Fetch the Correct Chain Head During AttestHead

beacon-chain/rpc/attester_server.go

@@ -39,13 +39,10 @@ func (as *AttesterServer) AttestHead(ctx context.Context, att *pbp2p.Attestation
 func (as *AttesterServer) AttestationInfoAtSlot(ctx context.Context, req *pb.AttestationInfoRequest) (*pb.AttestationInfoResponse, error) {
 	// Set the attestation data's beacon block root = hash_tree_root(head) where head
 	// is the validator's view of the head block of the beacon chain during the slot.
-	head, err := as.beaconDB.BlockBySlot(req.Slot)
+	head, err := as.beaconDB.ChainHead()
 	if err != nil {
 		return nil, fmt.Errorf("failed to retrieve chain head: %v", err)
 	}
-	if head == nil {
-		return nil, fmt.Errorf("no block found at slot %d", req.Slot)
-	}
 	blockRoot, err := ssz.TreeHash(head)
 	if err != nil {
 		return nil, fmt.Errorf("could not tree hash beacon block: %v", err)

beacon-chain/rpc/attester_server_test.go

@@ -34,30 +34,16 @@ func TestAttestHead(t *testing.T) {
 	}
 }
 
-func TestAttestationInfoAtSlot_NilHeadAtSlot(t *testing.T) {
-	db := internal.SetupDB(t)
-	defer internal.TeardownDB(t, db)
-	attesterServer := &AttesterServer{
-		beaconDB: db,
-	}
-	want := "no block found at slot 5"
-	req := &pb.AttestationInfoRequest{
-		Slot: 5,
-	}
-	if _, err := attesterServer.AttestationInfoAtSlot(context.Background(), req); !strings.Contains(err.Error(), want) {
-		t.Errorf("Expected %v, received %v", want, err)
-	}
-}
-
 func TestAttestationInfoAtSlot_EpochBoundaryFailure(t *testing.T) {
 	db := internal.SetupDB(t)
 	defer internal.TeardownDB(t, db)
 	beaconState := &pbp2p.BeaconState{
-		Slot:                   5,
+		Slot:                   params.BeaconConfig().GenesisSlot + 3*params.BeaconConfig().GenesisEpoch,
 		LatestBlockRootHash32S: make([][]byte, 20),
+		JustifiedEpoch:         params.BeaconConfig().GenesisEpoch,
 	}
 	block := blocks.NewGenesisBlock([]byte("stateroot"))
-	block.Slot = 100
+	block.Slot = params.BeaconConfig().GenesisSlot
 	attesterServer := &AttesterServer{
 		beaconDB: db,
 	}
@@ -68,9 +54,7 @@ func TestAttestationInfoAtSlot_EpochBoundaryFailure(t *testing.T) {
 		t.Fatalf("Could not update chain head in test db: %v", err)
 	}
 	want := "could not get epoch boundary block"
-	req := &pb.AttestationInfoRequest{
-		Slot: 100,
-	}
+	req := &pb.AttestationInfoRequest{}
 	if _, err := attesterServer.AttestationInfoAtSlot(context.Background(), req); !strings.Contains(err.Error(), want) {
 		t.Errorf("Expected %v, received %v", want, err)
 	}
@@ -105,9 +89,7 @@ func TestAttestationInfoAtSlot_JustifiedBlockFailure(t *testing.T) {
 		t.Fatalf("Could not update chain head in test db: %v", err)
 	}
 	want := "could not get justified block"
-	req := &pb.AttestationInfoRequest{
-		Slot: params.BeaconConfig().GenesisSlot + 1,
-	}
+	req := &pb.AttestationInfoRequest{}
 	if _, err := attesterServer.AttestationInfoAtSlot(context.Background(), req); !strings.Contains(err.Error(), want) {
 		t.Errorf("Expected %v, received %v", want, err)
 	}
@@ -153,12 +135,6 @@ func TestAttestationInfoAtSlot_Ok(t *testing.T) {
 	attesterServer := &AttesterServer{
 		beaconDB: db,
 	}
-	if err := attesterServer.beaconDB.SaveBlock(block); err != nil {
-		t.Fatalf("Could not save block in test db: %v", err)
-	}
-	if err := attesterServer.beaconDB.UpdateChainHead(block, beaconState); err != nil {
-		t.Fatalf("Could not update chain head in test db: %v", err)
-	}
 	if err := attesterServer.beaconDB.SaveBlock(epochBoundaryBlock); err != nil {
 		t.Fatalf("Could not save block in test db: %v", err)
 	}
@@ -171,8 +147,13 @@ func TestAttestationInfoAtSlot_Ok(t *testing.T) {
 	if err := attesterServer.beaconDB.UpdateChainHead(justifiedBlock, beaconState); err != nil {
 		t.Fatalf("Could not update chain head in test db: %v", err)
 	}
+	if err := attesterServer.beaconDB.SaveBlock(block); err != nil {
+		t.Fatalf("Could not save block in test db: %v", err)
+	}
+	if err := attesterServer.beaconDB.UpdateChainHead(block, beaconState); err != nil {
+		t.Fatalf("Could not update chain head in test db: %v", err)
+	}
 	req := &pb.AttestationInfoRequest{
-		Slot:  1 + params.BeaconConfig().GenesisSlot,
 		Shard: 0,
 	}
 	res, err := attesterServer.AttestationInfoAtSlot(context.Background(), req)