HHH-19874 Add test for issue

Author: dreab8

hibernate-core/src/test/java/org/hibernate/orm/test/query/SubselectFetchTest.java

@@ -0,0 +1,176 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ * Copyright Red Hat Inc. and Hibernate Authors
+ */
+package org.hibernate.orm.test.query;
+
+import jakarta.persistence.Entity;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.Id;
+import jakarta.persistence.ManyToOne;
+import jakarta.persistence.OneToMany;
+import jakarta.persistence.Table;
+import jakarta.persistence.Transient;
+import jakarta.persistence.Version;
+import org.hibernate.Hibernate;
+import org.hibernate.annotations.Fetch;
+import org.hibernate.annotations.FetchMode;
+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 java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+
+import static jakarta.persistence.CascadeType.PERSIST;
+import static jakarta.persistence.FetchType.EAGER;
+import static jakarta.persistence.FetchType.LAZY;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.hibernate.annotations.FetchMode.SUBSELECT;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+@DomainModel(
+		annotatedClasses = {
+				SubselectFetchTest.Element.class,
+				SubselectFetchTest.Node.class,
+		}
+)
+@SessionFactory
+public class SubselectFetchTest {
+
+	@BeforeEach
+	public void setUp(SessionFactoryScope scope) {
+		scope.inTransaction(
+				session -> {
+					Node basik = new Node( "Child" );
+					basik.parent = new Node( "Parent" );
+					basik.elements.add( new Element( basik ) );
+					basik.elements.add( new Element( basik ) );
+					basik.elements.add( new Element( basik ) );
+
+					session.persist( basik );
+				}
+		);
+	}
+
+	@AfterEach
+	@JiraKey("HHH-19868")
+	public void tearDown(SessionFactoryScope scope) {
+		scope.getSessionFactory().getSchemaManager().truncateMappedObjects();
+	}
+
+	@Test
+	void testEagerFetchQuery(SessionFactoryScope scope) {
+		scope.inTransaction( session -> {
+			List<Node> list = session.createSelectionQuery( "from Node order by id", Node.class ).getResultList();
+			assertThat( list ).hasSize( 2 );
+			assertThat( Hibernate.isInitialized( list.get( 0 ).elements ) ).isTrue();
+			assertThat( list.get( 0 ).elements ).hasSize( 3 );
+			assertThat( list.get( 1 ).elements ).isEmpty();
+		} );
+
+		scope.inTransaction( session -> {
+			List<Object[]> list = session.createSelectionQuery( "select distinct n, e from Node n join n.elements e order by n.id", Object[].class ).getResultList();
+			assertThat( list ).hasSize( 3 );
+			Object[] tup = list.get( 0 );
+			assertTrue( Hibernate.isInitialized( ( (Node) tup[0] ).elements ) );
+			assertThat(  ( (Node) tup[0] ).elements ).hasSize( 3 );
+		} );
+	}
+
+
+	@Entity(name = "Element")
+	@Table(name = "Element")
+	public static class Element {
+		@Id
+		@GeneratedValue
+		Integer id;
+
+		@ManyToOne
+		@Fetch(FetchMode.SELECT)
+		Node node;
+
+		public Element(Node node) {
+			this.node = node;
+		}
+
+		public Element() {
+		}
+	}
+
+	@Entity(name = "Node")
+	@Table(name = "Node")
+	public static class Node {
+
+		@Id
+		@GeneratedValue
+		Integer id;
+		@Version
+		Integer version;
+		String string;
+		@Transient
+		boolean loaded = false;
+
+		@ManyToOne(fetch = LAZY, cascade =  PERSIST)
+		Node parent;
+
+		@OneToMany(fetch = EAGER, cascade =  PERSIST , mappedBy = "node")
+		@Fetch(SUBSELECT)
+		List<Element> elements = new ArrayList<>();
+
+		public Node(String string) {
+			this.string = string;
+		}
+
+		public Node() {
+		}
+
+		public Integer getId() {
+			return id;
+		}
+
+		public void setId(Integer id) {
+			this.id = id;
+		}
+
+		public String getString() {
+			return string;
+		}
+
+		public void setString(String string) {
+			this.string = string;
+		}
+
+//		@PostLoad
+//		void postLoad() {
+//			loaded = true;
+//		}
+
+		@Override
+		public String toString() {
+			return id + ": " + string;
+		}
+
+		@Override
+		public boolean equals(Object o) {
+			if ( this == o ) {
+				return true;
+			}
+			if ( o == null || getClass() != o.getClass() ) {
+				return false;
+			}
+			Node node = (Node) o;
+			return Objects.equals( string, node.string );
+		}
+
+		@Override
+		public int hashCode() {
+			return Objects.hash( string );
+		}
+	}
+}