Hello,

Could bsoncxx::document::element::get_() functions - like get_oid(), get_double(), etc. -  throw a *bsoncxx::exception{error_code::k_unset_element} when the element is invalid ?
Currently, a BSON_ASSERT() abort the program in that case.

This would allow to do something like that :

try {

  myOID          = documentView["_id"].get_oid().value;
  myIntegerValue = documentView["count"].get_int32().value;

} catch (const std::exception& e) {

  if (e.code() == bsoncxx::error_code::k_unset_element) {

    throwIfFieldElementUnset(documentView, "_id");
    throwIfFieldElementUnset(documentView, "count");

  } else {
    
    throw;
  }
}

Also, it would be safer for case where the programmer wrongly use these methods on an invalid element : instead of aborting. exceptions would probably already be handled.