Updated threshold logic to use weights instead of amount of signers

node/actors/bft/src/leader/replica_commit.rs

@@ -70,7 +70,7 @@ impl StateMachine {
             });
         }
 
-        // Check that the message signer is in the validator set.
+        // Check that the message signer is in the validator committee.
         if !self.config.genesis().validators.contains(author) {
             return Err(Error::NonValidatorSigner {
                 signer: author.clone(),
@@ -140,8 +140,9 @@ impl StateMachine {
             by_proposal.entry(msg.msg.proposal).or_default().push(msg);
         }
         let threshold = self.config.genesis().validators.threshold();
-        let Some((_, replica_messages)) =
-            by_proposal.into_iter().find(|(_, v)| v.len() >= threshold)
+        let Some((_, replica_messages)) = by_proposal
+            .into_iter()
+            .find(|(_, v)| self.config.genesis().validators.weight_from_msgs(v) >= threshold)
         else {
             return Ok(());
         };

node/actors/bft/src/leader/replica_prepare.rs

@@ -144,21 +144,24 @@ impl StateMachine {
             .insert(author.clone(), signed_message);
 
         // Now we check if we have enough messages to continue.
-        let num_messages = self
+        let messages: Vec<&validator::Signed<validator::ReplicaPrepare>> = self
             .prepare_message_cache
             .get(&message.view.number)
             .unwrap()
-            .len();
+            .values()
+            .collect();
 
-        if num_messages < self.config.genesis().validators.threshold() {
+        let weight = self.config.genesis().validators.weight_from_msgs(&messages);
+        let threshold = self.config.genesis().validators.threshold();
+        if weight < threshold {
             return Ok(());
         }
 
         // Remove replica prepare messages for this view, so that we don't create a new block proposal
         // for this same view if we receive another replica prepare message after this.
         self.prepare_message_cache.remove(&message.view.number);
 
-        debug_assert_eq!(num_messages, self.config.genesis().validators.threshold());
+        debug_assert!(weight >= threshold);
 
         // ----------- Update the state machine --------------
 

node/libs/roles/src/validator/messages/consensus.rs

@@ -83,6 +83,9 @@ pub struct ValidatorCommittee {
 }
 
 impl ValidatorCommittee {
+    /// Required weight to verify signatures.
+    const THRESHOLD: usize = 100_00;
+
     /// Creates a new ValidatorCommittee from a list of validator public keys.
     pub fn new(validators: impl IntoIterator<Item = WeightedValidator>) -> anyhow::Result<Self> {
         let mut set = BTreeSet::new();
@@ -155,7 +158,7 @@ impl ValidatorCommittee {
 
     /// Signature threshold for this validator set.
     pub fn threshold(&self) -> usize {
-        threshold(self.len())
+        Self::THRESHOLD
     }
 
     /// Maximal number of faulty replicas allowed in this validator set.
@@ -164,14 +167,26 @@ impl ValidatorCommittee {
     }
 
     /// Compute the sum of signers weights.
-    pub fn weight(&self, signers: Signers) -> usize {
+    pub fn weight_from_signers(&self, signers: Signers) -> usize {
         self.weights
             .iter()
             .enumerate()
             .filter(|(i, _)| signers.0[*i])
             .map(|(_, weight)| weight)
             .sum()
     }
+
+    /// Compute the sum of signers weights.
+    pub fn weight_from_msgs<T: Variant<Msg>>(&self, signed: &Vec<&validator::Signed<T>>) -> usize {
+        signed
+            .iter()
+            .map(|s| {
+                self.weights[self
+                    .index(&s.key)
+                    .expect("Signer is not in validator committee")]
+            })
+            .sum()
+    }
 }
 
 /// Calculate the consensus threshold, the minimum number of votes for any consensus action to be valid,

node/libs/roles/src/validator/messages/leader_commit.rs

@@ -41,12 +41,12 @@ pub enum CommitQCVerifyError {
     /// Bad signer set.
     #[error("signers set doesn't match genesis")]
     BadSignersSet,
-    /// Not enough signers.
-    #[error("not enough signers: got {got}, want {want}")]
-    NotEnoughSigners {
-        /// Got signers.
+    /// Weight not reached.
+    #[error("Signers have not reached wanted weight: got {got}, want {want}")]
+    WeightNotReached {
+        /// Got weight.
         got: usize,
-        /// Want signers.
+        /// Want weight.
         want: usize,
     },
     /// Bad signature.
@@ -101,15 +101,11 @@ impl CommitQC {
         }
 
         // Verify the signer's weights is enough.
-        // TODO replace threshold check
-        let _weight = genesis.validators.weight(self.signers.clone());
-
-        // Verify that we have enough signers.
-        let num_signers = self.signers.count();
+        let weight = genesis.validators.weight_from_signers(self.signers.clone());
         let threshold = genesis.validators.threshold();
-        if num_signers < threshold {
-            return Err(Error::NotEnoughSigners {
-                got: num_signers,
+        if weight < threshold {
+            return Err(Error::WeightNotReached {
+                got: weight,
                 want: threshold,
             });
         }

node/libs/roles/src/validator/messages/leader_prepare.rs

@@ -30,12 +30,12 @@ pub enum PrepareQCVerifyError {
     /// Bad message format.
     #[error(transparent)]
     BadFormat(anyhow::Error),
-    /// Not enough signers.
-    #[error("not enough signers: got {got}, want {want}")]
-    NotEnoughSigners {
-        /// Got signers.
+    /// Weight not reached.
+    #[error("Signers have not reached wanted weight: got {got}, want {want}")]
+    WeightNotReached {
+        /// Got weight.
         got: usize,
-        /// Want signers.
+        /// Want weight.
         want: usize,
     },
     /// Bad signature.
@@ -127,14 +127,12 @@ impl PrepareQC {
             sum |= signers;
         }
 
-        let weight = genesis.validators.weight(sum.clone());
-        dbg!(weight);
-
-        // Verify that we have enough signers.
+        // Verify the signer's weights is enough.
+        let weight = genesis.validators.weight_from_signers(sum.clone());
         let threshold = genesis.validators.threshold();
-        if sum.count() < threshold {
-            return Err(Error::NotEnoughSigners {
-                got: sum.count(),
+        if weight < threshold {
+            return Err(Error::WeightNotReached {
+                got: weight,
                 want: threshold,
             });
         }

node/libs/roles/src/validator/tests.rs

@@ -221,7 +221,7 @@ fn test_commit_qc() {
         } else {
             assert_matches!(
                 qc.verify(&setup1.genesis),
-                Err(Error::NotEnoughSigners { .. })
+                Err(Error::WeightNotReached { .. })
             );
         }
 
@@ -265,7 +265,7 @@ fn test_prepare_qc() {
         } else {
             assert_matches!(
                 qc.verify(&setup1.genesis),
-                Err(Error::NotEnoughSigners { .. })
+                Err(Error::WeightNotReached { .. })
             );
         }
 
@@ -306,6 +306,9 @@ fn test_validator_committee_weights() {
         let key = &setup.keys[n];
         qc.add(&key.sign_msg(msg.clone()), &setup.genesis);
         let signers = &qc.map[&msg];
-        assert_eq!(genesis.validators.weight(signers.clone()), *weight);
+        assert_eq!(
+            genesis.validators.weight_from_signers(signers.clone()),
+            *weight
+        );
     }
 }