HHH-14820 - Customized EnumType not working with hbm mapping in Hibernate 6 (Reproducer)

A simple unit test illustrating issue HHH-14820 : since Hibernate ORM 6
the custom NamedEnumUserType is only instantiated once (while there are
two enums configured with this type)

hibernate-core/src/test/java/org/hibernate/orm/test/mapping/converted/enums/NamedEnumUserType.java

@@ -0,0 +1,21 @@
+package org.hibernate.orm.test.mapping.converted.enums;
+
+import java.util.Properties;
+
+import org.hibernate.type.EnumType;
+
+/**
+ * A simple user type where we force enums to be saved by name, not ordinal
+ * 
+ * @author gtoison
+ */
+public class NamedEnumUserType<T extends Enum<T>> extends EnumType<T> {
+	private static final long serialVersionUID = -4176945793071035928L;
+
+	@Override
+	public void setParameterValues(Properties parameters) {
+		parameters.setProperty(EnumType.NAMED, "true");
+
+		super.setParameterValues(parameters);
+	}
+}

hibernate-core/src/test/java/org/hibernate/orm/test/mapping/converted/enums/NamedEnumUserTypeTest.java

@@ -0,0 +1,50 @@
+/**
+ * 
+ */
+package org.hibernate.orm.test.mapping.converted.enums;
+
+import static org.hibernate.testing.transaction.TransactionUtil.doInHibernate;
+
+import org.hibernate.testing.TestForIssue;
+import org.hibernate.testing.junit4.BaseCoreFunctionalTestCase;
+import org.junit.Ignore;
+import org.junit.Test;
+
+/**
+ * @author gtoison
+ *
+ */
+public class NamedEnumUserTypeTest extends BaseCoreFunctionalTestCase {
+
+	@Override
+	protected String getBaseForMappings() {
+		return "";
+	}
+	
+	@Override
+	protected String[] getMappings() {
+		return new String[] { "org/hibernate/orm/test/mapping/converted/enums/PersonNamedEnumsUserType.xml" };
+	}
+
+	@Override
+	protected void prepareTest() {
+		doInHibernate( this::sessionFactory, s -> {
+			s.persist( Person.person( Gender.MALE, HairColor.BLACK ) );
+		} );
+	}
+
+	@Override
+	protected boolean isCleanupTestDataRequired() {
+		return true;
+	}
+	
+	@Ignore
+	@Test
+	@TestForIssue(jiraKey = "HHH-14820")
+	public void testNamedEnumUserType() {
+		// This fails because the same instance of NamedEnumUserType is used for both enums
+		doInHibernate( this::sessionFactory, s -> {
+			s.createQuery( "from Person p", Person.class );
+		} );
+	}
+}

hibernate-core/src/test/resources/org/hibernate/orm/test/mapping/converted/enums/PersonNamedEnumsUserType.xml

@@ -0,0 +1,30 @@
+<?xml version="1.0"?>
+<!--
+  ~ 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>.
+  -->
+<!DOCTYPE hibernate-mapping PUBLIC
+"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
+"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
+
+<hibernate-mapping>
+  <typedef name="gender" class="org.hibernate.orm.test.mapping.converted.enums.NamedEnumUserType">
+  	<param name="enumClass">org.hibernate.orm.test.mapping.converted.enums.Gender</param>
+  </typedef>
+  <typedef name="hairColor" class="org.hibernate.orm.test.mapping.converted.enums.NamedEnumUserType">
+  	<param name="enumClass">org.hibernate.orm.test.mapping.converted.enums.HairColor</param>
+  </typedef>
+  
+  <class name="org.hibernate.orm.test.mapping.converted.enums.Person">
+    <id name="id" type="long">
+      <generator class="native"></generator>
+    </id>
+
+    <property name="gender" not-null="true" type="gender"/>
+    <property name="hairColor" not-null="true" type="hairColor"/>
+    <property name="originalHairColor" type="hairColor"/>
+
+  </class>
+</hibernate-mapping>