GH-2225 - Improve label determination for inherited entities.

With multiple concrete implementations of an abstract class the
determination of the concrete node description for a result `n,
collect(r), collect(rn)` was flaky.
The abstract class' repository only gives its abstract label as an
anchor for the determination.
The initial mapping step looks through the whole result to figure the
labels for the "root node" but misses out to check for one node that
reflects the concrete initial "root node". This leads to the situation
that the concrete node description is getting randomly choosen from the
random set of possible candidates.

Closes #2225

Author: meistermeier

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

@@ -327,6 +327,15 @@ private List<String> getLabels(MapAccessor queryResult, @Nullable NodeDescriptio
 		} else if (queryResult instanceof Node) {
 			Node nodeRepresentation = (Node) queryResult;
 			nodeRepresentation.labels().forEach(labels::add);
+		} else if (containsOnePlainNode(queryResult)) {
+			for (Value value : queryResult.values()) {
+				if (value.hasType(nodeType)) {
+					Node node = value.asNode();
+					for (String label : node.labels()) {
+						labels.add(label);
+					}
+				}
+			}
 		} else if (!queryResult.get(Constants.NAME_OF_SYNTHESIZED_ROOT_NODE).isNull()) {
 			queryResult.get(Constants.NAME_OF_SYNTHESIZED_ROOT_NODE).asNode().labels().forEach(labels::add);
 		} else if (nodeDescription != null) {
@@ -335,6 +344,11 @@ private List<String> getLabels(MapAccessor queryResult, @Nullable NodeDescriptio
 		return labels;
 	}
 
+	private boolean containsOnePlainNode(MapAccessor queryResult) {
+		return StreamSupport.stream(queryResult.values().spliterator(), false)
+				.filter(value -> value.hasType(nodeType)).count() == 1L;
+	}
+
 	private <ET> ET instantiate(Neo4jPersistentEntity<ET> nodeDescription, MapAccessor values, MapAccessor allValues,
 			Collection<RelationshipDescription> relationships, Collection<String> surplusLabels,
 			Object lastMappedEntity) {

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

@@ -3571,6 +3571,28 @@ void findByIdWithTwoLevelInheritance(@Autowired SuperBaseClassRepository superBa
 			});
 		}
 
+		@Test // GH-2225
+		void findWithTemplateWithTwoLevelInheritance(@Autowired Neo4jTemplate neo4jTemplate) {
+			String someValue = "test";
+			String concreteClassName = "cc1";
+			Inheritance.ConcreteClassA ccA = new Inheritance.ConcreteClassA(concreteClassName, someValue);
+			ccA.others = Collections.singletonList(new Inheritance.ConcreteClassB("ccB", 41));
+			neo4jTemplate.save(ccA);
+			List<Inheritance.SuperBaseClass> ccAs = neo4jTemplate.findAll("MATCH (a:SuperBaseClass{name: 'cc1'})-[r]->(m) " +
+							"RETURN a, collect(r), collect(m)",
+					Inheritance.SuperBaseClass.class);
+			assertThat(ccAs).hasSize(1);
+			Inheritance.SuperBaseClass loadedCcA = ccAs.get(0);
+			assertThat(loadedCcA).isInstanceOfSatisfying(Inheritance.ConcreteClassA.class, o -> {
+				assertThat(o.getName()).isEqualTo(concreteClassName);
+				assertThat(o.getConcreteSomething()).isEqualTo(someValue);
+				assertThat(o.others).hasSize(1);
+				Inheritance.BaseClass relatedNode = o.others.get(0);
+				assertThat(relatedNode.getName()).isEqualTo("ccB");
+				assertThat(relatedNode).isInstanceOf(Inheritance.ConcreteClassB.class);
+			});
+		}
+
 		@Test
 		void findAllWithTwoLevelInheritance(@Autowired SuperBaseClassRepository superBaseClassRepository) {
 			Inheritance.ConcreteClassA ccA = new Inheritance.ConcreteClassA("cc1", "test");

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

@@ -361,6 +361,9 @@ public static class ConcreteClassA extends BaseClass {
 
 		private final String concreteSomething;
 
+		@Relationship("CONNECTED")
+		public List<BaseClass> others;
+
 		public ConcreteClassA(String name, String concreteSomething) {
 			super(name);
 			this.concreteSomething = concreteSomething;