io_loop: clear serialized frames on exit

When we hit an error, we properly cleared these, but on the 'correct' exit path, we didn't.
Let's use the frames poison as error if any, or fallback to ConnectionClosed

Fixes #409

Signed-off-by: Marc-Antoine Perennou <[email protected]>

src/frames.rs

@@ -92,6 +92,10 @@ impl Frames {
     pub(crate) fn clear_expected_replies(&self, channel_id: ChannelId, error: Error) {
         self.inner.lock().clear_expected_replies(channel_id, error);
     }
+
+    pub(crate) fn poison(&self) -> Option<Error> {
+        self.inner.lock().poison.clone()
+    }
 }
 
 #[derive(Default)]

src/io_loop.rs

@@ -170,6 +170,11 @@ impl IoLoop {
                         }
                     }
                     self.heartbeat.cancel();
+                    self.clear_serialized_frames(
+                        self.frames.poison().unwrap_or_else(|| {
+                            Error::InvalidConnectionState(ConnectionState::Closed)
+                        }),
+                    );
                     let internal_rpc = self.internal_rpc.clone();
                     if self.killswitch.killed() {
                         internal_rpc.register_internal_future(std::future::poll_fn(move |cx| {
@@ -247,12 +252,16 @@ impl IoLoop {
         }
         self.stop();
         self.channels.set_connection_error(error.clone());
+        self.clear_serialized_frames(error.clone());
+        Err(error)
+    }
+
+    fn clear_serialized_frames(&mut self, error: Error) {
         for (_, resolver) in std::mem::take(&mut self.serialized_frames) {
             if let Some(resolver) = resolver {
                 resolver.swear(Err(error.clone()));
             }
         }
-        Err(error)
     }
 
     fn attempt_flush(&mut self, writable_context: &mut Context<'_>) -> Result<()> {