From 96c4b9803901d9ee2a56dbd63ee595b31668fd4e Mon Sep 17 00:00:00 2001
From: Marco Belladelli <marco@hibernate.org>
Date: Wed, 28 Jun 2023 12:55:47 +0200
Subject: [PATCH] HHH-16803 Specially handle enum classes in nullLiteral

---
 .../query/sqm/internal/SqmCriteriaNodeBuilder.java        | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/hibernate-core/src/main/java/org/hibernate/query/sqm/internal/SqmCriteriaNodeBuilder.java b/hibernate-core/src/main/java/org/hibernate/query/sqm/internal/SqmCriteriaNodeBuilder.java
index 39995d76a8..88924a6d33 100644
--- a/hibernate-core/src/main/java/org/hibernate/query/sqm/internal/SqmCriteriaNodeBuilder.java
+++ b/hibernate-core/src/main/java/org/hibernate/query/sqm/internal/SqmCriteriaNodeBuilder.java
@@ -1294,8 +1294,12 @@ public class SqmCriteriaNodeBuilder implements NodeBuilder, SqmCreationContext,
 
 	@Override
 	public <T> SqmExpression<T> nullLiteral(Class<T> resultClass) {
-		final TypeConfiguration typeConfiguration = getTypeConfiguration();
-		final BasicType<T> basicTypeForJavaType = typeConfiguration.getBasicTypeForJavaType( resultClass );
+		if ( resultClass.isEnum() ) {
+			// No basic types are registered for enum java types, we have to use an untyped null literal in this case
+			return new SqmLiteralNull<>( this );
+		}
+		final BasicType<T> basicTypeForJavaType = getTypeConfiguration().getBasicTypeForJavaType( resultClass );
+		// if there's no basic type, it might be an entity type
 		final SqmExpressible<T> sqmExpressible = basicTypeForJavaType == null
 				? getDomainModel().managedType( resultClass )
 				: basicTypeForJavaType;