DATAES-937 - Repository queries with IN filters fail with empty input list.

Original PR: #525

src/main/java/org/springframework/data/elasticsearch/core/query/Criteria.java

@@ -16,7 +16,6 @@
 package org.springframework.data.elasticsearch.core.query;
 
 import java.util.Arrays;
-import java.util.Collection;
 import java.util.Collections;
 import java.util.LinkedHashSet;
 import java.util.LinkedList;
@@ -438,7 +437,7 @@ public class Criteria {
 	/**
 	 * Add a {@link OperationKey#IN} entry to the {@link #queryCriteriaEntries}. This will create a terms query, so don't
 	 * use it with text fields as these are analyzed and changed by Elasticsearch (converted to lowercase with the default
-	 * analyzer). If used for Strings, these should be marked a sfield type Keyword.
+	 * analyzer). If used for Strings, these should be marked as field type Keyword.
 	 *
 	 * @param values the argument to the operation
 	 * @return this object
@@ -743,11 +742,6 @@ public class Criteria {
 	}
 
 	private List<Object> toCollection(Object... values) {
-		if (values.length == 0 || (values.length > 1 && values[1] instanceof Collection)) {
-			throw new InvalidDataAccessApiUsageException(
-					"At least one element " + (values.length > 0 ? ("of argument of type " + values[1].getClass().getName()) : "")
-							+ " has to be present.");
-		}
 		return Arrays.asList(values);
 	}
 

src/main/java/org/springframework/data/elasticsearch/repository/support/SimpleElasticsearchRepository.java

@@ -148,8 +148,14 @@ public class SimpleElasticsearchRepository<T, ID> implements ElasticsearchReposi
 
 		Assert.notNull(ids, "ids can't be null.");
 
-		NativeSearchQuery query = new NativeSearchQueryBuilder().withIds(stringIdsRepresentation(ids)).build();
 		List<T> result = new ArrayList<>();
+		List<String> stringIds = stringIdsRepresentation(ids);
+
+		if (stringIds.isEmpty()) {
+			return result;
+		}
+
+		NativeSearchQuery query = new NativeSearchQueryBuilder().withIds(stringIds).build();
 		List<T> multiGetEntities = execute(operations -> operations.multiGet(query, entityClass, getIndexCoordinates()));
 
 		if (multiGetEntities != null) {

src/test/java/org/springframework/data/elasticsearch/repository/query/keywords/QueryKeywordsTests.java

@@ -23,12 +23,14 @@ import lombok.Getter;
 import lombok.NoArgsConstructor;
 import lombok.Setter;
 
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 import java.util.stream.Collectors;
 
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.DisplayName;
 import org.junit.jupiter.api.Test;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.context.annotation.Configuration;
@@ -249,7 +251,7 @@ class QueryKeywordsTests {
 		products.forEach(product -> assertThat(product.name).isEqualTo("Sugar"));
 	}
 
-	@Test
+	@Test // DATAES-239
 	void shouldSearchForNullValues() {
 		final List<Product> products = repository.findByName(null);
 
@@ -257,7 +259,7 @@ class QueryKeywordsTests {
 		assertThat(products.get(0).getId()).isEqualTo("6");
 	}
 
-	@Test
+	@Test // DATAES-239
 	void shouldDeleteWithNullValues() {
 		repository.deleteByName(null);
 
@@ -265,6 +267,24 @@ class QueryKeywordsTests {
 		assertThat(count).isEqualTo(5);
 	}
 
+	@Test // DATAES-937
+	@DisplayName("should return empty list on findById with empty input list")
+	void shouldReturnEmptyListOnFindByIdWithEmptyInputList() {
+
+		Iterable<Product> products = repository.findAllById(new ArrayList<>());
+
+		assertThat(products).isEmpty();
+	}
+
+	@Test // DATAES-937
+	@DisplayName("should return empty list on derived method with empty input list")
+	void shouldReturnEmptyListOnDerivedMethodWithEmptyInputList() {
+
+		Iterable<Product> products = repository.findAllByNameIn(new ArrayList<>());
+
+		assertThat(products).isEmpty();
+	}
+
 	/**
 	 * @author Mohsin Husen
 	 * @author Artur Konczak
@@ -344,6 +364,8 @@ class QueryKeywordsTests {
 		List<Product> findTop2ByName(String name);
 
 		void deleteByName(@Nullable String name);
+
+		List<Product> findAllByNameIn(List<String> names);
 	}
 
 }