GH-2452 - Improve mapping of constructor relationships.

Closes #2452

Author: meistermeier

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

@@ -429,7 +429,23 @@ public <T> T getParameterValue(PreferredConstructor.Parameter<T, Neo4jPersistent
 								String propertyFieldName = matchingProperty.getFieldName();
 								return r.getFieldName().equals(propertyFieldName);
 							}).findFirst().get();
-					result = createInstanceOfRelationships(matchingProperty, values, relationshipDescription, relationshipsFromResult, nodesFromResult).orElse(null);
+					// 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)
+							.orElseGet(() -> {
+								NodeDescription<?> parentNodeDescription = nodeDescription.getParentNodeDescription();
+								T resultValue = null;
+								while (parentNodeDescription != null) {
+									Optional<Object> value = createInstanceOfRelationships(matchingProperty, values, relationshipDescription, relationshipsFromResult, nodesFromResult, parentNodeDescription);
+									if (value.isPresent()) {
+										resultValue = (T) value.get();
+										break;
+									}
+									parentNodeDescription = parentNodeDescription.getParentNodeDescription();
+								}
+								return resultValue;
+							});
 				} else if (matchingProperty.isDynamicLabels()) {
 					result = createDynamicLabelsProperty(matchingProperty.getTypeInformation(), surplusLabels);
 				} else if (matchingProperty.isEntityWithRelationshipProperties()) {
@@ -518,13 +534,14 @@ private AssociationHandler<Neo4jPersistentProperty> populateFrom(MapAccessor que
 				}
 			}
 
-			createInstanceOfRelationships(persistentProperty, queryResult, (RelationshipDescription) association, relationshipsFromResult, nodesFromResult)
+			createInstanceOfRelationships(persistentProperty, queryResult, (RelationshipDescription) association, relationshipsFromResult, nodesFromResult, null)
 					.ifPresent(value -> propertyAccessor.setProperty(persistentProperty, value));
 		};
 	}
 
 	private Optional<Object> createInstanceOfRelationships(Neo4jPersistentProperty persistentProperty, MapAccessor values,
-			RelationshipDescription relationshipDescription, Collection<Relationship> relationshipsFromResult, Collection<Node> nodesFromResult) {
+		   RelationshipDescription relationshipDescription, Collection<Relationship> relationshipsFromResult,
+		   Collection<Node> nodesFromResult, @Nullable NodeDescription<?> nodeDescription) {
 
 		String typeOfRelationship = relationshipDescription.getType();
 		String sourceLabel = relationshipDescription.getSource().getPrimaryLabel();
@@ -558,8 +575,13 @@ private Optional<Object> createInstanceOfRelationships(Neo4jPersistentProperty p
 			mappedObjectHandler = (type, mappedObject) -> value.add(mappedObject);
 		}
 
-		String collectionName =
-				relationshipDescription.generateRelatedNodesCollectionName(relationshipDescription.getSource());
+		// 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()
+		);
 
 		Value list = values.get(collectionName);
 
@@ -672,7 +694,9 @@ private Collection<Node> extractNodes(MapAccessor allValues) {
 		return allNodesInResult;
 	}
 
-	private Collection<Relationship> extractMatchingRelationships(Collection<Relationship> relationshipsFromResult, RelationshipDescription relationshipDescription, String typeOfRelationship, Predicate<Relationship> relationshipPredicate) {
+	private Collection<Relationship> extractMatchingRelationships(Collection<Relationship> relationshipsFromResult,
+									  RelationshipDescription relationshipDescription, String typeOfRelationship,
+									  Predicate<Relationship> relationshipPredicate) {
 
 		Predicate<Relationship> onlyWithMatchingType = r -> r.type().equals(typeOfRelationship) || relationshipDescription.isDynamic();
 		return relationshipsFromResult.stream()

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

@@ -405,6 +405,27 @@ void shouldMatchPolymorphicKotlinInterfacesWhenFetchingAll(@Autowired CinemaRepo
 		});
 	}
 
+	@Test // GH-2452
+	void asdf(@Autowired ParentClassWithRelationshipRepository repository) {
+
+		long childId;
+		try (Session session = driver.session(bookmarkCapture.createSessionConfig())) {
+			childId = session
+					.run("CREATE (c:CCWR:PCWR{name:'child'})-[:LIVES_IN]->(:Continent:BaseTerritory:BaseEntity{nameEn:'continent', continentProperty:'small'}) return id(c) as id")
+					.single().get(0).asLong();
+			bookmarkCapture.seedWith(session.lastBookmark());
+		}
+
+		Inheritance.ParentClassWithRelationship potentialChildClass = repository.findById(childId).get();
+		assertThat(potentialChildClass).isInstanceOf(Inheritance.ChildClassWithRelationship.class);
+
+		Inheritance.ChildClassWithRelationship child = (Inheritance.ChildClassWithRelationship) potentialChildClass;
+		assertThat(child.name).isEqualTo("child");
+
+		assertThat(child.continent).isNotNull();
+		assertThat(child.continent.continentProperty).isEqualTo("small");
+	}
+
 	private Consumer<Inheritance.ParentModel2> twoDifferentInterfacesHaveBeenLoaded() {
 		return d -> {
 			assertThat(d.getIsRelatedTo()).hasSize(2);
@@ -455,6 +476,9 @@ interface PetsRepository extends Neo4jRepository<AbstractPet, Long> {
 
 	}
 
+	interface ParentClassWithRelationshipRepository extends Neo4jRepository<Inheritance.ParentClassWithRelationship, Long> {
+	}
+
 	interface BuildingRepository extends Neo4jRepository<Inheritance.Building, Long> {}
 
 	interface TerritoryRepository extends Neo4jRepository<Inheritance.BaseTerritory, Long> {}

src/test/java/org/springframework/data/neo4j/integration/shared/common/Inheritance.java

@@ -925,5 +925,37 @@ public void setIsActiveIn(
 		}
 	}
 
+	/**
+	 * Parent class with relationship definition in the constructor
+	 */
+	@Node("PCWR")
+	public static abstract class ParentClassWithRelationship {
+
+		@Id
+		@GeneratedValue
+		public final Long id;
+
+		@Relationship("LIVES_IN")
+ 		public final Continent continent;
+
+		public ParentClassWithRelationship(Long id, Continent continent) {
+			this.id = id;
+			this.continent = continent;
+		}
+	}
+
+	/**
+	 * Child class with relationship definition in the constructor
+	 */
+	@Node("CCWR")
+	public static class ChildClassWithRelationship extends ParentClassWithRelationship {
+
+		public String name;
+
+		public ChildClassWithRelationship(Long id, Continent continent) {
+			super(id, continent);
+		}
+	}
+
 
 }