Properly subtract the committee lookback range

ProvableHQ · Feb 15, 2024 · c78aaf5 · c78aaf5
1 parent b822aa8
commit c78aaf5
Show file tree

Hide file tree

Showing 2 changed files with 11 additions and 6 deletions.
diff --git a/ledger/src/advance.rs b/ledger/src/advance.rs
@@ -244,16 +244,18 @@ impl<N: Network, C: ConsensusStorage<N>> Ledger<N, C> {
                 let penultimate_round = subdag.anchor_round().saturating_sub(1);
                 // Get the round number for the previous committee. Note, we subtract 2 from odd rounds,
                 // because committees are updated in even rounds.
-                let committee_lookback_round = match penultimate_round % 2 == 0 {
+                let previous_penultimate_round = match penultimate_round % 2 == 0 {
                     true => penultimate_round.saturating_sub(1),
                     false => penultimate_round.saturating_sub(2),
                 };
+                let penultimate_committee_lookback_round =
+                    previous_penultimate_round.saturating_sub(Committee::<N>::COMMITTEE_LOOKBACK_RANGE);
                 // Retrieve the committee lookback.
-                let committee_lookback = self
-                    .get_committee_for_round(committee_lookback_round)?
-                    .ok_or(anyhow!("Failed to fetch committee for round {committee_lookback_round}"))?;
+                let previous_committee_lookback =
+                    self.get_committee_for_round(penultimate_committee_lookback_round)?
+                        .ok_or(anyhow!("Failed to fetch committee for round {penultimate_committee_lookback_round}"))?;
                 // Return the timestamp for the given committee lookback.
-                subdag.timestamp(&committee_lookback)
+                subdag.timestamp(&previous_committee_lookback)
             }
             None => OffsetDateTime::now_utc().unix_timestamp(),
         };

diff --git a/ledger/src/check_next_block.rs b/ledger/src/check_next_block.rs
@@ -99,10 +99,13 @@ impl<N: Network, C: ConsensusStorage<N>> Ledger<N, C> {
         let penultimate_round = block.round().saturating_sub(1);
         // Get the round number for the previous committee. Note, we subtract 2 from odd rounds,
         // because committees are updated in even rounds.
-        let penultimate_committee_lookback_round = match penultimate_round % 2 == 0 {
+        let previous_penultimate_round = match penultimate_round % 2 == 0 {
             true => penultimate_round.saturating_sub(1),
             false => penultimate_round.saturating_sub(2),
         };
+        // Get the previous committee lookback round.
+        let penultimate_committee_lookback_round =
+            previous_penultimate_round.saturating_sub(Committee::<N>::COMMITTEE_LOOKBACK_RANGE);
         // Retrieve the previous committee lookback.
         let previous_committee_lookback = self
             .get_committee_for_round(penultimate_committee_lookback_round)?