fix: Execute old slashing round if skipped during first round

yarn-project/cli/src/config/chain_l2_config.ts

@@ -68,6 +68,7 @@ const DefaultSlashConfig = {
   slashGracePeriodL2Slots: 32 * 2, // Two epochs from genesis
   slashOffenseExpirationRounds: 8,
   sentinelEnabled: true,
+  slashExecuteRoundsLookBack: 4,
 } satisfies Partial<L2ChainConfig>;
 
 export const stagingIgnitionL2ChainConfig: L2ChainConfig = {
@@ -148,6 +149,7 @@ export const stagingIgnitionL2ChainConfig: L2ChainConfig = {
   slashOffenseExpirationRounds: 8,
   sentinelEnabled: true,
   slashingDisableDuration: 5 * 24 * 60 * 60,
+  slashExecuteRoundsLookBack: 4,
 };
 
 export const stagingPublicL2ChainConfig: L2ChainConfig = {

yarn-project/end-to-end/src/e2e_p2p/inactivity_slash_with_consecutive_epochs.test.ts

@@ -1,5 +1,6 @@
-import type { EthAddress } from '@aztec/aztec.js';
+import { type EthAddress, retryUntil } from '@aztec/aztec.js';
 import { unique } from '@aztec/foundation/collection';
+import { OffenseType } from '@aztec/slasher';
 
 import { jest } from '@jest/globals';
 import 'jest-extended';
@@ -26,8 +27,14 @@ describe('e2e_p2p_inactivity_slash_with_consecutive_epochs', () => {
 
   it('only slashes validator inactive for N consecutive epochs', async () => {
     const [offlineValidator, reenabledValidator] = test.offlineValidators;
-    const { aztecEpochDuration, slashingExecutionDelayInRounds, slashingOffsetInRounds, slashingRoundSizeInEpochs } =
-      test.ctx.aztecNodeConfig;
+
+    const {
+      aztecEpochDuration,
+      slashingExecutionDelayInRounds,
+      slashingOffsetInRounds,
+      slashingRoundSizeInEpochs,
+      aztecSlotDuration,
+    } = test.ctx.aztecNodeConfig;
 
     const initialEpoch = Number(test.test.monitor.l2EpochNumber) + 1;
     test.logger.warn(`Waiting until end of epoch ${initialEpoch} to reenable validator ${reenabledValidator}`);
@@ -38,6 +45,18 @@ describe('e2e_p2p_inactivity_slash_with_consecutive_epochs', () => {
     expect(reenabledNode.getSequencer()!.validatorAddresses![0].toString()).toEqual(reenabledValidator.toString());
     await reenabledNode.getSequencer()!.start();
 
+    test.logger.warn(`Waiting until offenses are created for ${offlineValidator}`);
+    const offenses = await retryUntil(
+      async () => {
+        const offenses = await test.activeNodes[0].getSlashOffenses('all');
+        return offenses.length > 0 ? offenses : undefined;
+      },
+      'slash offenses',
+      slashInactivityConsecutiveEpochThreshold * aztecEpochDuration * aztecSlotDuration * 2,
+    );
+    expect(unique(offenses.map(o => o.validator.toString()))).toEqual([offlineValidator.toString()]);
+    expect(unique(offenses.map(o => o.offenseType))).toEqual([OffenseType.INACTIVITY]);
+
     test.logger.warn(`Expecting offline validator ${offlineValidator} to be slashed but not ${reenabledValidator}`);
     const slashed: EthAddress[] = [];
     test.rollup.listenToSlash(args => {
@@ -51,7 +70,7 @@ describe('e2e_p2p_inactivity_slash_with_consecutive_epochs', () => {
       slashInactivityConsecutiveEpochThreshold +
       (slashingExecutionDelayInRounds + slashingOffsetInRounds) * slashingRoundSizeInEpochs +
       5;
-    test.logger.warn(`Waiting until slot ${aztecEpochDuration * targetEpoch} (epoch ${targetEpoch})`);
+    test.logger.warn(`Waiting until slot ${aztecEpochDuration * targetEpoch} (epoch ${targetEpoch}) for slash`);
     await test.test.monitor.waitUntilL2Slot(aztecEpochDuration * targetEpoch);
     expect(unique(slashed.map(addr => addr.toString()))).toEqual([offlineValidator.toString()]);
   });

yarn-project/foundation/src/config/env_var.ts

@@ -209,6 +209,7 @@ export type EnvVar =
   | 'SLASH_GRACE_PERIOD_L2_SLOTS'
   | 'SLASH_OFFENSE_EXPIRATION_ROUNDS'
   | 'SLASH_MAX_PAYLOAD_SIZE'
+  | 'SLASH_EXECUTE_ROUNDS_LOOK_BACK'
   | 'SYNC_MODE'
   | 'SYNC_SNAPSHOTS_URL'
   | 'TELEMETRY'

yarn-project/slasher/src/config.ts

@@ -29,6 +29,7 @@ export const DefaultSlasherConfig: SlasherConfig = {
   slashOffenseExpirationRounds: 4,
   slashMaxPayloadSize: 50,
   slashGracePeriodL2Slots: 0,
+  slashExecuteRoundsLookBack: 4,
   slashSelfAllowed: false,
 };
 
@@ -144,6 +145,11 @@ export const slasherConfigMappings: ConfigMappingsType<SlasherConfig> = {
     env: 'SLASH_GRACE_PERIOD_L2_SLOTS',
     ...numberConfigHelper(DefaultSlasherConfig.slashGracePeriodL2Slots),
   },
+  slashExecuteRoundsLookBack: {
+    env: 'SLASH_EXECUTE_ROUNDS_LOOK_BACK',
+    description: 'How many rounds to look back when searching for a round to execute.',
+    ...numberConfigHelper(DefaultSlasherConfig.slashExecuteRoundsLookBack),
+  },
   slashSelfAllowed: {
     description: 'Whether to allow slashes to own validators',
     ...booleanConfigHelper(DefaultSlasherConfig.slashSelfAllowed),