From 2cd731a067fc74fd23240edae6366fa87939bb3d Mon Sep 17 00:00:00 2001
From: Anna Shaleva <shaleva.ann@nspcc.ru>
Date: Mon, 11 Nov 2024 19:58:12 +0300
Subject: [PATCH] check: extend ProcessBlock callback with error handler

For anti-MEV extension it's possible that some commits carry invalid
share which is impossible to check at the commit verification level.
In this case node should collect some more commits.

Signed-off-by: Anna Shaleva <shaleva.ann@nspcc.ru>
---
 check.go                        | 13 ++++++++++---
 config.go                       |  6 +++---
 dbft_test.go                    |  2 +-
 internal/consensus/consensus.go |  2 +-
 internal/simulation/main.go     |  3 ++-
 5 files changed, 17 insertions(+), 9 deletions(-)

diff --git a/check.go b/check.go
index 4109f721..7338ee05 100644
--- a/check.go
+++ b/check.go
@@ -112,8 +112,6 @@ func (d *DBFT[H]) checkCommit() {
 		return
 	}
 
-	d.lastBlockIndex = d.BlockIndex
-	d.lastBlockTime = d.Timer.Now()
 	d.block = d.CreateBlock()
 	hash := d.block.Hash()
 
@@ -124,8 +122,17 @@ func (d *DBFT[H]) checkCommit() {
 		zap.Stringer("merkle", d.block.MerkleRoot()),
 		zap.Stringer("prev", d.block.PrevHash()))
 
+	err := d.ProcessBlock(d.block)
+	if err != nil && d.isAntiMEVExtensionEnabled() { // errors not supported for AntiMEVExtensions mode off.
+		d.Logger.Info("can't process Block, waiting for more Commits to be collected",
+			zap.Error(err),
+			zap.Int("count", count))
+		return
+	}
+
+	d.lastBlockIndex = d.BlockIndex
+	d.lastBlockTime = d.Timer.Now()
 	d.blockProcessed = true
-	d.ProcessBlock(d.block)
 
 	// Do not initialize consensus process immediately. It's the caller's duty to
 	// start the new block acceptance process and call Reset at the
diff --git a/config.go b/config.go
index 3db107a2..6339d00e 100644
--- a/config.go
+++ b/config.go
@@ -51,7 +51,7 @@ type Config[H Hash] struct {
 	// ProcessBlock is called every time new preBlock is accepted.
 	ProcessPreBlock func(b PreBlock[H]) error
 	// ProcessBlock is called every time new block is accepted.
-	ProcessBlock func(b Block[H])
+	ProcessBlock func(b Block[H]) error
 	// GetBlock should return block with hash.
 	GetBlock func(h H) Block[H]
 	// WatchOnly tells if a node should only watch.
@@ -108,7 +108,7 @@ func defaultConfig[H Hash]() *Config[H] {
 		GetVerified:        func() []Transaction[H] { return make([]Transaction[H], 0) },
 		VerifyBlock:        func(Block[H]) bool { return true },
 		Broadcast:          func(ConsensusPayload[H]) {},
-		ProcessBlock:       func(Block[H]) {},
+		ProcessBlock:       func(Block[H]) error { return nil },
 		GetBlock:           func(H) Block[H] { return nil },
 		WatchOnly:          func() bool { return false },
 		CurrentHeight:      nil,
@@ -276,7 +276,7 @@ func WithBroadcast[H Hash](f func(m ConsensusPayload[H])) func(config *Config[H]
 }
 
 // WithProcessBlock sets ProcessBlock.
-func WithProcessBlock[H Hash](f func(b Block[H])) func(config *Config[H]) {
+func WithProcessBlock[H Hash](f func(b Block[H]) error) func(config *Config[H]) {
 	return func(cfg *Config[H]) {
 		cfg.ProcessBlock = f
 	}
diff --git a/dbft_test.go b/dbft_test.go
index da113e80..2fcdea1a 100644
--- a/dbft_test.go
+++ b/dbft_test.go
@@ -1131,7 +1131,7 @@ func (s *testState) getOptions() []func(*dbft.Config[crypto.Uint256]) {
 		}),
 		dbft.WithBroadcast[crypto.Uint256](func(p Payload) { s.ch = append(s.ch, p) }),
 		dbft.WithGetTx[crypto.Uint256](s.pool.Get),
-		dbft.WithProcessBlock[crypto.Uint256](func(b dbft.Block[crypto.Uint256]) { s.blocks = append(s.blocks, b) }),
+		dbft.WithProcessBlock[crypto.Uint256](func(b dbft.Block[crypto.Uint256]) error { s.blocks = append(s.blocks, b); return nil }),
 		dbft.WithWatchOnly[crypto.Uint256](func() bool { return false }),
 		dbft.WithGetBlock[crypto.Uint256](func(crypto.Uint256) dbft.Block[crypto.Uint256] { return nil }),
 		dbft.WithTimer[crypto.Uint256](timer.New()),
diff --git a/internal/consensus/consensus.go b/internal/consensus/consensus.go
index c4cd7b69..e0ebdd6d 100644
--- a/internal/consensus/consensus.go
+++ b/internal/consensus/consensus.go
@@ -13,7 +13,7 @@ func New(logger *zap.Logger, key dbft.PrivateKey, pub dbft.PublicKey,
 	getTx func(uint256 crypto.Uint256) dbft.Transaction[crypto.Uint256],
 	getVerified func() []dbft.Transaction[crypto.Uint256],
 	broadcast func(dbft.ConsensusPayload[crypto.Uint256]),
-	processBlock func(dbft.Block[crypto.Uint256]),
+	processBlock func(dbft.Block[crypto.Uint256]) error,
 	currentHeight func() uint32,
 	currentBlockHash func() crypto.Uint256,
 	getValidators func(...dbft.Transaction[crypto.Uint256]) []dbft.PublicKey,
diff --git a/internal/simulation/main.go b/internal/simulation/main.go
index 0a2973ec..0e12bc1a 100644
--- a/internal/simulation/main.go
+++ b/internal/simulation/main.go
@@ -179,7 +179,7 @@ func (n *simNode) GetValidators(...dbft.Transaction[crypto.Uint256]) []dbft.Publ
 	return n.validators
 }
 
-func (n *simNode) ProcessBlock(b dbft.Block[crypto.Uint256]) {
+func (n *simNode) ProcessBlock(b dbft.Block[crypto.Uint256]) error {
 	n.d.Logger.Debug("received block", zap.Uint32("height", b.Index()))
 
 	for _, tx := range b.Transactions() {
@@ -188,6 +188,7 @@ func (n *simNode) ProcessBlock(b dbft.Block[crypto.Uint256]) {
 
 	n.height = b.Index()
 	n.lastHash = b.Hash()
+	return nil
 }
 
 // VerifyPayload verifies that payload was received from a good validator.