HHH-17161 Add test for issue

hibernate-core/src/test/java/org/hibernate/orm/test/inheritance/JoinedInheritanceCollectionSameHierarchyTest.java

@@ -0,0 +1,138 @@
+/*
+ * 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.orm.test.inheritance;
+
+import java.util.List;
+
+import org.hibernate.testing.orm.junit.DomainModel;
+import org.hibernate.testing.orm.junit.Jira;
+import org.hibernate.testing.orm.junit.SessionFactory;
+import org.hibernate.testing.orm.junit.SessionFactoryScope;
+import org.junit.jupiter.api.AfterAll;
+import org.junit.jupiter.api.Test;
+
+import jakarta.persistence.Entity;
+import jakarta.persistence.FetchType;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.Id;
+import jakarta.persistence.Inheritance;
+import jakarta.persistence.InheritanceType;
+import jakarta.persistence.ManyToMany;
+import jakarta.persistence.ManyToOne;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+@DomainModel( annotatedClasses = {
+		// The user entities come first, so they get the lowest discriminator values
+		JoinedInheritanceCollectionSameHierarchyTest.UserEntity.class,
+		JoinedInheritanceCollectionSameHierarchyTest.BaseUser.class,
+		JoinedInheritanceCollectionSameHierarchyTest.SuperEntity.class,
+		JoinedInheritanceCollectionSameHierarchyTest.AbstractCompany.class,
+		JoinedInheritanceCollectionSameHierarchyTest.GoodCompany.class,
+		JoinedInheritanceCollectionSameHierarchyTest.BadCompany.class,
+		JoinedInheritanceCollectionSameHierarchyTest.CompanyRegistry.class,
+} )
+@SessionFactory
+@Jira( "https://hibernate.atlassian.net/browse/HHH-17161" )
+public class JoinedInheritanceCollectionSameHierarchyTest {
+	@Test
+	public void testGetDiscriminatorCollection(SessionFactoryScope scope) {
+		final Long id = scope.fromTransaction( session -> {
+			final UserEntity user = new UserEntity( "test_user" );
+			session.persist( user );
+			final GoodCompany company = new GoodCompany();
+			company.employee = user;
+			session.persist( company );
+			final CompanyRegistry companyRegistry = new CompanyRegistry( List.of( company ) );
+			session.persist( companyRegistry );
+			return companyRegistry.id;
+		} );
+		scope.inSession( session -> {
+			final CompanyRegistry companyRegistry = session.get( CompanyRegistry.class, id );
+			assertThat( companyRegistry.getCompanies() ).hasSize( 1 )
+					.extracting( AbstractCompany::getEmployee )
+					.extracting( UserEntity::getName )
+					.containsOnly( "test_user" );
+		} );
+	}
+
+	@AfterAll
+	public void tearDown(SessionFactoryScope scope) {
+		scope.inTransaction( session -> {
+			session.createMutationQuery( "delete from CompanyRegistry" ).executeUpdate();
+			session.createMutationQuery( "delete from AbstractCompany" ).executeUpdate();
+			session.createMutationQuery( "delete from SuperEntity" ).executeUpdate();
+		} );
+	}
+
+	@Entity( name = "SuperEntity" )
+	@Inheritance( strategy = InheritanceType.JOINED )
+	static abstract class SuperEntity {
+		@Id
+		@GeneratedValue
+		Long id;
+	}
+
+	@Entity( name = "CompanyRegistry" )
+	static class CompanyRegistry extends SuperEntity {
+		@ManyToMany( fetch = FetchType.LAZY )
+		List<AbstractCompany> companies;
+
+		public CompanyRegistry() {
+		}
+
+		public CompanyRegistry(List<AbstractCompany> companies) {
+			this.companies = companies;
+		}
+
+		public List<AbstractCompany> getCompanies() {
+			return companies;
+		}
+	}
+
+	@Entity( name = "AbstractCompany" )
+	abstract static class AbstractCompany extends SuperEntity {
+		@ManyToOne( fetch = FetchType.LAZY )
+		UserEntity employee;
+
+		public UserEntity getEmployee() {
+			return employee;
+		}
+	}
+
+	@Entity( name = "GoodCompany" )
+	static class GoodCompany extends AbstractCompany {
+	}
+
+	@Entity( name = "BadCompany" )
+	static class BadCompany extends AbstractCompany {
+		// (unused) sibling subtype for 'GoodCompany'
+	}
+
+	@Entity( name = "AbstractUser" )
+	static class BaseUser extends SuperEntity {
+		// necessary intermediate entity so 'BaseUser' is the first child type and gets the lowest discriminator value
+	}
+
+	@Entity( name = "UserEntity" )
+	static class UserEntity extends BaseUser {
+		private String name;
+
+		public UserEntity() {
+		}
+
+		public UserEntity(String name) {
+			this.name = name;
+		}
+
+		public String getName() {
+			return name;
+		}
+	}
+}
+
+