HHH-18945 Hibernate Processor - fails if entity extends mapped superclass with same simple class name

tooling/metamodel-generator/src/main/java/org/hibernate/processor/ClassWriter.java

@@ -7,7 +7,6 @@
 import org.hibernate.processor.annotation.InnerClassMetaAttribute;
 import org.hibernate.processor.model.MetaAttribute;
 import org.hibernate.processor.model.Metamodel;
-import org.hibernate.processor.util.StringUtil;
 
 import javax.annotation.processing.FilerException;
 import javax.lang.model.element.Element;
@@ -23,11 +22,10 @@
 import java.io.StringWriter;
 import java.time.OffsetDateTime;
 import java.time.format.DateTimeFormatter;
-import java.util.Arrays;
 import java.util.List;
 import java.util.Set;
-import java.util.stream.Collectors;
 
+import static org.hibernate.processor.util.TypeUtils.getGeneratedClassFullyQualifiedName;
 import static org.hibernate.processor.util.TypeUtils.isMemberType;
 
 /**
@@ -185,20 +183,10 @@ else if ( modifiers.contains( Modifier.PROTECTED ) ) {
 	}
 
 	private static String getFullyQualifiedClassName(Metamodel entity) {
-		final String metaModelPackage = entity.getPackageName();
-		final String packageNamePrefix = !metaModelPackage.isEmpty() ? metaModelPackage + "." : "";
-		final String className;
-		if ( entity.getElement().getKind() == ElementKind.PACKAGE ) {
-			className = getGeneratedClassName( entity );
-		}
-		else {
-			className = Arrays.stream(
-							entity.getQualifiedName().substring( packageNamePrefix.length() ).split( "\\." ) )
-					.map( StringUtil::removeDollar )
-					.map( part -> entity.isJakartaDataStyle() ? '_' + part : part + '_' )
-					.collect( Collectors.joining( "." ) );
-		}
-		return packageNamePrefix + className;
+		return entity.getElement() instanceof PackageElement packageElement
+				? packageElement.getQualifiedName().toString() + "." + getGeneratedClassName( entity )
+				: getGeneratedClassFullyQualifiedName(
+						(TypeElement) entity.getElement(), entity.getPackageName(), entity.isJakartaDataStyle() );
 	}
 
 	private static String getGeneratedClassName(Metamodel entity) {

tooling/metamodel-generator/src/main/java/org/hibernate/processor/annotation/AnnotationMetaEntity.java

@@ -88,6 +88,7 @@
 import static org.hibernate.processor.util.TypeUtils.findMappedSuperElement;
 import static org.hibernate.processor.util.TypeUtils.getAnnotationMirror;
 import static org.hibernate.processor.util.TypeUtils.getAnnotationValue;
+import static org.hibernate.processor.util.TypeUtils.getGeneratedClassFullyQualifiedName;
 import static org.hibernate.processor.util.TypeUtils.hasAnnotation;
 import static org.hibernate.processor.util.TypeUtils.implementsInterface;
 import static org.hibernate.processor.util.TypeUtils.primitiveClassMatchesKind;
@@ -175,6 +176,9 @@ public AnnotationMetaEntity(
 		this.quarkusInjection = context.isQuarkusInjection();
 		this.importContext = parent != null ? parent : new ImportContextImpl( getPackageName( context, element ) );
 		jakartaDataStaticModel = jakartaDataStaticMetamodel;
+		importContext.importType(
+				getGeneratedClassFullyQualifiedName( element, getPackageName( context, element ),
+						jakartaDataStaticModel ) );
 	}
 
 	public static AnnotationMetaEntity create(TypeElement element, Context context) {

tooling/metamodel-generator/src/main/java/org/hibernate/processor/util/TypeUtils.java

@@ -4,6 +4,7 @@
  */
 package org.hibernate.processor.util;
 
+import jakarta.persistence.AccessType;
 import org.checkerframework.checker.nullness.qual.Nullable;
 import org.hibernate.processor.Context;
 import org.hibernate.processor.MetaModelGenerationException;
@@ -29,8 +30,6 @@
 import javax.lang.model.util.Elements;
 import javax.lang.model.util.SimpleTypeVisitor8;
 import javax.tools.Diagnostic;
-
-import jakarta.persistence.AccessType;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
@@ -39,6 +38,7 @@
 import java.util.function.Function;
 
 import static java.beans.Introspector.decapitalize;
+import static org.hibernate.internal.util.StringHelper.split;
 import static org.hibernate.processor.util.AccessTypeInformation.DEFAULT_ACCESS_TYPE;
 import static org.hibernate.processor.util.Constants.ACCESS;
 import static org.hibernate.processor.util.Constants.BASIC;
@@ -671,6 +671,16 @@ public static boolean isMemberType(Element element) {
 		return element.getEnclosingElement() instanceof TypeElement;
 	}
 
+	public static String getGeneratedClassFullyQualifiedName(TypeElement element, String packageName, boolean jakartaDataStyle) {
+		final StringBuilder builder = new StringBuilder( !packageName.isEmpty() ? packageName + "." : "" );
+		final int length = builder.length();
+		for ( String s : split( ".", element.getQualifiedName().toString().substring( length ) ) ) {
+			String part = StringUtil.removeDollar( s );
+			builder.append( jakartaDataStyle ? '_' + part : part + '_' );
+		}
+		return builder.toString();
+	}
+
 	static class EmbeddedAttributeVisitor extends SimpleTypeVisitor8<@Nullable TypeElement, Element> {
 		private final Context context;
 

tooling/metamodel-generator/src/test/java/org/hibernate/processor/test/classnamecollision/ClassNameCollisionTest.java

@@ -0,0 +1,34 @@
+/*
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ * Copyright Red Hat Inc. and Hibernate Authors
+ */
+package org.hibernate.processor.test.classnamecollision;
+
+import org.hibernate.processor.test.util.CompilationTest;
+import org.hibernate.processor.test.util.WithClasses;
+import org.junit.Test;
+
+import static org.hibernate.processor.test.util.TestUtil.assertMetamodelClassGeneratedFor;
+import static org.hibernate.processor.test.util.TestUtil.getMetaModelSourceAsString;
+import static org.hibernate.processor.test.util.TestUtil.getMetamodelClassFor;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class ClassNameCollisionTest extends CompilationTest {
+
+	@Test
+	@WithClasses({
+			Something.class,
+			org.hibernate.processor.test.classnamecollision.somewhere.Something.class
+	})
+	public void testAmbiguousSimpleName() {
+		System.out.println( getMetaModelSourceAsString( Something.class ) );
+		assertMetamodelClassGeneratedFor( Something.class );
+		System.out.println( getMetaModelSourceAsString( org.hibernate.processor.test.classnamecollision.somewhere.Something.class ) );
+		assertMetamodelClassGeneratedFor( org.hibernate.processor.test.classnamecollision.somewhere.Something.class );
+		assertEquals(
+				getMetamodelClassFor( org.hibernate.processor.test.classnamecollision.somewhere.Something.class ).getName(),
+				getMetamodelClassFor( Something.class ).getSuperclass()
+						.getName() );
+	}
+
+}

tooling/metamodel-generator/src/test/java/org/hibernate/processor/test/classnamecollision/Something.java

@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ * Copyright Red Hat Inc. and Hibernate Authors
+ */
+package org.hibernate.processor.test.classnamecollision;
+
+import jakarta.persistence.Entity;
+
+@Entity
+public class Something extends org.hibernate.processor.test.classnamecollision.somewhere.Something {
+	String alphaValue;
+}

tooling/metamodel-generator/src/test/java/org/hibernate/processor/test/classnamecollision/somewhere/Something.java

@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ * Copyright Red Hat Inc. and Hibernate Authors
+ */
+package org.hibernate.processor.test.classnamecollision.somewhere;
+
+import jakarta.persistence.MappedSuperclass;
+
+@MappedSuperclass
+abstract public class Something {
+	String name;
+}