Closed
Description
Version
tokio v1.19.2, tokio master (4daeea8)
Platform
Windows 10 64 bit
Description
Attempting to resubscribe to a closed broadcast receiver will hang on calls to recv.
I tried this code:
Cargo.toml:
[package]
name = "tokio-broadcast-bug"
version = "0.0.0"
edition = "2021"
[dependencies]
tokio = { version = "1.19.2", features = ["full"] }main.rs:
#[tokio::main]
async fn main() {
let (tx, rx) = tokio::sync::broadcast::channel::<u32>(4);
drop(tx);
let mut rx_clone = rx.resubscribe();
drop(rx);
loop {
match rx_clone.recv().await {
Ok(msg) => {
println!("{}", msg);
}
Err(tokio::sync::broadcast::error::RecvError::Closed) => {
println!("Closed");
break;
}
Err(tokio::sync::broadcast::error::RecvError::Lagged(n)) => {
println!("Lagged by {n} messages");
}
}
}
println!("Done");
}I expected to see this happen:
The loop should exit.
Instead, this happened:
The program hangs indefinitely.
Furthermore, replacing the loop with a call to try_recv yields an Empty error instead of a Closed error.