From b5fb63d09139aeaad2348afe512dd33229a9481b Mon Sep 17 00:00:00 2001
From: Evgenii Stratonikov <evgeniy@nspcc.ru>
Date: Tue, 23 Jun 2020 13:39:19 +0300
Subject: [PATCH] *: specify first state root index in config

---
 config/protocol.testnet.yml   |  2 ++
 pkg/config/protocol_config.go | 12 +++++++-----
 pkg/network/server.go         | 13 ++++++++++++-
 3 files changed, 21 insertions(+), 6 deletions(-)

diff --git a/config/protocol.testnet.yml b/config/protocol.testnet.yml
index 711485d26..8ccb17005 100644
--- a/config/protocol.testnet.yml
+++ b/config/protocol.testnet.yml
@@ -2,6 +2,8 @@ ProtocolConfiguration:
   Magic: 1953787457
   AddressVersion: 23
   SecondsPerBlock: 15
+  EnableStateRoot: true
+  StateRootEnableIndex: 4380100
   LowPriorityThreshold: 0.000
   MemPoolSize: 50000
   StandbyValidators:
diff --git a/pkg/config/protocol_config.go b/pkg/config/protocol_config.go
index 1974bd72e..dff592038 100644
--- a/pkg/config/protocol_config.go
+++ b/pkg/config/protocol_config.go
@@ -36,11 +36,13 @@ type (
 		MaxFreeTransactionsPerBlock int `yaml:"MaxFreeTransactionsPerBlock"`
 		MemPoolSize                 int `yaml:"MemPoolSize"`
 		// SaveStorageBatch enables storage batch saving before every persist.
-		SaveStorageBatch  bool      `yaml:"SaveStorageBatch"`
-		SecondsPerBlock   int       `yaml:"SecondsPerBlock"`
-		SeedList          []string  `yaml:"SeedList"`
-		StandbyValidators []string  `yaml:"StandbyValidators"`
-		SystemFee         SystemFee `yaml:"SystemFee"`
+		SaveStorageBatch  bool     `yaml:"SaveStorageBatch"`
+		SecondsPerBlock   int      `yaml:"SecondsPerBlock"`
+		SeedList          []string `yaml:"SeedList"`
+		StandbyValidators []string `yaml:"StandbyValidators"`
+		// StateRootEnableIndex specifies starting height for state root calculations and exchange.
+		StateRootEnableIndex uint32    `yaml:"StateRootEnableIndex"`
+		SystemFee            SystemFee `yaml:"SystemFee"`
 		// Whether to verify received blocks.
 		VerifyBlocks bool `yaml:"VerifyBlocks"`
 		// Whether to verify transactions in received blocks.
diff --git a/pkg/network/server.go b/pkg/network/server.go
index 709da94aa..9364da476 100644
--- a/pkg/network/server.go
+++ b/pkg/network/server.go
@@ -602,7 +602,8 @@ func (s *Server) handleGetHeadersCmd(p Peer, gh *payload.GetBlocks) error {
 
 // handleGetRootsCmd processees `getroots` request.
 func (s *Server) handleGetRootsCmd(p Peer, gr *payload.GetStateRoots) error {
-	if !s.chain.GetConfig().EnableStateRoot {
+	cfg := s.chain.GetConfig()
+	if !cfg.EnableStateRoot || gr.Start < cfg.StateRootEnableIndex {
 		return nil
 	}
 	count := gr.Count
@@ -628,6 +629,9 @@ func (s *Server) handleRootsCmd(p Peer, rs *payload.StateRoots) error {
 		return nil
 	}
 	h := s.chain.StateHeight()
+	if h < s.chain.GetConfig().StateRootEnableIndex {
+		h = s.chain.GetConfig().StateRootEnableIndex
+	}
 	for i := range rs.Roots {
 		if rs.Roots[i].Index <= h {
 			continue
@@ -642,6 +646,13 @@ func (s *Server) handleRootsCmd(p Peer, rs *payload.StateRoots) error {
 func (s *Server) requestStateRoot(p Peer) error {
 	stateHeight := s.chain.StateHeight()
 	hdrHeight := s.chain.BlockHeight()
+	enableIndex := s.chain.GetConfig().StateRootEnableIndex
+	if hdrHeight < enableIndex {
+		return nil
+	}
+	if stateHeight < enableIndex {
+		stateHeight = enableIndex - 1
+	}
 	count := uint32(payload.MaxStateRootsAllowed)
 	if diff := hdrHeight - stateHeight; diff < count {
 		count = diff