internal error: entered unreachable code: reader indicated readiness but then returned pending

[joshbenz]

Hello all, this is a neat crate and LOVE the nom crate. I am considering using this crate in conjunction with https://crates.io/crates/async-ssh2-lite crate. I have an AsyncStream<tokio::net::TcpStream> and I get the following error.

thread 'main' panicked at 'internal error: entered unreachable code: reader indicated readiness but then returned pending', /home/jbenz/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-util-0.3.24/src/io/fill_buf.rs:41:21
stack backtrace:
   0: rust_begin_unwind
             at /rustc/4b91a6ea7258a947e59c6522cd5898e7c0a6a88f/library/std/src/panicking.rs:584:5
   1: core::panicking::panic_fmt
             at /rustc/4b91a6ea7258a947e59c6522cd5898e7c0a6a88f/library/core/src/panicking.rs:142:14
   2: core::panicking::unreachable_display
             at /rustc/4b91a6ea7258a947e59c6522cd5898e7c0a6a88f/library/core/src/panicking.rs:63:5
   3: <futures_util::io::fill_buf::FillBuf<R> as core::future::future::Future>::poll
             at /home/jbenz/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-util-0.3.24/src/io/fill_buf.rs:41:21
   4: <nom_bufreader::async_bufreader::BufReader<R> as nom_bufreader::AsyncParse<O,E,P>>::parse::{{closure}}
             at /home/jbenz/.cargo/registry/src/github.com-1ecc6299db9ec823/nom-bufreader-0.2.0/src/lib.rs:266:36
   5: <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll
             at /rustc/4b91a6ea7258a947e59c6522cd5898e7c0a6a88f/library/core/src/future/mod.rs:91:19
   6: <core::pin::Pin<P> as core::future::future::Future>::poll
             at /rustc/4b91a6ea7258a947e59c6522cd5898e7c0a6a88f/library/core/src/future/future.rs:124:9
   7: flicli::channel::ChannelReader::read::{{closure}}
             at ./src/channel.rs:54:48
   8: <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll
             at /rustc/4b91a6ea7258a947e59c6522cd5898e7c0a6a88f/library/core/src/future/mod.rs:91:19
   9: flicli::main::{{closure}}
             at ./src/main.rs:18:35
  10: <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll
             at /rustc/4b91a6ea7258a947e59c6522cd5898e7c0a6a88f/library/core/src/future/mod.rs:91:19
  11: tokio::park::thread::CachedParkThread::block_on::{{closure}}
             at /home/jbenz/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.21.0/src/park/thread.rs:267:54
  12: tokio::coop::with_budget::{{closure}}
             at /home/jbenz/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.21.0/src/coop.rs:102:9
  13: std::thread::local::LocalKey<T>::try_with
             at /rustc/4b91a6ea7258a947e59c6522cd5898e7c0a6a88f/library/std/src/thread/local.rs:445:16
  14: std::thread::local::LocalKey<T>::with
             at /rustc/4b91a6ea7258a947e59c6522cd5898e7c0a6a88f/library/std/src/thread/local.rs:421:9
  15: tokio::coop::with_budget
             at /home/jbenz/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.21.0/src/coop.rs:95:5
  16: tokio::coop::budget
             at /home/jbenz/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.21.0/src/coop.rs:72:5
  17: tokio::park::thread::CachedParkThread::block_on
             at /home/jbenz/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.21.0/src/park/thread.rs:267:31
  18: tokio::runtime::enter::Enter::block_on
             at /home/jbenz/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.21.0/src/runtime/enter.rs:152:13
  19: tokio::runtime::scheduler::multi_thread::MultiThread::block_on
             at /home/jbenz/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.21.0/src/runtime/scheduler/multi_thread/mod.rs:79:9
  20: tokio::runtime::Runtime::block_on
             at /home/jbenz/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.21.0/src/runtime/mod.rs:492:44
  21: flicli::main
             at ./src/main.rs:19:5
  22: core::ops::function::FnOnce::call_once
             at /rustc/4b91a6ea7258a947e59c6522cd5898e7c0a6a88f/library/core/src/ops/function.rs:248:5
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

The code I am trying to work with is

                let mut chan = sess.channel_session().await?;
                chan.request_pty("xterm", None, Some((80, 24, 0, 0))).await?;
                chan.shell().await?;
                stdin = chan.stream(0);
                stdout = chan.stream(0);
                stdin.write(b"environment no more\nfile dir\n").await?;
                stdin.flush().await?;
                let mut reader = BufReader::new(stdout.compat);
                let m = reader.parse(Self::method).await;

Sometimes the code runs successfully, but mostly it fails with the above error. I am unsure of if this is due to using AsyncStream (which does implement futures::AsyncRead) or if this is an issue with this crate. It's not a big deal if what I am trying to do is not possible, i will just go a different direction with my code, but I thought I would bring it up anyways.

Thanks!

[Qix-]

I'm also running into this problem, unfortunately. This crate is quite old, I wonder if something has changed.

Currently facing this with async-std and the first result is this issue (I am trying to use this crate too).