Socket leak starting with async-std 1.6.4

[tailhook]

This example:

async fn connect() {
    loop {
        match async_std::os::unix::net::UnixStream::connect("./non-existent").await {
            Ok(_) => unreachable!(),
            Err(e) if e.kind() == std::io::ErrorKind::NotFound => {}
            Err(e) => panic!("Unexpected error: {}", e),
        }
    }
}

fn main() {
    async_std::task::block_on(connect());
}

Crashes with thread 'main' panicked at 'Unexpected error: Too many open files (os error 24)', examples/test-connect.rs:6:23 while it shouldn't and didn't crash in 1.6.3. The crash means file descriptors are leaking (maybe because of a memory leak, but I didn't investigate further).

This file descriptor leak is still there in 1.6.5 and master as of f09fa42.

[yoshuawuyts]

Oh no; thanks for the report! This may be related to #888, which was tracked back to the changes in the latest async-io. Would you mind filing an issue with the async-io crate as well?

[yoshuawuyts]

This may also be related to smol-rs/async-io#31; not sure.

[tailhook]

So smol-rs/async-io#31 is fixed and this bug is still there on async-io 1.1.5.

The bug was introduced when socket2 got replaced with nb-connect, and the bug was in that nb-connect would not auto-close the socket if an error occurred before the end of connect().

I pushed a fix a moment ago in nb-connect v1.0.1. If you do cargo update, the problem should go away.

Thanks for the bug report!

[tailhook]

Yes it works. Thanks for the fix!