when use tokio::spawn i meet problem anyone can help

[LinYUAN-code]

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let addr = "127.0.0.1:8080";
    let listener = TcpListener::bind(addr).await?;
    println!("mysql running on {}", addr);

    loop {
        let (mut socket, _) = listener.accept().await?;
        println!("connected {:?}", socket);
        tokio::spawn(async move {
            let mut buf = [0; 1024];
            let mut command_buffer = String::new();

            let parser = Arc::new(Mutex::new(gen_parser()));
            loop {
                let mut buffer = String::new();

                match socket.read(&mut buf).await {
                    // socket closed
                    Ok(0) => return,
                    Ok(n) => command_buffer.push_str(from_utf8(&buf[0..n]).unwrap()),
                    Err(e) => {
                        eprintln!("failed to read from socket; err = {:?}", e);
                        return;
                    }
                };
                while let Some(index) = command_buffer.find(';') {
                    let command = command_buffer.as_str()[0..=index].to_string();
                    command_buffer = command_buffer.as_str()[(index + 1)..].to_string();

                    println!("{:?}", parser.lock().await.parse(command));
                    if let Err(e) = socket.write_all("detect command".as_bytes()).await {
                        eprintln!("failed to write to socket; err = {:?}", e);
                        return;
                    }
                }
            }
        });
    }
}

error:
future cannot be sent between threads safely
within impl chumsky::Parser<char, Statement, Error = Simple<char>>, the trait Send is not implemented for Rc<recursive::OnceCell<Box<(dyn chumsky::Parser<char, Expr, Error = Simple<char>> + 'static)>>>

[wackbyte]

I think this requires you to enable the sync feature flag for chumksy.

[LinYUAN-code]

I think this requires you to enable the sync feature flag for chumksy.

How could i do this? sor, i am new to rust.

[wackbyte]

In your Cargo.toml, you can enable feature flags on a dependency by doing something like:

[dependencies]
chumsky = { version = "0.9", features = ["sync"] } 

[zesterer]

Be aware that the sync feature will likely require some kind of revising before 1.0 is stable. See #543 for more information. It's not yet clear whether that revision will be breaking or not.

[nothendev]

I don't think the parser lock is even needed here, you could just have an Arc of the parser or you could just not store it and execute gen_parser inline, you won't even need the sync feature

[zesterer]

Unfortunately many parsers (like Recursive) are not Send + Sync because they use Rc internally. I do think that this requirement could be strengthened without issue though, since the added cost of an atomic increment would only apply on parser creation. That said, Recursive specifically might require some sort of lock internally due to the behaviour of .define(...), although interestingly #494 might actually provide a solution to this.