HHH-19756 Add test for issue

Author: mbellade

hibernate-core/src/test/java/org/hibernate/orm/test/inheritance/discriminator/JoinedDiscSameAttributeNameTest.java

@@ -0,0 +1,157 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ * Copyright Red Hat Inc. and Hibernate Authors
+ */
+package org.hibernate.orm.test.inheritance.discriminator;
+
+import jakarta.persistence.DiscriminatorColumn;
+import jakarta.persistence.DiscriminatorValue;
+import jakarta.persistence.Entity;
+import jakarta.persistence.Id;
+import jakarta.persistence.Inheritance;
+import jakarta.persistence.InheritanceType;
+import jakarta.persistence.Table;
+import jakarta.persistence.Tuple;
+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.BeforeAll;
+import org.junit.jupiter.api.Test;
+
+import java.util.List;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+@DomainModel(annotatedClasses = {
+		JoinedDiscSameAttributeNameTest.Ancestor.class,
+		JoinedDiscSameAttributeNameTest.DescendantA.class,
+		JoinedDiscSameAttributeNameTest.DescendantB.class,
+		JoinedDiscSameAttributeNameTest.DescendantTak.class,
+		JoinedDiscSameAttributeNameTest.DescendantD.class,
+})
+@SessionFactory
+@Jira( "https://hibernate.atlassian.net/browse/HHH-19756" )
+public class JoinedDiscSameAttributeNameTest {
+	@Test
+	void testCoalesceSameType(SessionFactoryScope scope) {
+		scope.inTransaction( session -> {
+			final var cb = session.getCriteriaBuilder();
+			final var query = cb.createTupleQuery();
+			final var root = query.from( Ancestor.class );
+			final var dscCRoot = cb.treat( root, DescendantTak.class );
+
+			query.select( cb.tuple(
+					root.get( JoinedDiscSameAttributeNameTest_.Ancestor_.id ).alias( "id" ),
+					cb.coalesce(
+							dscCRoot.get( JoinedDiscSameAttributeNameTest_.DescendantTak_.subtitle ),
+							dscCRoot.get( JoinedDiscSameAttributeNameTest_.DescendantTak_.title )
+					).alias( "description" )
+			) ).orderBy( cb.asc( root.get( JoinedDiscSameAttributeNameTest_.Ancestor_.id ) ) );
+
+			final var resultList = session.createSelectionQuery( query ).getResultList();
+			assertResults( resultList, null, "title", null );
+		} );
+	}
+
+	@Test
+	void testCoalesceDifferentTypes(SessionFactoryScope scope) {
+		scope.inTransaction( session -> {
+			final var cb = session.getCriteriaBuilder();
+			final var query = cb.createTupleQuery();
+			final var root = query.from( Ancestor.class );
+			final var dscARoot = cb.treat( root, DescendantA.class );
+			final var dscCRoot = cb.treat( root, DescendantTak.class );
+			final var dscDRoot = cb.treat( root, DescendantD.class );
+
+			query.select( cb.tuple(
+					root.get( JoinedDiscSameAttributeNameTest_.Ancestor_.id ).alias( "id" ),
+					cb.coalesce(
+							dscDRoot.get( JoinedDiscSameAttributeNameTest_.DescendantD_.subtitle ),
+							cb.coalesce(
+									cb.coalesce(
+											dscARoot.get( JoinedDiscSameAttributeNameTest_.DescendantA_.subtitle ),
+											dscARoot.get( JoinedDiscSameAttributeNameTest_.DescendantA_.title )
+									),
+									cb.coalesce(
+											dscCRoot.get( JoinedDiscSameAttributeNameTest_.DescendantTak_.subtitle ),
+											dscCRoot.get( JoinedDiscSameAttributeNameTest_.DescendantTak_.title )
+									)
+							)
+					).alias( "description" )
+			) ).orderBy( cb.asc( root.get( JoinedDiscSameAttributeNameTest_.Ancestor_.id ) ) );
+
+			final var resultList = session.createSelectionQuery( query ).getResultList();
+			assertResults( resultList, null, "title", "subtitle" );
+		} );
+	}
+
+	private static void assertResults(List<Tuple> resultList, String... expected) {
+		assertThat( resultList ).hasSize( expected.length );
+		for ( int i = 0; i < expected.length; i++ ) {
+			final var r = resultList.get( i );
+			assertThat( r.get( 0, Integer.class) ).isEqualTo( i + 1 );
+			assertThat( r.get( 1, String.class ) ).isEqualTo( expected[i] );
+		}
+	}
+
+	@BeforeAll
+	public void setUp(SessionFactoryScope scope) {
+		scope.inTransaction( session -> {
+			final var descendantA = new DescendantA();
+			descendantA.id = 1;
+			session.persist( descendantA );
+			final var descendantTak = new DescendantTak();
+			descendantTak.id = 2;
+			descendantTak.title = "title";
+			session.persist( descendantTak );
+			final var descendantD = new DescendantD();
+			descendantD.id = 3;
+			descendantD.subtitle = "subtitle";
+			session.persist( descendantD );
+		} );
+	}
+
+	@AfterAll
+	public void tearDown(SessionFactoryScope scope) {
+		scope.getSessionFactory().getSchemaManager().truncateMappedObjects();
+	}
+
+	@Entity(name = "Ancestor")
+	@Table(name = "t_ancestor")
+	@Inheritance(strategy = InheritanceType.JOINED)
+	@DiscriminatorColumn(name = "def_type_id")
+	static abstract class Ancestor {
+		@Id
+		Integer id;
+	}
+
+	@Entity(name = "DescendantA")
+	@DiscriminatorValue("A")
+	@Table(name = "t_descendant_a")
+	static class DescendantA extends Ancestor {
+		String title;
+		String subtitle;
+	}
+
+	@Entity(name = "DescendantB")
+	@Table(name = "t_descendant_b")
+	static abstract class DescendantB extends Ancestor {
+	}
+
+	@Entity(name = "DescendantTak")
+	@DiscriminatorValue("C")
+	@Table(name = "t_descendant_c")
+	static class DescendantTak extends DescendantB {
+		String title;
+		String subtitle;
+	}
+
+	@Entity(name = "DescendantD")
+	@DiscriminatorValue("D")
+	@Table(name = "t_descendant_d")
+	static class DescendantD extends DescendantB {
+		String subtitle;
+	}
+}