From 56cf0c414c796edf01c0329fbfcb123057a5653e Mon Sep 17 00:00:00 2001
From: Gavin King <gavin@hibernate.org>
Date: Sat, 17 Jun 2023 12:26:38 +0200
Subject: [PATCH] HHH-16813 don't add @Generated annotations if it's going to
 cause a compilation failure

---
 .../hibernate/jpamodelgen/ClassWriter.java    | 32 ++++++++++++-------
 .../JPAMetaModelEntityProcessor.java          |  6 ++++
 .../GeneratedAnnotationTest.java              |  2 +-
 3 files changed, 27 insertions(+), 13 deletions(-)

diff --git a/tooling/metamodel-generator/src/main/java/org/hibernate/jpamodelgen/ClassWriter.java b/tooling/metamodel-generator/src/main/java/org/hibernate/jpamodelgen/ClassWriter.java
index 805d62d819..b02506b8ce 100644
--- a/tooling/metamodel-generator/src/main/java/org/hibernate/jpamodelgen/ClassWriter.java
+++ b/tooling/metamodel-generator/src/main/java/org/hibernate/jpamodelgen/ClassWriter.java
@@ -98,6 +98,10 @@ public final class ClassWriter {
 		StringWriter sw = new StringWriter();
 		try ( PrintWriter pw = new PrintWriter(sw) ) {
 
+			if ( entity.getElement() instanceof TypeElement ) {
+				pw.println(writeStaticMetaModelAnnotation(entity));
+			}
+
 			if (context.addGeneratedAnnotation()) {
 				pw.println(writeGeneratedAnnotation(entity, context));
 			}
@@ -105,10 +109,6 @@ public final class ClassWriter {
 				pw.println(writeSuppressWarnings());
 			}
 
-			if ( entity.getElement() instanceof TypeElement ) {
-				pw.println(writeStaticMetaModelAnnotation(entity));
-			}
-
 			printClassDeclaration(entity, pw, context);
 
 			pw.println();
@@ -203,18 +203,26 @@ public final class ClassWriter {
 
 	private static String writeGeneratedAnnotation(Metamodel entity, Context context) {
 		StringBuilder generatedAnnotation = new StringBuilder();
-		generatedAnnotation.append( "@" )
+		generatedAnnotation
+				.append( "@" )
 				.append( entity.importType( "jakarta.annotation.Generated" ) )
-				.append( "(value = \"" )
-				.append( JPAMetaModelEntityProcessor.class.getName() );
+				.append( "(" );
 		if ( context.addGeneratedDate() ) {
-			generatedAnnotation.append( "\", date = \"" )
+			generatedAnnotation
+					.append( "value = " );
+		}
+		generatedAnnotation
+				.append( "\"" )
+				.append( JPAMetaModelEntityProcessor.class.getName() )
+				.append( "\"" );
+		if ( context.addGeneratedDate() ) {
+			generatedAnnotation
+					.append( ", date = " )
+					.append( "\"" )
 					.append( SIMPLE_DATE_FORMAT.get().format( new Date() ) )
-					.append( "\")" );
-		}
-		else {
-			generatedAnnotation.append( "\")" );
+					.append( "\"" );
 		}
+		generatedAnnotation.append( ")" );
 		return generatedAnnotation.toString();
 	}
 
diff --git a/tooling/metamodel-generator/src/main/java/org/hibernate/jpamodelgen/JPAMetaModelEntityProcessor.java b/tooling/metamodel-generator/src/main/java/org/hibernate/jpamodelgen/JPAMetaModelEntityProcessor.java
index ec691d8c3d..6e2defbfd0 100644
--- a/tooling/metamodel-generator/src/main/java/org/hibernate/jpamodelgen/JPAMetaModelEntityProcessor.java
+++ b/tooling/metamodel-generator/src/main/java/org/hibernate/jpamodelgen/JPAMetaModelEntityProcessor.java
@@ -90,6 +90,12 @@ public class JPAMetaModelEntityProcessor extends AbstractProcessor {
 			boolean addGeneratedAnnotation = Boolean.parseBoolean( tmp );
 			context.setAddGeneratedAnnotation( addGeneratedAnnotation );
 		}
+		else {
+			PackageElement jakartaAnnotationPackage =
+					context.getProcessingEnvironment().getElementUtils()
+							.getPackageElement( "jakarta.annotation" );
+			context.setAddGeneratedAnnotation( jakartaAnnotationPackage != null );
+		}
 
 		tmp = env.getOptions().get( JPAMetaModelEntityProcessor.ADD_GENERATION_DATE );
 		boolean addGenerationDate = Boolean.parseBoolean( tmp );
diff --git a/tooling/metamodel-generator/src/test/java/org/hibernate/jpamodelgen/test/generatedannotation/GeneratedAnnotationTest.java b/tooling/metamodel-generator/src/test/java/org/hibernate/jpamodelgen/test/generatedannotation/GeneratedAnnotationTest.java
index b0125b1bce..be70a73db1 100644
--- a/tooling/metamodel-generator/src/test/java/org/hibernate/jpamodelgen/test/generatedannotation/GeneratedAnnotationTest.java
+++ b/tooling/metamodel-generator/src/test/java/org/hibernate/jpamodelgen/test/generatedannotation/GeneratedAnnotationTest.java
@@ -28,7 +28,7 @@ public class GeneratedAnnotationTest extends CompilationTest {
 
 		// need to check the source because @Generated is not a runtime annotation
 		String metaModelSource = getMetaModelSourceAsString( TestEntity.class );
-		String generatedString = "@Generated(value = \"org.hibernate.jpamodelgen.JPAMetaModelEntityProcessor\")";
+		String generatedString = "@Generated(\"org.hibernate.jpamodelgen.JPAMetaModelEntityProcessor\")";
 		assertTrue( "@Generated should be added to the metamodel.", metaModelSource.contains( generatedString ) );
 	}
 }