GH-2788 - Fix implementation class detection for Node annotated interfaces.

Closes #2788

Author: meistermeier

src/main/java/org/springframework/data/neo4j/core/mapping/Neo4jMappingContext.java

@@ -289,7 +289,8 @@ protected <T> Neo4jPersistentEntity<?> createPersistentEntity(TypeInformation<T>
 		}
 
 		// determine super class to create the node hierarchy
-		Class<? super T> superclass = typeInformation.getType().getSuperclass();
+		Class<T> type = typeInformation.getType();
+		Class<? super T> superclass = type.getSuperclass();
 
 		if (isValidParentNode(superclass)) {
 			synchronized (this) {
@@ -303,6 +304,17 @@ protected <T> Neo4jPersistentEntity<?> createPersistentEntity(TypeInformation<T>
 			}
 		}
 
+		for (Class<?> typeInterface : type.getInterfaces()) {
+			if (isValidEntityInterface(typeInterface)) {
+				super.setStrict(false);
+				Neo4jPersistentEntity<?> parentNodeDescription = getPersistentEntity(typeInterface);
+				if (parentNodeDescription != null) {
+					parentNodeDescription.addChildNodeDescription(newEntity);
+				}
+				this.setStrict(strict);
+			}
+		}
+
 		return newEntity;
 	}
 
@@ -316,6 +328,10 @@ private static boolean isValidParentNode(@Nullable Class<?> parentClass) {
 			   parentClass.isAnnotationPresent(Node.class);
 	}
 
+	private static boolean isValidEntityInterface(Class<?> typeInterface) {
+		return typeInterface.isAnnotationPresent(Node.class);
+	}
+
 	/*
 	 * (non-Javadoc)
 	 * @see org.springframework.data.mapping.context.AbstractMappingContext#createPersistentProperty(org.springframework.data.mapping.model.Property, org.springframework.data.mapping.model.MutablePersistentEntity, org.springframework.data.mapping.model.SimpleTypeHolder)

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

@@ -333,6 +333,44 @@ void mixedInterfaces(@Autowired Neo4jTemplate template) {
 		}
 	}
 
+	@Test // GH-2788
+	void detectPropertiesAndRelationshipsOfImplementingEntities(@Autowired Neo4jTemplate template) {
+		String id;
+		try (Session session = driver.session(bookmarkCapture.createSessionConfig()); Transaction transaction = session.beginTransaction()) {
+			id = transaction.run("" +
+							"CREATE (e:`GH-2788-Entity`) " +
+							"CREATE (e)-[:RELATED_TO]-> (a:`GH-2788-Interface`:`GH-2788-A` {name:'A'}) " +
+							"CREATE (e)-[:RELATED_TO]-> (b:`GH-2788-Interface`:`GH-2788-B` {name:'B'}) " +
+							"CREATE (a)-[:RELATED_TO]-> (:`Gh2788ArelatedEntity`) " +
+							"CREATE (b)-[:RELATED_TO]-> (:`Gh2788BrelatedEntity`) " +
+							"RETURN elementId(e)")
+					.single().get(0).asString();
+			transaction.commit();
+			bookmarkCapture.seedWith(session.lastBookmarks());
+		}
+
+		Optional<Inheritance.Gh2788Entity> gh2788Entity = transactionTemplate.execute(tx ->
+				template.findById(id, Inheritance.Gh2788Entity.class));
+
+		assertThat(gh2788Entity).hasValueSatisfying(v -> {
+			List<Inheritance.Gh2788Interface> relatedTo = v.relatedTo;
+			assertThat(relatedTo).allSatisfy(relatedElement -> {
+				if (relatedElement instanceof Inheritance.Gh2788A relatedAelement) {
+					assertThat(relatedAelement.name).isEqualTo("A");
+					assertThat(relatedAelement.relatedTo)
+							.hasSize(1)
+							.hasOnlyElementsOfType(Inheritance.Gh2788ArelatedEntity.class);
+				} else if (relatedElement instanceof Inheritance.Gh2788B relatedBelement) {
+					assertThat(relatedBelement.name).isEqualTo("B");
+					assertThat(relatedBelement.relatedTo)
+							.hasSize(1)
+							.hasOnlyElementsOfType(Inheritance.Gh2788BrelatedEntity.class);
+				}
+			});
+
+		});
+	}
+
 	@Test // GH-2262
 	void shouldMatchPolymorphicClassesWhenFetchedById(@Autowired DivisionRepository repository) {
 

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

@@ -983,5 +983,84 @@ public ChildClassWithRelationship(Long id, Continent continent) {
 		}
 	}
 
+	/**
+	 * Entity that has an interface-based relationship.
+	 * For testing that the properties and relationships of the implementing classes will also get fetched.
+	 */
+	@Node("GH-2788-Entity")
+	public static class Gh2788Entity {
+		@Id @GeneratedValue public String id;
+		public List<Gh2788Interface> relatedTo;
+	}
+
+	/**
+	 * Interface for relationship
+	 */
+	@Node("GH-2788-Interface")
+	public interface Gh2788Interface {
+		String getName();
+	}
+
+	/**
+	 * First implementation
+	 */
+	@Node("GH-2788-A")
+	public static class Gh2788A implements Gh2788Interface {
+		@Id @GeneratedValue String id;
+
+		public final String name;
+		public final String aValue;
+		public final List<Gh2788ArelatedEntity> relatedTo;
+
+		public Gh2788A(String name, String aValue, List<Gh2788ArelatedEntity> relatedTo) {
+			this.name = name;
+			this.aValue = aValue;
+			this.relatedTo = relatedTo;
+		}
+
+		@Override
+		public String getName() {
+			return name;
+		}
+	}
+
+	/**
+	 * Related entity for first implementation
+	 */
+	@Node
+	public static class Gh2788ArelatedEntity {
+		@Id @GeneratedValue String id;
+	}
+
+	/**
+	 * Second implementation
+	 */
+	@Node("GH-2788-B")
+	public static class Gh2788B implements Gh2788Interface {
+		@Id @GeneratedValue String id;
+
+		public final String name;
+		public final String bValue;
+		public final List<Gh2788BrelatedEntity> relatedTo;
+
+		public Gh2788B(String name, String bValue, List<Gh2788BrelatedEntity> relatedTo) {
+			this.name = name;
+			this.bValue = bValue;
+			this.relatedTo = relatedTo;
+		}
+
+		@Override
+		public String getName() {
+			return name;
+		}
+	}
+
+	/**
+	 * Related entity for second implementation
+	 */
+	@Node
+	public static class Gh2788BrelatedEntity {
+		@Id @GeneratedValue String id;
+	}
 
 }