Fix remote path status state

Author: flub

quinn-proto/src/connection/mod.rs

@@ -570,6 +570,16 @@ impl Connection {
         }
     }
 
+    /// Returns the remote path status
+    // TODO(flub): Probably should also be some kind of path event?  Not even sure if I like
+    //    this as an API, but for now it allows me to write a test easily.
+    // TODO(flub): Technically this should be a Result<Option<PathSTatus>>?
+    pub fn remote_path_status(&self, path_id: PathId) -> Option<PathStatus> {
+        self.paths
+            .get(&path_id)
+            .and_then(|path| path.data.status.remote_status)
+    }
+
     /// Gets the [`PathData`] for a known [`PathId`].
     ///
     /// Will panic if the path_id does not reference any known path.

quinn-proto/src/connection/paths.rs

@@ -487,7 +487,7 @@ pub(super) struct PathStatusState {
     /// This is the number of the *next* path status frame to be sent.
     pub(super) local_seq: VarInt,
     /// The status set by the remote
-    pub(super) remote_status: PathStatus,
+    pub(super) remote_status: Option<PathStatus>,
     /// Remote sequence number, for both PATH_AVAIALABLE and PATH_BACKUP
     pub(super) remote_seq: Option<VarInt>,
 }
@@ -500,8 +500,8 @@ impl PathStatusState {
             return;
         }
         self.remote_seq = Some(seq);
-        let prev = std::mem::replace(&mut self.remote_status, status);
-        if prev != status {
+        let prev = std::mem::replace(&mut self.remote_status, Some(status));
+        if prev != Some(status) {
             debug!(?status, ?seq, "remote changed path status");
         }
     }

quinn-proto/src/tests/multipath.rs

@@ -96,7 +96,6 @@ fn path_status() {
     let _guard = subscribe();
     let (mut pair, client_ch, server_ch) = multipath_pair();
 
-    info!("client sets PATH_BACKUP");
     let client_conn = pair.client_conn_mut(client_ch);
     let prev_status = client_conn
         .set_path_status(PathId::ZERO, PathStatus::Backup)
@@ -108,15 +107,7 @@ fn path_status() {
 
     let server_conn = pair.server_conn_mut(server_ch);
     assert_eq!(
-        server_conn.path_status(PathId::ZERO).unwrap(),
+        server_conn.remote_path_status(PathId::ZERO).unwrap(),
         PathStatus::Backup
     );
-
-    info!("server sets PATH_AVAILABLE");
-    server_conn
-        .set_path_status(PathId::ZERO, PathStatus::Available)
-        .unwrap();
-
-    // Send the frame to the client
-    pair.drive()
 }