Avoid nested Document conversion to primitive types for fields with an explicit write target.

We now no longer attempt to convert query Documents into primitive types to avoid e.g. Document to String conversion.

Closes: #3783
Original Pull Request: #3797

Author: mp911de

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/QueryMapper.java

@@ -696,7 +696,8 @@ protected boolean isKeyword(String candidate) {
 	@Nullable
 	private Object applyFieldTargetTypeHintToValue(Field documentField, @Nullable Object value) {
 
-		if (value == null || documentField.getProperty() == null || !documentField.getProperty().hasExplicitWriteTarget()) {
+		if (value == null || documentField.getProperty() == null || !documentField.getProperty().hasExplicitWriteTarget()
+				|| value instanceof Document || value instanceof DBObject) {
 			return value;
 		}
 

spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/convert/QueryMapperUnitTests.java

@@ -33,19 +33,13 @@
 import org.bson.types.ObjectId;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
-import org.junit.jupiter.api.extension.ExtendWith;
-import org.mockito.Mock;
-import org.mockito.junit.jupiter.MockitoExtension;
-import org.mockito.junit.jupiter.MockitoSettings;
-import org.mockito.quality.Strictness;
 
 import org.springframework.core.convert.converter.Converter;
 import org.springframework.data.annotation.Id;
 import org.springframework.data.convert.WritingConverter;
 import org.springframework.data.domain.Sort;
 import org.springframework.data.domain.Sort.Direction;
 import org.springframework.data.geo.Point;
-import org.springframework.data.mongodb.MongoDatabaseFactory;
 import org.springframework.data.mongodb.core.DocumentTestUtils;
 import org.springframework.data.mongodb.core.Person;
 import org.springframework.data.mongodb.core.geo.GeoJsonPoint;
@@ -55,6 +49,7 @@
 import org.springframework.data.mongodb.core.mapping.Document;
 import org.springframework.data.mongodb.core.mapping.Field;
 import org.springframework.data.mongodb.core.mapping.FieldType;
+import org.springframework.data.mongodb.core.mapping.MongoId;
 import org.springframework.data.mongodb.core.mapping.MongoMappingContext;
 import org.springframework.data.mongodb.core.mapping.MongoPersistentEntity;
 import org.springframework.data.mongodb.core.mapping.TextScore;
@@ -77,22 +72,21 @@
  * @author Mark Paluch
  * @author David Julia
  */
-@ExtendWith(MockitoExtension.class)
-@MockitoSettings(strictness = Strictness.LENIENT)
 public class QueryMapperUnitTests {
 
 	private QueryMapper mapper;
 	private MongoMappingContext context;
 	private MappingMongoConverter converter;
 
-	@Mock MongoDatabaseFactory factory;
-
 	@BeforeEach
 	void beforeEach() {
 
+		MongoCustomConversions conversions = new MongoCustomConversions();
 		this.context = new MongoMappingContext();
+		this.context.setSimpleTypeHolder(conversions.getSimpleTypeHolder());
 
-		this.converter = new MappingMongoConverter(new DefaultDbRefResolver(factory), context);
+		this.converter = new MappingMongoConverter(NoOpDbRefResolver.INSTANCE, context);
+		this.converter.setCustomConversions(conversions);
 		this.converter.afterPropertiesSet();
 
 		this.mapper = new QueryMapper(converter);
@@ -1152,6 +1146,25 @@ void allowsUsingFieldPathsForPropertiesHavingCustomConversionRegistered() {
 				.isEqualTo(new org.bson.Document("address.street", "1007 Mountain Drive"));
 	}
 
+	@Test // GH-3783
+	void retainsId$InWithStringArray() {
+
+		org.bson.Document mappedQuery = mapper.getMappedObject(
+				org.bson.Document.parse("{ _id : { $in: [\"5b8bedceb1e0bfc07b008828\"]}}"),
+				context.getPersistentEntity(WithExplicitStringId.class));
+		assertThat(mappedQuery.get("_id")).isEqualTo(org.bson.Document.parse("{ $in: [\"5b8bedceb1e0bfc07b008828\"]}"));
+	}
+
+	@Test // GH-3783
+	void mapsId$InInToObjectIds() {
+
+		org.bson.Document mappedQuery = mapper.getMappedObject(
+				org.bson.Document.parse("{ _id : { $in: [\"5b8bedceb1e0bfc07b008828\"]}}"),
+				context.getPersistentEntity(ClassWithDefaultId.class));
+		assertThat(mappedQuery.get("_id"))
+				.isEqualTo(org.bson.Document.parse("{ $in: [ {$oid: \"5b8bedceb1e0bfc07b008828\" } ]}"));
+	}
+
 	class WithDeepArrayNesting {
 
 		List<WithNestedArray> level0;
@@ -1215,6 +1228,18 @@ class Sample {
 		@Id private String foo;
 	}
 
+	class WithStringId {
+
+		@MongoId String id;
+		String name;
+	}
+
+	class WithExplicitStringId {
+
+		@MongoId(FieldType.STRING) String id;
+		String name;
+	}
+
 	class BigIntegerId {
 
 		@Id private BigInteger id;