HHH-4309 Test and fix overriding generators in subclasses works

documentation/src/main/asciidoc/userguide/chapters/domain/identifiers.adoc

@@ -4,6 +4,7 @@
 :core-project-dir: {root-project-dir}/hibernate-core
 :core-test-base: {core-project-dir}/src/test/java/org/hibernate/orm/test
 :example-dir-identifier: {core-test-base}/mapping/identifier
+:example-dir-generated: {core-test-base}/mapping/generated
 :example-dir-associations: {core-test-base}/associations
 :jpaJavadocUrl: https://javadoc.io/doc/jakarta.persistence/jakarta.persistence-api/latest/jakarta.persistence
 :extrasdir: extras
@@ -392,6 +393,24 @@ include::{example-dir-identifier}/SequenceGeneratorConfiguredTest.java[tag=ident
 Again the mapping specifies `explicit_product_sequence` as the physical sequence name, but it also specifies an
 explicit allocation-size ("increment by").
 
+The scope of the generator name can be controlled with the <<settings-hibernate.jpa.compliance.global_id_generators,`hibernate.jpa.compliance.global_id_generators`>>
+configuration setting. With <<settings-compliance,JPA compliance>> enabled, the name scope is global i.e.
+there may not be two generator definitions with the same name. Historically, Hibernate ORM used a local scope i.e.
+every managed type may have a generator with the same name, preferring the "local" definition over a more distant one.
+This behavior allows to model e.g. a mapped superclass with a generator that should apply to subclasses by default,
+yet allow an entity subclass to choose a custom generator by simply specifying the same generator name.
+
+[[identifiers-generators-sequence-override]]
+.Sequence override
+====
+[source,java]
+----
+include::{example-dir-generated}/override/SequenceGeneratorOverrideTest.java[tag=identifiers-generators-sequence-override-example, indent=0]
+----
+====
+
+In this case, `base_sequence` will be used when a `Entity1` is persisted,
+whereas for persists of a `Entity2`, Hibernate ORM will use `sub_sequence`.
 
 [[identifiers-generators-identity]]
 ==== Using IDENTITY columns

hibernate-core/src/main/java/org/hibernate/boot/model/internal/AbstractEntityIdGeneratorResolver.java

@@ -64,14 +64,24 @@ public AbstractEntityIdGeneratorResolver(
 	@Override
 	public final void doSecondPass(Map<String, PersistentClass> persistentClasses) throws MappingException {
 		switch ( generatedValue.strategy() ) {
-			case UUID -> GeneratorAnnotationHelper.handleUuidStrategy( idValue, idMember, buildingContext );
+			case UUID -> handleUuidStrategy();
 			case IDENTITY -> GeneratorAnnotationHelper.handleIdentityStrategy( idValue );
 			case SEQUENCE -> handleSequenceStrategy();
 			case TABLE -> handleTableStrategy();
 			case AUTO -> handleAutoStrategy();
 		}
 	}
 
+	private void handleUuidStrategy() {
+		GeneratorAnnotationHelper.handleUuidStrategy(
+				idValue,
+				idMember,
+				buildingContext.getMetadataCollector().getClassDetailsRegistry()
+						.getClassDetails( entityMapping.getClassName() ),
+				buildingContext
+		);
+	}
+
 	private void handleSequenceStrategy() {
 		if ( generatedValue.generator().isBlank() ) {
 			handleUnnamedSequenceGenerator();

hibernate-core/src/main/java/org/hibernate/boot/model/internal/GeneratorAnnotationHelper.java

@@ -13,6 +13,7 @@
 import java.util.function.Consumer;
 import java.util.function.Function;
 
+import org.checkerframework.checker.nullness.qual.Nullable;
 import org.hibernate.annotations.GenericGenerator;
 import org.hibernate.annotations.IdGeneratorType;
 import org.hibernate.annotations.Parameter;
@@ -61,8 +62,9 @@ public class GeneratorAnnotationHelper {
 	public static <A extends Annotation> A findLocalizedMatch(
 			AnnotationDescriptor<A> generatorAnnotationType,
 			MemberDetails idMember,
-			Function<A,String> nameExtractor,
-			String matchName,
+			ClassDetails entityType,
+			@Nullable Function<A,String> nameExtractor,
+			@Nullable String matchName,
 			MetadataBuildingContext context) {
 		final SourceModelBuildingContext sourceModelContext =
 				context.getMetadataCollector().getSourceModelBuildingContext();
@@ -88,7 +90,26 @@ public static <A extends Annotation> A findLocalizedMatch(
 			}
 		}
 
-		// next, on the class
+		// next, on the entity class
+		for ( A generatorAnnotation :
+				entityType.getRepeatedAnnotationUsages( generatorAnnotationType, sourceModelContext ) ) {
+			if ( nameExtractor != null ) {
+				final String registrationName = nameExtractor.apply( generatorAnnotation );
+				if ( registrationName.isEmpty() ) {
+					if ( possibleMatch == null ) {
+						possibleMatch = generatorAnnotation;
+					}
+				}
+				else if ( registrationName.equals( matchName ) ) {
+					return generatorAnnotation;
+				}
+			}
+			else {
+				return generatorAnnotation;
+			}
+		}
+
+		// next, on the declaring class
 		for ( A generatorAnnotation:
 				idMember.getDeclaringType().getRepeatedAnnotationUsages( generatorAnnotationType, sourceModelContext ) ) {
 			if ( nameExtractor != null ) {
@@ -296,10 +317,12 @@ public static <A extends Annotation> void prepareForUse(
 	public static void handleUuidStrategy(
 			SimpleValue idValue,
 			MemberDetails idMember,
+			ClassDetails entityClass,
 			MetadataBuildingContext context) {
 		final org.hibernate.annotations.UuidGenerator generatorConfig = findLocalizedMatch(
 				HibernateAnnotations.UUID_GENERATOR,
 				idMember,
+				entityClass,
 				null,
 				null,
 				context

hibernate-core/src/main/java/org/hibernate/boot/model/internal/IdBagIdGeneratorResolverSecondPass.java

@@ -71,7 +71,13 @@ public IdBagIdGeneratorResolverSecondPass(
 	public void doSecondPass(Map<String, PersistentClass> idGeneratorDefinitionMap) throws MappingException {
 		final GeneratedValue generatedValue = idBagMember.getDirectAnnotationUsage( GeneratedValue.class );
 		switch ( generatedValue.strategy() ) {
-			case UUID -> handleUuidStrategy( idValue, idBagMember, buildingContext );
+			case UUID -> handleUuidStrategy(
+					idValue,
+					idBagMember,
+					buildingContext.getMetadataCollector().getClassDetailsRegistry()
+							.getClassDetails( entityMapping.getClassName() ),
+					buildingContext
+			);
 			case IDENTITY -> handleIdentityStrategy( idValue );
 			case SEQUENCE -> handleSequenceStrategy(
 					generatorName,
@@ -121,6 +127,8 @@ private void handleTableStrategy(
 		final TableGenerator localizedTableMatch = findLocalizedMatch(
 				JpaAnnotations.TABLE_GENERATOR,
 				idBagMember,
+				buildingContext.getMetadataCollector().getClassDetailsRegistry()
+						.getClassDetails( entityMapping.getClassName() ),
 				TableGenerator::name,
 				generatorName,
 				buildingContext
@@ -164,6 +172,8 @@ private void handleSequenceStrategy(
 		final SequenceGenerator localizedSequencedMatch = findLocalizedMatch(
 				JpaAnnotations.SEQUENCE_GENERATOR,
 				idBagMember,
+				buildingContext.getMetadataCollector().getClassDetailsRegistry()
+						.getClassDetails( entityMapping.getClassName() ),
 				SequenceGenerator::name,
 				generatorName,
 				buildingContext
@@ -235,6 +245,8 @@ private void handleAutoStrategy(
 		final SequenceGenerator localizedSequencedMatch = findLocalizedMatch(
 				JpaAnnotations.SEQUENCE_GENERATOR,
 				idBagMember,
+				buildingContext.getMetadataCollector().getClassDetailsRegistry()
+						.getClassDetails( entityMapping.getClassName() ),
 				SequenceGenerator::name,
 				generatorName,
 				buildingContext
@@ -247,6 +259,8 @@ private void handleAutoStrategy(
 		final TableGenerator localizedTableMatch = findLocalizedMatch(
 				JpaAnnotations.TABLE_GENERATOR,
 				idBagMember,
+				buildingContext.getMetadataCollector().getClassDetailsRegistry()
+						.getClassDetails( entityMapping.getClassName() ),
 				TableGenerator::name,
 				generatorName,
 				buildingContext

hibernate-core/src/main/java/org/hibernate/boot/model/internal/IdGeneratorResolverSecondPass.java

@@ -58,6 +58,8 @@ protected void handleUnnamedSequenceGenerator() {
 		final SequenceGenerator localizedMatch = findLocalizedMatch(
 				JpaAnnotations.SEQUENCE_GENERATOR,
 				idMember,
+				buildingContext.getMetadataCollector().getClassDetailsRegistry()
+						.getClassDetails( entityMapping.getClassName() ),
 				null,
 				null,
 				buildingContext
@@ -77,6 +79,8 @@ protected void handleNamedSequenceGenerator() {
 		final SequenceGenerator localizedMatch = findLocalizedMatch(
 				JpaAnnotations.SEQUENCE_GENERATOR,
 				idMember,
+				buildingContext.getMetadataCollector().getClassDetailsRegistry()
+						.getClassDetails( entityMapping.getClassName() ),
 				SequenceGenerator::name,
 				generator,
 				buildingContext
@@ -147,6 +151,8 @@ protected void handleUnnamedTableGenerator() {
 		final TableGenerator localizedMatch = findLocalizedMatch(
 				JpaAnnotations.TABLE_GENERATOR,
 				idMember,
+				buildingContext.getMetadataCollector().getClassDetailsRegistry()
+						.getClassDetails( entityMapping.getClassName() ),
 				null,
 				null,
 				buildingContext
@@ -161,6 +167,8 @@ protected void handleNamedTableGenerator() {
 		final TableGenerator localizedTableMatch = findLocalizedMatch(
 				JpaAnnotations.TABLE_GENERATOR,
 				idMember,
+				buildingContext.getMetadataCollector().getClassDetailsRegistry()
+						.getClassDetails( entityMapping.getClassName() ),
 				TableGenerator::name,
 				generator,
 				buildingContext
@@ -229,6 +237,8 @@ protected void handleUnnamedAutoGenerator() {
 		final SequenceGenerator localizedSequenceMatch = findLocalizedMatch(
 				JpaAnnotations.SEQUENCE_GENERATOR,
 				idMember,
+				buildingContext.getMetadataCollector().getClassDetailsRegistry()
+						.getClassDetails( entityMapping.getClassName() ),
 				null,
 				null,
 				buildingContext
@@ -241,6 +251,8 @@ protected void handleUnnamedAutoGenerator() {
 		final TableGenerator localizedTableMatch = findLocalizedMatch(
 				JpaAnnotations.TABLE_GENERATOR,
 				idMember,
+				buildingContext.getMetadataCollector().getClassDetailsRegistry()
+						.getClassDetails( entityMapping.getClassName() ),
 				null,
 				null,
 				buildingContext
@@ -253,6 +265,8 @@ protected void handleUnnamedAutoGenerator() {
 		final GenericGenerator localizedGenericMatch = findLocalizedMatch(
 				HibernateAnnotations.GENERIC_GENERATOR,
 				idMember,
+				buildingContext.getMetadataCollector().getClassDetailsRegistry()
+						.getClassDetails( entityMapping.getClassName() ),
 				null,
 				null,
 				buildingContext
@@ -274,7 +288,13 @@ protected void handleUnnamedAutoGenerator() {
 
 		if ( idMember.getType().isImplementor( UUID.class )
 				|| idMember.getType().isImplementor( String.class ) ) {
-			GeneratorAnnotationHelper.handleUuidStrategy( idValue, idMember, buildingContext );
+			GeneratorAnnotationHelper.handleUuidStrategy(
+					idValue,
+					idMember,
+					buildingContext.getMetadataCollector().getClassDetailsRegistry()
+							.getClassDetails( entityMapping.getClassName() ),
+					buildingContext
+			);
 			return;
 		}
 
@@ -313,7 +333,13 @@ protected void handleNamedAutoGenerator() {
 
 		if ( idMember.getType().isImplementor( UUID.class )
 				|| idMember.getType().isImplementor( String.class ) ) {
-			GeneratorAnnotationHelper.handleUuidStrategy( idValue, idMember, buildingContext );
+			GeneratorAnnotationHelper.handleUuidStrategy(
+					idValue,
+					idMember,
+					buildingContext.getMetadataCollector().getClassDetailsRegistry()
+							.getClassDetails( entityMapping.getClassName() ),
+					buildingContext
+			);
 			return;
 		}
 
@@ -331,6 +357,8 @@ private boolean handleAsLocalAutoGenerator() {
 		final SequenceGenerator localizedSequenceMatch = findLocalizedMatch(
 				JpaAnnotations.SEQUENCE_GENERATOR,
 				idMember,
+				buildingContext.getMetadataCollector().getClassDetailsRegistry()
+						.getClassDetails( entityMapping.getClassName() ),
 				SequenceGenerator::name,
 				generator,
 				buildingContext
@@ -343,6 +371,8 @@ private boolean handleAsLocalAutoGenerator() {
 		final TableGenerator localizedTableMatch = findLocalizedMatch(
 				JpaAnnotations.TABLE_GENERATOR,
 				idMember,
+				buildingContext.getMetadataCollector().getClassDetailsRegistry()
+						.getClassDetails( entityMapping.getClassName() ),
 				TableGenerator::name,
 				generator,
 				buildingContext
@@ -355,6 +385,8 @@ private boolean handleAsLocalAutoGenerator() {
 		final GenericGenerator localizedGenericMatch = findLocalizedMatch(
 				HibernateAnnotations.GENERIC_GENERATOR,
 				idMember,
+				buildingContext.getMetadataCollector().getClassDetailsRegistry()
+						.getClassDetails( entityMapping.getClassName() ),
 				GenericGenerator::name,
 				generator,
 				buildingContext

hibernate-core/src/main/java/org/hibernate/boot/model/internal/StrictIdGeneratorResolverSecondPass.java

@@ -220,7 +220,13 @@ private void handleAutoGenerator(String globalRegistrationName) {
 		// Implicit handling of UUID generation
 		if ( idMember.getType().isImplementor( UUID.class )
 				|| idMember.getType().isImplementor( String.class ) ) {
-			handleUuidStrategy( idValue, idMember, buildingContext );
+			handleUuidStrategy(
+					idValue,
+					idMember,
+					buildingContext.getMetadataCollector().getClassDetailsRegistry()
+							.getClassDetails( entityMapping.getClassName() ),
+					buildingContext
+			);
 			return;
 		}
 

hibernate-core/src/test/java/org/hibernate/orm/test/mapping/generated/override/GenericGeneratorOverrideTest.java

@@ -0,0 +1,80 @@
+/*
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ * Copyright Red Hat Inc. and Hibernate Authors
+ */
+package org.hibernate.orm.test.mapping.generated.override;
+
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.Id;
+import jakarta.persistence.MappedSuperclass;
+import org.hibernate.annotations.GenericGenerator;
+import org.hibernate.engine.spi.SessionFactoryImplementor;
+import org.hibernate.generator.Generator;
+import org.hibernate.id.UUIDGenerator;
+import org.hibernate.id.UUIDHexGenerator;
+import org.hibernate.persister.entity.EntityPersister;
+import org.hibernate.testing.orm.junit.DomainModel;
+import org.hibernate.testing.orm.junit.Jira;
+import org.hibernate.testing.orm.junit.SessionFactory;
+import org.hibernate.testing.orm.junit.SessionFactoryScope;
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+
+@DomainModel(
+		annotatedClasses = {
+				GenericGeneratorOverrideTest.Entity1.class,
+				GenericGeneratorOverrideTest.Entity2.class,
+		}
+)
+@SessionFactory
+@Jira("https://hibernate.atlassian.net/browse/HHH-4309")
+public class GenericGeneratorOverrideTest {
+
+	@Test
+	public void test(SessionFactoryScope scope) {
+		SessionFactoryImplementor sf = scope.getSessionFactory();
+		EntityPersister p1 = sf.getRuntimeMetamodels()
+				.getMappingMetamodel()
+				.getEntityDescriptor( Entity1.class.getName() );
+		EntityPersister p2 = sf.getRuntimeMetamodels()
+				.getMappingMetamodel()
+				.getEntityDescriptor( Entity2.class.getName() );
+
+		Generator generator1 = p1.getGenerator();
+		Generator generator2 = p2.getGenerator();
+		assertThat( generator1 ).isInstanceOf( UUIDGenerator.class );
+		assertThat( generator2 ).isInstanceOf( UUIDHexGenerator.class );
+	}
+
+	@MappedSuperclass
+	@GenericGenerator(name = "my-generator", strategy = "uuid2")
+	public static abstract class BaseEntity {
+		@Id
+		@GeneratedValue(generator = "my-generator")
+		private String id;
+
+		public String getId() {
+			return id;
+		}
+
+		public void setId(final String id) {
+			this.id = id;
+		}
+	}
+
+	@jakarta.persistence.Entity(name = "Entity1")
+	public static class Entity1 extends BaseEntity {
+		public Entity1() {
+		}
+	}
+
+	@jakarta.persistence.Entity(name = "Entity2")
+	@GenericGenerator(name = "my-generator", strategy = "uuid.hex")
+	public static class Entity2 extends BaseEntity {
+		public Entity2() {
+		}
+	}
+
+}