Use primary error as context of NoWitnessLeft error (#477)

informalsystems · Jul 24, 2020 · cf4a28d · cf4a28d
1 parent 548d76d
commit cf4a28d
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Showing 2 changed files with 14 additions and 9 deletions.
diff --git a/light-client/src/peer_list.rs b/light-client/src/peer_list.rs
@@ -138,7 +138,10 @@ impl<T> PeerList<T> {
     /// ## Errors
     /// - If there are no witness left, returns `ErrorKind::NoWitnessLeft`.
     #[post(ret.is_ok() ==> Self::invariant(&self))]
-    pub fn replace_faulty_primary(&mut self) -> Result<PeerId, Error> {
+    pub fn replace_faulty_primary(
+        &mut self,
+        primary_error: Option<Error>,
+    ) -> Result<PeerId, Error> {
         self.faulty_nodes.insert(self.primary);
 
         if let Some(new_primary) = self.witnesses.iter().next().copied() {
@@ -147,7 +150,11 @@ impl<T> PeerList<T> {
             return Ok(new_primary);
         }
 
-        bail!(ErrorKind::NoWitnessLeft)
+        if let Some(err) = primary_error {
+            bail!(ErrorKind::NoWitnessLeft.context(err))
+        } else {
+            bail!(ErrorKind::NoWitnessLeft)
+        }
     }
 }
 
@@ -283,7 +290,7 @@ mod tests {
     fn replace_faulty_primary_succeeds() {
         let mut peer_list = dummy_peer_list();
         assert_eq!(peer_list.primary(), &1);
-        let new_primary = peer_list.replace_faulty_primary();
+        let new_primary = peer_list.replace_faulty_primary(None);
         assert_eq!(new_primary.unwrap(), b());
         assert_eq!(peer_list.primary(), &2);
         assert!(peer_list.witnesses_ids().is_empty());
@@ -292,8 +299,8 @@ mod tests {
     #[test]
     fn replace_faulty_primary_fails_if_no_more_witnesses() {
         let mut peer_list = dummy_peer_list();
-        let _ = peer_list.replace_faulty_primary().unwrap();
-        let new_primary = peer_list.replace_faulty_primary();
+        let _ = peer_list.replace_faulty_primary(None).unwrap();
+        let new_primary = peer_list.replace_faulty_primary(None);
         assert_eq!(
             new_primary.err().map(|e| e.kind().clone()),
             Some(ErrorKind::NoWitnessLeft)

diff --git a/light-client/src/supervisor.rs b/light-client/src/supervisor.rs
@@ -253,11 +253,9 @@ impl Supervisor {
                 }
             }
             // Verification failed
-            Err(_err) => {
-                // TODO: Log/record error
-
+            Err(err) => {
                 // Swap primary, and continue with new primary, if there is any witness left.
-                self.peers.replace_faulty_primary()?;
+                self.peers.replace_faulty_primary(Some(err))?;
                 self.verify(height)
             }
         }