From f1740a6a5ae4288afd3b547f4064719236aecc37 Mon Sep 17 00:00:00 2001
From: Potuz <potuz@prysmaticlabs.com>
Date: Thu, 8 Aug 2024 10:51:40 -0300
Subject: [PATCH] Move slasher handling down the pipeline (#14322)

---
 .../sync/validate_beacon_attestation.go       | 80 ++++++++++---------
 1 file changed, 41 insertions(+), 39 deletions(-)

diff --git a/beacon-chain/sync/validate_beacon_attestation.go b/beacon-chain/sync/validate_beacon_attestation.go
index 2cea8638bbd4..860b0d8a2ba7 100644
--- a/beacon-chain/sync/validate_beacon_attestation.go
+++ b/beacon-chain/sync/validate_beacon_attestation.go
@@ -113,46 +113,19 @@ func (s *Service) validateCommitteeIndexBeaconAttestation(ctx context.Context, p
 		committeeIndex = data.CommitteeIndex
 	}
 
-	if features.Get().EnableSlasher {
-		// Feed the indexed attestation to slasher if enabled. This action
-		// is done in the background to avoid adding more load to this critical code path.
-		go func() {
-			// Using a different context to prevent timeouts as this operation can be expensive
-			// and we want to avoid affecting the critical code path.
-			ctx := context.TODO()
-			preState, err := s.cfg.chain.AttestationTargetState(ctx, data.Target)
-			if err != nil {
-				log.WithError(err).Error("Could not retrieve pre state")
-				tracing.AnnotateError(span, err)
-				return
-			}
-			committee, err := helpers.BeaconCommitteeFromState(ctx, preState, data.Slot, committeeIndex)
-			if err != nil {
-				log.WithError(err).Error("Could not get attestation committee")
-				tracing.AnnotateError(span, err)
-				return
-			}
-			indexedAtt, err := attestation.ConvertToIndexed(ctx, att, committee)
-			if err != nil {
-				log.WithError(err).Error("Could not convert to indexed attestation")
-				tracing.AnnotateError(span, err)
-				return
-			}
-			s.cfg.slasherAttestationsFeed.Send(&types.WrappedIndexedAtt{IndexedAtt: indexedAtt})
-		}()
-	}
-
-	// Verify this the first attestation received for the participating validator for the slot.
-	if s.hasSeenCommitteeIndicesSlot(data.Slot, data.CommitteeIndex, att.GetAggregationBits()) {
-		return pubsub.ValidationIgnore, nil
-	}
+	if !features.Get().EnableSlasher {
+		// Verify this the first attestation received for the participating validator for the slot.
+		if s.hasSeenCommitteeIndicesSlot(data.Slot, data.CommitteeIndex, att.GetAggregationBits()) {
+			return pubsub.ValidationIgnore, nil
+		}
 
-	// Reject an attestation if it references an invalid block.
-	if s.hasBadBlock(bytesutil.ToBytes32(data.BeaconBlockRoot)) ||
-		s.hasBadBlock(bytesutil.ToBytes32(data.Target.Root)) ||
-		s.hasBadBlock(bytesutil.ToBytes32(data.Source.Root)) {
-		attBadBlockCount.Inc()
-		return pubsub.ValidationReject, errors.New("attestation data references bad block root")
+		// Reject an attestation if it references an invalid block.
+		if s.hasBadBlock(bytesutil.ToBytes32(data.BeaconBlockRoot)) ||
+			s.hasBadBlock(bytesutil.ToBytes32(data.Target.Root)) ||
+			s.hasBadBlock(bytesutil.ToBytes32(data.Source.Root)) {
+			attBadBlockCount.Inc()
+			return pubsub.ValidationReject, errors.New("attestation data references bad block root")
+		}
 	}
 
 	// Verify the block being voted and the processed state is in beaconDB and the block has passed validation if it's in the beaconDB.
@@ -203,6 +176,35 @@ func (s *Service) validateCommitteeIndexBeaconAttestation(ctx context.Context, p
 		return validationRes, err
 	}
 
+	if features.Get().EnableSlasher {
+		// Feed the indexed attestation to slasher if enabled. This action
+		// is done in the background to avoid adding more load to this critical code path.
+		go func() {
+			// Using a different context to prevent timeouts as this operation can be expensive
+			// and we want to avoid affecting the critical code path.
+			ctx := context.TODO()
+			preState, err := s.cfg.chain.AttestationTargetState(ctx, data.Target)
+			if err != nil {
+				log.WithError(err).Error("Could not retrieve pre state")
+				tracing.AnnotateError(span, err)
+				return
+			}
+			committee, err := helpers.BeaconCommitteeFromState(ctx, preState, data.Slot, committeeIndex)
+			if err != nil {
+				log.WithError(err).Error("Could not get attestation committee")
+				tracing.AnnotateError(span, err)
+				return
+			}
+			indexedAtt, err := attestation.ConvertToIndexed(ctx, att, committee)
+			if err != nil {
+				log.WithError(err).Error("Could not convert to indexed attestation")
+				tracing.AnnotateError(span, err)
+				return
+			}
+			s.cfg.slasherAttestationsFeed.Send(&types.WrappedIndexedAtt{IndexedAtt: indexedAtt})
+		}()
+	}
+
 	s.setSeenCommitteeIndicesSlot(data.Slot, data.CommitteeIndex, att.GetAggregationBits())
 
 	msg.ValidatorData = att