PendingAttestations: allow for request to specify a slot (#1922)

* PendingAttestations: allow for request to specify a slot

* enhance the test

beacon-chain/rpc/proposer_server.go

@@ -75,10 +75,17 @@ func (ps *ProposerServer) PendingAttestations(ctx context.Context, req *pb.Pendi
 		return nil, fmt.Errorf("could not retrieve pending attestations from operations service: %v", err)
 	}
 
+	// Use the optional proposal block slot parameter as the current slot for
+	// determining the validity window for attestations.
+	currentSlot := req.ProposalBlockSlot
+	if currentSlot == 0 {
+		currentSlot = beaconState.Slot
+	}
+
 	// Remove any attestation from the list if their slot is before the start of
 	// the previous epoch. This should be handled in the operationService cleanup
 	// method, but we should filter here in case it wasn't yet processed.
-	boundary := beaconState.Slot - params.BeaconConfig().SlotsPerEpoch
+	boundary := currentSlot - params.BeaconConfig().SlotsPerEpoch
 	attsWithinBoundary := make([]*pbp2p.Attestation, 0, len(atts))
 	for _, att := range atts {
 		if att.Data.Slot > boundary {
@@ -90,7 +97,7 @@ func (ps *ProposerServer) PendingAttestations(ctx context.Context, req *pb.Pendi
 	if req.FilterReadyForInclusion {
 		var attsReadyForInclusion []*pbp2p.Attestation
 		for _, val := range atts {
-			if val.Data.Slot+params.BeaconConfig().MinAttestationInclusionDelay <= beaconState.Slot {
+			if val.Data.Slot+params.BeaconConfig().MinAttestationInclusionDelay <= currentSlot {
 				attsReadyForInclusion = append(attsReadyForInclusion, val)
 			}
 		}

beacon-chain/rpc/proposer_server_test.go

@@ -188,7 +188,12 @@ func TestPendingAttestations_FiltersExpiredAttestations(t *testing.T) {
 	if err := db.SaveState(beaconState); err != nil {
 		t.Fatal(err)
 	}
-	res, err := proposerServer.PendingAttestations(context.Background(), &pb.PendingAttestationsRequest{})
+	res, err := proposerServer.PendingAttestations(
+		context.Background(),
+		&pb.PendingAttestationsRequest{
+			ProposalBlockSlot: currentSlot,
+		},
+	)
 	if err != nil {
 		t.Fatalf("Unexpected error fetching pending attestations: %v", err)
 	}

proto/beacon/rpc/v1/services.proto

@@ -59,6 +59,7 @@ message AttestationDataResponse {
 
 message PendingAttestationsRequest {
     bool filter_ready_for_inclusion = 1;
+    uint64 proposal_block_slot = 2;
 }
 
 message PendingAttestationsResponse {
@@ -146,4 +147,4 @@ enum ValidatorStatus {
     WITHDRAWABLE = 4;
     EXITED = 5;
     EXITED_SLASHED = 6;
-}
+}

validator/client/validator_propose.go

@@ -82,6 +82,7 @@ func (v *validator) ProposeBlock(ctx context.Context, slot uint64) {
 	// Fetch pending attestations seen by the beacon node.
 	attResp, err := v.proposerClient.PendingAttestations(ctx, &pb.PendingAttestationsRequest{
 		FilterReadyForInclusion: true,
+		ProposalBlockSlot:       slot,
 	})
 	if err != nil {
 		log.Errorf("Failed to fetch pending attestations from the beacon node: %v", err)