HHH-19085 NPE when using null value in CriteriaUpdate

hibernate-core/src/main/java/org/hibernate/query/sqm/internal/AbstractSqmSelectionQuery.java

@@ -9,6 +9,7 @@
 import org.hibernate.engine.spi.SharedSessionContractImplementor;
 import org.hibernate.query.spi.QueryParameterImplementor;
 import org.hibernate.query.sqm.tree.expression.JpaCriteriaParameter;
+import org.hibernate.query.sqm.tree.expression.ValueBindJpaCriteriaParameter;
 import org.hibernate.type.BindableType;
 import org.hibernate.query.KeyedPage;
 import org.hibernate.query.KeyedResultList;
@@ -149,15 +150,12 @@ protected static void bindValueBindCriteriaParameters(
 			if ( sqmParameter instanceof SqmJpaCriteriaParameterWrapper<?> wrapper ) {
 				@SuppressWarnings("unchecked")
 				final var criteriaParameter = (JpaCriteriaParameter<Object>) wrapper.getJpaCriteriaParameter();
-				final var value = criteriaParameter.getValue();
-				// We don't set a null value, unless the type is also null which
-				// is the case when using HibernateCriteriaBuilder.value
-				if ( value != null || criteriaParameter.getNodeType() == null ) {
+				if ( criteriaParameter instanceof ValueBindJpaCriteriaParameter<?> ) {
 					// Use the anticipated type for binding the value if possible
 					//noinspection unchecked
 					final var parameter = (QueryParameterImplementor<Object>) entry.getKey();
 					bindings.getBinding( parameter )
-							.setBindValue( value, criteriaParameter.getAnticipatedType() );
+							.setBindValue( criteriaParameter.getValue(), criteriaParameter.getAnticipatedType() );
 				}
 			}
 		}

hibernate-core/src/main/java/org/hibernate/query/sqm/internal/SqmCriteriaNodeBuilder.java

@@ -2146,7 +2146,10 @@ else if ( value instanceof SqmExpression<?> ) {
 	}
 
 	private <T> boolean isInstance(BindableType<? extends T> bindableType, T value) {
-		if ( bindableType instanceof SqmExpressible<?> expressible ) {
+		if ( value == null ) {
+			return true;
+		}
+		else if ( bindableType instanceof SqmExpressible<?> expressible ) {
 			return expressible.getExpressibleJavaType().isInstance( value );
 		}
 		else {

hibernate-core/src/test/java/org/hibernate/orm/test/jpa/criteria/CriteriaUpdateAssociationSetNullValueTest.java

@@ -0,0 +1,132 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ * Copyright Red Hat Inc. and Hibernate Authors
+ */
+package org.hibernate.orm.test.jpa.criteria;
+
+import jakarta.persistence.Basic;
+import jakarta.persistence.CascadeType;
+import jakarta.persistence.Entity;
+import jakarta.persistence.Id;
+import jakarta.persistence.ManyToOne;
+import jakarta.persistence.criteria.CriteriaBuilder;
+import jakarta.persistence.criteria.CriteriaUpdate;
+import jakarta.persistence.criteria.Root;
+import org.hibernate.SessionFactory;
+import org.hibernate.testing.orm.junit.EntityManagerFactoryScope;
+import org.hibernate.testing.orm.junit.JiraKey;
+import org.hibernate.testing.orm.junit.Jpa;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.AssertionsForClassTypes.assertThat;
+
+
+@Jpa(
+		annotatedClasses = {
+				CriteriaUpdateAssociationSetNullValueTest.Parent.class,
+				CriteriaUpdateAssociationSetNullValueTest.Child.class}
+)
+@JiraKey("HHH-19085")
+public class CriteriaUpdateAssociationSetNullValueTest {
+
+	private static final Long PARENT_ID = 1L;
+
+	@BeforeEach
+	public void setUp(EntityManagerFactoryScope scope) {
+		scope.inTransaction(
+				em -> {
+					em.persist( new Parent( PARENT_ID, "Lionello", new Child( 2L, "Andrea" ) ) );
+				}
+
+		);
+	}
+
+	@AfterEach
+	public void tearDown(EntityManagerFactoryScope scope) {
+		scope.getEntityManagerFactory().unwrap( SessionFactory.class ).getSchemaManager().truncateMappedObjects();
+	}
+
+	@Test
+	void testUpdateSetAssociationToNullValue(EntityManagerFactoryScope scope) {
+		scope.inTransaction(
+				em -> {
+					CriteriaBuilder cb = em.getCriteriaBuilder();
+					CriteriaUpdate<Parent> update = cb.createCriteriaUpdate( Parent.class );
+					Root<Parent> msg = update.from( Parent.class );
+					update.set( msg.get( "child" ), (Child) null );
+					em.createQuery( update ).executeUpdate();
+				}
+		);
+
+		scope.inTransaction(
+				em -> {
+					Parent parent = em.find( Parent.class, PARENT_ID );
+					assertThat( parent ).isNotNull();
+					assertThat( parent.getName() ).isNotNull();
+					assertThat( parent.getChild() ).isNull();
+				}
+		);
+	}
+
+	@Entity(name = "Parent")
+	public static class Parent {
+
+		@Id
+		private Long id;
+
+		@Basic
+		private String name;
+
+		@ManyToOne(cascade = CascadeType.PERSIST)
+		private Child child;
+
+		public Parent() {
+		}
+
+		public Parent(Long id, String name, Child child) {
+			this.id = id;
+			this.name = name;
+			this.child = child;
+		}
+
+		public Long getId() {
+			return id;
+		}
+
+		public String getName() {
+			return name;
+		}
+
+		public Child getChild() {
+			return child;
+		}
+	}
+
+	@Entity(name = "Child")
+	public static class Child {
+
+		@Id
+		private Long id;
+
+		private String name;
+
+		public Child() {
+		}
+
+		public Child(Long id, String name) {
+			this.id = id;
+			this.name = name;
+		}
+
+		public Long getId() {
+			return id;
+		}
+
+		public String getName() {
+			return name;
+		}
+	}
+
+}