implement Session.fetch() for bytecode-enhanced proxies

had to add a way to easily set collectionsInDefaultFetchGroup

hibernate-core/src/main/java/org/hibernate/boot/SessionFactoryBuilder.java

@@ -694,6 +694,15 @@ public interface SessionFactoryBuilder {
 	 */
 	SessionFactoryBuilder applySqlFunction(String registrationName, SqmFunctionDescriptor functionDescriptor);
 
+	/**
+	 * Should collections be included in the default fetch group when bytecode enhancement is used?
+	 *
+	 * @param enabled {@code true} collections should be included
+	 *
+	 * @return {@code this}, for method chaining
+	 */
+	SessionFactoryBuilder applyCollectionsInDefaultFetchGroup(boolean enabled);
+
 	SessionFactoryBuilder allowOutOfTransactionUpdateOperations(boolean allow);
 
 	/**

hibernate-core/src/main/java/org/hibernate/boot/internal/SessionFactoryBuilderImpl.java

@@ -387,6 +387,12 @@ public class SessionFactoryBuilderImpl implements SessionFactoryBuilderImplement
 		return this;
 	}
 
+	@Override
+	public SessionFactoryBuilder applyCollectionsInDefaultFetchGroup(boolean enabled) {
+		this.optionsBuilder.enableCollectionInDefaultFetchGroup( enabled );
+		return this;
+	}
+
 	@Override
 	public SessionFactoryBuilder allowOutOfTransactionUpdateOperations(boolean allow) {
 		this.optionsBuilder.allowOutOfTransactionUpdateOperations( allow );

hibernate-core/src/main/java/org/hibernate/boot/internal/SessionFactoryOptionsBuilder.java

@@ -110,7 +110,6 @@ import static org.hibernate.cfg.AvailableSettings.JPA_CALLBACKS_ENABLED;
 import static org.hibernate.cfg.AvailableSettings.JTA_TRACK_BY_THREAD;
 import static org.hibernate.cfg.AvailableSettings.LOG_SESSION_METRICS;
 import static org.hibernate.cfg.AvailableSettings.MAX_FETCH_DEPTH;
-import static org.hibernate.cfg.AvailableSettings.MULTI_TENANT_CONNECTION_PROVIDER;
 import static org.hibernate.cfg.AvailableSettings.MULTI_TENANT_IDENTIFIER_RESOLVER;
 import static org.hibernate.cfg.AvailableSettings.NATIVE_EXCEPTION_HANDLING_51_COMPLIANCE;
 import static org.hibernate.cfg.AvailableSettings.OMIT_JOIN_OF_SUPERCLASS_TABLES;
@@ -146,9 +145,9 @@ import static org.hibernate.internal.log.DeprecationLogger.DEPRECATION_LOGGER;
  * In-flight state of {@link SessionFactoryOptions}
  * during {@link org.hibernate.boot.SessionFactoryBuilder} processing.
  *
- * The intention is that SessionFactoryBuilder internally creates and populates
- * this builder, which is then used to construct the SessionFactoryOptions
- * as part of building the SessionFactory ({@link org.hibernate.boot.SessionFactoryBuilder#build})
+ * The intention is that {@code SessionFactoryBuilder} internally creates and populates
+ * this builder, which is then used to construct the {@code SessionFactoryOptions}
+ * as part of building the {@code SessionFactory} ({@link org.hibernate.boot.SessionFactoryBuilder#build})
  *
  * @author Steve Ebersole
  */

hibernate-core/src/main/java/org/hibernate/boot/spi/AbstractDelegatingSessionFactoryBuilder.java

@@ -368,6 +368,12 @@ public abstract class AbstractDelegatingSessionFactoryBuilder<T extends SessionF
 		return getThis();
 	}
 
+	@Override
+	public SessionFactoryBuilder applyCollectionsInDefaultFetchGroup(boolean enabled) {
+		delegate.applyCollectionsInDefaultFetchGroup( enabled );
+		return getThis();
+	}
+
 	@Override
 	public T allowOutOfTransactionUpdateOperations(boolean allow) {
 		delegate.allowOutOfTransactionUpdateOperations( allow );

hibernate-core/src/main/java/org/hibernate/internal/StatelessSessionImpl.java

@@ -15,6 +15,7 @@ import org.hibernate.LockMode;
 import org.hibernate.SessionException;
 import org.hibernate.StatelessSession;
 import org.hibernate.UnresolvableObjectException;
+import org.hibernate.bytecode.enhance.spi.interceptor.EnhancementAsProxyLazinessInterceptor;
 import org.hibernate.bytecode.spi.BytecodeEnhancementMetadata;
 import org.hibernate.cache.spi.access.EntityDataAccess;
 import org.hibernate.collection.spi.PersistentCollection;
@@ -23,6 +24,8 @@ import org.hibernate.engine.internal.Versioning;
 import org.hibernate.engine.spi.EntityKey;
 import org.hibernate.engine.spi.LoadQueryInfluencers;
 import org.hibernate.engine.spi.PersistenceContext;
+import org.hibernate.engine.spi.PersistentAttributeInterceptable;
+import org.hibernate.engine.spi.PersistentAttributeInterceptor;
 import org.hibernate.engine.transaction.internal.jta.JtaStatusHelper;
 import org.hibernate.engine.transaction.jta.platform.spi.JtaPlatform;
 import org.hibernate.id.IdentifierGeneratorHelper;
@@ -388,6 +391,24 @@ public class StatelessSessionImpl extends AbstractSharedSessionContract implemen
 				}
 			}
 		}
+		else if ( association instanceof PersistentAttributeInterceptable) {
+			final PersistentAttributeInterceptor interceptor =
+					( (PersistentAttributeInterceptable) association ).$$_hibernate_getInterceptor();
+			if ( interceptor instanceof EnhancementAsProxyLazinessInterceptor) {
+				EnhancementAsProxyLazinessInterceptor proxyInterceptor =
+						(EnhancementAsProxyLazinessInterceptor) interceptor;
+				proxyInterceptor.setSession( this );
+				try {
+					proxyInterceptor.forceInitialize( association, null );
+				}
+				finally {
+					proxyInterceptor.unsetSession();
+					if ( persistenceContext.isLoadFinished() ) {
+						persistenceContext.clear();
+					}
+				}
+			}
+		}
 		else if ( association instanceof PersistentCollection ) {
 			PersistentCollection<?> persistentCollection = (PersistentCollection<?>) association;
 			if ( !persistentCollection.wasInitialized() ) {

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

@@ -216,7 +216,6 @@ import org.hibernate.sql.SimpleSelect;
 import org.hibernate.sql.Template;
 import org.hibernate.sql.Update;
 import org.hibernate.sql.ast.Clause;
-import org.hibernate.sql.ast.SqlAstJoinType;
 import org.hibernate.sql.ast.spi.FromClauseAccess;
 import org.hibernate.sql.ast.spi.SimpleFromClauseAccessImpl;
 import org.hibernate.sql.ast.spi.SqlAliasBase;
@@ -4252,10 +4251,9 @@ public abstract class AbstractEntityPersister
 			final EntityKey entityKey = proxyInterceptor.getEntityKey();
 			final Object identifier = entityKey.getIdentifier();
 
-
-			LoadEvent loadEvent = new LoadEvent( identifier, entity, (EventSource)session, false );
 			Object loaded = null;
-			if ( canReadFromCache ) {
+			if ( canReadFromCache && session instanceof EventSource ) {
+				LoadEvent loadEvent = new LoadEvent( identifier, entity, (EventSource) session, false );
 				loaded = CacheEntityLoaderHelper.INSTANCE.loadFromSecondLevelCache( loadEvent, this, entityKey );
 			}
 			if ( loaded == null ) {