Insertion of document with duplicate fields permitted in C++

Using the C++ driver, nothing prevents a user from inserting a document that has two fields which share a name. I don't believe that the behavior of future updates on this document is documented or well-defined (as a sidenote, operating on this document can't crash the server, right?).

See:

> db.test.find()

{ "_id" : ObjectId("5058f25f7d54ac9bc09d4e57"), "a" : 0, "a" : 0 }

>

as a product of:

#include "mongo/client/dbclient.h"

using namespace mongo;

int main() {

  DBClientConnection c;

  c.connect("localhost");

  BSONObj bsonData = BSON("a" << 0 << "a" << 0);

  c.insert("test.test", bsonData);

  return 0;

}