DATAES-753 - Reactive Elasticsearch repository: Bulk update fails on empty entity list.

Original PR: spring-projects#398

Author: sothawo

src/main/java/org/springframework/data/elasticsearch/core/ReactiveDocumentOperations.java

@@ -88,7 +88,7 @@ default <T> Mono<T> save(Mono<? extends T> entityPublisher, IndexCoordinates ind
 
 	/**
 	 * Index entities under the given {@literal type} in the given {@literal index}. If the {@literal index} is
-	 * {@literal null} or empty the index name provided via entity metadata is used. Same for the {@literal type}.
+	 * {@literal null} or empty the index name provided via entity metadata is used.
 	 *
 	 * @param entities must not be {@literal null}.
 	 * @param index the target index, must not be {@literal null}
@@ -104,7 +104,7 @@ default <T> Flux<T> saveAll(Iterable<T> entities, IndexCoordinates index) {
 
 	/**
 	 * Index entities under the given {@literal type} in the given {@literal index}. If the {@literal index} is
-	 * {@literal null} or empty the index name provided via entity metadata is used. Same for the {@literal type}.
+	 * {@literal null} or empty the index name provided via entity metadata is used.
 	 *
 	 * @param entities must not be {@literal null}.
 	 * @param index the target index, must not be {@literal null}
@@ -228,7 +228,7 @@ default <T> Mono<T> findById(String id, Class<T> entityType, IndexCoordinates in
 	 * @param entity must not be {@literal null}.
 	 * @return a {@link Mono} emitting the {@literal id} of the removed document.
 	 */
-	 Mono<String> delete(Object entity);
+	Mono<String> delete(Object entity);
 
 	/**
 	 * Delete the given entity extracting index and type from entity metadata.
@@ -237,7 +237,7 @@ default <T> Mono<T> findById(String id, Class<T> entityType, IndexCoordinates in
 	 * @param index the target index, must not be {@literal null}
 	 * @return a {@link Mono} emitting the {@literal id} of the removed document.
 	 */
-	 Mono<String> delete(Object entity, IndexCoordinates index);
+	Mono<String> delete(Object entity, IndexCoordinates index);
 
 	/**
 	 * Delete the entity with given {@literal id}.

src/main/java/org/springframework/data/elasticsearch/core/ReactiveElasticsearchTemplate.java

@@ -160,6 +160,11 @@ public <T> Flux<T> saveAll(Mono<? extends Collection<? extends T>> entities, Ind
 			List<AdaptibleEntity<? extends T>> adaptibleEntities = entityList.stream() //
 					.map(e -> operations.forEntity(e, converter.getConversionService())) //
 					.collect(Collectors.toList());
+
+			if (adaptibleEntities.isEmpty()) {
+				return Flux.empty();
+			}
+
 			Iterator<AdaptibleEntity<? extends T>> iterator = adaptibleEntities.iterator();
 			List<IndexQuery> indexRequests = adaptibleEntities.stream() //
 					.map(e -> getIndexQuery(e.getBean(), e)) //
@@ -366,7 +371,7 @@ protected Mono<GetResult> doGet(GetRequest request) {
 	 * @see org.springframework.data.elasticsearch.core.ReactiveElasticsearchOperations#delete(Object, String, String)
 	 */
 	@Override
-	public  Mono<String> delete(Object entity, IndexCoordinates index) {
+	public Mono<String> delete(Object entity, IndexCoordinates index) {
 
 		Entity<?> elasticsearchEntity = operations.forEntity(entity);
 

src/test/java/org/springframework/data/elasticsearch/core/ReactiveElasticsearchTemplateTests.java

@@ -811,6 +811,13 @@ void shouldSaveAll() {
 				.verifyComplete();
 	}
 
+	@Test // DATAES-753
+	void shouldReturnEmptyFluxOnSaveAllWithEmptyInput() {
+		template.saveAll(Collections.emptyList(), IndexCoordinates.of(DEFAULT_INDEX)) //
+				.as(StepVerifier::create) //
+				.verifyComplete();
+	}
+
 	@Data
 	@Document(indexName = "marvel")
 	static class Person {