HHH-18894 Hibernate 6.6 enum literal is considered field literal instead

hibernate-core/src/main/java/org/hibernate/metamodel/model/domain/internal/JpaMetamodelImpl.java

@@ -319,7 +319,21 @@ public Set<EmbeddableType<?>> getEmbeddables() {
 
 	@Override
 	public EnumJavaType<?> getEnumType(String className) {
-		return enumJavaTypes.get( className );
+		final EnumJavaType<?> enumJavaType = enumJavaTypes.get( className );
+		if ( enumJavaType != null ) {
+			return enumJavaType;
+		}
+		final ClassLoaderService classLoaderService = serviceRegistry.getService( ClassLoaderService.class );
+		try {
+			final Class<Object> clazz = classLoaderService.classForName( className );
+			if ( clazz == null || !clazz.isEnum() ) {
+				return null;
+			}
+			return new EnumJavaType( clazz );
+		}
+		catch (ClassLoadingException e) {
+			throw new RuntimeException( e );
+		}
 	}
 
 	@Override

hibernate-core/src/test/java/org/hibernate/orm/test/query/SelectUnknownEnumLiteralTest.java

@@ -0,0 +1,64 @@
+/*
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ * Copyright Red Hat Inc. and Hibernate Authors
+ */
+package org.hibernate.orm.test.query;
+
+import jakarta.persistence.Entity;
+import jakarta.persistence.Id;
+import jakarta.persistence.Tuple;
+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.AfterAll;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+@DomainModel(annotatedClasses = SelectUnknownEnumLiteralTest.Transaction.class)
+@SessionFactory
+public class SelectUnknownEnumLiteralTest {
+
+	@BeforeAll
+	void setup(SessionFactoryScope scope) {
+		scope.inTransaction( em -> em.persist( new Transaction( 1L, "abc" ) ) );
+	}
+
+	@AfterAll
+	void clean(SessionFactoryScope scope) {
+		scope.inTransaction( em -> em.createMutationQuery( "delete from Tx" ).executeUpdate() );
+	}
+
+	@Test
+	void test(SessionFactoryScope scope) {
+		final List<Tuple> tuples = scope.fromSession( em ->
+				em.createQuery(
+						"SELECT org.hibernate.orm.test.query.SelectUnknownEnumLiteralTest$Type.TRANSACTION, e.id, e.reference FROM Tx e",
+						Tuple.class ).getResultList() );
+		assertEquals( 1, tuples.size() );
+		assertEquals( Type.TRANSACTION, tuples.get( 0 ).get( 0 ) );
+		assertEquals( 1L, tuples.get( 0 ).get( 1 ) );
+	}
+
+	@Entity(name = "Tx")
+	static class Transaction {
+		@Id
+		Long id;
+		String reference;
+
+		Transaction() {
+		}
+
+		Transaction(Long id, String reference) {
+			this.id = id;
+			this.reference = reference;
+		}
+	}
+
+	enum Type {
+		TRANSACTION, DIRECT_DEBIT_GROUP, DIRECT_DEBIT
+	}
+}