From d099c2790b59eab53800602b0ccf52c05f31b812 Mon Sep 17 00:00:00 2001
From: Nishant Das <nishdas93@gmail.com>
Date: Sat, 4 Jun 2022 09:58:03 +0800
Subject: [PATCH] Add Back Timestamp Related Deposit Processing (#10806)

* use it

* add test

* fix

Co-authored-by: terencechain <terence@prysmaticlabs.com>
---
 beacon-chain/powchain/block_reader.go |  2 +-
 beacon-chain/powchain/service.go      | 15 +++++++++-----
 beacon-chain/powchain/service_test.go | 30 +++++++++++++++++++++++++--
 3 files changed, 39 insertions(+), 8 deletions(-)

diff --git a/beacon-chain/powchain/block_reader.go b/beacon-chain/powchain/block_reader.go
index 6ce9cda9f..704713065 100644
--- a/beacon-chain/powchain/block_reader.go
+++ b/beacon-chain/powchain/block_reader.go
@@ -210,7 +210,7 @@ func (s *Service) retrieveHeaderInfo(ctx context.Context, bNum uint64) (*types.H
 			return nil, err
 		}
 		if blk == nil {
-			return nil, errors.New("header with the provided number does not exist")
+			return nil, errors.Errorf("header with the number %d does not exist", bNum)
 		}
 		if err := s.headerCache.AddHeader(blk); err != nil {
 			return nil, err
diff --git a/beacon-chain/powchain/service.go b/beacon-chain/powchain/service.go
index 3a3dc8034..ac4b1aaa7 100644
--- a/beacon-chain/powchain/service.go
+++ b/beacon-chain/powchain/service.go
@@ -369,12 +369,17 @@ func (s *Service) ETH1ConnectionErrors() []error {
 
 // refers to the latest eth1 block which follows the condition: eth1_timestamp +
 // SECONDS_PER_ETH1_BLOCK * ETH1_FOLLOW_DISTANCE <= current_unix_time
-func (s *Service) followedBlockHeight(_ context.Context) (uint64, error) {
-	latestValidBlock := uint64(0)
-	if s.latestEth1Data.BlockHeight > params.BeaconConfig().Eth1FollowDistance {
-		latestValidBlock = s.latestEth1Data.BlockHeight - params.BeaconConfig().Eth1FollowDistance
+func (s *Service) followedBlockHeight(ctx context.Context) (uint64, error) {
+	followTime := params.BeaconConfig().Eth1FollowDistance * params.BeaconConfig().SecondsPerETH1Block
+	latestBlockTime := uint64(0)
+	if s.latestEth1Data.BlockTime > followTime {
+		latestBlockTime = s.latestEth1Data.BlockTime - followTime
 	}
-	return latestValidBlock, nil
+	blk, err := s.BlockByTimestamp(ctx, latestBlockTime)
+	if err != nil {
+		return 0, err
+	}
+	return blk.Number.Uint64(), nil
 }
 
 func (s *Service) initDepositCaches(ctx context.Context, ctrs []*ethpb.DepositContainer) error {
diff --git a/beacon-chain/powchain/service_test.go b/beacon-chain/powchain/service_test.go
index fba5c3d89..10d2e430e 100644
--- a/beacon-chain/powchain/service_test.go
+++ b/beacon-chain/powchain/service_test.go
@@ -81,7 +81,8 @@ func (g *goodNotifier) StateFeed() *event.Feed {
 }
 
 type goodFetcher struct {
-	backend *backends.SimulatedBackend
+	backend     *backends.SimulatedBackend
+	blockNumMap map[uint64]*gethTypes.Header
 }
 
 func (_ *goodFetcher) Close() {}
@@ -104,12 +105,15 @@ func (g *goodFetcher) HeaderByHash(_ context.Context, hash common.Hash) (*gethTy
 }
 
 func (g *goodFetcher) HeaderByNumber(_ context.Context, number *big.Int) (*gethTypes.Header, error) {
-	if g.backend == nil {
+	if g.backend == nil && g.blockNumMap == nil {
 		return &gethTypes.Header{
 			Number: big.NewInt(15),
 			Time:   150,
 		}, nil
 	}
+	if g.blockNumMap != nil {
+		return g.blockNumMap[number.Uint64()], nil
+	}
 	var header *gethTypes.Header
 	if number == nil {
 		header = g.backend.Blockchain().CurrentHeader()
@@ -864,6 +868,28 @@ func TestService_CacheBlockHeaders(t *testing.T) {
 	assert.Equal(t, 5, rClient.numOfCalls)
 }
 
+func TestService_FollowBlock(t *testing.T) {
+	followTime := params.BeaconConfig().Eth1FollowDistance * params.BeaconConfig().SecondsPerETH1Block
+	followTime += 10000
+	bMap := make(map[uint64]*gethTypes.Header)
+	for i := uint64(3000); i > 0; i-- {
+		bMap[i] = &gethTypes.Header{
+			Number: big.NewInt(int64(i)),
+			Time:   followTime + (i * 40),
+		}
+	}
+	s := &Service{
+		cfg:             &config{eth1HeaderReqLimit: 1000},
+		eth1DataFetcher: &goodFetcher{blockNumMap: bMap},
+		headerCache:     newHeaderCache(),
+		latestEth1Data:  &ethpb.LatestETH1Data{BlockTime: (3000 * 40) + followTime, BlockHeight: 3000},
+	}
+	h, err := s.followedBlockHeight(context.Background())
+	assert.NoError(t, err)
+	// With a much higher blocktime, the follow height is respectively shortened.
+	assert.Equal(t, uint64(2283), h)
+}
+
 type slowRPCClient struct {
 	limit      int
 	numOfCalls int