void testMergeParentWithChildren2(SessionFactoryScope scope) {
+		scope.inTransaction(
+				session -> {
+					Parent parent = new Parent( ID_PARENT_WITH_CHILDREN, "new name" );
+					Parent merged = session.merge( parent );
+
+				}
+		);
+		scope.inTransaction(
+				session -> {
+					Parent parent = session.get( Parent.class, ID_PARENT_WITH_CHILDREN );
+					assertThat( parent.getName() ).isEqualTo( "new name" );
+					assertThat( parent.getChildren().size() ).isEqualTo( 1 );
+
+					List<Child> children = session.createQuery( "Select c from Child c", Child.class ).list();
+					assertThat( children.size() ).isEqualTo( 1 );
+				}
+		);
+	}
+
+	@Entity(name = "Parent")
+	public static class Parent {
+
+		@Id
+		private Long id;
+
+		private String name;
+
+		@OneToMany(cascade = CascadeType.MERGE, mappedBy = "parent")
+		private List<Child> children;
+
+		public Parent() {
+		}
+
+		public Parent(Long id, String name) {
+			this.id = id;
+			this.name = name;
+		}
+
+		public Long getId() {
+			return id;
+		}
+
+		public void setId(Long id) {
+			this.id = id;
+		}
+
+		public String getName() {
+			return name;
+		}
+
+		public void setName(String name) {
+			this.name = name;
+		}
+
+		public List<Child> getChildren() {
+			return children;
+		}
+
+		public void setChildren(List<Child> children) {
+			this.children = children;
+		}
+
+		public void addChild(Child child) {
+			if ( children == null ) {
+				children = new ArrayList<Child>();
+			}
+			children.add( child );
+			child.setParent( this );
+		}
+	}
+
+	@Entity(name = "Child")
+	public static class Child {
+
+		@Id
+		private Long id;
+
+		private String name;
+
+		public Child() {
+		}
+
+		public Child(Long id, String name) {
+			this.id = id;
+			this.name = name;
+		}
+
+		@ManyToOne
+		@JoinColumn
+		private Parent parent;
+
+		public Long getId() {
+			return id;
+		}
+
+		public void setId(Long id) {
+			this.id = id;
+		}
+
+		public String getName() {
+			return name;
+		}
+
+		public void setName(String name) {
+			this.name = name;
+		}
+
+		public Parent getParent() {
+			return parent;
+		}
+
+		public void setParent(Parent parent) {
+			this.parent = parent;
+		}
+	}
+
+}

hibernate-core/src/test/java/org/hibernate/orm/test/jpa/orphan/onetomany/merge/MergeCascadeTest.java

@@ -0,0 +1,200 @@
+/*
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ * Copyright Red Hat Inc. and Hibernate Authors
+ */
+package org.hibernate.orm.test.jpa.orphan.onetomany.merge;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.hibernate.testing.orm.junit.DomainModel;
+import org.hibernate.testing.orm.junit.JiraKey;
+import org.hibernate.testing.orm.junit.SessionFactory;
+import org.hibernate.testing.orm.junit.SessionFactoryScope;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import jakarta.persistence.CascadeType;
+import jakarta.persistence.Entity;
+import jakarta.persistence.Id;
+import jakarta.persistence.OneToMany;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+@DomainModel(
+		annotatedClasses = {
+				MergeCascadeTest.Parent.class,
+				MergeCascadeTest.Child.class,
+		}
+)
+@SessionFactory
+@JiraKey("HHH-18389")
+public class MergeCascadeTest {
+
+	private static final Long ID_PARENT_WITHOUT_CHILDREN = 1L;
+	private static final Long ID_PARENT_WITH_CHILDREN = 2L;
+
+	@BeforeEach
+	public void setUp(SessionFactoryScope scope) {
+		scope.inTransaction(
+				session -> {
+					Parent parent = new Parent( ID_PARENT_WITHOUT_CHILDREN, "old name" );
+					session.persist( parent );
+
+					Parent parent2 = new Parent( ID_PARENT_WITH_CHILDREN, "old name" );
+					Child child = new Child( 2l, "Child" );
+					parent2.addChild( child );
+
+					session.persist( child );
+					session.persist( parent2 );
+				}
+		);
+	}
+
+	@AfterEach
+	private void tearDown(SessionFactoryScope scope) {
+		scope.inTransaction(
+				session -> {
+					session.createMutationQuery( "delete from Parent" ).executeUpdate();
+					session.createMutationQuery( "delete from Child" ).executeUpdate();
+				}
+		);
+	}
+
+	@Test
+	public void testMergeParentWihoutChildren(SessionFactoryScope scope) {
+		scope.inTransaction(
+				session -> {
+					Parent parent = new Parent( ID_PARENT_WITHOUT_CHILDREN, "new name" );
+					Parent merged = session.merge( parent );
+					assertThat( merged.getName() ).isEqualTo( "new name" );
+				}
+		);
+	}
+
+	@Test
+	public void testMergeParentWithChildren(SessionFactoryScope scope) {
+		scope.inTransaction(
+				session -> {
+					Parent parent = new Parent( ID_PARENT_WITH_CHILDREN, "new name" );
+					Child child = new Child( 2l, "Child" );
+					parent.addChild( child );
+					Parent merged = session.merge( parent );
+					assertThat( merged.getName() ).isEqualTo( "new name" );
+				}
+		);
+		scope.inTransaction(
+				session -> {
+					Parent parent = session.get( Parent.class, ID_PARENT_WITH_CHILDREN );
+					assertThat( parent.getChildren().size() ).isEqualTo( 1 );
+				}
+		);
+	}
+
+	@Test
+	public void testMergeParentWithChildren2(SessionFactoryScope scope) {
+		scope.inTransaction(
+				session -> {
+					Parent parent = new Parent( ID_PARENT_WITH_CHILDREN, "new name" );
+					session.merge( parent );
+				}
+		);
+		scope.inTransaction(
+				session -> {
+					Parent parent = session.get( Parent.class, ID_PARENT_WITH_CHILDREN );
+					assertThat( parent.getName() ).isEqualTo( "new name" );
+					assertThat( parent.getChildren().size() ).isEqualTo( 0 );
+
+					List<Child> children = session.createQuery( "Select c from Child c", Child.class ).list();
+					assertThat( children.size() ).isEqualTo( 1 );
+				}
+		);
+	}
+
+	@Entity(name = "Parent")
+	public static class Parent {
+
+		@Id
+		private Long id;
+
+		private String name;
+
+		@OneToMany(cascade = CascadeType.MERGE)
+		private List<Child> children;
+
+		public Parent() {
+		}
+
+		public Parent(Long id, String name) {
+			this.id = id;
+			this.name = name;
+		}
+
+		public Long getId() {
+			return id;
+		}
+
+		public void setId(Long id) {
+			this.id = id;
+		}
+
+		public String getName() {
+			return name;
+		}
+
+		public void setName(String name) {
+			this.name = name;
+		}
+
+		public List<Child> getChildren() {
+			return children;
+		}
+
+		public void setChildren(List<Child> children) {
+			this.children = children;
+		}
+
+		public void addChild(Child child) {
+			if ( children == null ) {
+				children = new ArrayList<Child>();
+			}
+			children.add( child );
+		}
+	}
+
+	@Entity(name = "Child")
+	public static class Child {
+
+		@Id
+		private Long id;
+
+		private String name;
+
+		public Child() {
+		}
+
+		public Child(Long id, String name) {
+			this.id = id;
+			this.name = name;
+		}
+
+		public Long getId() {
+			return id;
+		}
+
+		public void setId(Long id) {
+			this.id = id;
+		}
+
+		public String getName() {
+			return name;
+		}
+
+		public void setName(String name) {
+			this.name = name;
+		}
+
+	}
+
+}

hibernate-core/src/test/java/org/hibernate/orm/test/jpa/orphan/onetomany/merge/MergeOrphanRemovalBidirectionalTest.java

@@ -0,0 +1,217 @@
+/*
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ * Copyright Red Hat Inc. and Hibernate Authors
+ */
+package org.hibernate.orm.test.jpa.orphan.onetomany.merge;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.hibernate.testing.orm.junit.DomainModel;
+import org.hibernate.testing.orm.junit.JiraKey;
+import org.hibernate.testing.orm.junit.SessionFactory;
+import org.hibernate.testing.orm.junit.SessionFactoryScope;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import jakarta.persistence.Entity;
+import jakarta.persistence.Id;
+import jakarta.persistence.JoinColumn;
+import jakarta.persistence.ManyToOne;
+import jakarta.persistence.OneToMany;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+@DomainModel(
+		annotatedClasses = {
+				MergeOrphanRemovalBidirectionalTest.Parent.class,
+				MergeOrphanRemovalBidirectionalTest.Child.class,
+		}
+)
+@SessionFactory
+@JiraKey("HHH-18389")
+public class MergeOrphanRemovalBidirectionalTest {
+
+	private static final Long ID_PARENT_WITHOUT_CHILDREN = 1L;
+	private static final Long ID_PARENT_WITH_CHILDREN = 2L;
+
+	@BeforeEach
+	public void setUp(SessionFactoryScope scope) {
+		scope.inTransaction(
+				session -> {
+					Parent parent = new Parent( ID_PARENT_WITHOUT_CHILDREN, "old name" );
+					session.persist( parent );
+
+					Parent parent2 = new Parent( ID_PARENT_WITH_CHILDREN, "old name" );
+					Child child = new Child( 2l, "Child" );
+					parent2.addChild( child );
+
+					session.persist( child );
+					session.persist( parent2 );
+				}
+		);
+	}
+
+	@AfterEach
+	private void tearDown(SessionFactoryScope scope) {
+		scope.inTransaction(
+				session -> {
+					session.createMutationQuery( "delete from Child" ).executeUpdate();
+					session.createMutationQuery( "delete from Parent" ).executeUpdate();
+				}
+		);
+	}
+
+	@Test
+	public void testMergeParentWihoutChildren(SessionFactoryScope scope) {
+		scope.inTransaction(
+				session -> {
+					Parent parent = new Parent( ID_PARENT_WITHOUT_CHILDREN, "new name" );
+					Parent merged = session.merge( parent );
+					assertThat( merged.getName() ).isEqualTo( "new name" );
+
+				}
+		);
+	}
+
+	@Test
+	public void testMergeParentWithChildren(SessionFactoryScope scope) {
+		scope.inTransaction(
+				session -> {
+					Parent parent = new Parent( ID_PARENT_WITH_CHILDREN, "new name" );
+					Child child = new Child( 2l, "Child" );
+					parent.addChild( child );
+					Parent merged = session.merge( parent );
+					assertThat( merged.getName() ).isEqualTo( "new name" );
+
+				}
+		);
+		scope.inTransaction(
+				session -> {
+					Parent parent = session.get( Parent.class, ID_PARENT_WITH_CHILDREN );
+					assertThat( parent.getChildren().size() ).isEqualTo( 1 );
+
+				}
+		);
+	}
+
+	@Test
+	public void testMergeParentWithChildren2(SessionFactoryScope scope) {
+		scope.inTransaction(
+				session -> {
+					Parent parent = new Parent( ID_PARENT_WITH_CHILDREN, "new name" );
+					Parent merged = session.merge( parent );
+
+				}
+		);
+		scope.inTransaction(
+				session -> {
+					Parent parent = session.get( Parent.class, ID_PARENT_WITH_CHILDREN );
+					assertThat( parent.getName() ).isEqualTo( "new name" );
+					assertThat( parent.getChildren().size() ).isEqualTo( 0 );
+
+					List<Child> children = session.createQuery( "Select c from Child c", Child.class ).list();
+					assertThat( children.size() ).isEqualTo( 0 );
+				}
+		);
+	}
+
+	@Entity(name = "Parent")
+	public static class Parent {
+
+		@Id
+		private Long id;
+
+		private String name;
+
+		@OneToMany(orphanRemoval = true, mappedBy = "parent")
+		private List<Child> children;
+
+		public Parent() {
+		}
+
+		public Parent(Long id, String name) {
+			this.id = id;
+			this.name = name;
+		}
+
+		public Long getId() {
+			return id;
+		}
+
+		public void setId(Long id) {
+			this.id = id;
+		}
+
+		public String getName() {
+			return name;
+		}
+
+		public void setName(String name) {
+			this.name = name;
+		}
+
+		public List<Child> getChildren() {
+			return children;
+		}
+
+		public void setChildren(List<Child> children) {
+			this.children = children;
+		}
+
+		public void addChild(Child child) {
+			if ( children == null ) {
+				children = new ArrayList<Child>();
+			}
+			children.add( child );
+			child.setParent( this );
+		}
+	}
+
+	@Entity(name = "Child")
+	public static class Child {
+
+		@Id
+		private Long id;
+
+		private String name;
+
+		public Child() {
+		}
+
+		public Child(Long id, String name) {
+			this.id = id;
+			this.name = name;
+		}
+
+		@ManyToOne
+		@JoinColumn
+		private Parent parent;
+
+		public Long getId() {
+			return id;
+		}
+
+		public void setId(Long id) {
+			this.id = id;
+		}
+
+		public String getName() {
+			return name;
+		}
+
+		public void setName(String name) {
+			this.name = name;
+		}
+
+		public Parent getParent() {
+			return parent;
+		}
+
+		public void setParent(Parent parent) {
+			this.parent = parent;
+		}
+	}
+
+}

hibernate-core/src/test/java/org/hibernate/orm/test/jpa/orphan/onetomany/merge/MergeOrphanRemovalTest.java

@@ -0,0 +1,229 @@
+/*
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ * Copyright Red Hat Inc. and Hibernate Authors
+ */
+package org.hibernate.orm.test.jpa.orphan.onetomany.merge;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.hibernate.testing.orm.junit.DomainModel;
+import org.hibernate.testing.orm.junit.JiraKey;
+import org.hibernate.testing.orm.junit.SessionFactory;
+import org.hibernate.testing.orm.junit.SessionFactoryScope;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import jakarta.persistence.Entity;
+import jakarta.persistence.Id;
+import jakarta.persistence.OneToMany;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+@DomainModel(
+		annotatedClasses = {
+				MergeOrphanRemovalTest.Parent.class,
+				MergeOrphanRemovalTest.Child.class,
+		}
+)
+@SessionFactory
+@JiraKey("HHH-18389")
+public class MergeOrphanRemovalTest {
+
+	private static final Long ID_PARENT_WITHOUT_CHILDREN = 1L;
+	private static final Long ID_PARENT_WITH_CHILDREN = 2L;
+
+	@BeforeEach
+	public void setUp(SessionFactoryScope scope) {
+		scope.inTransaction(
+				session -> {
+					Parent parent = new Parent( ID_PARENT_WITHOUT_CHILDREN, "old name" );
+					session.persist( parent );
+
+					Parent parent2 = new Parent( ID_PARENT_WITH_CHILDREN, "old name" );
+					Child child = new Child( 2l, "Child" );
+					parent2.addChild( child );
+
+					session.persist( child );
+					session.persist( parent2 );
+				}
+		);
+	}
+
+	@AfterEach
+	private void tearDown(SessionFactoryScope scope) {
+		scope.inTransaction(
+				session -> {
+					session.createMutationQuery( "delete from Parent" ).executeUpdate();
+					session.createMutationQuery( "delete from Child" ).executeUpdate();
+				}
+		);
+	}
+
+	@Test
+	public void testMergeParentWihoutChildren(SessionFactoryScope scope) {
+		scope.inTransaction(
+				session -> {
+					Parent parent = new Parent( ID_PARENT_WITHOUT_CHILDREN, "new name" );
+					Parent merged = session.merge( parent );
+					assertThat( merged.getName() ).isEqualTo( "new name" );
+
+				}
+		);
+	}
+
+	@Test
+	public void testMergeParentWithChildren(SessionFactoryScope scope) {
+		scope.inTransaction(
+				session -> {
+					Parent parent = new Parent( ID_PARENT_WITH_CHILDREN, "new name" );
+					Child child = new Child( 2l, "Child" );
+					parent.addChild( child );
+					Parent merged = session.merge( parent );
+					assertThat( merged.getName() ).isEqualTo( "new name" );
+
+				}
+		);
+		scope.inTransaction(
+				session -> {
+					Parent parent = session.get( Parent.class, ID_PARENT_WITH_CHILDREN );
+					assertThat( parent.getChildren().size() ).isEqualTo( 1 );
+
+				}
+		);
+	}
+
+	@Test
+	public void testMergeParentWithChildren2(SessionFactoryScope scope) {
+		scope.inTransaction(
+				session -> {
+					Parent parent = new Parent( ID_PARENT_WITH_CHILDREN, "new name" );
+					Parent merged = session.merge( parent );
+
+				}
+		);
+		scope.inTransaction(
+				session -> {
+					Parent parent = session.get( Parent.class, ID_PARENT_WITH_CHILDREN );
+					assertThat( parent.getName() ).isEqualTo( "new name" );
+					assertThat( parent.getChildren().size() ).isEqualTo( 0 );
+
+					List<Child> children = session.createQuery( "Select c from Child c", Child.class ).list();
+					assertThat( children.size() ).isEqualTo( 0 );
+				}
+		);
+	}
+
+	@Test
+	public void testMergeParentWithChildren3(SessionFactoryScope scope) {
+		scope.inTransaction(
+				session -> {
+					Parent parent = new Parent( ID_PARENT_WITH_CHILDREN, "new name" );
+					Child child = new Child( 3l, "Child2" );
+					parent.addChild( child );
+					session.persist( child );
+					Parent merged = session.merge( parent );
+
+				}
+		);
+		scope.inTransaction(
+				session -> {
+					Parent parent = session.get( Parent.class, ID_PARENT_WITH_CHILDREN );
+					assertThat( parent.getName() ).isEqualTo( "new name" );
+					assertThat( parent.getChildren().size() ).isEqualTo( 1 );
+					assertThat( parent.getChildren().get( 0 ).getName() ).isEqualTo( "Child2" );
+
+					List<Child> children = session.createQuery( "Select c from Child c", Child.class ).list();
+					assertThat( children.size() ).isEqualTo( 1 );
+					assertThat( children.get( 0 ).getName() ).isEqualTo( "Child2" );
+				}
+		);
+	}
+
+	@Entity(name = "Parent")
+	public static class Parent {
+
+		@Id
+		private Long id;
+
+		private String name;
+
+		@OneToMany(orphanRemoval = true)
+		private List<Child> children;
+
+		public Parent() {
+		}
+
+		public Parent(Long id, String name) {
+			this.id = id;
+			this.name = name;
+		}
+
+		public Long getId() {
+			return id;
+		}
+
+		public void setId(Long id) {
+			this.id = id;
+		}
+
+		public String getName() {
+			return name;
+		}
+
+		public void setName(String name) {
+			this.name = name;
+		}
+
+		public List<Child> getChildren() {
+			return children;
+		}
+
+		public void setChildren(List<Child> children) {
+			this.children = children;
+		}
+
+		public void addChild(Child child) {
+			if ( children == null ) {
+				children = new ArrayList<Child>();
+			}
+			children.add( child );
+		}
+	}
+
+	@Entity(name = "Child")
+	public static class Child {
+
+		@Id
+		private Long id;
+
+		private String name;
+
+		public Child() {
+		}
+
+		public Child(Long id, String name) {
+			this.id = id;
+			this.name = name;
+		}
+
+		public Long getId() {
+			return id;
+		}
+
+		public void setId(Long id) {
+			this.id = id;
+		}
+
+		public String getName() {
+			return name;
+		}
+
+		public void setName(String name) {
+			this.name = name;
+		}
+
+	}
+
+}

hibernate-core/src/test/java/org/hibernate/orm/test/jpa/orphan/onetomany/merge/MergeTest.java

@@ -0,0 +1,200 @@
+/*
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ * Copyright Red Hat Inc. and Hibernate Authors
+ */
+package org.hibernate.orm.test.jpa.orphan.onetomany.merge;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.hibernate.testing.orm.junit.DomainModel;
+import org.hibernate.testing.orm.junit.JiraKey;
+import org.hibernate.testing.orm.junit.SessionFactory;
+import org.hibernate.testing.orm.junit.SessionFactoryScope;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import jakarta.persistence.Entity;
+import jakarta.persistence.Id;
+import jakarta.persistence.OneToMany;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+@DomainModel(
+		annotatedClasses = {
+				MergeTest.Parent.class,
+				MergeTest.Child.class,
+		}
+)
+@SessionFactory
+@JiraKey("HHH-18389")
+public class MergeTest {
+
+	private static final Long ID_PARENT_WITHOUT_CHILDREN = 1L;
+	private static final Long ID_PARENT_WITH_CHILDREN = 2L;
+
+	@BeforeEach
+	public void setUp(SessionFactoryScope scope) {
+		scope.inTransaction(
+				session -> {
+					Parent parent = new Parent( ID_PARENT_WITHOUT_CHILDREN, "old name" );
+					session.persist( parent );
+
+					Parent parent2 = new Parent( ID_PARENT_WITH_CHILDREN, "old name" );
+					Child child = new Child( 2l, "Child" );
+					parent2.addChild( child );
+
+					session.persist( child );
+					session.persist( parent2 );
+				}
+		);
+	}
+
+	@AfterEach
+	private void tearDown(SessionFactoryScope scope) {
+		scope.inTransaction(
+				session -> {
+					session.createMutationQuery( "delete from Parent" ).executeUpdate();
+					session.createMutationQuery( "delete from Child" ).executeUpdate();
+				}
+		);
+	}
+
+	@Test
+	public void testMergeParentWihoutChildren(SessionFactoryScope scope) {
+		scope.inTransaction(
+				session -> {
+					Parent parent = new Parent( ID_PARENT_WITHOUT_CHILDREN, "new name" );
+					Parent merged = session.merge( parent );
+					assertThat( merged.getName() ).isEqualTo( "new name" );
+				}
+		);
+	}
+
+	@Test
+	public void testMergeParentWithChildren(SessionFactoryScope scope) {
+		scope.inTransaction(
+				session -> {
+					Parent parent = new Parent( ID_PARENT_WITH_CHILDREN, "new name" );
+					Child child = new Child( 2l, "Child" );
+					parent.addChild( child );
+					Parent merged = session.merge( parent );
+					assertThat( merged.getName() ).isEqualTo( "new name" );
+				}
+		);
+		scope.inTransaction(
+				session -> {
+					Parent parent = session.get( Parent.class, ID_PARENT_WITH_CHILDREN );
+					assertThat( parent.getChildren().size() ).isEqualTo( 1 );
+				}
+		);
+	}
+
+	@Test
+	public void testMergeParentWithChildren2(SessionFactoryScope scope) {
+		scope.inTransaction(
+				session -> {
+					Parent parent = new Parent( ID_PARENT_WITH_CHILDREN, "new name" );
+					session.merge( parent );
+				}
+		);
+		scope.inTransaction(
+				session -> {
+					Parent parent = session.get( Parent.class, ID_PARENT_WITH_CHILDREN );
+					assertThat( parent.getName() ).isEqualTo( "new name" );
+					assertThat( parent.getChildren().size() ).isEqualTo( 0 );
+
+					List<Child> children = session.createQuery( "Select c from Child c", Child.class ).list();
+					assertThat( children.size() ).isEqualTo( 1 );
+				}
+		);
+	}
+
+
+	@Entity(name = "Parent")
+	public static class Parent {
+
+		@Id
+		private Long id;
+
+		private String name;
+
+		@OneToMany
+		private List<Child> children;
+
+		public Parent() {
+		}
+
+		public Parent(Long id, String name) {
+			this.id = id;
+			this.name = name;
+		}
+
+		public Long getId() {
+			return id;
+		}
+
+		public void setId(Long id) {
+			this.id = id;
+		}
+
+		public String getName() {
+			return name;
+		}
+
+		public void setName(String name) {
+			this.name = name;
+		}
+
+		public List<Child> getChildren() {
+			return children;
+		}
+
+		public void setChildren(List<Child> children) {
+			this.children = children;
+		}
+
+		public void addChild(Child child) {
+			if ( children == null ) {
+				children = new ArrayList<Child>();
+			}
+			children.add( child );
+		}
+	}
+
+	@Entity(name = "Child")
+	public static class Child {
+
+		@Id
+		private Long id;
+
+		private String name;
+
+		public Child() {
+		}
+
+		public Child(Long id, String name) {
+			this.id = id;
+			this.name = name;
+		}
+
+		public Long getId() {
+			return id;
+		}
+
+		public void setId(Long id) {
+			this.id = id;
+		}
+
+		public String getName() {
+			return name;
+		}
+
+		public void setName(String name) {
+			this.name = name;
+		}
+
+	}
+
+}