HHH-19874 NullPointerException in org.hibernate.sql.ast.tree.from.TableGroup.resolveTableReference

hibernate-core/src/main/java/org/hibernate/engine/internal/StatefulPersistenceContext.java

@@ -417,7 +417,10 @@ public EntityHolder claimEntityHolderIfPossible(
 		else {
 			newEntityHolder = null;
 		}
-		holder.entityInitializer = initializer;
+		if ( holder.processingState != processingState ) {
+			holder.entityInitializer = initializer;
+			holder.processingState = processingState;
+		}
 		return holder;
 	}
 
@@ -2193,7 +2196,8 @@ private static class EntityHolderImpl implements EntityHolder, Serializable {
 		private Object entity;
 		private Object proxy;
 		private @Nullable EntityEntry entityEntry;
-		private EntityInitializer<?> entityInitializer;
+		private @Nullable EntityInitializer<?> entityInitializer;
+		private @Nullable JdbcValuesSourceProcessingState processingState;
 		private EntityHolderState state;
 
 		private EntityHolderImpl() {
@@ -2231,10 +2235,15 @@ public Object getProxy() {
 		}
 
 		@Override
-		public EntityInitializer<?> getEntityInitializer() {
+		public @Nullable EntityInitializer<?> getEntityInitializer() {
 			return entityInitializer;
 		}
 
+		@Override
+		public @Nullable JdbcValuesSourceProcessingState getJdbcValuesProcessingState() {
+			return processingState;
+		}
+
 		@Override
 		public void markAsReloaded(JdbcValuesSourceProcessingState processingState) {
 			processingState.registerReloadedEntityHolder( this );
@@ -2256,8 +2265,9 @@ public boolean isDetached() {
 		}
 
 		@Override
-		public void resetEntityInitialier(){
+		public void resetEntityInitialier() {
 			entityInitializer = null;
+			processingState = null;
 		}
 
 		public EntityHolderImpl withEntity(EntityKey entityKey, EntityPersister descriptor, Object entity) {
@@ -2269,7 +2279,11 @@ public EntityHolderImpl withProxy(EntityKey entityKey, EntityPersister descripto
 		}
 
 		public EntityHolderImpl withData(EntityKey entityKey, EntityPersister descriptor, Object entity, Object proxy) {
-			assert entityKey != null && descriptor != null && entityInitializer == null && state == EntityHolderState.UNINITIALIZED;
+			assert entityKey != null
+				&& descriptor != null
+				&& entityInitializer == null
+				&& processingState == null
+				&& state == EntityHolderState.UNINITIALIZED;
 			this.entityKey = entityKey;
 			this.descriptor = descriptor;
 			this.entity = entity;

hibernate-core/src/main/java/org/hibernate/engine/spi/EntityHolder.java

@@ -35,6 +35,11 @@ public interface EntityHolder {
 	 * Will be {@code null} if entity is initialized already or the entity holder is not claimed yet.
 	 */
 	@Nullable EntityInitializer<?> getEntityInitializer();
+	/**
+	 * The {@link JdbcValuesSourceProcessingState} for the entity initializer that claims to initialize the entity for this holder.
+	 * Will be {@code null} if entity is initialized already or the entity holder is not claimed yet.
+	 */
+	@Nullable JdbcValuesSourceProcessingState getJdbcValuesProcessingState();
 
 	/**
 	 * The proxy if there is one and otherwise the entity.

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

@@ -1249,7 +1249,12 @@ else if ( isResultInitializer() ) {
 					}
 				}
 				else if ( data.entityHolder.getEntityInitializer() != this ) {
-					data.setState( State.INITIALIZED );
+					// The other initializer will take care of initialization
+					if ( !hasLazyInitializingSubAssemblers ) {
+						// but we can only skip the initialization phase of this initializer,
+						// if this initializer does not initialize lazy basic attributes
+						data.setState( State.INITIALIZED );
+					}
 				}
 				else if ( data.shallowCached ) {
 					// For shallow cached entities, only the id is available, so ensure we load the data immediately

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

@@ -240,8 +240,10 @@ protected void initialize(
 				}
 			}
 			else if ( holder.getEntityInitializer() != this ) {
-				// the entity is already being loaded elsewhere
-				data.setState( State.INITIALIZED );
+				// the entity is already being loaded elsewhere in this processing level
+				if ( holder.getJdbcValuesProcessingState() == data.getRowProcessingState().getJdbcValuesSourceProcessingState() ) {
+					data.setState( State.INITIALIZED );
+				}
 				return;
 			}
 			else if ( data.getInstance() == null ) {

hibernate-core/src/test/java/org/hibernate/orm/test/fetch/FetchModeSubselectAndQueryJoinTest.java

@@ -0,0 +1,101 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ * Copyright Red Hat Inc. and Hibernate Authors
+ */
+package org.hibernate.orm.test.fetch;
+
+import jakarta.persistence.CascadeType;
+import jakarta.persistence.Entity;
+import jakarta.persistence.FetchType;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.Id;
+import jakarta.persistence.ManyToOne;
+import jakarta.persistence.OneToMany;
+import jakarta.persistence.Table;
+import jakarta.persistence.Tuple;
+import org.hibernate.annotations.Fetch;
+import org.hibernate.annotations.FetchMode;
+import org.hibernate.testing.orm.junit.DomainModel;
+import org.hibernate.testing.orm.junit.JiraKey;
+import org.hibernate.testing.orm.junit.SessionFactory;
+import org.hibernate.testing.orm.junit.SessionFactoryScope;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+@DomainModel(
+		annotatedClasses = {
+				FetchModeSubselectAndQueryJoinTest.Node.class,
+				FetchModeSubselectAndQueryJoinTest.Element.class
+		}
+)
+@SessionFactory
+@JiraKey( "HHH-19949" )
+public class FetchModeSubselectAndQueryJoinTest {
+
+	@BeforeAll
+	public void setUp(SessionFactoryScope scope) {
+		scope.inTransaction(
+				session -> {
+					Node basik = new Node( "Child" );
+					basik.elements.add( new Element( basik ) );
+					basik.elements.add( new Element( basik ) );
+					session.persist( basik );
+				}
+		);
+	}
+
+	@Test
+	public void tesSelect(SessionFactoryScope scope) {
+		scope.inTransaction(
+				session -> {
+					List<Tuple> results = session.createSelectionQuery(
+							"select distinct n, e from Node n join n.elements e ", Tuple.class ).getResultList();
+					assertThat( results ).hasSize( 2 );
+				}
+		);
+	}
+
+	@Entity(name = "Element")
+	@Table(name = "Element")
+	public static class Element {
+		@Id
+		@GeneratedValue
+		Integer id;
+
+		@ManyToOne
+		Node node;
+
+		public Element(Node node) {
+			this.node = node;
+		}
+
+		Element() {
+		}
+	}
+
+	@Entity(name = "Node")
+	@Table(name = "Node")
+	public static class Node {
+
+		@Id
+		@GeneratedValue
+		Integer id;
+		String string;
+
+		@OneToMany(fetch = FetchType.EAGER, cascade = CascadeType.PERSIST, mappedBy = "node")
+		@Fetch(FetchMode.SUBSELECT)
+		List<Element> elements = new ArrayList<>();
+
+		public Node(String string) {
+			this.string = string;
+		}
+
+		Node() {
+		}
+	}
+}