HHH-18945 Import generated class full qualified name to prevent importing other classes with same simple name

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

@@ -7,7 +7,6 @@ package org.hibernate.processor;
 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.PrintWriter;
 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 @@ public final class ClassWriter {
 	}
 
 	private static String getFullyQualifiedClassName(Metamodel entity) {
-		final String metaModelPackage = entity.getPackageName();
+		return entity.getElement() instanceof PackageElement packageElement
-		final String packageNamePrefix = !metaModelPackage.isEmpty() ? metaModelPackage + "." : "";
+				? packageElement.getQualifiedName().toString() + "." + getGeneratedClassName( entity )
-		final String className;
+				: getGeneratedClassFullyQualifiedName(
-		if ( entity.getElement().getKind() == ElementKind.PACKAGE ) {
+						(TypeElement) entity.getElement(), entity.getPackageName(), entity.isJakartaDataStyle() );
-			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;
 	}
 
 	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.extendsClass;
 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 class AnnotationMetaEntity extends AnnotationMeta {
 		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.ElementFilter;
 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;
@@ -38,6 +37,7 @@ import java.util.Map;
 import java.util.Set;
 
 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;
@@ -665,6 +665,16 @@ public final class TypeUtils {
 		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;