HHH-18282 fix generate error sql in case of @DiscriminatorValue("not null")

Author: lrobot

hibernate-core/src/main/java/org/hibernate/persister/entity/AbstractEntityPersister.java

@@ -3222,7 +3222,13 @@ else if ( discriminatorValue == NOT_NULL_DISCRIMINATOR ) {
 				return junction;
 			}
 
-			junction.add( new NullnessPredicate( sqlExpression ) );
+			if ( hasNonNull ) {
+				return new NullnessPredicate( sqlExpression, true );
+			}
+			else if ( hasNull ) {
+				junction.add( new NullnessPredicate( sqlExpression ) );				
+			}
+
 			junction.add( predicate );
 			return junction;
 		}

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

@@ -0,0 +1,135 @@
+/*
+ * 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.discriminator;
+
+import java.sql.Statement;
+import java.util.List;
+import java.util.Map;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+import jakarta.persistence.DiscriminatorValue;
+import jakarta.persistence.Entity;
+import jakarta.persistence.Id;
+import jakarta.persistence.Inheritance;
+import jakarta.persistence.InheritanceType;
+import jakarta.persistence.criteria.CriteriaQuery;
+import jakarta.persistence.criteria.Root;
+
+import org.hibernate.testing.TestForIssue;
+import org.hibernate.testing.orm.junit.DomainModel;
+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.Test;
+
+
+import static org.assertj.core.api.Assertions.assertThat;
+/**
+ * @author [email protected]
+ * how to run this test case: ./gradlew :hibernate-core:test --tests '*DiscriminatorSuperClassTest'
+ */
+@TestForIssue(jiraKey = "HHH-18282")
+@DomainModel(
+		annotatedClasses = {
+			SingleTableNotNullDiscriminatorSuperClassTest.RootEntity.class,
+			SingleTableNotNullDiscriminatorSuperClassTest.Val1Entity.class,
+			SingleTableNotNullDiscriminatorSuperClassTest.Val2Entity.class,
+			SingleTableNotNullDiscriminatorSuperClassTest.OtherEntity.class,
+			SingleTableNotNullDiscriminatorSuperClassTest.NotNullEntity.class
+		}
+)
+@SessionFactory
+public class SingleTableNotNullDiscriminatorSuperClassTest {
+
+	@AfterEach
+	public void tearDown(SessionFactoryScope scope) {
+		scope.inTransaction(
+				session ->
+						session.createQuery( "delete from root_ent" ).executeUpdate()
+		);
+	}
+
+	@Test
+	public void test(SessionFactoryScope scope) {
+		scope.inTransaction( session -> {
+			Val1Entity val1 = new Val1Entity();
+			val1.setId( 1L );
+
+			Val2Entity val2 = new Val2Entity();
+			val2.setId( 2L );
+			
+			RootEntity root = new RootEntity();
+			root.setId( 3L );
+
+			OtherEntity otherEntity = new OtherEntity();
+			otherEntity.setId( 4L );
+			
+			session.persist( val1 );
+			session.persist( val2 );
+			session.persist( root );
+			session.persist( otherEntity );
+
+		} );
+
+		scope.inTransaction( session -> {
+			// can ref more from spring-data: SimpleJpaRepository
+			final CriteriaQuery<NotNullEntity> criteriaQuery = session.getCriteriaBuilder().createQuery( NotNullEntity.class );
+			final Root<NotNullEntity> root = criteriaQuery.from( NotNullEntity.class );
+			criteriaQuery.select( root );
+
+			Map<Long, NotNullEntity> entities = session.createQuery( criteriaQuery ).getResultList()
+					.stream()
+					.collect( Collectors.toMap( NotNullEntity::getId, Function.identity() ) );
+			assertThat( entities ).hasSize( 3 );  //select NotNullEntity and all it subclasses only, not select RootEntity
+			assertThat( entities ).extractingByKey( 1L ).isInstanceOf( Val1Entity.class );
+			assertThat( entities ).extractingByKey( 2L ).isInstanceOf( Val2Entity.class );
+			// assertThat( entities ).extractingByKey( 3L ).isInstanceOf( RootEntity.class );
+			assertThat( entities ).extractingByKey( 4L ).isInstanceOf( NotNullEntity.class );
+		} );
+	}
+
+	@Entity(name = "root_ent")
+	@DiscriminatorValue("null")
+	public static class RootEntity {
+
+		@Id
+		private Long id;
+
+		private String name;
+
+		public Long getId() {
+			return id;
+		}
+
+		public void setId(Long id) {
+			this.id = id;
+		}
+	}
+
+	@Entity(name = "val1_ent")
+	@DiscriminatorValue("val1")
+	public static class Val1Entity extends NotNullEntity {
+
+	}
+
+	@Entity(name = "val2_ent")
+	@DiscriminatorValue("val2")
+	public static class Val2Entity extends NotNullEntity {
+
+	}
+
+	@Entity(name = "other_ent")
+	@DiscriminatorValue("other")
+	public static class OtherEntity extends NotNullEntity {
+	}
+
+	@Entity(name = "notnull_ent")
+	@DiscriminatorValue("not null")
+	public static class NotNullEntity extends RootEntity {
+
+	}
+}