GH-2117 - Exclude relationships from projections when not projected.

This fixes #2117.

Author: michael-simons

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

@@ -393,6 +393,7 @@ private MapProjection projectPropertiesAndRelationships(NodeDescription<?> nodeD
 		List<Object> contentOfProjection = new ArrayList<>(propertiesProjection);
 
 		Collection<RelationshipDescription> relationships = getRelationshipDescriptionsUpAndDown(nodeDescription);
+		relationships.removeIf(r -> !includeProperty.test(r.getFieldName()));
 
 		if (nodeDescription.containsPossibleCircles()) {
 			Node node = anyNode(nodeName);
@@ -401,8 +402,7 @@ private MapProjection projectPropertiesAndRelationships(NodeDescription<?> nodeD
 			contentOfProjection.add(Constants.NAME_OF_PATHS);
 			contentOfProjection.add(Cypher.listBasedOn(p).returning(p));
 		} else {
-			contentOfProjection.addAll(
-					generateListsFor(relationships, nodeName, includeProperty, processedRelationships));
+			contentOfProjection.addAll(generateListsFor(relationships, nodeName, processedRelationships));
 		}
 		return Cypher.anyNode(nodeName).project(contentOfProjection);
 	}
@@ -599,16 +599,13 @@ private List<Object> projectNodeProperties(NodeDescription<?> nodeDescription, S
 	 * @see CypherGenerator#projectNodeProperties
 	 */
 	private List<Object> generateListsFor(Collection<RelationshipDescription> relationships, SymbolicName nodeName,
-			Predicate<String> includeField, List<RelationshipDescription> processedRelationships) {
+			List<RelationshipDescription> processedRelationships) {
 
 		List<Object> mapProjectionLists = new ArrayList<>();
 
 		for (RelationshipDescription relationshipDescription : relationships) {
 
 			String fieldName = relationshipDescription.getFieldName();
-			if (!includeField.test(fieldName)) {
-				continue;
-			}
 
 			// if we already processed the other way before, do not try to jump in the infinite loop
 			// unless it is a root node relationship

src/main/java/org/springframework/data/neo4j/repository/query/CypherQueryCreator.java

@@ -162,6 +162,8 @@ private class PropertyPathWrapper {
 			this.propertyPath = propertyPath;
 		}
 
+
+
 		public PersistentPropertyPath<?> getPropertyPath() {
 			return propertyPath;
 		}

src/test/java/org/springframework/data/neo4j/integration/movies/AdvancedMappingIT.java

@@ -36,6 +36,8 @@
 import org.springframework.context.annotation.Configuration;
 import org.springframework.data.neo4j.config.AbstractNeo4jConfig;
 import org.springframework.data.neo4j.core.Neo4jTemplate;
+import org.springframework.data.neo4j.repository.Neo4jRepository;
+import org.springframework.data.neo4j.repository.config.EnableNeo4jRepositories;
 import org.springframework.data.neo4j.test.Neo4jExtension;
 import org.springframework.data.neo4j.test.Neo4jIntegrationTest;
 import org.springframework.transaction.annotation.EnableTransactionManagement;
@@ -83,6 +85,62 @@ static void setupData(@Autowired Driver driver) throws IOException {
 		}
 	}
 
+	interface MovieProjection {
+
+		String getTitle();
+
+		List<Actor> getActors();
+	}
+
+	static class MovieDTO {
+
+		private final String title;
+
+		private final List<Actor> actors;
+
+		MovieDTO(String title, List<Actor> actors) {
+			this.title = title;
+			this.actors = actors;
+		}
+
+		public String getTitle() {
+			return title;
+		}
+
+		public List<Actor> getActors() {
+			return actors;
+		}
+	}
+
+	interface MovieRepository extends Neo4jRepository<Movie, String> {
+
+		MovieProjection findProjectionByTitle(String title);
+
+		MovieDTO findDTOByTitle(String title);
+	}
+
+	@Test // GH-2117
+	void bothCyclicAndNonCyclicRelationshipsAreExcludedFromProjections(@Autowired MovieRepository movieRepository) {
+
+		// The movie domain is a good fit for this test
+		// as the cyclic dependencies is pretty slow to retrieve from Neo4j
+		// this does OOM in most setups.
+		MovieProjection projection = movieRepository.findProjectionByTitle("The Matrix");
+		assertThat(projection.getTitle()).isNotNull();
+		assertThat(projection.getActors()).isNotEmpty();
+	}
+
+	@Test // GH-2117
+	void bothCyclicAndNonCyclicRelationshipsAreExcludedFromDTOProjections(@Autowired MovieRepository movieRepository) {
+
+		// The movie domain is a good fit for this test
+		// as the cyclic dependencies is pretty slow to retrieve from Neo4j
+		// this does OOM in most setups.
+		MovieDTO dtoProjection = movieRepository.findDTOByTitle("The Matrix");
+		assertThat(dtoProjection.getTitle()).isNotNull();
+		assertThat(dtoProjection.getActors()).isNotEmpty();
+	}
+
 	@Test // GH-2114
 	void bothStartAndEndNodeOfPathsMustBeLookedAt(@Autowired Neo4jTemplate template) {
 
@@ -237,6 +295,7 @@ void pathMappingWithAdditionalInformationShouldWork(@Autowired Neo4jTemplate tem
 
 	@Configuration
 	@EnableTransactionManagement
+	@EnableNeo4jRepositories(considerNestedRepositories = true)
 	static class Config extends AbstractNeo4jConfig {
 
 		@Bean