HIP-30: Shard reduction

core/state_processor.go

@@ -185,7 +185,7 @@ func (p *StateProcessor) Process(
 		}
 	}
 
-	if err := MayTestnetShardReduction(p.bc, statedb, header); err != nil {
+	if err := MayShardReduction(p.bc, statedb, header); err != nil {
 		return nil, nil, nil, nil, 0, nil, statedb, err
 	}
 
@@ -442,13 +442,16 @@ func StakingToMessage(
 	return msg, nil
 }
 
-// MayTestnetShardReduction handles the change in the number of Shards. It will mark the affected validator as inactive.
+// MayShardReduction handles the change in the number of Shards. It will mark the affected validator as inactive.
 // This function does not handle all cases, only for ShardNum from 4 to 2.
-func MayTestnetShardReduction(bc ChainContext, statedb *state.DB, header *block.Header) error {
+func MayShardReduction(bc ChainContext, statedb *state.DB, header *block.Header) error {
 	isBeaconChain := header.ShardID() == shard.BeaconChainShardID
 	isLastBlock := shard.Schedule.IsLastBlock(header.Number().Uint64())
-	isTestnet := nodeconfig.GetDefaultConfig().GetNetworkType() == nodeconfig.Testnet
-	if !(isTestnet && isBeaconChain && isLastBlock) {
+	networkType := nodeconfig.GetDefaultConfig().GetNetworkType()
+	isTestnet := networkType == nodeconfig.Testnet
+	isMainnet := networkType == nodeconfig.Mainnet
+	isReducenet := isMainnet || isTestnet
+	if !(isReducenet && isBeaconChain && isLastBlock) {
 		return nil
 	}
 	curInstance := shard.Schedule.InstanceForEpoch(header.Epoch())
@@ -479,6 +482,15 @@ func MayTestnetShardReduction(bc ChainContext, statedb *state.DB, header *block.
 		for _, pubKey := range validator.SlotPubKeys {
 			curShard := new(big.Int).Mod(pubKey.Big(), big.NewInt(int64(curNumShards))).Uint64()
 			nextShard := new(big.Int).Mod(pubKey.Big(), big.NewInt(int64(nextNumShards))).Uint64()
+			// background: any editValidator transactions take effect at next epoch.
+			// assumption: shard reduction happens at epoch X.
+			// validators who wish to continue validating after the shard reduction occurs
+			// must have a different node running with a key from shard 0 or 1.
+			// this key must be added to the validator during epoch X - 1
+			// and keys belonging to shards 2 and 3 removed at that point in time.
+			// the different node running will be unelected, but continue syncing in X - 1.
+			// if elected, it will start validating in epoch X.
+			// once epoch X begins, they can terminate servers from shards 2 and 3.
 			if curShard >= uint64(nextNumShards) || curShard != nextShard {
 				validator.Status = effective.Inactive
 				break

internal/chain/reward.go

@@ -224,7 +224,9 @@ func getDefaultStakingReward(bc engine.ChainReader, epoch *big.Int, blockNum uin
 		}
 	} else {
 		// Mainnet (other nets):
-		if bc.Config().IsTwoSeconds(epoch) {
+		if bc.Config().IsHIP30(epoch) {
+			defaultReward = stakingReward.HIP30StakedBlocks
+		} else if bc.Config().IsTwoSeconds(epoch) {
 			defaultReward = stakingReward.TwoSecStakedBlocks
 		} else if bc.Config().IsFiveSeconds(epoch) {
 			defaultReward = stakingReward.FiveSecStakedBlocks

internal/configs/sharding/testnet.go

@@ -161,7 +161,6 @@ var (
 		feeCollectorsTestnet, numeric.ZeroDec(), ethCommon.Address{},
 		testnetReshardingEpoch, TestnetSchedule.BlocksPerEpoch(),
 	)
-
 	testnetV5 = MustNewInstance(
 		2, 30, 8, 0.15,
 		numeric.MustNewDecFromStr("0.90"), genesis.TNHarmonyAccountsV1,

node/node_newblock.go

@@ -265,7 +265,7 @@ func (node *Node) ProposeNewBlock(commitSigs chan []byte) (*types.Block, error)
 		}
 	}
 
-	node.Worker.ApplyTestnetShardReduction()
+	node.Worker.ApplyShardReduction()
 	// Prepare shard state
 	var shardState *shard.State
 	if shardState, err = node.Blockchain().SuperCommitteeForNextEpoch(

node/worker/worker.go

@@ -224,9 +224,9 @@ func (w *Worker) commitStakingTransaction(
 	return nil
 }
 
-// ApplyTestnetShardReduction only used to reduce shards of Testnet
-func (w *Worker) ApplyTestnetShardReduction() {
-	core.MayTestnetShardReduction(w.chain, w.current.state, w.current.header)
+// ApplyShardReduction only used to reduce shards of Testnet
+func (w *Worker) ApplyShardReduction() {
+	core.MayShardReduction(w.chain, w.current.state, w.current.header)
 }
 
 var (

staking/reward/values.go

@@ -31,6 +31,13 @@ var (
 	TwoSecStakedBlocks = numeric.NewDecFromBigInt(new(big.Int).Mul(
 		big.NewInt(7*denominations.Nano), big.NewInt(denominations.Nano),
 	))
+	// HIP30StakedBlocks is the reward received after HIP-30 goes into
+	// effect. It is simply double the TwoSecStakedBlocks reward, since
+	// the number of shards is being halved and we keep emission
+	// constant.
+	HIP30StakedBlocks = numeric.NewDecFromBigInt(new(big.Int).Mul(
+		big.NewInt(14*denominations.Nano), big.NewInt(denominations.Nano),
+	))
 
 	// TotalInitialTokens is the total amount of tokens (in ONE) at block 0 of the network.
 	// This should be set/change on the node's init according to the core.GenesisSpec.