GH-2462 - Support mapping of intermediate hiearchy relationships.

Closes #2462

Author: meistermeier

src/main/java/org/springframework/data/neo4j/core/mapping/CypherGenerator.java

@@ -550,7 +550,7 @@ private MapProjection projectPropertiesAndRelationships(PropertyFilter.RelaxedPr
 		List<Object> propertiesProjection = projectNodeProperties(parentPath, nodeDescription, nodeName, relationshipDescription, includedProperties);
 		List<Object> contentOfProjection = new ArrayList<>(propertiesProjection);
 
-		contentOfProjection.addAll(generateListsFor(parentPath, relationships, nodeName, includedProperties, processedRelationships));
+		contentOfProjection.addAll(generateListsFor(parentPath, nodeDescription, relationships, nodeName, includedProperties, processedRelationships));
 		return Cypher.anyNode(nodeName).project(contentOfProjection);
 	}
 
@@ -612,7 +612,7 @@ private List<Object> projectNodeProperties(PropertyFilter.RelaxedPropertyPath pa
 	/**
 	 * @see CypherGenerator#projectNodeProperties
 	 */
-	private List<Object> generateListsFor(PropertyFilter.RelaxedPropertyPath parentPath, Collection<RelationshipDescription> relationships, SymbolicName nodeName,
+	private List<Object> generateListsFor(PropertyFilter.RelaxedPropertyPath parentPath, Neo4jPersistentEntity<?> nodeDescription, Collection<RelationshipDescription> relationships, SymbolicName nodeName,
 										  Predicate<PropertyFilter.RelaxedPropertyPath> includedProperties, List<RelationshipDescription> processedRelationships) {
 
 		List<Object> mapProjectionLists = new ArrayList<>();
@@ -628,17 +628,17 @@ private List<Object> generateListsFor(PropertyFilter.RelaxedPropertyPath parentP
 				continue;
 			}
 
-			generateListFor(parentPath, relationshipDescription, nodeName, processedRelationships, fieldName, mapProjectionLists, includedProperties);
+			generateListFor(parentPath, nodeDescription, relationshipDescription, nodeName, processedRelationships, fieldName, mapProjectionLists, includedProperties);
 		}
 
 		return mapProjectionLists;
 	}
 
-	private void generateListFor(PropertyFilter.RelaxedPropertyPath parentPath, RelationshipDescription relationshipDescription, SymbolicName nodeName,
+	private void generateListFor(PropertyFilter.RelaxedPropertyPath parentPath, Neo4jPersistentEntity<?> nodeDescription, RelationshipDescription relationshipDescription, SymbolicName nodeName,
 								 List<RelationshipDescription> processedRelationships, String fieldName, List<Object> mapProjectionLists, Predicate<PropertyFilter.RelaxedPropertyPath> includedProperties) {
 
 		String relationshipType = relationshipDescription.getType();
-		String relationshipTargetName = relationshipDescription.generateRelatedNodesCollectionName(relationshipDescription.getSource());
+		String relationshipTargetName = relationshipDescription.generateRelatedNodesCollectionName(nodeDescription);
 		String sourcePrimaryLabel = relationshipDescription.getSource().getMostAbstractParentLabel(relationshipDescription.getSource());
 		String targetPrimaryLabel = relationshipDescription.getTarget().getPrimaryLabel();
 		List<String> targetAdditionalLabels = relationshipDescription.getTarget().getAdditionalLabels();

src/main/java/org/springframework/data/neo4j/core/mapping/DefaultNeo4jEntityConverter.java

@@ -342,16 +342,8 @@ private <ET> void populateProperties(MapAccessor queryResult, Neo4jPersistentEnt
 		// store unless we temporarily put it there.
 		knownObjects.storeObject(internalId, mappedObject);
 
-		// Fill associations
-		// If the nodeDescription is a more abstract class as the concrete node description,
-		// it might contain associations not named CONCRETE_TYPE_TARGET but ABSTRACT_TYPE_TARGET.
-		// Those won't get caught by the most concrete node description.
-		if (nodeDescription != concreteNodeDescription) {
-			nodeDescription.doWithAssociations(
-					populateFrom(queryResult, propertyAccessor, isConstructorParameter, objectAlreadyMapped, relationshipsFromResult, nodesFromResult));
-		}
 		concreteNodeDescription.doWithAssociations(
-				populateFrom(queryResult, propertyAccessor, isConstructorParameter, objectAlreadyMapped, relationshipsFromResult, nodesFromResult));
+				populateFrom(queryResult, nodeDescription, propertyAccessor, isConstructorParameter, objectAlreadyMapped, relationshipsFromResult, nodesFromResult));
 	}
 
 	@Nullable
@@ -432,12 +424,12 @@ public <T> T getParameterValue(PreferredConstructor.Parameter<T, Neo4jPersistent
 					// If we cannot find any value it does not mean that there isn't any.
 					// The result set might contain associations not named CONCRETE_TYPE_TARGET but ABSTRACT_TYPE_TARGET.
 					// For this we bubble up the hierarchy of NodeDescriptions.
-					result = createInstanceOfRelationships(matchingProperty, values, relationshipDescription, relationshipsFromResult, nodesFromResult, null)
+					result = createInstanceOfRelationships(matchingProperty, values, relationshipDescription, nodeDescription, relationshipsFromResult, nodesFromResult)
 							.orElseGet(() -> {
 								NodeDescription<?> parentNodeDescription = nodeDescription.getParentNodeDescription();
 								T resultValue = null;
 								while (parentNodeDescription != null) {
-									Optional<Object> value = createInstanceOfRelationships(matchingProperty, values, relationshipDescription, relationshipsFromResult, nodesFromResult, parentNodeDescription);
+									Optional<Object> value = createInstanceOfRelationships(matchingProperty, values, relationshipDescription, parentNodeDescription, relationshipsFromResult, nodesFromResult);
 									if (value.isPresent()) {
 										resultValue = (T) value.get();
 										break;
@@ -491,7 +483,7 @@ private static Object getValueOrDefault(boolean ownerIsKotlinType, Class<?> rawT
 		return value == null && !ownerIsKotlinType && rawType.isPrimitive() ? ReflectionUtils.getPrimitiveDefault(rawType) : value;
 	}
 
-	private AssociationHandler<Neo4jPersistentProperty> populateFrom(MapAccessor queryResult,
+	private AssociationHandler<Neo4jPersistentProperty> populateFrom(MapAccessor queryResult, NodeDescription<?> baseDescription,
 			PersistentPropertyAccessor<?> propertyAccessor, Predicate<Neo4jPersistentProperty> isConstructorParameter,
 		    boolean objectAlreadyMapped, Collection<Relationship> relationshipsFromResult, Collection<Node> nodesFromResult) {
 
@@ -534,14 +526,14 @@ private AssociationHandler<Neo4jPersistentProperty> populateFrom(MapAccessor que
 				return;
 			}
 
-			createInstanceOfRelationships(persistentProperty, queryResult, (RelationshipDescription) association, relationshipsFromResult, nodesFromResult, null)
+			createInstanceOfRelationships(persistentProperty, queryResult, (RelationshipDescription) association, baseDescription, relationshipsFromResult, nodesFromResult)
 					.ifPresent(value -> propertyAccessor.setProperty(persistentProperty, value));
 		};
 	}
 
 	private Optional<Object> createInstanceOfRelationships(Neo4jPersistentProperty persistentProperty, MapAccessor values,
-		   RelationshipDescription relationshipDescription, Collection<Relationship> relationshipsFromResult,
-		   Collection<Node> nodesFromResult, @Nullable NodeDescription<?> nodeDescription) {
+		   RelationshipDescription relationshipDescription, NodeDescription<?> baseDescription, Collection<Relationship> relationshipsFromResult,
+		   Collection<Node> nodesFromResult) {
 
 		String typeOfRelationship = relationshipDescription.getType();
 		String sourceLabel = relationshipDescription.getSource().getPrimaryLabel();
@@ -575,13 +567,7 @@ private Optional<Object> createInstanceOfRelationships(Neo4jPersistentProperty p
 			mappedObjectHandler = (type, mappedObject) -> value.add(mappedObject);
 		}
 
-		// Generate name driven by the (nullable) NodeDescription of necessary,
-		// because it might contain associations not named CONCRETE_TYPE_TARGET but ABSTRACT_TYPE_TARGET
-		String collectionName = relationshipDescription.generateRelatedNodesCollectionName(
-				nodeDescription != null
-						? nodeDescription
-						: relationshipDescription.getSource()
-		);
+		String collectionName = relationshipDescription.generateRelatedNodesCollectionName(baseDescription);
 
 		Value list = values.get(collectionName);
 

src/main/java/org/springframework/data/neo4j/core/mapping/DefaultNeo4jPersistentEntity.java

@@ -512,11 +512,15 @@ public void addChildNodeDescription(NodeDescription<?> child) {
 	}
 
 	@Override
-	public Set<NodeDescription<?>> getChildNodeDescriptionsInHierarchy() {
-		Set<NodeDescription<?>> childNodes = new HashSet<>(childNodeDescriptions);
+	public List<NodeDescription<?>> getChildNodeDescriptionsInHierarchy() {
+		List<NodeDescription<?>> childNodes = new ArrayList<>(childNodeDescriptions);
 
 		for (NodeDescription<?> childNodeDescription : childNodeDescriptions) {
-			childNodes.addAll(childNodeDescription.getChildNodeDescriptionsInHierarchy());
+			for (NodeDescription<?> grantChildNodeDescription : childNodeDescription.getChildNodeDescriptionsInHierarchy()) {
+				if (!childNodes.contains(grantChildNodeDescription)) {
+					childNodes.add(grantChildNodeDescription);
+				}
+			}
 		}
 		return childNodes;
 	}

src/test/java/org/springframework/data/neo4j/integration/imperative/InheritanceMappingIT.java

@@ -406,7 +406,7 @@ void shouldMatchPolymorphicKotlinInterfacesWhenFetchingAll(@Autowired CinemaRepo
 	}
 
 	@Test // GH-2452
-	void asdf(@Autowired ParentClassWithRelationshipRepository repository) {
+	void loadAndPopulateRelationshipFromTheHierarchy(@Autowired ParentClassWithRelationshipRepository repository) {
 
 		long childId;
 		try (Session session = driver.session(bookmarkCapture.createSessionConfig())) {