chore: tally slashing pruning improvements

yarn-project/slasher/README.md

@@ -185,7 +185,7 @@ These settings are configured locally on each validator node:
 - `slashProposeInvalidAttestationsPenalty`: Penalty for PROPOSED_INSUFFICIENT_ATTESTATIONS and PROPOSED_INCORRECT_ATTESTATIONS
 - `slashAttestDescendantOfInvalidPenalty`: Penalty for ATTESTED_DESCENDANT_OF_INVALID
 - `slashUnknownPenalty`: Default penalty for unknown offense types
-- `slashMaxPayloadSize`: Maximum size of slash payloads. In the empire model this limits offenses per payload; in the tally model it limits offenses considered when building the vote for a round (same prioritization: uncontroversial first, then by amount and age), so that execution payload stays within gas limits.
+- `slashMaxPayloadSize`: Maximum size of slash payloads. In the empire model this limits offenses per payload. In the tally model it limits the number of **unique validators** (across all committees and epochs in a round) that receive non-zero votes. When this cap is hit, the lowest-severity validator-epoch pairs are zeroed out first, so the most severe slashes are always preserved. Note that multiple offenses for the same validator in the same epoch are summed and counted as a single validator entry against this limit.
 - `slashMinPenaltyPercentage`: Agree to slashes if they are at least this percentage of the configured penalty (empire model)
 - `slashMaxPenaltyPercentage`: Agree to slashes if they are at most this percentage of the configured penalty (empire model)
 

yarn-project/slasher/src/tally_slasher_client.ts

@@ -362,18 +362,13 @@ export class TallySlasherClient implements ProposerSlashActionProvider, SlasherC
     const committees = await this.collectCommitteesActiveDuringRound(slashedRound);
     const epochsForCommittees = getEpochsForRound(slashedRound, this.settings);
     const { slashMaxPayloadSize } = this.config;
-    const { votes, truncatedCount } = getSlashConsensusVotesFromOffenses(
+    const votes = getSlashConsensusVotesFromOffenses(
       offensesToSlash,
       committees,
       epochsForCommittees.map(e => BigInt(e)),
       { ...this.settings, maxSlashedValidators: slashMaxPayloadSize },
+      this.log,
     );
-    if (truncatedCount > 0) {
-      this.log.warn(
-        `Vote truncated: ${truncatedCount} validator-epoch pairs dropped to stay within gas limit of ${slashMaxPayloadSize}`,
-        { slotNumber, currentRound, slashedRound },
-      );
-    }
     if (votes.every(v => v === 0)) {
       this.log.warn(`Computed votes for offenses are all zero. Skipping vote.`, {
         slotNumber,

yarn-project/stdlib/src/slashing/tally.test.ts

@@ -41,7 +41,7 @@ describe('TallySlashingHelpers', () => {
 
       const committees = [[mockValidator1, mockValidator2, mockValidator3]];
       const epochsForCommittees = [5n]; // Committee for epoch 5
-      const { votes } = getSlashConsensusVotesFromOffenses(offenses, committees, epochsForCommittees, settings);
+      const votes = getSlashConsensusVotesFromOffenses(offenses, committees, epochsForCommittees, settings);
 
       expect(votes).toHaveLength(4); // Padded to targetCommitteeSize
       expect(votes[0]).toEqual(2); // Only 25n from epoch 5 offense for validator1
@@ -62,7 +62,7 @@ describe('TallySlashingHelpers', () => {
 
       const committees = [[mockValidator1]];
       const epochsForCommittees = [5n];
-      const { votes } = getSlashConsensusVotesFromOffenses(offenses, committees, epochsForCommittees, settings);
+      const votes = getSlashConsensusVotesFromOffenses(offenses, committees, epochsForCommittees, settings);
 
       expect(votes).toHaveLength(4); // Padded to targetCommitteeSize
       expect(votes[0]).toEqual(3); // Capped at MAX_SLASH_UNITS_PER_VALIDATOR
@@ -91,7 +91,7 @@ describe('TallySlashingHelpers', () => {
       ];
 
       const epochsForCommittees = [5n, 6n]; // Committees for epochs 5 and 6
-      const { votes } = getSlashConsensusVotesFromOffenses(offenses, committees, epochsForCommittees, settings);
+      const votes = getSlashConsensusVotesFromOffenses(offenses, committees, epochsForCommittees, settings);
 
       expect(votes).toHaveLength(8); // 2 committees × 4 targetCommitteeSize
       expect(votes[0]).toEqual(2); // validator1 in committee1
@@ -125,7 +125,7 @@ describe('TallySlashingHelpers', () => {
         [mockValidator1, mockValidator3],
       ];
       const epochsForCommittees = [5n, 6n];
-      const { votes } = getSlashConsensusVotesFromOffenses(offenses, committees, epochsForCommittees, settings);
+      const votes = getSlashConsensusVotesFromOffenses(offenses, committees, epochsForCommittees, settings);
 
       expect(votes).toHaveLength(8); // 2 committees × 4 targetCommitteeSize
       expect(votes[0]).toEqual(2); // validator1 in committee1, epoch 5 offense (20n)
@@ -150,7 +150,7 @@ describe('TallySlashingHelpers', () => {
 
       const committees: EthAddress[][] = [];
       const epochsForCommittees: bigint[] = [];
-      const { votes } = getSlashConsensusVotesFromOffenses(offenses, committees, epochsForCommittees, settings);
+      const votes = getSlashConsensusVotesFromOffenses(offenses, committees, epochsForCommittees, settings);
 
       expect(votes).toEqual([]);
     });
@@ -167,7 +167,7 @@ describe('TallySlashingHelpers', () => {
 
       const committees = [[mockValidator2, mockValidator3]];
       const epochsForCommittees = [5n];
-      const { votes } = getSlashConsensusVotesFromOffenses(offenses, committees, epochsForCommittees, settings);
+      const votes = getSlashConsensusVotesFromOffenses(offenses, committees, epochsForCommittees, settings);
 
       expect(votes).toHaveLength(4); // Padded to targetCommitteeSize
       expect(votes[0]).toEqual(0); // validator2 has no offenses
@@ -197,7 +197,7 @@ describe('TallySlashingHelpers', () => {
         [mockValidator1, mockValidator3],
       ];
       const epochsForCommittees = [5n, 6n];
-      const { votes } = getSlashConsensusVotesFromOffenses(offenses, committees, epochsForCommittees, settings);
+      const votes = getSlashConsensusVotesFromOffenses(offenses, committees, epochsForCommittees, settings);
 
       expect(votes).toHaveLength(8); // 2 committees × 4 targetCommitteeSize
       expect(votes[0]).toEqual(3); // validator1 in committee1, always-slash (30n)
@@ -228,7 +228,7 @@ describe('TallySlashingHelpers', () => {
 
       const committees = [[mockValidator1, mockValidator2, mockValidator3]];
       const epochsForCommittees = [2n]; // Committee for epoch 2
-      const { votes } = getSlashConsensusVotesFromOffenses(offenses, committees, epochsForCommittees, settings);
+      const votes = getSlashConsensusVotesFromOffenses(offenses, committees, epochsForCommittees, settings);
 
       expect(votes).toHaveLength(4); // Padded to targetCommitteeSize
       expect(votes[0]).toEqual(BlockNumber(1)); // validator1: 15n offense maps to epoch 2
@@ -255,7 +255,7 @@ describe('TallySlashingHelpers', () => {
 
       const committees = [[mockValidator1, mockValidator2]];
       const epochsForCommittees = [2n];
-      const { votes } = getSlashConsensusVotesFromOffenses(offenses, committees, epochsForCommittees, settings);
+      const votes = getSlashConsensusVotesFromOffenses(offenses, committees, epochsForCommittees, settings);
 
       expect(votes).toHaveLength(4); // Padded to targetCommitteeSize
       expect(votes[0]).toEqual(2); // validator1: 10n + 15n = 25n total for epoch 2
@@ -288,7 +288,7 @@ describe('TallySlashingHelpers', () => {
 
       const committees = [[mockValidator1, mockValidator2]];
       const epochsForCommittees = [3n];
-      const { votes } = getSlashConsensusVotesFromOffenses(offenses, committees, epochsForCommittees, settings);
+      const votes = getSlashConsensusVotesFromOffenses(offenses, committees, epochsForCommittees, settings);
 
       expect(votes).toHaveLength(4); // Padded to targetCommitteeSize
       expect(votes[0]).toEqual(2); // validator1: 8n + 7n + 5n = 20n total
@@ -318,7 +318,7 @@ describe('TallySlashingHelpers', () => {
         [mockValidator1, mockValidator3],
       ];
       const epochsForCommittees = [5n, 6n];
-      const { votes } = getSlashConsensusVotesFromOffenses(offenses, committees, epochsForCommittees, settings);
+      const votes = getSlashConsensusVotesFromOffenses(offenses, committees, epochsForCommittees, settings);
 
       expect(votes).toHaveLength(8); // 2 committees × 4 targetCommitteeSize
       expect(votes[0]).toEqual(3); // validator1 committee1: 20n(always) + 15n(epoch5) = 35n
@@ -352,7 +352,7 @@ describe('TallySlashingHelpers', () => {
         [mockValidator1, mockValidator2],
       ];
       const epochsForCommittees = [0n, 1n];
-      const { votes } = getSlashConsensusVotesFromOffenses(offenses, committees, epochsForCommittees, settings);
+      const votes = getSlashConsensusVotesFromOffenses(offenses, committees, epochsForCommittees, settings);
 
       expect(votes).toHaveLength(8); // 2 committees × 4 targetCommitteeSize
       expect(votes[0]).toEqual(BlockNumber(1)); // validator1 epoch0: 15n offense
@@ -383,7 +383,7 @@ describe('TallySlashingHelpers', () => {
 
       const committees = [[mockValidator1, mockValidator2, mockValidator3]];
       const epochsForCommittees = [5n];
-      const { votes } = getSlashConsensusVotesFromOffenses(offenses, committees, epochsForCommittees, settings);
+      const votes = getSlashConsensusVotesFromOffenses(offenses, committees, epochsForCommittees, settings);
 
       expect(votes).toHaveLength(4); // Padded to targetCommitteeSize
       expect(votes[0]).toEqual(0); // validator1: 0n amount = 0 slash units
@@ -409,7 +409,7 @@ describe('TallySlashingHelpers', () => {
       ];
 
       const epochsForCommittees = [5n, 6n, 7n];
-      const { votes } = getSlashConsensusVotesFromOffenses(offenses, committees, epochsForCommittees, settings);
+      const votes = getSlashConsensusVotesFromOffenses(offenses, committees, epochsForCommittees, settings);
 
       // Should be 12 elements (4 per committee), not 8
       expect(votes).toHaveLength(12);
@@ -437,7 +437,7 @@ describe('TallySlashingHelpers', () => {
       ];
 
       const epochsForCommittees = [5n, 6n];
-      const { votes } = getSlashConsensusVotesFromOffenses(offenses, committees, epochsForCommittees, settings);
+      const votes = getSlashConsensusVotesFromOffenses(offenses, committees, epochsForCommittees, settings);
 
       expect(votes).toHaveLength(8);
       expect(votes.slice(0, 4)).toEqual([0, 0, 0, 0]); // Padded empty committee
@@ -460,7 +460,7 @@ describe('TallySlashingHelpers', () => {
       ];
 
       const epochsForCommittees = [5n, 6n];
-      const { votes } = getSlashConsensusVotesFromOffenses(offenses, committees, epochsForCommittees, settings);
+      const votes = getSlashConsensusVotesFromOffenses(offenses, committees, epochsForCommittees, settings);
 
       expect(votes).toHaveLength(8);
       expect(votes.slice(0, 4)).toEqual([0, 2, 0, 0]); // validator2 in first committee (20n = 2 units)
@@ -477,12 +477,11 @@ describe('TallySlashingHelpers', () => {
       const committees = [[mockValidator1, mockValidator2, mockValidator3, mockValidator4]];
       const epochsForCommittees = [5n];
       // Only 2 slashed validators allowed; validator3 should be zeroed out
-      const { votes, truncatedCount } = getSlashConsensusVotesFromOffenses(offenses, committees, epochsForCommittees, {
+      const votes = getSlashConsensusVotesFromOffenses(offenses, committees, epochsForCommittees, {
         ...settings,
         maxSlashedValidators: 2,
       });
 
-      expect(truncatedCount).toBe(1);
       expect(votes).toHaveLength(4);
       expect(votes[0]).toEqual(3); // validator1: included (1st)
       expect(votes[1]).toEqual(2); // validator2: included (2nd)
@@ -510,12 +509,11 @@ describe('TallySlashingHelpers', () => {
       const epochsForCommittees = [5n, 6n];
       // Limit of 3: validator1@epoch5, validator2@epoch5, validator1@epoch6 are included;
       // validator3@epoch6 is zeroed out
-      const { votes, truncatedCount } = getSlashConsensusVotesFromOffenses(offenses, committees, epochsForCommittees, {
+      const votes = getSlashConsensusVotesFromOffenses(offenses, committees, epochsForCommittees, {
         ...settings,
         maxSlashedValidators: 3,
       });
 
-      expect(truncatedCount).toBe(1);
       expect(votes).toHaveLength(8); // 2 committees × 4 targetCommitteeSize
       expect(votes[0]).toEqual(3); // validator1 @ epoch5: included (1st)
       expect(votes[1]).toEqual(2); // validator2 @ epoch5: included (2nd)
@@ -527,6 +525,34 @@ describe('TallySlashingHelpers', () => {
       expect(votes[7]).toEqual(0); // padded
     });
 
+    it('truncates based on validator count, not offense count', () => {
+      // 3 offenses for validator1, 2 for validator2, 1 for validator3 — but only 2 validators allowed.
+      // Truncation must cut one validator (not one offense record).
+      const offenses: Offense[] = [
+        { validator: mockValidator1, amount: 15n, offenseType: OffenseType.INACTIVITY, epochOrSlot: 5n },
+        { validator: mockValidator1, amount: 8n, offenseType: OffenseType.DATA_WITHHOLDING, epochOrSlot: 5n },
+        { validator: mockValidator1, amount: 5n, offenseType: OffenseType.VALID_EPOCH_PRUNED, epochOrSlot: 5n },
+        { validator: mockValidator2, amount: 20n, offenseType: OffenseType.INACTIVITY, epochOrSlot: 5n },
+        { validator: mockValidator2, amount: 5n, offenseType: OffenseType.DATA_WITHHOLDING, epochOrSlot: 5n },
+        { validator: mockValidator3, amount: 10n, offenseType: OffenseType.INACTIVITY, epochOrSlot: 5n },
+      ];
+
+      const committees = [[mockValidator1, mockValidator2, mockValidator3, mockValidator4]];
+      const epochsForCommittees = [5n];
+      // validator1: 15n+8n+5n=28n → 2 units, validator2: 20n+5n=25n → 2 units, validator3: 10n → 1 unit
+      // Limit of 2 validators: validator3 (lowest vote) is zeroed out
+      const votes = getSlashConsensusVotesFromOffenses(offenses, committees, epochsForCommittees, {
+        ...settings,
+        maxSlashedValidators: 2,
+      });
+
+      expect(votes).toHaveLength(4);
+      expect(votes[0]).toEqual(2); // validator1: 28n → 2 units, included
+      expect(votes[1]).toEqual(2); // validator2: 25n → 2 units, included
+      expect(votes[2]).toEqual(0); // validator3: 10n → 1 unit, zeroed out (only 2 validators allowed)
+      expect(votes[3]).toEqual(0); // validator4: no offenses
+    });
+
     it('handles multiple consecutive empty committees', () => {
       const offenses: Offense[] = [
         {
@@ -545,7 +571,7 @@ describe('TallySlashingHelpers', () => {
       ];
 
       const epochsForCommittees = [5n, 6n, 7n, 8n];
-      const { votes } = getSlashConsensusVotesFromOffenses(offenses, committees, epochsForCommittees, settings);
+      const votes = getSlashConsensusVotesFromOffenses(offenses, committees, epochsForCommittees, settings);
 
       expect(votes).toHaveLength(16); // 4 committees × 4 targetCommitteeSize
       expect(votes.slice(0, 4)).toEqual([0, 0, 0, 0]); // Committee 0: no matching offenses

yarn-project/stdlib/src/slashing/tally.ts

@@ -1,6 +1,7 @@
 import { sumBigint } from '@aztec/foundation/bigint';
 import { padArrayEnd } from '@aztec/foundation/collection';
 import { EthAddress } from '@aztec/foundation/eth-address';
+import { type Logger, createLogger } from '@aztec/foundation/log';
 import type { PartialBy } from '@aztec/foundation/types';
 
 import { getEpochForOffense } from './helpers.js';
@@ -13,7 +14,8 @@ import type { Offense, ValidatorSlashVote } from './types.js';
  * @param epochsForCommittees - Array of epochs corresponding to each committee
  * @param settings - Settings including slashingAmounts and optional validator override lists
  * @param settings.maxSlashedValidators - If set, limits the total number of [validator, epoch] pairs
- *   with non-zero votes.
+ *   with non-zero votes. The lowest-vote pairs are zeroed out to stay within the limit.
+ * @param logger - Logger, logs which validators were dropped.
  * @returns Array of ValidatorSlashVote, where each vote is how many slash units the validator in that position should be slashed
  */
 export function getSlashConsensusVotesFromOffenses(
@@ -26,7 +28,8 @@ export function getSlashConsensusVotesFromOffenses(
     targetCommitteeSize: number;
     maxSlashedValidators?: number;
   },
-): { votes: ValidatorSlashVote[]; truncatedCount: number } {
+  logger: Logger = createLogger('slasher:tally'),
+): ValidatorSlashVote[] {
   const { slashingAmounts, targetCommitteeSize, maxSlashedValidators } = settings;
 
   if (committees.length !== epochsForCommittees.length) {
@@ -58,7 +61,7 @@ export function getSlashConsensusVotesFromOffenses(
 
   // if a cap is set, zero out the lowest-vote [validator, epoch] pairs so that the most severe slashes stay.
   if (maxSlashedValidators === undefined) {
-    return { votes, truncatedCount: 0 };
+    return votes;
   }
 
   const nonZeroByDescendingVote = [...votes.entries()].filter(([, vote]) => vote > 0).sort(([, a], [, b]) => b - a);
@@ -68,7 +71,22 @@ export function getSlashConsensusVotesFromOffenses(
     votes[idx] = 0;
   }
 
-  return { votes, truncatedCount: toTruncate.length };
+  if (toTruncate.length > 0) {
+    const truncated = toTruncate.map(([idx]) => {
+      const committeeIndex = Math.floor(idx / targetCommitteeSize);
+      const positionInCommittee = idx % targetCommitteeSize;
+      return {
+        validator: committees[committeeIndex][positionInCommittee].toString(),
+        epoch: epochsForCommittees[committeeIndex],
+      };
+    });
+    logger.warn(
+      `Truncated ${toTruncate.length} validator-epoch pairs to stay within limit of ${maxSlashedValidators}`,
+      { truncated },
+    );
+  }
+
+  return votes;
 }
 
 /** Returns the slash vote for the given amount to slash. */