HHH-8775 - Exception when mapping a class more than once - applying tests from https://github.com/hibernate/hibernate-orm/pull/677 + fix

hibernate-entitymanager/src/main/java/org/hibernate/jpa/event/internal/jpa/CallbackRegistryImpl.java

@@ -101,6 +101,11 @@ public class CallbackRegistryImpl implements CallbackRegistry {
 		}
 	}
 
+	@Override
+	public boolean hasRegisteredCallbacks(Class entityClass, Class annotationClass) {
+		final HashMap<Class, Callback[]> map = determineAppropriateCallbackMap( annotationClass );
+		return map != null && map.containsKey( entityClass );
+	}
 
 	/**
 	 * Great care should be taken calling this.  Not a fan of it being public, but that is needed because of

hibernate-entitymanager/src/main/java/org/hibernate/jpa/event/internal/jpa/LegacyCallbackProcessor.java

@@ -51,6 +51,18 @@ public class LegacyCallbackProcessor implements CallbackProcessor {
 			final XClass entityXClass = reflectionManager.classForName( entityClassName );
 			final Class entityClass = reflectionManager.toClass( entityXClass );
 			for ( Class annotationClass : CALLBACK_ANNOTATION_CLASSES ) {
+				if ( callbackRegistry.hasRegisteredCallbacks( entityClass, annotationClass ) ) {
+					// this most likely means we have a class mapped multiple times using the hbm.xml
+					// "entity name" feature
+					log.debugf(
+							"CallbackRegistry reported that Class [%s] already had %s callbacks registered; " +
+									"assuming this means the class was mapped twice " +
+									"(using hbm.xml entity-name support) - skipping subsequent registrations",
+							entityClassName,
+							annotationClass.getSimpleName()
+					);
+					continue;
+				}
 				final Callback[] callbacks = resolveCallbacks( entityXClass, annotationClass, reflectionManager );
 				callbackRegistry.addEntityCallbacks( entityClass, annotationClass, callbacks );
 			}

hibernate-entitymanager/src/main/java/org/hibernate/jpa/event/spi/jpa/CallbackRegistry.java

@@ -12,17 +12,19 @@ import java.io.Serializable;
  * @author Steve Ebersole
  */
 public interface CallbackRegistry extends Serializable {
-	public void preCreate(Object entity);
-	public boolean hasPostCreateCallbacks(Class entityClass);
-	public void postCreate(Object entity);
+	void preCreate(Object entity);
+	boolean hasPostCreateCallbacks(Class entityClass);
+	void postCreate(Object entity);
 
-	public boolean preUpdate(Object entity);
-	public boolean hasPostUpdateCallbacks(Class entityClass);
-	public void postUpdate(Object entity);
+	boolean preUpdate(Object entity);
+	boolean hasPostUpdateCallbacks(Class entityClass);
+	void postUpdate(Object entity);
 
-	public void preRemove(Object entity);
-	public boolean hasPostRemoveCallbacks(Class entityClass);
-	public void postRemove(Object entity);
+	void preRemove(Object entity);
+	boolean hasPostRemoveCallbacks(Class entityClass);
+	void postRemove(Object entity);
 
-	public boolean postLoad(Object entity);
+	boolean postLoad(Object entity);
+
+	boolean hasRegisteredCallbacks(Class entityClass, Class annotationClass);
 }

hibernate-entitymanager/src/test/java/org/hibernate/jpa/test/callbacks/hbmxml/Entity.java

@@ -0,0 +1,31 @@
+/*
+ * 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>.
+ */
+package org.hibernate.jpa.test.callbacks.hbmxml;
+
+/**
+ * @author Steve Ebersole
+ */
+public class Entity {
+	private Long id;
+	private String name;
+
+	public Long getId() {
+		return id;
+	}
+
+	public void setId(Long id) {
+		this.id = id;
+	}
+
+	public String getName() {
+		return name;
+	}
+
+	public void setName(String name) {
+		this.name = name;
+	}
+}

hibernate-entitymanager/src/test/java/org/hibernate/jpa/test/callbacks/hbmxml/MappingClassMoreThanOnceTest.java

@@ -0,0 +1,56 @@
+/*
+ * 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>.
+ */
+package org.hibernate.jpa.test.callbacks.hbmxml;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import org.hibernate.jpa.AvailableSettings;
+import org.hibernate.jpa.HibernateEntityManagerFactory;
+import org.hibernate.jpa.boot.spi.Bootstrap;
+import org.hibernate.jpa.boot.spi.EntityManagerFactoryBuilder;
+import org.hibernate.jpa.test.BaseEntityManagerFunctionalTestCase;
+
+import org.hibernate.testing.TestForIssue;
+import org.hibernate.testing.junit4.BaseUnitTestCase;
+import org.junit.Test;
+
+/**
+ * @author Felix Feisst (feisst dot felix at gmail dot com)
+ */
+public class MappingClassMoreThanOnceTest extends BaseUnitTestCase {
+	/**
+	 * Tests that an entity manager can be created when a class is mapped more than once.
+	 */
+	@Test
+	@TestForIssue(jiraKey = "HHH-8775")
+//	@FailureExpected(jiraKey = "HHH-8775")
+	public void testBootstrapWithClassMappedMOreThanOnce() {
+		Map settings = new HashMap(  );
+		settings.put( AvailableSettings.HBXML_FILES, "org/hibernate/jpa/test/callbacks/hbmxml/ClassMappedMoreThanOnce.hbm.xml" );
+
+		final EntityManagerFactoryBuilder builder = Bootstrap.getEntityManagerFactoryBuilder(
+				new BaseEntityManagerFunctionalTestCase.TestingPersistenceUnitDescriptorImpl( getClass().getSimpleName() ),
+				settings
+		);
+
+		HibernateEntityManagerFactory emf = null;
+		try {
+			emf = builder.build().unwrap( HibernateEntityManagerFactory.class );
+		}
+		finally {
+			if ( emf != null ) {
+				try {
+					emf.close();
+				}
+				catch (Exception ignore) {
+				}
+			}
+		}
+	}
+
+}

hibernate-entitymanager/src/test/resources/org/hibernate/jpa/test/callbacks/hbmxml/ClassMappedMoreThanOnce.hbm.xml

@@ -0,0 +1,33 @@
+<?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 package="org.hibernate.jpa.test.callbacks.hbmxml">
+
+    <class entity-name="Entity1" name="Entity" table="ENTITY1">
+        <id name="id" column="id" type="long">
+            <generator class="native"/>
+        </id>
+        <property name="name" type="string">
+            <column name="NAME" length="20" not-null="true"/>
+        </property>
+    </class>
+    <class entity-name="Entity2" name="Entity" table="ENTITY2">
+        <id name="id" column="id" type="long">
+            <generator class="native"/>
+        </id>
+        <property name="name" type="string">
+            <column name="NAME" length="20" not-null="true"/>
+        </property>
+    </class>
+
+</hibernate-mapping>
+
+