Fix a race condition in Derived Field parsing from search request

Signed-off-by: Rishabh Maurya <[email protected]>

Author: rishabhmaurya

server/src/main/java/org/opensearch/index/mapper/DefaultDerivedFieldResolver.java

@@ -12,6 +12,7 @@
 import org.apache.logging.log4j.Logger;
 import org.opensearch.common.regex.Regex;
 import org.opensearch.index.query.QueryShardContext;
+import org.opensearch.ingest.IngestDocument;
 import org.opensearch.script.Script;
 
 import java.io.IOException;
@@ -189,9 +190,10 @@ private void initDerivedFieldTypes(Map<String, Object> derivedFieldsObject, List
 
     private Map<String, DerivedFieldType> getAllDerivedFieldTypeFromObject(Map<String, Object> derivedFieldObject) {
         Map<String, DerivedFieldType> derivedFieldTypes = new HashMap<>();
+        // deep copy of derivedFieldObject is required as DocumentMapperParser modifies the map
         DocumentMapper documentMapper = queryShardContext.getMapperService()
             .documentMapperParser()
-            .parse(DerivedFieldMapper.CONTENT_TYPE, derivedFieldObject);
+            .parse(DerivedFieldMapper.CONTENT_TYPE, IngestDocument.deepCopyMap(derivedFieldObject));
         if (documentMapper != null && documentMapper.mappers() != null) {
             for (Mapper mapper : documentMapper.mappers()) {
                 if (mapper instanceof DerivedFieldMapper) {