fix: clear peer_mgr candidate post pfx change.

We do not carry over candidates into new prefix, cos its not expected to succeed after merge if the voters arent super-majority in new pfx. This change clears the candidate state in peer_mgr accordingly.

src/peer_manager.rs

@@ -360,6 +360,11 @@ impl PeerManager {
         );
     }
 
+    /// Removes any existing candidate
+    pub fn clear_candidate(&mut self) {
+        self.candidate = Candidate::None;
+    }
+
     /// Adds a potential candidate to the candidate list setting its state to `VotedFor`.  If
     /// another ongoing (i.e. unapproved) candidate exists, or if the candidate is unsuitable for
     /// adding to our section, returns an error.

src/states/node.rs

@@ -991,6 +991,10 @@ impl Node {
         self.gen_pfx_info = Some(gen_pfx_info);
         let _ = self.init_parsec()?; // We don't reset the chain on prefix change.
 
+        // Clear any pending candidate
+        // TODO: maybe also disconnect if currently connected.
+        self.peer_mgr.clear_candidate();
+
         let neighbour_infos: Vec<_> = self.chain.neighbour_infos().cloned().collect();
         for ni in neighbour_infos {
             if sibling_pfx != *ni.prefix() {
@@ -1021,8 +1025,6 @@ impl Node {
         cached_events
             .iter()
             .filter(|event| match **event {
-                // FIXME: once has_unconsensused_observations only considers votes than Obs
-                // can enable this similar to Offline event
                 NetworkEvent::Online(_pub_id, _) => false,
                 NetworkEvent::Offline(pub_id) => {
                     our_pfx.matches(pub_id.name()) && !completed_events.contains(event)

tests/mock_crust/churn.rs

@@ -155,7 +155,7 @@ fn random_churn<R: Rng>(
     let len = nodes.len();
     let section_count = count_sections(nodes);
     if section_count > 1 && !rng.gen_weighted_bool(section_count as u32) {
-        // Use min_sec_size than section size to prevent collapsing any groups.
+        // Use min_sec_size rather than section size to prevent collapsing any groups.
         let max_drop = (nodes[0].chain().min_sec_size() - 1)
             * (QUORUM_DENOMINATOR - QUORUM_NUMERATOR)
             / QUORUM_DENOMINATOR;