DATAMONGO-1605 - Retain type of SpEL expression result when used in @Query.

Fix issue where any result of a SpEL expression had been treated as quoted String within the resulting MongoDB query.

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/query/ExpressionEvaluatingParameterBinder.java

@@ -170,6 +170,12 @@ class ExpressionEvaluatingParameterBinder {
 
 		} else {
 
+			if (isExpression) {
+
+				buffer.deleteCharAt(quotationMarkIndex);
+				return;
+			}
+
 			if (quotationMark == '\'') {
 				buffer.replace(quotationMarkIndex, quotationMarkIndex + 1, "\"");
 			}
@@ -199,7 +205,7 @@ class ExpressionEvaluatingParameterBinder {
 				return (String) value;
 			}
 
-			return QuotedString.unquote(JSON.serialize(value));
+			return binding.isExpression() ? JSON.serialize(value) : QuotedString.unquote(JSON.serialize(value));
 		}
 
 		if (value instanceof byte[]) {
@@ -213,6 +219,10 @@ class ExpressionEvaluatingParameterBinder {
 			return base64representation;
 		}
 
+		if (binding.isExpression() && value instanceof String) {
+			return "\"" + JSON.serialize(value) + "\"";
+		}
+
 		return JSON.serialize(value);
 	}
 

spring-data-mongodb/src/test/java/org/springframework/data/mongodb/repository/query/StringBasedMongoQueryUnitTests.java

@@ -581,6 +581,26 @@ public class StringBasedMongoQueryUnitTests {
 				is((DBObject) JSON.parse("{ 'lastname' : { '$regex' : '^(calamity|John regalia|regalia)'} }")));
 	}
 
+	@Test // DATAMONGO-1605
+	public void findUsingSpelShouldRetainParameterType() throws Exception {
+
+		StringBasedMongoQuery mongoQuery = createQueryForMethod("findByUsingSpel", Object.class);
+		ConvertingParameterAccessor accessor = StubParameterAccessor.getAccessor(converter, 100.01D);
+
+		org.springframework.data.mongodb.core.query.Query query = mongoQuery.createQuery(accessor);
+		assertThat(query.getQueryObject(), is((DBObject) new BasicDBObject().append("arg0", 100.01D)));
+	}
+
+	@Test // DATAMONGO-1605
+	public void findUsingSpelShouldRetainNullValues() throws Exception {
+
+		StringBasedMongoQuery mongoQuery = createQueryForMethod("findByUsingSpel", Object.class);
+		ConvertingParameterAccessor accessor = StubParameterAccessor.getAccessor(converter, new Object[]{null});
+
+		org.springframework.data.mongodb.core.query.Query query = mongoQuery.createQuery(accessor);
+		assertThat(query.getQueryObject(), is((DBObject) new BasicDBObject().append("arg0", null)));
+	}
+
 	private StringBasedMongoQuery createQueryForMethod(String name, Class<?>... parameters) throws Exception {
 
 		Method method = SampleRepository.class.getMethod(name, parameters);
@@ -669,5 +689,8 @@ public class StringBasedMongoQueryUnitTests {
 
 		@Query("{ 'lastname' : { '$regex' : '^(?0|John ?1|?1)'} }") // use spel or some regex string this is fucking bad
 		Person findByLastnameRegex(String lastname, String alternative);
+
+		@Query("{ arg0 : ?#{[0]} }")
+		List<Person> findByUsingSpel(Object arg0);
 	}
 }