Remove check for duplicates in pending attestation queue

The current queue will only save 1 unaggregated attestation for a pending block because we wrap the object into a SignedAggregatedAttestationAndProof with a zeroed aggregator.

beacon-chain/sync/pending_attestations_queue.go

@@ -1,6 +1,7 @@
 package sync
 
 import (
+	"bytes"
 	"context"
 	"encoding/hex"
 	"sync"
@@ -157,7 +158,8 @@ func (s *Service) processAttestations(ctx context.Context, attestations []*ethpb
 
 // This defines how pending attestations is saved in the map. The key is the
 // root of the missing block. The value is the list of pending attestations
-// that voted for that block root.
+// that voted for that block root. The caller of this function is responsible
+// for not sending repeated attestations to the pending queue.
 func (s *Service) savePendingAtt(att *ethpb.SignedAggregateAttestationAndProof) {
 	root := bytesutil.ToBytes32(att.Message.Aggregate.Data.BeaconBlockRoot)
 
@@ -178,17 +180,32 @@ func (s *Service) savePendingAtt(att *ethpb.SignedAggregateAttestationAndProof)
 		s.blkRootToPendingAtts[root] = []*ethpb.SignedAggregateAttestationAndProof{att}
 		return
 	}
-
-	// Skip if the attestation from the same aggregator already exists in the pending queue.
+	// Skip if the attestation from the same aggregator already exists in
+	// the pending queue.
 	for _, a := range s.blkRootToPendingAtts[root] {
-		if a.Message.AggregatorIndex == att.Message.AggregatorIndex {
+		if attsAreEqual(att, a) {
 			return
 		}
 	}
-
 	s.blkRootToPendingAtts[root] = append(s.blkRootToPendingAtts[root], att)
 }
 
+func attsAreEqual(a, b *ethpb.SignedAggregateAttestationAndProof) bool {
+	if a.Signature != nil {
+		return b.Signature != nil && a.Message.AggregatorIndex == b.Message.AggregatorIndex
+	}
+	if b.Signature != nil {
+		return false
+	}
+	if a.Message.Aggregate.Data.Slot != b.Message.Aggregate.Data.Slot {
+		return false
+	}
+	if a.Message.Aggregate.Data.CommitteeIndex != b.Message.Aggregate.Data.CommitteeIndex {
+		return false
+	}
+	return bytes.Equal(a.Message.Aggregate.AggregationBits, b.Message.Aggregate.AggregationBits)
+}
+
 // This validates the pending attestations in the queue are still valid.
 // If not valid, a node will remove it in the queue in place. The validity
 // check specifies the pending attestation could not fall one epoch behind