HHH-18608 NPE in EntityInitializerImpl.resolveInstanceSubInitializers

hibernate-core/src/main/java/org/hibernate/persister/entity/AbstractEntityPersister.java

@@ -276,6 +276,7 @@
 import org.hibernate.type.ComponentType;
 import org.hibernate.type.CompositeType;
 import org.hibernate.type.EntityType;
+import org.hibernate.type.ManyToOneType;
 import org.hibernate.type.Type;
 import org.hibernate.type.descriptor.java.JavaType;
 import org.hibernate.type.descriptor.java.MutabilityPlan;
@@ -1183,6 +1184,15 @@ private static List<UniqueKeyEntry> initUniqueKeyEntries(final AbstractEntityPer
 						uniqueKeys.add( new UniqueKeyEntry( ukName, index, type ) );
 					}
 				}
+				else if ( associationType instanceof ManyToOneType manyToOneType
+						&& manyToOneType.isLogicalOneToOne() && manyToOneType.isReferenceToPrimaryKey() ) {
+					final AttributeMapping attributeMapping = aep.findAttributeMapping( manyToOneType.getPropertyName() );
+					if ( attributeMapping != null ) {
+						final int index = attributeMapping.getStateArrayPosition();
+						final Type type = aep.getPropertyTypes()[index];
+						uniqueKeys.add( new UniqueKeyEntry( manyToOneType.getPropertyName(), index, type ) );
+					}
+				}
 			}
 		}
 		return toSmallList( uniqueKeys );

hibernate-core/src/main/java/org/hibernate/sql/results/graph/entity/internal/EntityInitializerImpl.java

@@ -23,6 +23,7 @@
 import org.hibernate.cache.spi.access.AccessType;
 import org.hibernate.cache.spi.access.EntityDataAccess;
 import org.hibernate.cache.spi.entry.CacheEntry;
+import org.hibernate.engine.internal.ForeignKeys;
 import org.hibernate.engine.spi.EntityEntry;
 import org.hibernate.engine.spi.EntityHolder;
 import org.hibernate.engine.spi.EntityKey;
@@ -75,6 +76,7 @@
 import org.hibernate.sql.results.jdbc.spi.JdbcValuesSourceProcessingOptions;
 import org.hibernate.sql.results.jdbc.spi.RowProcessingState;
 import org.hibernate.stat.spi.StatisticsImplementor;
+import org.hibernate.type.ManyToOneType;
 import org.hibernate.type.Type;
 import org.hibernate.type.descriptor.java.MutabilityPlan;
 
@@ -622,6 +624,8 @@ private boolean areKeysEqual(Object key1, Object key2) {
 	protected void resolveInstanceSubInitializers(EntityInitializerData data) {
 		final int subclassId = data.concreteDescriptor.getSubclassId();
 		final EntityEntry entityEntry = data.entityHolder.getEntityEntry();
+		assert entityEntry != null : "This method should only be called if the entity is already initialized";
+
 		final Initializer<?>[] initializers;
 		final ImmutableBitSet maybeLazySet;
 		if ( data.entityHolder.getEntityInitializer() == this ) {
@@ -981,11 +985,13 @@ else if ( lazyInitializer.isUninitialized() ) {
 			registerLoadingEntity( data, data.entityInstanceForNotify );
 		}
 		else {
-			data.setState( State.INITIALIZED );
 			data.entityInstanceForNotify = lazyInitializer.getImplementation();
 			data.concreteDescriptor = session.getEntityPersister( null, data.entityInstanceForNotify );
 			resolveEntityKey( data, lazyInitializer.getIdentifier() );
 			data.entityHolder = persistenceContext.getEntityHolder( data.entityKey );
+			// Even though the lazyInitializer reports it is initialized, check if the entity holder reports initialized,
+			// because in a nested initialization scenario, this nested initializer must initialize the entity
+			data.setState( data.entityHolder.isInitialized() ? State.INITIALIZED : State.RESOLVED );
 		}
 		if ( identifierAssembler != null ) {
 			final Initializer<?> initializer = identifierAssembler.getInitializer();
@@ -1582,11 +1588,22 @@ protected void registerPossibleUniqueKeyEntries(
 			// one used here, which it will be
 
 			if ( resolvedEntityState[index] != null ) {
+				final Object key;
+				if ( type instanceof ManyToOneType manyToOneType ) {
+					key = ForeignKeys.getEntityIdentifierIfNotUnsaved(
+							manyToOneType.getAssociatedEntityName(),
+							resolvedEntityState[index],
+							session
+					);
+				}
+				else {
+					key = resolvedEntityState[index];
+				}
 				final EntityUniqueKey entityUniqueKey = new EntityUniqueKey(
 						data.concreteDescriptor.getRootEntityDescriptor().getEntityName(),
 						//polymorphism comment above
 						ukName,
-						resolvedEntityState[index],
+						key,
 						type,
 						session.getFactory()
 				);

hibernate-core/src/test/java/org/hibernate/orm/test/bytecode/enhancement/batch/RefreshAndBatchTest.java

@@ -0,0 +1,205 @@
+/*
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ * Copyright Red Hat Inc. and Hibernate Authors
+ */
+package org.hibernate.orm.test.bytecode.enhancement.batch;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.hibernate.Hibernate;
+import org.hibernate.annotations.BatchSize;
+import org.hibernate.cfg.AvailableSettings;
+
+import org.hibernate.testing.bytecode.enhancement.extension.BytecodeEnhanced;
+import org.hibernate.testing.orm.junit.DomainModel;
+import org.hibernate.testing.orm.junit.JiraKey;
+import org.hibernate.testing.orm.junit.ServiceRegistry;
+import org.hibernate.testing.orm.junit.SessionFactory;
+import org.hibernate.testing.orm.junit.SessionFactoryScope;
+import org.hibernate.testing.orm.junit.Setting;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import jakarta.persistence.CascadeType;
+import jakarta.persistence.Column;
+import jakarta.persistence.Entity;
+import jakarta.persistence.FetchType;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.Id;
+import jakarta.persistence.JoinColumn;
+import jakarta.persistence.ManyToOne;
+import jakarta.persistence.OneToMany;
+import jakarta.persistence.OneToOne;
+import jakarta.persistence.Table;
+
+import static org.assertj.core.api.AssertionsForClassTypes.assertThat;
+
+@DomainModel(
+		annotatedClasses = {
+				RefreshAndBatchTest.User.class,
+				RefreshAndBatchTest.UserInfo.class,
+				RefreshAndBatchTest.Phone.class,
+		}
+
+)
+@SessionFactory
+@ServiceRegistry(
+		settings = {
+				@Setting(name = AvailableSettings.DEFAULT_BATCH_FETCH_SIZE, value = "100")
+
+		}
+)
+@JiraKey("HHH-18608")
+@BytecodeEnhanced(runNotEnhancedAsWell = true)
+public class RefreshAndBatchTest {
+
+	@BeforeEach
+	public void setUp(SessionFactoryScope scope) {
+		scope.inTransaction(
+				session -> {
+					UserInfo info = new UserInfo( "info" );
+					Phone phone = new Phone( "123456" );
+					info.addPhone( phone );
+					User user = new User( 1L, "user1", info );
+					session.persist( user );
+				}
+		);
+	}
+
+	@AfterEach
+	public void tearDown(SessionFactoryScope scope) {
+		scope.inTransaction(
+				session -> {
+					session.createMutationQuery( "delete User" ).executeUpdate();
+					session.createMutationQuery( "delete Phone" ).executeUpdate();
+					session.createMutationQuery( "delete UserInfo" ).executeUpdate();
+				}
+		);
+	}
+
+	@Test
+	public void testRefresh(SessionFactoryScope scope) {
+		scope.inTransaction(
+				session -> {
+					User user = session.createQuery( "select u from User u where u.id = :id", User.class )
+							.setParameter( "id", 1L )
+							.getSingleResult();
+					assertThat( Hibernate.isInitialized( user.getInfo() ) ).isFalse();
+					session.refresh( user.getInfo() );
+					assertThat( Hibernate.isInitialized( user.getInfo() ) ).isTrue();
+				}
+		);
+	}
+
+	@Entity(name = "User")
+	@Table(name = "USER_TABLE")
+	@BatchSize(size = 5)
+	public static class User {
+
+		@Id
+		private Long id;
+
+		@Column
+		private String name;
+
+		@OneToOne(cascade = CascadeType.ALL, fetch = FetchType.LAZY)
+		@JoinColumn(name = "INFO_ID", referencedColumnName = "ID")
+		private UserInfo info;
+
+		public User() {
+		}
+
+		public User(long id, String name, UserInfo info) {
+			this.id = id;
+			this.name = name;
+			this.info = info;
+			info.user = this;
+		}
+
+		public long getId() {
+			return id;
+		}
+
+		public String getName() {
+			return name;
+		}
+
+		public UserInfo getInfo() {
+			return info;
+		}
+	}
+
+	@Entity(name = "UserInfo")
+	public static class UserInfo {
+		@Id
+		@GeneratedValue
+		private Long id;
+
+		@OneToOne(mappedBy = "info", fetch = FetchType.LAZY)
+		private User user;
+
+		private String info;
+
+		@OneToMany(mappedBy = "info", cascade = CascadeType.ALL, fetch = FetchType.LAZY)
+		private List<Phone> phoneList;
+
+		public long getId() {
+			return id;
+		}
+
+		public UserInfo() {
+		}
+
+		public UserInfo(String info) {
+			this.info = info;
+		}
+
+		public User getUser() {
+			return user;
+		}
+
+		public String getInfo() {
+			return info;
+		}
+
+		public List<Phone> getPhoneList() {
+			return phoneList;
+		}
+
+		public void addPhone(Phone phone) {
+			if ( phoneList == null ) {
+				phoneList = new ArrayList<>();
+			}
+			this.phoneList.add( phone );
+			phone.info = this;
+		}
+	}
+
+	@Entity(name = "Phone")
+	public static class Phone {
+		@Id
+		@Column(name = "PHONE_NUMBER")
+		private String number;
+
+		@ManyToOne
+		@JoinColumn(name = "INFO_ID")
+		private UserInfo info;
+
+		public Phone() {
+		}
+
+		public Phone(String number) {
+			this.number = number;
+		}
+
+		public String getNumber() {
+			return number;
+		}
+
+		public UserInfo getInfo() {
+			return info;
+		}
+	}
+}