consortium/v2: distribute finality reward for the voters in parent block (#337)

* consortium/v2: distribute finality reward for the voters in parent block

Because the finality votes are assembled after we FinalizeAndAssemble the block
and the finality reward distribution transaction is in FinalizeAndAssemble, we
cannot reward the finality voters in the current block right away. Instead, the
reward distribution is delayed until next block. So in the FinalizeAndAssemble,
we look at the finality voters in the parent header and distribute reward to
them.

* consortium/v2: integrate with the finality tracking contract

This commit integrates with the finality tracking contract
(axieinfinity/ronin-dpos-contracts#279) to record the
finality reward for voters.

Author: minh-bq

consensus/consortium/common/contract.go

@@ -15,6 +15,7 @@ import (
 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/ethereum/go-ethereum/common/math"
 	"github.com/ethereum/go-ethereum/consensus"
+	finalityTracking "github.com/ethereum/go-ethereum/consensus/consortium/generated_contracts/finality_tracking"
 	"github.com/ethereum/go-ethereum/consensus/consortium/generated_contracts/profile"
 	roninValidatorSet "github.com/ethereum/go-ethereum/consensus/consortium/generated_contracts/ronin_validator_set"
 	slashIndicator "github.com/ethereum/go-ethereum/consensus/consortium/generated_contracts/slash_indicator"
@@ -69,6 +70,7 @@ type ContractIntegrator struct {
 	roninValidatorSetSC *roninValidatorSet.RoninValidatorSet
 	slashIndicatorSC    *slashIndicator.SlashIndicator
 	profileSC           *profile.Profile
+	finalityTrackingSC  *finalityTracking.FinalityTracking
 	signTxFn            SignerTxFn
 	coinbase            common.Address
 }
@@ -93,11 +95,18 @@ func NewContractIntegrator(config *chainParams.ChainConfig, backend bind.Contrac
 		return nil, err
 	}
 
+	// Create Finality Tracking contract instance
+	finalityTrackingSC, err := finalityTracking.NewFinalityTracking(config.ConsortiumV2Contracts.FinalityTracking, backend)
+	if err != nil {
+		return nil, err
+	}
+
 	return &ContractIntegrator{
 		chainId:             config.ChainID,
 		roninValidatorSetSC: roninValidatorSetSC,
 		slashIndicatorSC:    slashIndicatorSC,
 		profileSC:           profileSC,
+		finalityTrackingSC:  finalityTrackingSC,
 		signTxFn:            signTxFn,
 		signer:              types.LatestSignerForChainID(config.ChainID),
 		coinbase:            coinbase,
@@ -214,8 +223,7 @@ func (c *ContractIntegrator) Slash(opts *ApplyTransactOpts, spoiledValidator com
 
 func (c *ContractIntegrator) FinalityReward(opts *ApplyTransactOpts, votedValidators []common.Address) error {
 	nonce := opts.State.GetNonce(c.coinbase)
-	// FIXME: Change this
-	tx, err := c.slashIndicatorSC.SlashUnavailability(getTransactionOpts(c.coinbase, nonce, c.chainId, c.signTxFn), common.Address{})
+	tx, err := c.finalityTrackingSC.RecordFinality(getTransactionOpts(c.coinbase, nonce, c.chainId, c.signTxFn), votedValidators)
 	if err != nil {
 		return err
 	}

consensus/consortium/generated_contracts/finality_tracking/finality_tracking.go

@@ -729,17 +729,24 @@ func (c *Consortium) processSystemTransactions(chain consensus.ChainHeaderReader
 
 	_, _, _, contract := c.readSignerAndContract()
 
-	if c.chainConfig.IsShillin(header.Number) {
-		extraData, err := finality.DecodeExtra(header.Extra, c.chainConfig.IsShillin(header.Number))
+	// If the parent's block includes the finality votes, distribute reward for the voters
+	if c.chainConfig.IsShillin(new(big.Int).Sub(header.Number, common.Big1)) {
+		parentHeader := chain.GetHeaderByHash(header.ParentHash)
+		extraData, err := finality.DecodeExtra(parentHeader.Extra, true)
 		if err != nil {
 			return err
 		}
 		if extraData.HasFinalityVote == 1 {
+			parentSnap, err := c.snapshot(chain, parentHeader.Number.Uint64()-1, parentHeader.ParentHash, nil)
+			if err != nil {
+				return err
+			}
+
 			votedValidatorPositions := extraData.FinalityVotedValidators.Indices()
 			var votedValidators []common.Address
 			for _, position := range votedValidatorPositions {
 				// The header has been verified so there must be no out of bound here
-				votedValidators = append(votedValidators, snap.ValidatorsWithBlsPub[position].Address)
+				votedValidators = append(votedValidators, parentSnap.ValidatorsWithBlsPub[position].Address)
 			}
 
 			if err := contract.FinalityReward(transactOpts, votedValidators); err != nil {

consensus/consortium/v2/consortium.go

@@ -573,6 +573,7 @@ type ConsortiumV2Contracts struct {
 	RoninValidatorSet common.Address `json:"roninValidatorSet"`
 	SlashIndicator    common.Address `json:"slashIndicator"`
 	ProfileContract   common.Address `json:"profileContract"`
+	FinalityTracking  common.Address `json:"finalityTracking"`
 }
 
 func (c *ConsortiumV2Contracts) IsSystemContract(address common.Address) bool {
@@ -619,11 +620,16 @@ func (c *ChainConfig) String() string {
 		profileContract = c.ConsortiumV2Contracts.ProfileContract
 	}
 
+	finalityTrackingContract := common.HexToAddress("")
+	if c.ConsortiumV2Contracts != nil {
+		finalityTrackingContract = c.ConsortiumV2Contracts.FinalityTracking
+	}
+
 	chainConfigFmt := "{ChainID: %v Homestead: %v DAO: %v DAOSupport: %v EIP150: %v EIP155: %v EIP158: %v Byzantium: %v Constantinople: %v "
 	chainConfigFmt += "Petersburg: %v Istanbul: %v, Odysseus: %v, Fenix: %v, Muir Glacier: %v, Berlin: %v, London: %v, Arrow Glacier: %v, "
 	chainConfigFmt += "Engine: %v, Blacklist Contract: %v, Fenix Validator Contract: %v, ConsortiumV2: %v, ConsortiumV2.RoninValidatorSet: %v, "
 	chainConfigFmt += "ConsortiumV2.SlashIndicator: %v, ConsortiumV2.StakingContract: %v, Puffy: %v, Buba: %v, Olek: %v, Shillin: %v, "
-	chainConfigFmt += "ConsortiumV2.ProfileContract: %v}"
+	chainConfigFmt += "ConsortiumV2.ProfileContract: %v, ConsortiumV2.FinalityTracking: %v}"
 
 	return fmt.Sprintf(chainConfigFmt,
 		c.ChainID,
@@ -655,6 +661,7 @@ func (c *ChainConfig) String() string {
 		c.OlekBlock,
 		c.ShillinBlock,
 		profileContract.Hex(),
+		finalityTrackingContract.Hex(),
 	)
 }