keep a copy of channel 0 when initiating connetion closure

The channel 0 will get removed once the connection has finished closing (as it is still used during the process).
This avoids hitting an error when removing it while we already did.

Fixes #382

Signed-off-by: Marc-Antoine Perennou <Marc-Antoine@Perennou.com>

src/channels.rs

@@ -122,7 +122,7 @@ impl Channels {
 
     pub(crate) fn set_connection_closed(&self, error: Error) {
         self.connection_status.set_state(ConnectionState::Closed);
-        for (id, channel) in self.inner.lock().channels.drain() {
+        for (id, channel) in self.inner.lock().take_channels().drain() {
             self.frames.clear_expected_replies(id, error.clone());
             channel.set_closed(error.clone());
         }
@@ -140,7 +140,7 @@ impl Channels {
         self.connection_status.set_state(ConnectionState::Error);
         self.frames.drop_pending(error.clone());
         self.error_handler.on_error(error.clone());
-        for (id, channel) in self.inner.lock().channels.drain() {
+        for (id, channel) in self.inner.lock().take_channels().drain() {
             self.frames.clear_expected_replies(id, error.clone());
             channel.set_connection_error(error.clone());
         }
@@ -369,4 +369,13 @@ impl Inner {
         }
         Err(Error::ChannelsLimitReached)
     }
+
+    fn take_channels(&mut self) -> HashMap<ChannelId, Channel> {
+        let channel0 = self.channels.get(&0).cloned();
+        let channels = std::mem::take(&mut self.channels);
+        if let Some(channel0) = channel0 {
+            self.channels.insert(0, channel0);
+        }
+        channels
+    }
 }