Add epoch to threshold functions to allow dynamically sized committees

crates/hotshot/src/traits/election/randomized_committee.rs

@@ -163,17 +163,17 @@ impl<TYPES: NodeType> Membership<TYPES> for RandomizedCommittee<TYPES> {
     }
 
     /// Get the voting success threshold for the committee
-    fn success_threshold(&self) -> NonZeroU64 {
+    fn success_threshold(&self, _epoch: <TYPES as NodeType>::Epoch) -> NonZeroU64 {
         NonZeroU64::new(((self.stake_table.len() as u64 * 2) / 3) + 1).unwrap()
     }
 
     /// Get the voting failure threshold for the committee
-    fn failure_threshold(&self) -> NonZeroU64 {
+    fn failure_threshold(&self, _epoch: <TYPES as NodeType>::Epoch) -> NonZeroU64 {
         NonZeroU64::new(((self.stake_table.len() as u64) / 3) + 1).unwrap()
     }
 
     /// Get the voting upgrade threshold for the committee
-    fn upgrade_threshold(&self) -> NonZeroU64 {
+    fn upgrade_threshold(&self, _epoch: <TYPES as NodeType>::Epoch) -> NonZeroU64 {
         NonZeroU64::new(max(
             (self.stake_table.len() as u64 * 9) / 10,
             ((self.stake_table.len() as u64 * 2) / 3) + 1,

crates/hotshot/src/traits/election/randomized_committee_members.rs

@@ -11,7 +11,6 @@ use std::{
     num::NonZeroU64,
 };
 
-use ethereum_types::U256;
 use hotshot_types::{
     traits::{
         election::Membership,
@@ -21,6 +20,7 @@ use hotshot_types::{
     },
     PeerConfig,
 };
+use primitive_types::U256;
 use rand::{rngs::StdRng, Rng};
 use utils::anytrace::Result;
 
@@ -231,20 +231,20 @@ impl<TYPES: NodeType, CONFIG: QuorumFilterConfig> Membership<TYPES>
     }
 
     /// Get the voting success threshold for the committee
-    fn success_threshold(&self) -> NonZeroU64 {
-        let len = self.stake_table.len() / 2; // Divide by two as we are flipping between odds and evens
+    fn success_threshold(&self, epoch: <TYPES as NodeType>::Epoch) -> NonZeroU64 {
+        let len = self.total_nodes(epoch);
         NonZeroU64::new(((len as u64 * 2) / 3) + 1).unwrap()
     }
 
     /// Get the voting failure threshold for the committee
-    fn failure_threshold(&self) -> NonZeroU64 {
-        let len = self.stake_table.len() / 2; // Divide by two as we are flipping between odds and evens
+    fn failure_threshold(&self, epoch: <TYPES as NodeType>::Epoch) -> NonZeroU64 {
+        let len = self.total_nodes(epoch);
         NonZeroU64::new(((len as u64) / 3) + 1).unwrap()
     }
 
     /// Get the voting upgrade threshold for the committee
-    fn upgrade_threshold(&self) -> NonZeroU64 {
-        let len = self.stake_table.len() / 2; // Divide by two as we are flipping between odds and evens
+    fn upgrade_threshold(&self, epoch: <TYPES as NodeType>::Epoch) -> NonZeroU64 {
+        let len = self.total_nodes(epoch);
         NonZeroU64::new(max((len as u64 * 9) / 10, ((len as u64 * 2) / 3) + 1)).unwrap()
     }
 }

crates/hotshot/src/traits/election/static_committee.rs

@@ -156,17 +156,17 @@ impl<TYPES: NodeType> Membership<TYPES> for StaticCommittee<TYPES> {
     }
 
     /// Get the voting success threshold for the committee
-    fn success_threshold(&self) -> NonZeroU64 {
+    fn success_threshold(&self, _epoch: <TYPES as NodeType>::Epoch) -> NonZeroU64 {
         NonZeroU64::new(((self.stake_table.len() as u64 * 2) / 3) + 1).unwrap()
     }
 
     /// Get the voting failure threshold for the committee
-    fn failure_threshold(&self) -> NonZeroU64 {
+    fn failure_threshold(&self, _epoch: <TYPES as NodeType>::Epoch) -> NonZeroU64 {
         NonZeroU64::new(((self.stake_table.len() as u64) / 3) + 1).unwrap()
     }
 
     /// Get the voting upgrade threshold for the committee
-    fn upgrade_threshold(&self) -> NonZeroU64 {
+    fn upgrade_threshold(&self, _epoch: <TYPES as NodeType>::Epoch) -> NonZeroU64 {
         NonZeroU64::new(max(
             (self.stake_table.len() as u64 * 9) / 10,
             ((self.stake_table.len() as u64 * 2) / 3) + 1,

crates/hotshot/src/traits/election/static_committee_leader_two_views.rs

@@ -157,17 +157,17 @@ impl<TYPES: NodeType> Membership<TYPES> for StaticCommitteeLeaderForTwoViews<TYP
     }
 
     /// Get the voting success threshold for the committee
-    fn success_threshold(&self) -> NonZeroU64 {
+    fn success_threshold(&self, _epoch: <TYPES as NodeType>::Epoch) -> NonZeroU64 {
         NonZeroU64::new(((self.stake_table.len() as u64 * 2) / 3) + 1).unwrap()
     }
 
     /// Get the voting failure threshold for the committee
-    fn failure_threshold(&self) -> NonZeroU64 {
+    fn failure_threshold(&self, _epoch: <TYPES as NodeType>::Epoch) -> NonZeroU64 {
         NonZeroU64::new(((self.stake_table.len() as u64) / 3) + 1).unwrap()
     }
 
     /// Get the voting upgrade threshold for the committee
-    fn upgrade_threshold(&self) -> NonZeroU64 {
+    fn upgrade_threshold(&self, _epoch: <TYPES as NodeType>::Epoch) -> NonZeroU64 {
         NonZeroU64::new(((self.stake_table.len() as u64 * 9) / 10) + 1).unwrap()
     }
 }

crates/testing/src/helpers.rs

@@ -223,7 +223,7 @@ pub async fn build_assembled_sig<
     let real_qc_pp: <TYPES::SignatureKey as SignatureKey>::QcParams =
         <TYPES::SignatureKey as SignatureKey>::public_parameter(
             stake_table.clone(),
-            U256::from(CERT::threshold(membership)),
+            U256::from(CERT::threshold(membership, epoch)),
         );
     let total_nodes = stake_table.len();
     let signers = bitvec![1; total_nodes];

crates/types/src/simple_certificate.rs

@@ -37,16 +37,22 @@ use crate::{
 /// Trait which allows use to inject different threshold calculations into a Certificate type
 pub trait Threshold<TYPES: NodeType> {
     /// Calculate a threshold based on the membership
-    fn threshold<MEMBERSHIP: Membership<TYPES>>(membership: &MEMBERSHIP) -> u64;
+    fn threshold<MEMBERSHIP: Membership<TYPES>>(
+        membership: &MEMBERSHIP,
+        epoch: <TYPES as NodeType>::Epoch,
+    ) -> u64;
 }
 
 /// Defines a threshold which is 2f + 1 (Amount needed for Quorum)
 #[derive(Serialize, Deserialize, Eq, Hash, PartialEq, Debug, Clone)]
 pub struct SuccessThreshold {}
 
 impl<TYPES: NodeType> Threshold<TYPES> for SuccessThreshold {
-    fn threshold<MEMBERSHIP: Membership<TYPES>>(membership: &MEMBERSHIP) -> u64 {
-        membership.success_threshold().into()
+    fn threshold<MEMBERSHIP: Membership<TYPES>>(
+        membership: &MEMBERSHIP,
+        epoch: <TYPES as NodeType>::Epoch,
+    ) -> u64 {
+        membership.success_threshold(epoch).into()
     }
 }
 
@@ -55,8 +61,11 @@ impl<TYPES: NodeType> Threshold<TYPES> for SuccessThreshold {
 pub struct OneHonestThreshold {}
 
 impl<TYPES: NodeType> Threshold<TYPES> for OneHonestThreshold {
-    fn threshold<MEMBERSHIP: Membership<TYPES>>(membership: &MEMBERSHIP) -> u64 {
-        membership.failure_threshold().into()
+    fn threshold<MEMBERSHIP: Membership<TYPES>>(
+        membership: &MEMBERSHIP,
+        epoch: <TYPES as NodeType>::Epoch,
+    ) -> u64 {
+        membership.failure_threshold(epoch).into()
     }
 }
 
@@ -65,8 +74,11 @@ impl<TYPES: NodeType> Threshold<TYPES> for OneHonestThreshold {
 pub struct UpgradeThreshold {}
 
 impl<TYPES: NodeType> Threshold<TYPES> for UpgradeThreshold {
-    fn threshold<MEMBERSHIP: Membership<TYPES>>(membership: &MEMBERSHIP) -> u64 {
-        membership.upgrade_threshold().into()
+    fn threshold<MEMBERSHIP: Membership<TYPES>>(
+        membership: &MEMBERSHIP,
+        epoch: <TYPES as NodeType>::Epoch,
+    ) -> u64 {
+        membership.upgrade_threshold(epoch).into()
     }
 }
 
@@ -156,7 +168,7 @@ impl<TYPES: NodeType, VOTEABLE: Voteable + 'static, THRESHOLD: Threshold<TYPES>>
         }
         let real_qc_pp = <TYPES::SignatureKey as SignatureKey>::public_parameter(
             membership.stake_table(epoch),
-            U256::from(Self::threshold(membership)),
+            U256::from(Self::threshold(membership, epoch)),
         );
         let Ok(commit) = self.data_commitment(upgrade_lock).await else {
             return false;
@@ -167,8 +179,11 @@ impl<TYPES: NodeType, VOTEABLE: Voteable + 'static, THRESHOLD: Threshold<TYPES>>
             self.signatures.as_ref().unwrap(),
         )
     }
-    fn threshold<MEMBERSHIP: Membership<TYPES>>(membership: &MEMBERSHIP) -> u64 {
-        THRESHOLD::threshold(membership)
+    fn threshold<MEMBERSHIP: Membership<TYPES>>(
+        membership: &MEMBERSHIP,
+        epoch: <TYPES as NodeType>::Epoch,
+    ) -> u64 {
+        THRESHOLD::threshold(membership, epoch)
     }
     fn data(&self) -> &Self::Voteable {
         &self.data

crates/types/src/traits/election.rs

@@ -89,11 +89,11 @@ pub trait Membership<TYPES: NodeType>: Clone + Debug + Send + Sync {
     fn total_nodes(&self, epoch: TYPES::Epoch) -> usize;
 
     /// Returns the threshold for a specific `Membership` implementation
-    fn success_threshold(&self) -> NonZeroU64;
+    fn success_threshold(&self, epoch: TYPES::Epoch) -> NonZeroU64;
 
     /// Returns the threshold for a specific `Membership` implementation
-    fn failure_threshold(&self) -> NonZeroU64;
+    fn failure_threshold(&self, epoch: TYPES::Epoch) -> NonZeroU64;
 
     /// Returns the threshold required to upgrade the network protocol
-    fn upgrade_threshold(&self) -> NonZeroU64;
+    fn upgrade_threshold(&self, epoch: TYPES::Epoch) -> NonZeroU64;
 }

crates/types/src/vote.rs

@@ -80,7 +80,10 @@ pub trait Certificate<TYPES: NodeType>: HasViewNumber<TYPES> {
     ) -> impl std::future::Future<Output = bool>;
     /// Returns the amount of stake needed to create this certificate
     // TODO: Make this a static ratio of the total stake of `Membership`
-    fn threshold<MEMBERSHIP: Membership<TYPES>>(membership: &MEMBERSHIP) -> u64;
+    fn threshold<MEMBERSHIP: Membership<TYPES>>(
+        membership: &MEMBERSHIP,
+        epoch: <TYPES as NodeType>::Epoch,
+    ) -> u64;
     /// Get the commitment which was voted on
     fn data(&self) -> &Self::Voteable;
     /// Get the vote commitment which the votes commit to
@@ -199,12 +202,12 @@ impl<
         *total_stake_casted += stake_table_entry.stake();
         total_vote_map.insert(key, (vote.signature(), vote_commitment));
 
-        if *total_stake_casted >= CERT::threshold(membership).into() {
+        if *total_stake_casted >= CERT::threshold(membership, epoch).into() {
             // Assemble QC
             let real_qc_pp: <<TYPES as NodeType>::SignatureKey as SignatureKey>::QcParams =
                 <TYPES::SignatureKey as SignatureKey>::public_parameter(
                     stake_table,
-                    U256::from(CERT::threshold(membership)),
+                    U256::from(CERT::threshold(membership, epoch)),
                 );
 
             let real_qc_sig = <TYPES::SignatureKey as SignatureKey>::assemble(