Fix reactive flow.

Author: michael-simons

src/main/java/org/springframework/data/neo4j/core/ReactiveNeo4jTemplate.java

@@ -454,7 +454,7 @@ private <T> Mono<ExecutableQuery<T>> createExecutableQuery(Class<T> domainType,
 				returnTuple != null
 						? returnTuple.getIncludedProperties()
 						: Collections.emptyList());
-		if (containsPossibleCircles) {
+		if (containsPossibleCircles && !queryFragments.isScalarValueReturn()) {
 			return createQueryAndParameters(entityMetaData, queryFragments, parameters)
 					.flatMap(finalQueryAndParameters ->
 							createExecutableQuery(domainType, renderer.render(GenericQueryAndParameters.STATEMENT),
@@ -759,7 +759,7 @@ public <T> Mono<ExecutableQuery<T>> toExecutableQuery(PreparedQuery<T> preparedQ
 
 				Map<String, Object> parameters = queryFragmentsAndParameters.getParameters();
 
-				if (containsPossibleCircles) {
+				if (containsPossibleCircles && !queryFragments.isScalarValueReturn()) {
 					GenericQueryAndParameters genericQueryAndParameters =
 							createQueryAndParameters(entityMetaData, queryFragments, parameters).block();
 
@@ -768,7 +768,6 @@ public <T> Mono<ExecutableQuery<T>> toExecutableQuery(PreparedQuery<T> preparedQ
 				} else {
 					cypherQuery = renderer.render(queryFragments.toStatement());
 				}
-
 			}
 
 			ReactiveNeo4jClient.MappingSpec<T> mappingSpec = this.neo4jClient.query(cypherQuery)

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

@@ -979,6 +979,12 @@ void countByPropertyWithPossibleCircles(@Autowired PetRepository repository) {
 			assertThat(repository.countByName("Luna")).isEqualTo(1L);
 		}
 
+		@Test // GH-2157
+		void countByCustomQueryShouldWork(@Autowired PetRepository repository) {
+			createFriendlyPets();
+			assertThat(repository.countAllByName("Luna")).isEqualTo(4L);
+		}
+
 		@Test // GH-2157
 		void existsByPropertyWithPossibleCircles(@Autowired PetRepository repository) {
 			createFriendlyPets();
@@ -3874,8 +3880,10 @@ interface PetRepository extends Neo4jRepository<Pet, Long> {
 
 		long countByName(String name);
 
-		boolean existsByName(String name);
+		@Query(value = "RETURN size($0)", count = true)
+		long countAllByName(String name);
 
+		boolean existsByName(String name);
 	}
 
 	interface RelationshipRepository extends Neo4jRepository<PersonWithRelationship, Long> {

src/test/java/org/springframework/data/neo4j/integration/reactive/ReactiveRepositoryIT.java

@@ -998,18 +998,32 @@ void loadEntityWithRelationshipWithAssignedId(@Autowired ReactivePetRepository r
 		@Test
 		void findEntityWithSelfReferencesInBothDirections(@Autowired ReactivePetRepository repository) {
 
-			long petId;
-
-			try (Session session = createSession()) {
-				petId = session.run("CREATE (luna:Pet{name:'Luna'})-[:Has]->(daphne:Pet{name:'Daphne'})"
-						+ "-[:Has]->(luna2:Pet{name:'Luna'})" + "RETURN id(luna) as id").single().get("id").asLong();
-			}
+			long petId = createFriendlyPets();
 
 			StepVerifier.create(repository.findById(petId)).assertNext(loadedPet -> {
 				assertThat(loadedPet.getFriends().get(0).getName()).isEqualTo("Daphne");
 				assertThat(loadedPet.getFriends().get(0).getFriends().get(0).getName()).isEqualTo("Luna");
 			}).verifyComplete();
 		}
+
+		@Test // GH-2157
+		void countByPropertyWithPossibleCircles(@Autowired ReactivePetRepository repository) {
+			createFriendlyPets();
+			StepVerifier.create(repository.countByName("Luna")).expectNext(1L).verifyComplete();
+		}
+
+		@Test // GH-2157
+		void existsByPropertyWithPossibleCircles(@Autowired ReactivePetRepository repository) {
+			createFriendlyPets();
+			StepVerifier.create(repository.existsByName("Luna")).expectNext(true).verifyComplete();
+		}
+
+		private long createFriendlyPets() {
+			try (Session session = createSession()) {
+				return session.run("CREATE (luna:Pet{name:'Luna'})-[:Has]->(daphne:Pet{name:'Daphne'})"
+								   + "-[:Has]->(luna)" + "RETURN id(luna) as id").single().get("id").asLong();
+			}
+		}
 	}
 
 	@Nested
@@ -2470,7 +2484,11 @@ interface ReactiveHobbyWithRelationshipWithPropertiesRepository
 		Flux<AltHobby> loadFromCustomQuery(@Param("personId") Long personId);
 	}
 
-	interface ReactivePetRepository extends ReactiveNeo4jRepository<Pet, Long> {}
+	interface ReactivePetRepository extends ReactiveNeo4jRepository<Pet, Long> {
+		Mono<Long> countByName(String name);
+
+		Mono<Boolean> existsByName(String name);
+	}
 
 	interface ReactiveRelationshipRepository extends ReactiveNeo4jRepository<PersonWithRelationship, Long> {