we have a document that includes a collection with an array that is sometimes empty. If we access the database and iterate through the documents, the ones with empty arrays throw an exception when we use to_json().

example document:
{
"_id":

{ "$oid": "553ab2f6d7e9e61537efb919" }

,
"uid": "CA1236300671005",
"deviceType": "GX440",
"location": "",
"deviceData":

{ "ssid": "", "mdn": "", "imea": "990000561959919", "sim": "89148000000382974468", "firmwareVersion": "4.3.5.010B", "imsi": "311480038944334", "carrier": "VERIZON", "checkinInterval": 15 }

,
"checkinData": []
}

example code:
mongocxx::instance instance{};
std::string uri_string = "mongodb://-------.feeneywireless.com:27017";
mongocxx::client conn

{mongocxx::uri(uri_string)}

;

std::string dbname = "devices_db";
auto db = conn[dbname];

auto cursor = db["device"].find({});
for(auto&& doc : cursor) {
std::string teststring;
try

{ teststring = bsoncxx::to_json(doc); }

catch (exception e)

{ printf("error"); }

std:cout << teststring << std::endl;
}

Looking at bsoncxx->json.cpp there is no check for an empty array.
void visit_value(const types::b_array& value)

{ out << "[" << std::endl; stack.push_back(true); visit_children(value.value); pad(); out << "]"; }

I tried to add something along the lines of
void visit_value(const types::b_array& value) {
out << "[" << std::endl;
if(value.value.length != 0)

{ stack.push_back(true); visit_children(value.value); pad(); }

out << "]";
}
but couldn't figure out how to check for the empty array.

Thanks for your help.