Fix getValidatorCandidates to get the registered candidates in the gi…

…ven epoch for the next epoch, adjust when we rotate the committee and tests accordingly

pkg/protocol/sybilprotection/sybilprotectionv1/performance/performance.go

@@ -134,14 +134,15 @@ func (t *Tracker) TrackCandidateBlock(block *blocks.Block) {
 
 }
 
+// EligibleValidatorCandidates returns the eligible validator candidates registered in the given epoch for the next epoch.
 func (t *Tracker) EligibleValidatorCandidates(epoch iotago.EpochIndex) (ds.Set[iotago.AccountID], error) {
 	t.mutex.RLock()
 	defer t.mutex.RUnlock()
 
 	return t.getValidatorCandidates(epoch)
 }
 
-// ValidatorCandidates returns the registered validator candidates for the given epoch.
+// ValidatorCandidates returns the eligible validator candidates registered in the given epoch for the next epoch.
 func (t *Tracker) ValidatorCandidates(epoch iotago.EpochIndex) (ds.Set[iotago.AccountID], error) {
 	t.mutex.RLock()
 	defer t.mutex.RUnlock()
@@ -152,14 +153,7 @@ func (t *Tracker) ValidatorCandidates(epoch iotago.EpochIndex) (ds.Set[iotago.Ac
 func (t *Tracker) getValidatorCandidates(epoch iotago.EpochIndex) (ds.Set[iotago.AccountID], error) {
 	candidates := ds.NewSet[iotago.AccountID]()
 
-	// Epoch 0 has no candidates as it's the genesis committee.
-	if epoch == 0 {
-		return candidates, nil
-	}
-
-	// we store candidates in the store for the epoch of their activity, but the passed argument points to the target epoch,
-	// so it's necessary to subtract one epoch from the passed value
-	candidateStore, err := t.committeeCandidatesInEpochFunc(epoch - 1)
+	candidateStore, err := t.committeeCandidatesInEpochFunc(epoch)
 	if err != nil {
 		return nil, ierrors.Wrapf(err, "error while retrieving candidates for epoch %d", epoch)
 	}

pkg/protocol/sybilprotection/sybilprotectionv1/performance/tracker_test.go

@@ -136,28 +136,8 @@ func TestManager_Candidates(t *testing.T) {
 		ts.Instance.TrackCandidateBlock(blocks.NewBlock(lo.PanicOnErr(model.BlockFromBlock(block6))))
 	}
 
-	require.True(t, lo.PanicOnErr(ts.Instance.EligibleValidatorCandidates(1)).HasAll(ds.NewReadableSet(issuer1, issuer2, issuer3)))
-	require.True(t, lo.PanicOnErr(ts.Instance.ValidatorCandidates(1)).HasAll(ds.NewReadableSet(issuer1, issuer2, issuer3)))
-	require.True(t, lo.PanicOnErr(ts.Instance.EligibleValidatorCandidates(2)).IsEmpty())
-	require.True(t, lo.PanicOnErr(ts.Instance.ValidatorCandidates(2)).IsEmpty())
-
-	// retrieve epoch candidates for epoch 0, because we candidates prefixed with epoch in which they candidated
-	candidatesStore, err := ts.Instance.committeeCandidatesInEpochFunc(0)
-	require.NoError(t, err)
-
-	candidacySlotIssuer1, err := candidatesStore.Get(issuer1[:])
-	require.NoError(t, err)
-	require.Equal(t, iotago.SlotIndex(1).MustBytes(), candidacySlotIssuer1)
-
-	candidacySlotIssuer2, err := candidatesStore.Get(issuer2[:])
-	require.NoError(t, err)
-	require.Equal(t, iotago.SlotIndex(2).MustBytes(), candidacySlotIssuer2)
-
-	candidacySlotIssuer3, err := candidatesStore.Get(issuer3[:])
-	require.NoError(t, err)
-	require.Equal(t, iotago.SlotIndex(3).MustBytes(), candidacySlotIssuer3)
-
-	ts.Instance.ClearCandidates()
-
-	require.True(t, ts.Instance.nextEpochCommitteeCandidates.IsEmpty())
+	require.True(t, lo.PanicOnErr(ts.Instance.EligibleValidatorCandidates(0)).HasAll(ds.NewReadableSet(issuer1, issuer2, issuer3)))
+	require.True(t, lo.PanicOnErr(ts.Instance.ValidatorCandidates(0)).HasAll(ds.NewReadableSet(issuer1, issuer2, issuer3)))
+	require.True(t, lo.PanicOnErr(ts.Instance.EligibleValidatorCandidates(1)).IsEmpty())
+	require.True(t, lo.PanicOnErr(ts.Instance.ValidatorCandidates(1)).IsEmpty())
 }

pkg/protocol/sybilprotection/sybilprotectionv1/sybilprotection.go

@@ -401,7 +401,9 @@ func (o *SybilProtection) selectNewCommittee(slot iotago.SlotIndex) (*account.Ac
 	timeProvider := o.apiProvider.APIForSlot(slot).TimeProvider()
 	currentEpoch := timeProvider.EpochFromSlot(slot)
 	nextEpoch := currentEpoch + 1
-	candidates, err := o.performanceTracker.EligibleValidatorCandidates(nextEpoch)
+
+	// We get the list of candidates for the next epoch. They are registered in the current epoch.
+	candidates, err := o.performanceTracker.EligibleValidatorCandidates(currentEpoch)
 	if err != nil {
 		return nil, ierrors.Wrapf(err, "failed to retrieve candidates for epoch %d", nextEpoch)
 	}

pkg/tests/committee_rotation_test.go

@@ -100,7 +100,7 @@ func Test_TopStakersRotation(t *testing.T) {
 		ts.IssueCandidacyAnnouncementInSlot("node5-candidacy:2", 11, "node4-candidacy:3", ts.Wallet("node3"))
 
 		// Assert that only candidates that issued before slot 11 are considered.
-		ts.AssertSybilProtectionCandidates(1, []iotago.AccountID{
+		ts.AssertSybilProtectionCandidates(0, []iotago.AccountID{
 			ts.Node("node1").Validator.AccountID,
 			ts.Node("node4").Validator.AccountID,
 			ts.Node("node5").Validator.AccountID,
@@ -121,7 +121,7 @@ func Test_TopStakersRotation(t *testing.T) {
 	{
 		ts.IssueBlocksAtSlots("wave-5:", []iotago.SlotIndex{18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30}, 4, "wave-4:17.3", ts.Nodes(), true, nil)
 
-		ts.AssertSybilProtectionCandidates(2, []iotago.AccountID{}, ts.Nodes()...)
+		ts.AssertSybilProtectionCandidates(1, []iotago.AccountID{}, ts.Nodes()...)
 		ts.AssertLatestCommitmentSlotIndex(28, ts.Nodes()...)
 		ts.AssertLatestFinalizedSlot(27, ts.Nodes()...)
 		ts.AssertSybilProtectionCommittee(2, []iotago.AccountID{
@@ -144,7 +144,7 @@ func Test_TopStakersRotation(t *testing.T) {
 
 		ts.AssertLatestCommitmentSlotIndex(43, ts.Nodes()...)
 		// Even though we have a candidate, the committee should be reused as we did not finalize at epochNearingThreshold before epoch end - maxCommittableAge was committed
-		ts.AssertSybilProtectionCandidates(3, []iotago.AccountID{
+		ts.AssertSybilProtectionCandidates(2, []iotago.AccountID{
 			ts.Node("node6").Validator.AccountID,
 		}, ts.Nodes()...)
 		// Check that the committee is reused.
@@ -166,7 +166,7 @@ func Test_TopStakersRotation(t *testing.T) {
 		ts.AssertLatestCommitmentSlotIndex(59, ts.Nodes()...)
 		ts.AssertLatestFinalizedSlot(58, ts.Nodes()...)
 		// We finalized at epochEnd-epochNearingThreshold, so the committee should be rotated even if there is just one candidate.
-		ts.AssertSybilProtectionCandidates(4, []iotago.AccountID{
+		ts.AssertSybilProtectionCandidates(3, []iotago.AccountID{
 			ts.Node("node3").Validator.AccountID,
 		}, ts.Nodes()...)
 		ts.AssertSybilProtectionCommittee(4, []iotago.AccountID{