sync: don't panic in oneshot::try_recv (#3674)

tokio-rs · Apr 4, 2021 · f93bc9b · f93bc9b
1 parent b05b9a1
commit f93bc9b
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Showing 2 changed files with 13 additions and 1 deletion.
diff --git a/tokio/src/sync/oneshot.rs b/tokio/src/sync/oneshot.rs
@@ -672,7 +672,7 @@ impl<T> Receiver<T> {
                 return Err(TryRecvError::Empty);
             }
         } else {
-            panic!("called after complete");
+            Err(TryRecvError::Closed)
         };
 
         self.inner = None;

diff --git a/tokio/tests/sync_oneshot.rs b/tokio/tests/sync_oneshot.rs
@@ -2,6 +2,7 @@
 #![cfg(feature = "full")]
 
 use tokio::sync::oneshot;
+use tokio::sync::oneshot::error::TryRecvError;
 use tokio_test::*;
 
 use std::future::Future;
@@ -190,6 +191,17 @@ fn close_after_recv() {
     rx.close();
 }
 
+#[test]
+fn try_recv_after_completion() {
+    let (tx, mut rx) = oneshot::channel::<i32>();
+
+    tx.send(17).unwrap();
+
+    assert_eq!(17, rx.try_recv().unwrap());
+    assert_eq!(Err(TryRecvError::Closed), rx.try_recv());
+    rx.close();
+}
+
 #[test]
 fn drops_tasks() {
     let (mut tx, mut rx) = oneshot::channel::<i32>();