From 01c824387653bbf8a3de4e6585bdcccfbcda6f9d Mon Sep 17 00:00:00 2001
From: Marco Belladelli <marco@hibernate.org>
Date: Tue, 17 Oct 2023 12:38:59 +0200
Subject: [PATCH] HHH-17299 Add test for issue

---
 .../TreatedSubclassSameTypeTest.java          | 148 ++++++++++++++++++
 1 file changed, 148 insertions(+)
 create mode 100644 hibernate-core/src/test/java/org/hibernate/orm/test/inheritance/TreatedSubclassSameTypeTest.java

diff --git a/hibernate-core/src/test/java/org/hibernate/orm/test/inheritance/TreatedSubclassSameTypeTest.java b/hibernate-core/src/test/java/org/hibernate/orm/test/inheritance/TreatedSubclassSameTypeTest.java
new file mode 100644
index 0000000000..af2c6b54ab
--- /dev/null
+++ b/hibernate-core/src/test/java/org/hibernate/orm/test/inheritance/TreatedSubclassSameTypeTest.java
@@ -0,0 +1,148 @@
+/*
+ * 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.function.Function;
+
+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 jakarta.persistence.Entity;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.Id;
+import jakarta.persistence.Inheritance;
+import jakarta.persistence.InheritanceType;
+import jakarta.persistence.ManyToOne;
+import jakarta.persistence.criteria.CriteriaBuilder;
+import jakarta.persistence.criteria.CriteriaQuery;
+import jakarta.persistence.criteria.Root;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * @author Marco Belladelli
+ */
+@DomainModel( annotatedClasses = {
+		TreatedSubclassSameTypeTest.MyEntity1.class,
+		TreatedSubclassSameTypeTest.MyEntity2.class,
+		TreatedSubclassSameTypeTest.MySubEntity1.class,
+} )
+@SessionFactory
+@Jira( "https://hibernate.atlassian.net/browse/HHH-17299" )
+public class TreatedSubclassSameTypeTest {
+	@BeforeAll
+	public void setUp(SessionFactoryScope scope) {
+		scope.inTransaction( session -> {
+			session.persist( new MyEntity1() );
+			final MyEntity2 entity2 = new MyEntity2( "entity2" );
+			final MySubEntity1 entity1 = new MySubEntity1( entity2 );
+			session.persist( entity2 );
+			session.persist( entity1 );
+		} );
+	}
+
+	@AfterAll
+	public void tearDown(SessionFactoryScope scope) {
+		scope.inTransaction( session -> {
+			session.createMutationQuery( "delete from MyEntity1" ).executeUpdate();
+			session.createMutationQuery( "delete from MyEntity2" ).executeUpdate();
+		} );
+	}
+
+	@Test
+	public void testJoinOnTreat(SessionFactoryScope scope) {
+		executeQuery( scope, criteria -> criteria.from( MyEntity1.class ), true );
+	}
+
+	@Test
+	public void testJoin(SessionFactoryScope scope) {
+		executeQuery( scope, criteria -> criteria.from( MyEntity1.class ), false );
+	}
+
+	@Test
+	public void testJoinOnTreatedSubtype(SessionFactoryScope scope) {
+		executeQuery( scope, criteria -> criteria.from( MySubEntity1.class ), true );
+	}
+
+	@Test
+	public void testJoinOnSubtype(SessionFactoryScope scope) {
+		executeQuery( scope, criteria -> criteria.from( MySubEntity1.class ), false );
+	}
+
+	@SuppressWarnings( "unchecked" )
+	private void executeQuery(
+			SessionFactoryScope scope,
+			Function<CriteriaQuery<MyEntity1>, Root<? extends MyEntity1>> rootSupplier,
+			boolean treat) {
+		scope.inTransaction( session -> {
+			final CriteriaBuilder cb = session.getCriteriaBuilder();
+			final CriteriaQuery<MyEntity1> criteria = cb.createQuery( MyEntity1.class );
+			final Root<? extends MyEntity1> root = rootSupplier.apply( criteria );
+			final Root<MySubEntity1> subRoot;
+			if ( treat ) {
+				subRoot = cb.treat( ( (Root<MyEntity1>) root ), MySubEntity1.class );
+			}
+			else {
+				subRoot = (Root<MySubEntity1>) root;
+			}
+			criteria.where( cb.equal( subRoot.join( "ref" ).get( "name" ), "entity2" ) );
+			final MyEntity1 result = session.createQuery( criteria ).getSingleResult();
+			assertThat( result ).isInstanceOf( MySubEntity1.class );
+			assertThat( ( (MySubEntity1) result ).getRef().getName() ).isEqualTo( "entity2" );
+		} );
+	}
+
+	@Entity( name = "MyEntity1" )
+	@Inheritance( strategy = InheritanceType.SINGLE_TABLE )
+	public static class MyEntity1 {
+		@Id
+		@GeneratedValue
+		private Long id;
+	}
+
+	@Entity( name = "MySubEntity1" )
+	public static class MySubEntity1 extends MyEntity1 {
+		@ManyToOne
+		private MyEntity2 ref;
+
+		public MySubEntity1() {
+		}
+
+		public MySubEntity1(MyEntity2 ref) {
+			this.ref = ref;
+		}
+
+		public MyEntity2 getRef() {
+			return ref;
+		}
+	}
+
+	@Entity( name = "MyEntity2" )
+	public static class MyEntity2 {
+		@Id
+		@GeneratedValue
+		private Long id;
+
+		private String name;
+
+		public MyEntity2() {
+		}
+
+		public MyEntity2(String name) {
+			this.name = name;
+		}
+
+		public String getName() {
+			return name;
+		}
+	}
+}