Do Not Retrieve From DB For Block Roots (#7028)

* don't use db

beacon-chain/sync/rpc_beacon_blocks_by_range.go

@@ -117,12 +117,16 @@ func (s *Service) writeBlockRangeToStream(ctx context.Context, startSlot, endSlo
 		traceutil.AnnotateError(span, err)
 		return err
 	}
-	roots, err := s.db.BlockRoots(ctx, filter)
-	if err != nil {
-		log.WithError(err).Debug("Failed to retrieve block roots")
-		s.writeErrorResponseToStream(responseCodeServerError, genericError, stream)
-		traceutil.AnnotateError(span, err)
-		return err
+	roots := make([][32]byte, 0, len(blks))
+	for _, b := range blks {
+		root, err := stateutil.BlockRoot(b.Block)
+		if err != nil {
+			log.WithError(err).Debug("Failed to retrieve block root")
+			s.writeErrorResponseToStream(responseCodeServerError, genericError, stream)
+			traceutil.AnnotateError(span, err)
+			return err
+		}
+		roots = append(roots, root)
 	}
 	// handle genesis case
 	if startSlot == 0 {

beacon-chain/sync/rpc_beacon_blocks_by_range_test.go

@@ -89,9 +89,15 @@ func TestRPCBeaconBlocksByRange_RPCHandlerReturnsSortedBlocks(t *testing.T) {
 	}
 
 	endSlot := req.StartSlot + (req.Step * (req.Count - 1))
+	expectedRoots := make([][32]byte, req.Count)
 	// Populate the database with blocks that would match the request.
-	for i := endSlot; i >= req.StartSlot; i -= req.Step {
-		require.NoError(t, d.SaveBlock(context.Background(), &ethpb.SignedBeaconBlock{Block: &ethpb.BeaconBlock{Slot: i}}))
+	for i, j := endSlot, req.Count-1; i >= req.StartSlot; i -= req.Step {
+		blk := &ethpb.SignedBeaconBlock{Block: &ethpb.BeaconBlock{Slot: i}}
+		rt, err := stateutil.BlockRoot(blk.Block)
+		require.NoError(t, err)
+		expectedRoots[j] = rt
+		require.NoError(t, d.SaveBlock(context.Background(), blk))
+		j--
 	}
 
 	// Start service with 160 as allowed blocks capacity (and almost zero capacity recovery).
@@ -106,14 +112,19 @@ func TestRPCBeaconBlocksByRange_RPCHandlerReturnsSortedBlocks(t *testing.T) {
 	p2.BHost.SetStreamHandler(pcl, func(stream network.Stream) {
 		defer wg.Done()
 		prevSlot := uint64(0)
-		for i := req.StartSlot; i < req.StartSlot+req.Count*req.Step; i += req.Step {
+		require.Equal(t, uint64(len(expectedRoots)), req.Count, "Number of roots not expected")
+		for i, j := req.StartSlot, 0; i < req.StartSlot+req.Count*req.Step; i += req.Step {
 			expectSuccess(t, r, stream)
 			res := &ethpb.SignedBeaconBlock{}
 			assert.NoError(t, r.p2p.Encoding().DecodeWithMaxLength(stream, res))
 			if res.Block.Slot < prevSlot {
 				t.Errorf("Received block is unsorted with slot %d lower than previous slot %d", res.Block.Slot, prevSlot)
 			}
+			rt, err := stateutil.BlockRoot(res.Block)
+			require.NoError(t, err)
+			assert.Equal(t, expectedRoots[j], rt, "roots not equal")
 			prevSlot = res.Block.Slot
+			j++
 		}
 	})