HHH-19703 NativeQueryImpl#addScalar(String, Class) fails when no JavaType is registered

hibernate-core/src/main/java/org/hibernate/query/sql/internal/NativeQueryImpl.java

@@ -1174,7 +1174,14 @@ public NativeQueryImplementor<R> addScalar(String columnAlias, @SuppressWarnings
 
 	@Override
 	public NativeQueryImplementor<R> addScalar(String columnAlias, @SuppressWarnings("rawtypes") Class javaType) {
-		return registerBuilder( Builders.scalar( columnAlias, javaType, getSessionFactory() ) );
+		@SuppressWarnings("unchecked")
+		final BasicType<?> basicType = getBasicTypeRegistry().getRegisteredType( javaType );
+		if ( basicType != null ) {
+			return registerBuilder( Builders.scalar( columnAlias, basicType ) );
+		}
+		else {
+			return registerBuilder( Builders.scalar( columnAlias, javaType, getSessionFactory() ) );
+		}
 	}
 
 	@Override

hibernate-core/src/test/java/org/hibernate/orm/test/id/usertype/AddScalarTest.java

@@ -0,0 +1,132 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ * Copyright Red Hat Inc. and Hibernate Authors
+ */
+package org.hibernate.orm.test.id.usertype;
+
+import jakarta.persistence.Entity;
+import jakarta.persistence.Id;
+import jakarta.persistence.Table;
+import org.hibernate.boot.model.TypeContributions;
+import org.hibernate.boot.model.TypeContributor;
+import org.hibernate.query.NativeQuery;
+import org.hibernate.service.ServiceRegistry;
+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.hibernate.type.SqlTypes;
+import org.hibernate.type.descriptor.WrapperOptions;
+import org.hibernate.usertype.UserType;
+import org.junit.jupiter.api.AfterAll;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.util.UUID;
+
+import static org.junit.jupiter.api.Assertions.assertInstanceOf;
+
+@DomainModel(
+		annotatedClasses = AddScalarTest.Book.class,
+		typeContributors = AddScalarTest.UuidTypeContributor.class
+)
+@SessionFactory
+@JiraKey(value = "HHH-19703")
+public class AddScalarTest {
+
+	@BeforeAll
+	static void init(SessionFactoryScope scope) {
+		scope.inTransaction( session ->
+				session.persist( new Book( 1L, UUID.randomUUID().toString() ) ) );
+	}
+
+	@AfterAll
+	static void clean(SessionFactoryScope scope) {
+		scope.inTransaction( session ->
+				session.createMutationQuery( "delete from Book" ).executeUpdate() );
+	}
+
+	@Test
+	public void test(SessionFactoryScope scope) {
+		final var actual = scope.fromSession( session ->
+				session.createNativeQuery( "select uuid from book where id=:id" )
+						.setParameter( "id", Long.valueOf( 1 ) )
+						.unwrap( NativeQuery.class )
+						.addScalar( "uuid", Uuid.class )
+						.getSingleResult() );
+		assertInstanceOf( Uuid.class, actual );
+	}
+
+	@Entity(name = "Book")
+	@Table(name = "book")
+	static class Book {
+
+		@Id
+		private Long id;
+
+		private String uuid;
+
+		public Book() {
+		}
+
+		public Book(Long id, String uuid) {
+			this.id = id;
+			this.uuid = uuid;
+		}
+	}
+
+	record Uuid(UUID uuid) {
+
+	}
+
+	static class UuidType implements UserType<Uuid> {
+
+		@Override
+		public int getSqlType() {
+			return SqlTypes.VARCHAR;
+		}
+
+		@Override
+		public Class<Uuid> returnedClass() {
+			return Uuid.class;
+		}
+
+		@Override
+		public Uuid deepCopy(Uuid value) {
+			return new Uuid( value.uuid );
+		}
+
+		@Override
+		public boolean isMutable() {
+			return false;
+		}
+
+		@Override
+		public Uuid nullSafeGet(ResultSet rs, int position, WrapperOptions options) throws SQLException {
+			final var result = rs.getString( position );
+			return rs.wasNull() ? null : new Uuid( UUID.fromString( result ) );
+		}
+
+		@Override
+		public void nullSafeSet(PreparedStatement st, Uuid value, int position, WrapperOptions options)
+				throws SQLException {
+			if ( value == null ) {
+				st.setNull( position, getSqlType() );
+			}
+			else {
+				st.setObject( position, value.uuid.toString(), getSqlType() );
+			}
+		}
+	}
+
+	static class UuidTypeContributor implements TypeContributor {
+
+		@Override
+		public void contribute(TypeContributions typeContributions, ServiceRegistry serviceRegistry) {
+			typeContributions.contributeType( new UuidType() );
+		}
+	}
+}