HHH-16833 Add test for issue

hibernate-core/src/test/java/org/hibernate/orm/test/version/VersionedBidirectionalOneToOneMergeTest.java

@@ -0,0 +1,73 @@
+package org.hibernate.orm.test.version;
+
+import java.util.UUID;
+
+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.Test;
+
+import jakarta.persistence.Entity;
+import jakarta.persistence.Id;
+import jakarta.persistence.JoinColumn;
+import jakarta.persistence.OneToOne;
+import jakarta.persistence.Version;
+
+@DomainModel(
+		annotatedClasses = {
+				VersionedBidirectionalOneToOneMergeTest.TestEntity.class,
+				VersionedBidirectionalOneToOneMergeTest.AnotherTestEntity.class
+		}
+)
+@SessionFactory
+@JiraKey("HHH-16833")
+public class VersionedBidirectionalOneToOneMergeTest {
+
+	@Test
+	public void testMerge(SessionFactoryScope scope) {
+		AnotherTestEntity anotherTestEntity = new AnotherTestEntity();
+		scope.inTransaction(
+				session -> {
+					session.persist( anotherTestEntity );
+				}
+		);
+
+		scope.inTransaction(
+				session -> {
+					TestEntity testEntity = new TestEntity( anotherTestEntity );
+					session.persist( testEntity );
+				}
+		);
+	}
+
+	@Entity(name = "TestEntity")
+	public static class TestEntity {
+		@Id
+		UUID uuid = UUID.randomUUID();
+
+		@Version
+		Long version;
+
+		@OneToOne
+		@JoinColumn(name = "OTHER_ENTITY_ID")
+		AnotherTestEntity anotherTestEntity;
+
+		public TestEntity() {
+		}
+
+		public TestEntity(AnotherTestEntity anotherTestEntity) {
+			this.anotherTestEntity = anotherTestEntity;
+		}
+	}
+
+	@Entity(name = "AnotherTestEntity")
+	public static class AnotherTestEntity {
+		@Id
+		UUID uuid = UUID.randomUUID();
+
+		@OneToOne(mappedBy = "anotherTestEntity")
+		TestEntity testEntity;
+
+	}
+}