HHH-19626 Hibernate processor may fail to process entities with generics

tooling/metamodel-generator/src/jakartaData/java/org/hibernate/processor/test/data/generic/MyActualEntity.java

@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ * Copyright Red Hat Inc. and Hibernate Authors
+ */
+package org.hibernate.processor.test.data.generic;
+
+import jakarta.persistence.Entity;
+
+@Entity
+public class MyActualEntity extends MyMappedSuperclass<Integer> {
+	public String myString;
+}

tooling/metamodel-generator/src/jakartaData/java/org/hibernate/processor/test/data/generic/MyActualEntityRepository.java

@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ * Copyright Red Hat Inc. and Hibernate Authors
+ */
+package org.hibernate.processor.test.data.generic;
+
+import jakarta.data.repository.CrudRepository;
+import jakarta.data.repository.Repository;
+
+@Repository
+public interface MyActualEntityRepository extends CrudRepository<MyActualEntity, Integer> {
+}

tooling/metamodel-generator/src/jakartaData/java/org/hibernate/processor/test/data/generic/MyMappedSuperclass.java

@@ -0,0 +1,17 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ * Copyright Red Hat Inc. and Hibernate Authors
+ */
+package org.hibernate.processor.test.data.generic;
+
+import jakarta.persistence.Id;
+import jakarta.persistence.MappedSuperclass;
+
+import java.io.Serializable;
+
+@MappedSuperclass
+public class MyMappedSuperclass<ID extends Serializable> {
+	@Id
+	private ID id;
+
+}

tooling/metamodel-generator/src/jakartaData/java/org/hibernate/processor/test/data/generic/MyMappedSuperclassTest.java

@@ -0,0 +1,25 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ * Copyright Red Hat Inc. and Hibernate Authors
+ */
+package org.hibernate.processor.test.data.generic;
+
+import org.hibernate.processor.test.util.CompilationTest;
+import org.hibernate.processor.test.util.TestUtil;
+import org.hibernate.processor.test.util.WithClasses;
+import org.junit.jupiter.api.Test;
+
+import static org.hibernate.processor.test.util.TestUtil.assertMetamodelClassGeneratedFor;
+
+@CompilationTest
+public class MyMappedSuperclassTest {
+
+	@Test
+	@WithClasses({MyActualEntity.class, MyActualEntityRepository.class, MyMappedSuperclass.class})
+	void smoke() {
+		System.out.println( TestUtil.getMetaModelSourceAsString( MyMappedSuperclass.class ) );
+		System.out.println( TestUtil.getMetaModelSourceAsString( MyActualEntity.class ) );
+		assertMetamodelClassGeneratedFor( MyMappedSuperclass.class );
+		assertMetamodelClassGeneratedFor( MyActualEntity.class );
+	}
+}

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

@@ -67,6 +67,7 @@
 import static java.beans.Introspector.decapitalize;
 import static java.lang.Boolean.FALSE;
 import static java.util.Collections.emptyList;
+import static java.util.Objects.requireNonNullElse;
 import static java.util.stream.Collectors.toList;
 import static javax.lang.model.util.ElementFilter.fieldsIn;
 import static javax.lang.model.util.ElementFilter.methodsIn;
@@ -100,6 +101,7 @@
 import static org.hibernate.processor.util.TypeUtils.implementsInterface;
 import static org.hibernate.processor.util.TypeUtils.primitiveClassMatchesKind;
 import static org.hibernate.processor.util.TypeUtils.propertyName;
+import static org.hibernate.processor.util.TypeUtils.resolveTypeMirror;
 
 /**
  * Class used to collect meta information about an annotated type (entity, embeddable or mapped superclass).
@@ -2526,7 +2528,15 @@ enum FieldType {
 				return null;
 			}
 
-			if ( checkParameterType( entityType, param, memberType( member ) ) ) {
+			final var memberType = memberType( member );
+			final var attributeType = requireNonNullElse(
+					resolveTypeMirror(
+							entityType,
+							member.getEnclosingElement(),
+							memberType.toString()
+					), memberType
+			);
+			if ( checkParameterType( entityType, param, attributeType ) ) {
 				return FieldType.MULTIVALUED;
 			}
 			else if ( containsAnnotation( param, PATTERN ) ) {

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

@@ -30,13 +30,17 @@
 import javax.lang.model.util.Elements;
 import javax.lang.model.util.SimpleTypeVisitor8;
 import javax.tools.Diagnostic;
+import java.util.Collection;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 import java.util.Set;
+import java.util.stream.Stream;
 
 import static java.beans.Introspector.decapitalize;
+import static java.util.stream.Stream.concat;
 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;
@@ -779,4 +783,41 @@ public static boolean isPrimitive(String paramType) {
 
 	public static final Set<String> PRIMITIVE_TYPES =
 			Set.of("boolean", "char", "long", "int", "short", "byte", "double", "float");
+
+	public static TypeMirror resolveTypeMirror(TypeElement typeElement, Element element, String name) {
+		final var mirrorMap = resolveTypeParameters( typeElement.asType(), element, Map.of(), new HashSet<>() );
+		return mirrorMap == null ? null : mirrorMap.get( name );
+	}
+
+	private static Map<String, TypeMirror> resolveTypeParameters(TypeMirror type, Element element, Map<String, TypeMirror> parametersMap, Collection<Element> visited) {
+		if ( !(type instanceof DeclaredType declaredType
+			&& declaredType.asElement() instanceof TypeElement typeElement) ) {
+			return null;
+		}
+		if ( !visited.add( typeElement ) ) {
+			return null;
+		}
+		final var generic = typeElement.getTypeParameters();
+		final var map = new HashMap<String, TypeMirror>();
+		var typeArguments = declaredType.getTypeArguments();
+		if ( !(typeArguments.isEmpty() || generic.size() == typeArguments.size()) ) {
+			return null;
+		}
+		for ( var n = 0; n < generic.size(); ++n ) {
+			final var mirror = typeArguments.isEmpty()
+					? generic.get( 0 ).getBounds().get( 0 )
+					: typeArguments.get( n );
+			final var value = mirror.toString();
+			map.put( generic.get( n ).toString(), parametersMap.getOrDefault( value, mirror ) );
+		}
+		if ( typeElement.equals( element ) ) {
+			return map;
+		}
+		return concat(
+				Stream.of( typeElement.getSuperclass() ),
+				typeElement.getInterfaces().stream()
+		).map( tm -> resolveTypeParameters( tm, element, map, visited ) )
+				.filter( Objects::nonNull )
+				.findFirst().orElse( null );
+	}
 }