Ensure duplicated attestations are only counted as 1 in block proposal.

CHANGELOG.md

@@ -1,4 +1,5 @@
 Development
+  - ensure duplicated attestations are only counted as 1 in block proposal score
   - ensure genesis attesters are scheduled appropriately
   - do not continue if attempt to acquire a semaphore fails
   - fetch validators without balances, for (much) faster response from Prysm

strategies/beaconblockproposal/best/score.go

@@ -33,12 +33,35 @@ func scoreBeaconBlockProposal(ctx context.Context, name string, blockProposal *s
 	immediateAttestationScore := float64(0)
 	attestationScore := float64(0)
 
-	// Add attestation scores.
+	// We need to avoid duplicates in attestations.
+	// Map is slot -> committee index -> validator committee index -> attested.
+	attested := make(map[uint64]map[uint64]map[uint64]bool)
 	for _, attestation := range blockProposal.Body.Attestations {
-		inclusionDistance := float64(blockProposal.Slot - attestation.Data.Slot)
-		attestationScore += float64(attestation.AggregationBits.Count()) * (float64(0.75) + float64(0.25)/inclusionDistance)
-		if inclusionDistance == 1 {
-			immediateAttestationScore += float64(attestation.AggregationBits.Count()) * (float64(0.75) + float64(0.25)/inclusionDistance)
+		slotAttested, exists := attested[attestation.Data.Slot]
+		if !exists {
+			slotAttested = make(map[uint64]map[uint64]bool)
+			attested[attestation.Data.Slot] = slotAttested
+		}
+		committeeAttested, exists := slotAttested[attestation.Data.Index]
+		if !exists {
+			committeeAttested = make(map[uint64]bool)
+			slotAttested[attestation.Data.Index] = committeeAttested
+		}
+		for i := uint64(0); i < attestation.AggregationBits.Len(); i++ {
+			if attestation.AggregationBits.BitAt(i) {
+				committeeAttested[i] = true
+			}
+		}
+	}
+
+	// Calculate inclusion score.
+	for slot, slotAttested := range attested {
+		inclusionDistance := float64(blockProposal.Slot - slot)
+		for _, committeeAttested := range slotAttested {
+			attestationScore += float64(len(committeeAttested)) * (float64(0.75) + float64(0.25)/inclusionDistance)
+			if inclusionDistance == 1 {
+				immediateAttestationScore += float64(len(committeeAttested)) * (float64(0.75) + float64(0.25)/inclusionDistance)
+			}
 		}
 	}
 

strategies/beaconblockproposal/best/score_internal_test.go

@@ -30,6 +30,14 @@ func aggregationBits(set uint64, total uint64) bitfield.Bitlist {
 	return bits
 }
 
+func specificAggregationBits(set []uint64, total uint64) bitfield.Bitlist {
+	bits := bitfield.NewBitlist(total)
+	for _, pos := range set {
+		bits.SetBitAt(pos, true)
+	}
+	return bits
+}
+
 func TestScore(t *testing.T) {
 	tests := []struct {
 		name  string
@@ -130,6 +138,29 @@ func TestScore(t *testing.T) {
 			},
 			score: 1450,
 		},
+		{
+			name: "DuplicateAttestations",
+			block: &spec.BeaconBlock{
+				Slot: 12345,
+				Body: &spec.BeaconBlockBody{
+					Attestations: []*spec.Attestation{
+						{
+							AggregationBits: specificAggregationBits([]uint64{1, 2, 3}, 128),
+							Data: &spec.AttestationData{
+								Slot: 12344,
+							},
+						},
+						{
+							AggregationBits: specificAggregationBits([]uint64{2, 3, 4}, 128),
+							Data: &spec.AttestationData{
+								Slot: 12344,
+							},
+						},
+					},
+				},
+			},
+			score: 4,
+		},
 	}
 
 	for _, test := range tests {