exit without error message

[tesla-cat]

Description

• without the try-catch block the code works
• but after adding that try-catch block, and after sending json data to the websocket server, the program exits without error message

void handle_message(uWS::WebSocket<false, true, PerSocketData>* ws,
                    string_view msg, uWS::OpCode code) {
    json data = json::parse(msg);

     try {
        OptimizerInput inp = data.get<OptimizerInput>();
    } catch (const exception& e) {
        cerr << e.what() << '\n';
    }

    ws->send(data.dump(), code);
}

Reproduction steps

• the websocket server can run
• aftering sending json data to it from the frontend, the server exits without an error message.
• everything works without the try-catch part of the code

Expected vs. actual results

expect to see error message

Minimal code example

No response

Error messages

No response

Compiler and operating system

windows, Visual Studio 16

Library version

nlohmann_json/3.11.2

Validation

• The bug also occurs if the latest version from the develop branch is used.
• I can successfully compile and run the unit tests.

[nlohmann]

Without knowing what any of the called functions do, there is little I can do. Can you provide a stacktrace?

[tesla-cat]

• thanks for the quick reply
• i added this line std::cout << boost::stacktrace::stacktrace();, but it still just exits without printing any error message

void handle_message(uWS::WebSocket<false, true, PerSocketData>* ws,
                    string_view msg, uWS::OpCode code) {
    json data = json::parse(msg);

    try {
        OptimizerInput inp = data.get<OptimizerInput>();
    } catch (const exception& e) {
        cerr << e.what() << '\n';
        std::cout << boost::stacktrace::stacktrace();
    }

    ws->send(data.dump(), code);
}

[nlohmann]

Can you set a breakpoint to the line where you call parse and find the last line before the exit?

(This looks like an issue in your setup - the library throws exceptions inherited from std::exception, and so far we never saw an issue.

[tesla-cat]

the exit is caused by OptimizerInput inp = data.get<OptimizerInput>(); because everything works after removing it

[nlohmann]

Can you then debug into it? get does not throw too many exceptions.