HHH-19387 - Fix concrete descriptor when left join returns null in a cached query

Author: mira-silhavy

hibernate-core/src/main/java/org/hibernate/sql/results/graph/entity/internal/EntityInitializerImpl.java

@@ -1634,6 +1634,10 @@ public void resolveState(EntityInitializerData data) {
 						castNonNull( discriminatorAssembler ),
 						entityDescriptor
 				);
+				if (data.concreteDescriptor == null) {
+					// Return because the value is null
+					return;
+				}
 			}
 		}
 		resolveEntityState( data );

hibernate-core/src/test/java/org/hibernate/orm/test/querycache/EntityWithCollectionReloadCacheInheritanceTest.java

@@ -0,0 +1,178 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ * Copyright Red Hat Inc. and Hibernate Authors
+ */
+package org.hibernate.orm.test.querycache;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.Set;
+
+import org.hibernate.annotations.JdbcTypeCode;
+import org.hibernate.type.SqlTypes;
+
+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.Access;
+import jakarta.persistence.Column;
+import jakarta.persistence.DiscriminatorColumn;
+import jakarta.persistence.DiscriminatorValue;
+import jakarta.persistence.Entity;
+import jakarta.persistence.Enumerated;
+import jakarta.persistence.FetchType;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.Id;
+import jakarta.persistence.JoinColumn;
+import jakarta.persistence.JoinTable;
+import jakarta.persistence.ManyToMany;
+
+import static jakarta.persistence.AccessType.FIELD;
+import static jakarta.persistence.EnumType.STRING;
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * @author miroslav silhavy
+ */
+@DomainModel(annotatedClasses = {
+		EntityWithCollectionReloadCacheInheritanceTest.HighSchoolStudent.class,
+		EntityWithCollectionReloadCacheInheritanceTest.DefaultSubject.class,
+		EntityWithCollectionReloadCacheInheritanceTest.EnglishSubject.class
+})
+@SessionFactory
+@Jira("https://hibernate.atlassian.net/browse/HHH-19387")
+public class EntityWithCollectionReloadCacheInheritanceTest {
+
+	@Test
+	public void test(SessionFactoryScope scope) {
+		scope.inTransaction( session -> {
+			List<HighSchoolStudent> list = session.createQuery(
+							"select s" +
+									" from HighSchoolStudent s left join fetch s.subjects m" +
+									" where s.name in :names", HighSchoolStudent.class
+					)
+					.setParameter( "names", Arrays.asList( "Brian" ) )
+					.setCacheable( true )
+					.list();
+
+			assertThat( list ).hasSize( 1 );
+
+			list = session.createQuery(
+							"select s" +
+									" from HighSchoolStudent s left join fetch s.subjects m" +
+									" where s.name in :names", HighSchoolStudent.class
+					)
+					.setParameter( "names", Arrays.asList( "Andrew", "Brian" ) )
+					.setCacheable( true )
+					.list();
+
+			assertThat( list ).hasSize( 2 );
+		} );
+	}
+
+	@BeforeAll
+	public void setUp(SessionFactoryScope scope) {
+		scope.inTransaction( session -> {
+			HighSchoolStudent s1 = new HighSchoolStudent();
+			s1.setName( "Andrew" );
+			session.persist( s1 );
+
+			HighSchoolStudent s2 = new HighSchoolStudent();
+			s2.setName( "Brian" );
+			session.persist( s2 );
+		} );
+	}
+
+	@AfterAll
+	public void tearDown(SessionFactoryScope scope) {
+		scope.getSessionFactory().getSchemaManager().truncateMappedObjects();
+	}
+
+	@Entity(name = "HighSchoolStudent")
+	@Access(FIELD)
+	static class HighSchoolStudent {
+
+		@Id
+		@GeneratedValue
+		@Column(name = "id")
+		private Long id;
+
+		@Column(name = "name")
+		private String name;
+
+		@ManyToMany(targetEntity = DefaultSubject.class, fetch = FetchType.LAZY)
+		@JoinTable(name = "STUDENT_SUBJECT",
+				joinColumns = { @JoinColumn(name = "student_id") },
+				inverseJoinColumns = { @JoinColumn(name = "subject_id") }
+		)
+		private Set<DefaultSubject> subjects;
+
+		public Long getId() {
+			return id;
+		}
+
+		public void setId(Long id) {
+			this.id = id;
+		}
+
+		public String getName() {
+			return name;
+		}
+
+		public void setName(String name) {
+			this.name = name;
+		}
+
+		public Set<DefaultSubject> getSubjects() {
+			return subjects;
+		}
+
+		public void setMajors(Set<DefaultSubject> subjects) {
+			this.subjects = subjects;
+		}
+
+	}
+
+	@Entity(name = "DefaultSubject")
+	@DiscriminatorValue("DEFAULT")
+	@DiscriminatorColumn(name = "TYPE", length = 20)
+	@Access(FIELD)
+	static class DefaultSubject {
+
+		enum SubjectType {
+			DEFAULT,
+			ENGLISH
+		}
+
+		@Column(name = "TYPE", nullable = false, length = 20, insertable = false, updatable = false)
+		@Enumerated(STRING)
+		@JdbcTypeCode(SqlTypes.VARCHAR)
+		private SubjectType type;
+
+		@Id
+		@GeneratedValue
+		@Column(name = "id")
+		private Long id;
+
+		public Long getId() {
+			return id;
+		}
+
+		public void setId(Long id) {
+			this.id = id;
+		}
+
+	}
+
+	@Entity(name = "EnglishSubject")
+	@DiscriminatorValue("ENGLISH")
+	@Access(FIELD)
+	static class EnglishSubject extends DefaultSubject {
+	}
+
+}