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

pom.xml

@@ -5,7 +5,7 @@
 
 	<groupId>org.springframework.data</groupId>
 	<artifactId>spring-data-mongodb-parent</artifactId>
-	<version>3.3.0-SNAPSHOT</version>
+	<version>3.3.0-3783-SNAPSHOT</version>
 	<packaging>pom</packaging>
 
 	<name>Spring Data MongoDB</name>

spring-data-mongodb-benchmarks/pom.xml

@@ -7,7 +7,7 @@
 	<parent>
 		<groupId>org.springframework.data</groupId>
 		<artifactId>spring-data-mongodb-parent</artifactId>
-		<version>3.3.0-SNAPSHOT</version>
+		<version>3.3.0-3783-SNAPSHOT</version>
 		<relativePath>../pom.xml</relativePath>
 	</parent>
 

spring-data-mongodb-distribution/pom.xml

@@ -14,7 +14,7 @@
 	<parent>
 		<groupId>org.springframework.data</groupId>
 		<artifactId>spring-data-mongodb-parent</artifactId>
-		<version>3.3.0-SNAPSHOT</version>
+		<version>3.3.0-3783-SNAPSHOT</version>
 		<relativePath>../pom.xml</relativePath>
 	</parent>
 

spring-data-mongodb/pom.xml

@@ -11,7 +11,7 @@
 	<parent>
 		<groupId>org.springframework.data</groupId>
 		<artifactId>spring-data-mongodb-parent</artifactId>
-		<version>3.3.0-SNAPSHOT</version>
+		<version>3.3.0-3783-SNAPSHOT</version>
 		<relativePath>../pom.xml</relativePath>
 	</parent>
 

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

@@ -778,7 +778,8 @@ 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

@@ -33,8 +33,7 @@
 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.junit.jupiter.MockitoExtension;
+
 import org.springframework.core.convert.converter.Converter;
 import org.springframework.data.annotation.Id;
 import org.springframework.data.annotation.Transient;
@@ -83,9 +82,12 @@ public class QueryMapperUnitTests {
 	@BeforeEach
 	void beforeEach() {
 
+		MongoCustomConversions conversions = new MongoCustomConversions();
 		this.context = new MongoMappingContext();
+		this.context.setSimpleTypeHolder(conversions.getSimpleTypeHolder());
 
 		this.converter = new MappingMongoConverter(NoOpDbRefResolver.INSTANCE, context);
+		this.converter.setCustomConversions(conversions);
 		this.converter.afterPropertiesSet();
 
 		this.mapper = new QueryMapper(converter);
@@ -1335,6 +1337,25 @@ void mapStringIdFieldProjection() {
 		assertThat(mappedFields).containsEntry("_id", 1);
 	}
 
+	@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;
@@ -1404,6 +1425,12 @@ class WithStringId {
 		String name;
 	}
 
+	class WithExplicitStringId {
+
+		@MongoId(FieldType.STRING) String id;
+		String name;
+	}
+
 	class BigIntegerId {
 
 		@Id private BigInteger id;