From 93f8cb8df2bb0dceb7921556165a8ed8efed9151 Mon Sep 17 00:00:00 2001 From: Carl Lerche Date: Mon, 21 Sep 2020 14:29:22 -0700 Subject: sync: fix missing notification during mpsc close (#2854) When the mpsc channel receiver closes the channel, receiving should return `None` once all in-progress sends have completed. When a sender reserves capacity, this prevents the receiver from fully shutting down. Previously, when the sender, after reserving capacity, dropped without sending a message, the receiver was not notified. This results in blocking the shutdown process until all sender handles drop. This patch adds a receiver notification when the channel is both closed and all outstanding sends have completed. --- tokio/tests/sync_mpsc.rs | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) (limited to 'tokio/tests') diff --git a/tokio/tests/sync_mpsc.rs b/tokio/tests/sync_mpsc.rs index f571a71c..919bddbf 100644 --- a/tokio/tests/sync_mpsc.rs +++ b/tokio/tests/sync_mpsc.rs @@ -534,3 +534,25 @@ async fn blocking_send_async() { let (mut tx, _rx) = mpsc::channel::<()>(1); let _ = tx.blocking_send(()); } + +#[test] +fn ready_close_cancel_bounded() { + use futures::future::poll_fn; + + let (mut tx, mut rx) = mpsc::channel::<()>(100); + let _tx2 = tx.clone(); + + { + let mut ready = task::spawn(async { poll_fn(|cx| tx.poll_ready(cx)).await }); + assert_ready_ok!(ready.poll()); + } + + rx.close(); + + let mut recv = task::spawn(async { rx.recv().await }); + assert_pending!(recv.poll()); + + drop(tx); + + assert!(recv.is_woken()); +} -- cgit v1.2.3