feat: [v0.45.12] add minimum commission rate to x/staking (#182)

Co-authored-by: Hansol Lee <38912532+hansol-medi@users.noreply.github.com>

Makefile

@@ -10,9 +10,9 @@ BINDIR ?= $(GOPATH)/bin
 BUILDDIR ?= $(CURDIR)/build
 SIMAPP = ./simapp
 MOCKS_DIR = $(CURDIR)/tests/mocks
-HTTPS_GIT := https://github.com/cosmos/cosmos-sdk.git
+HTTPS_GIT := https://github.com/medibloc/cosmos-sdk.git
 DOCKER := $(shell which docker)
-DOCKER_BUF := $(DOCKER) run --rm -v $(CURDIR):/workspace --workdir /workspace bufbuild/buf
+DOCKER_BUF := $(DOCKER) run --rm -v $(CURDIR):/workspace --workdir /workspace bufbuild/buf:0.56.0
 
 export GO111MODULE = on
 
@@ -396,7 +396,7 @@ proto-lint:
 	@$(DOCKER_BUF) lint --error-format=json
 
 proto-check-breaking:
-	@$(DOCKER_BUF) breaking --against $(HTTPS_GIT)#branch=master
+	@$(DOCKER_BUF) breaking --against $(HTTPS_GIT)#branch=v0.45.12-panacea
 
 
 TM_URL              = https://raw.githubusercontent.com/tendermint/tendermint/v0.34.22/proto/tendermint

docs/core/proto-docs.md

@@ -6728,6 +6728,7 @@ Params defines the parameters for the staking module.
 | `max_entries` | [uint32](#uint32) |  | max_entries is the max entries for either unbonding delegation or redelegation (per pair/trio). |
 | `historical_entries` | [uint32](#uint32) |  | historical_entries is the number of historical entries to persist. |
 | `bond_denom` | [string](#string) |  | bond_denom defines the bondable coin denomination. |
+| `min_commission_rate` | [string](#string) |  | min_commission_rate is the chain-wide minimum commission rate that a validator can charge their delegators |
 
 
 

proto/cosmos/staking/v1beta1/staking.proto

@@ -282,6 +282,12 @@ message Params {
   uint32 historical_entries = 4 [(gogoproto.moretags) = "yaml:\"historical_entries\""];
   // bond_denom defines the bondable coin denomination.
   string bond_denom = 5 [(gogoproto.moretags) = "yaml:\"bond_denom\""];
+  // min_commission_rate is the chain-wide minimum commission rate that a validator can charge their delegators
+  string min_commission_rate = 6 [
+    (gogoproto.moretags)   = "yaml:\"min_commission_rate\"",
+    (gogoproto.customtype) = "github.com/cosmos/cosmos-sdk/types.Dec",
+    (gogoproto.nullable)   = false
+  ];
 }
 
 // DelegationResponse is equivalent to Delegation except that it contains a

x/staking/client/testutil/suite.go

@@ -876,12 +876,13 @@ func (s *IntegrationTestSuite) TestGetCmdQueryParams() {
 historical_entries: 10000
 max_entries: 7
 max_validators: 100
+min_commission_rate: "0.000000000000000000"
 unbonding_time: 1814400s`,
 		},
 		{
 			"with json output",
 			[]string{fmt.Sprintf("--%s=json", tmcli.OutputFlag)},
-			`{"unbonding_time":"1814400s","max_validators":100,"max_entries":7,"historical_entries":10000,"bond_denom":"stake"}`,
+			`{"unbonding_time":"1814400s","max_validators":100,"max_entries":7,"historical_entries":10000,"bond_denom":"stake","min_commission_rate":"0.000000000000000000"}`,
 		},
 	}
 	for _, tc := range testCases {

x/staking/keeper/msg_server.go

@@ -74,6 +74,11 @@ func (k msgServer) CreateValidator(goCtx context.Context, msg *types.MsgCreateVa
 	if err != nil {
 		return nil, err
 	}
+
+	if msg.Commission.Rate.LT(k.MinCommissionRate(ctx)) {
+		return nil, sdkerrors.Wrapf(types.ErrCommissionLTMinRate, "cannot set validator commission to less than minimum rate of %s", k.MinCommissionRate(ctx))
+	}
+
 	commission := types.NewCommissionWithTime(
 		msg.Commission.Rate, msg.Commission.MaxRate,
 		msg.Commission.MaxChangeRate, ctx.BlockHeader().Time,

x/staking/keeper/msg_server_test.go

@@ -0,0 +1,40 @@
+package keeper_test
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	tmproto "github.com/tendermint/tendermint/proto/tendermint/types"
+
+	"github.com/cosmos/cosmos-sdk/simapp"
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	"github.com/cosmos/cosmos-sdk/x/staking"
+	stakingtypes "github.com/cosmos/cosmos-sdk/x/staking/types"
+)
+
+func TestCreateValidatorWithLessThanMinCommission(t *testing.T) {
+	PKS := simapp.CreateTestPubKeys(1)
+	valConsPk1 := PKS[0]
+
+	app := simapp.Setup(false)
+	ctx := app.BaseApp.NewContext(false, tmproto.Header{})
+	addrs := simapp.AddTestAddrs(app, ctx, 3, sdk.NewInt(1234))
+	// set min commission rate to non-zero
+	params := app.StakingKeeper.GetParams(ctx)
+	params.MinCommissionRate = sdk.NewDecWithPrec(1, 2)
+	app.StakingKeeper.SetParams(ctx, params)
+
+	// create validator with 0% commission
+	msg, err := stakingtypes.NewMsgCreateValidator(
+		sdk.ValAddress(addrs[0]),
+		valConsPk1,
+		sdk.NewInt64Coin(sdk.DefaultBondDenom, 100),
+		stakingtypes.Description{},
+		stakingtypes.NewCommissionRates(sdk.NewDec(0), sdk.NewDecWithPrec(5, 1), sdk.NewDec(0)),
+		sdk.OneInt())
+	require.NoError(t, err)
+
+	sh := staking.NewHandler(app.StakingKeeper)
+	_, err = sh(ctx, msg)
+	require.Error(t, err)
+}

x/staking/keeper/params.go

@@ -39,6 +39,12 @@ func (k Keeper) BondDenom(ctx sdk.Context) (res string) {
 	return
 }
 
+// MinCommissionRate - Minimum validator commission rate
+func (k Keeper) MinCommissionRate(ctx sdk.Context) (res sdk.Dec) {
+	k.paramstore.Get(ctx, types.KeyMinCommissionRate, &res)
+	return
+}
+
 // PowerReduction - is the amount of staking tokens required for 1 unit of consensus-engine power.
 // Currently, this returns a global variable that the app developer can tweak.
 // TODO: we might turn this into an on-chain param:
@@ -55,6 +61,7 @@ func (k Keeper) GetParams(ctx sdk.Context) types.Params {
 		k.MaxEntries(ctx),
 		k.HistoricalEntries(ctx),
 		k.BondDenom(ctx),
+		k.MinCommissionRate(ctx),
 	)
 }
 

x/staking/keeper/validator.go

@@ -142,6 +142,10 @@ func (k Keeper) UpdateValidatorCommission(ctx sdk.Context,
 		return commission, err
 	}
 
+	if newRate.LT(k.MinCommissionRate(ctx)) {
+		return commission, fmt.Errorf("cannot set validator commission to less than minimum rate of %s", k.MinCommissionRate(ctx))
+	}
+
 	commission.Rate = newRate
 	commission.UpdateTime = blockTime
 

x/staking/keeper/validator_test.go

@@ -1043,6 +1043,10 @@ func TestUpdateValidatorCommission(t *testing.T) {
 	app, ctx, _, addrVals := bootstrapValidatorTest(t, 1000, 20)
 	ctx = ctx.WithBlockHeader(tmproto.Header{Time: time.Now().UTC()})
 
+	params := app.StakingKeeper.GetParams(ctx)
+	params.MinCommissionRate = sdk.MustNewDecFromStr("0.05")
+	app.StakingKeeper.SetParams(ctx, params)
+
 	commission1 := types.NewCommissionWithTime(
 		sdk.NewDecWithPrec(1, 1), sdk.NewDecWithPrec(3, 1),
 		sdk.NewDecWithPrec(1, 1), time.Now().UTC().Add(time.Duration(-1)*time.Hour),
@@ -1067,6 +1071,7 @@ func TestUpdateValidatorCommission(t *testing.T) {
 		{val2, sdk.NewDecWithPrec(-1, 1), true},
 		{val2, sdk.NewDecWithPrec(4, 1), true},
 		{val2, sdk.NewDecWithPrec(3, 1), true},
+		{val2, sdk.NewDecWithPrec(1, 2), true}, // Commission rate below minimum
 		{val2, sdk.NewDecWithPrec(2, 1), false},
 	}
 

x/staking/legacy/v040/migrate.go

@@ -6,18 +6,19 @@ import (
 	codectypes "github.com/cosmos/cosmos-sdk/codec/types"
 	v034staking "github.com/cosmos/cosmos-sdk/x/staking/legacy/v034"
 	v038staking "github.com/cosmos/cosmos-sdk/x/staking/legacy/v038"
+	v040staking "github.com/cosmos/cosmos-sdk/x/staking/types"
 )
 
-func migrateBondStatus(oldStatus v034staking.BondStatus) BondStatus {
+func migrateBondStatus(oldStatus v034staking.BondStatus) v040staking.BondStatus {
 	switch oldStatus {
 	case v034staking.Unbonded:
-		return Unbonded
+		return v040staking.Unbonded
 
 	case v034staking.Unbonding:
-		return Unbonding
+		return v040staking.Unbonding
 
 	case v034staking.Bonded:
-		return Bonded
+		return v040staking.Bonded
 
 	default:
 		panic(fmt.Errorf("invalid bond status %d", oldStatus))
@@ -30,29 +31,29 @@ func migrateBondStatus(oldStatus v034staking.BondStatus) BondStatus {
 // - Convert addresses from bytes to bech32 strings.
 // - Update BondStatus staking constants.
 // - Re-encode in v0.40 GenesisState.
-func Migrate(stakingState v038staking.GenesisState) *GenesisState {
-	newLastValidatorPowers := make([]LastValidatorPower, len(stakingState.LastValidatorPowers))
+func Migrate(stakingState v038staking.GenesisState) *v040staking.GenesisState {
+	newLastValidatorPowers := make([]v040staking.LastValidatorPower, len(stakingState.LastValidatorPowers))
 	for i, oldLastValidatorPower := range stakingState.LastValidatorPowers {
-		newLastValidatorPowers[i] = LastValidatorPower{
+		newLastValidatorPowers[i] = v040staking.LastValidatorPower{
 			Address: oldLastValidatorPower.Address.String(),
 			Power:   oldLastValidatorPower.Power,
 		}
 	}
 
-	newValidators := make([]Validator, len(stakingState.Validators))
+	newValidators := make([]v040staking.Validator, len(stakingState.Validators))
 	for i, oldValidator := range stakingState.Validators {
 		pkAny, err := codectypes.NewAnyWithValue(oldValidator.ConsPubKey)
 		if err != nil {
 			panic(fmt.Sprintf("Can't pack validator consensus PK as Any: %s", err))
 		}
-		newValidators[i] = Validator{
+		newValidators[i] = v040staking.Validator{
 			OperatorAddress: oldValidator.OperatorAddress.String(),
 			ConsensusPubkey: pkAny,
 			Jailed:          oldValidator.Jailed,
 			Status:          migrateBondStatus(oldValidator.Status),
 			Tokens:          oldValidator.Tokens,
 			DelegatorShares: oldValidator.DelegatorShares,
-			Description: Description{
+			Description: v040staking.Description{
 				Moniker:         oldValidator.Description.Moniker,
 				Identity:        oldValidator.Description.Identity,
 				Website:         oldValidator.Description.Website,
@@ -61,8 +62,8 @@ func Migrate(stakingState v038staking.GenesisState) *GenesisState {
 			},
 			UnbondingHeight: oldValidator.UnbondingHeight,
 			UnbondingTime:   oldValidator.UnbondingCompletionTime,
-			Commission: Commission{
-				CommissionRates: CommissionRates{
+			Commission: v040staking.Commission{
+				CommissionRates: v040staking.CommissionRates{
 					Rate:          oldValidator.Commission.Rate,
 					MaxRate:       oldValidator.Commission.MaxRate,
 					MaxChangeRate: oldValidator.Commission.MaxChangeRate,
@@ -73,61 +74,62 @@ func Migrate(stakingState v038staking.GenesisState) *GenesisState {
 		}
 	}
 
-	newDelegations := make([]Delegation, len(stakingState.Delegations))
+	newDelegations := make([]v040staking.Delegation, len(stakingState.Delegations))
 	for i, oldDelegation := range stakingState.Delegations {
-		newDelegations[i] = Delegation{
+		newDelegations[i] = v040staking.Delegation{
 			DelegatorAddress: oldDelegation.DelegatorAddress.String(),
 			ValidatorAddress: oldDelegation.ValidatorAddress.String(),
 			Shares:           oldDelegation.Shares,
 		}
 	}
 
-	newUnbondingDelegations := make([]UnbondingDelegation, len(stakingState.UnbondingDelegations))
+	newUnbondingDelegations := make([]v040staking.UnbondingDelegation, len(stakingState.UnbondingDelegations))
 	for i, oldUnbondingDelegation := range stakingState.UnbondingDelegations {
-		newEntries := make([]UnbondingDelegationEntry, len(oldUnbondingDelegation.Entries))
+		newEntries := make([]v040staking.UnbondingDelegationEntry, len(oldUnbondingDelegation.Entries))
 		for j, oldEntry := range oldUnbondingDelegation.Entries {
-			newEntries[j] = UnbondingDelegationEntry{
+			newEntries[j] = v040staking.UnbondingDelegationEntry{
 				CreationHeight: oldEntry.CreationHeight,
 				CompletionTime: oldEntry.CompletionTime,
 				InitialBalance: oldEntry.InitialBalance,
 				Balance:        oldEntry.Balance,
 			}
 		}
 
-		newUnbondingDelegations[i] = UnbondingDelegation{
+		newUnbondingDelegations[i] = v040staking.UnbondingDelegation{
 			DelegatorAddress: oldUnbondingDelegation.DelegatorAddress.String(),
 			ValidatorAddress: oldUnbondingDelegation.ValidatorAddress.String(),
 			Entries:          newEntries,
 		}
 	}
 
-	newRedelegations := make([]Redelegation, len(stakingState.Redelegations))
+	newRedelegations := make([]v040staking.Redelegation, len(stakingState.Redelegations))
 	for i, oldRedelegation := range stakingState.Redelegations {
-		newEntries := make([]RedelegationEntry, len(oldRedelegation.Entries))
+		newEntries := make([]v040staking.RedelegationEntry, len(oldRedelegation.Entries))
 		for j, oldEntry := range oldRedelegation.Entries {
-			newEntries[j] = RedelegationEntry{
+			newEntries[j] = v040staking.RedelegationEntry{
 				CreationHeight: oldEntry.CreationHeight,
 				CompletionTime: oldEntry.CompletionTime,
 				InitialBalance: oldEntry.InitialBalance,
 				SharesDst:      oldEntry.SharesDst,
 			}
 		}
 
-		newRedelegations[i] = Redelegation{
+		newRedelegations[i] = v040staking.Redelegation{
 			DelegatorAddress:    oldRedelegation.DelegatorAddress.String(),
 			ValidatorSrcAddress: oldRedelegation.ValidatorSrcAddress.String(),
 			ValidatorDstAddress: oldRedelegation.ValidatorDstAddress.String(),
 			Entries:             newEntries,
 		}
 	}
 
-	return &GenesisState{
-		Params: Params{
+	return &v040staking.GenesisState{
+		Params: v040staking.Params{
 			UnbondingTime:     stakingState.Params.UnbondingTime,
 			MaxValidators:     uint32(stakingState.Params.MaxValidators),
 			MaxEntries:        uint32(stakingState.Params.MaxEntries),
 			HistoricalEntries: uint32(stakingState.Params.HistoricalEntries),
 			BondDenom:         stakingState.Params.BondDenom,
+			MinCommissionRate: v040staking.DefaultMinCommissionRate,
 		},
 		LastTotalPower:       stakingState.LastTotalPower,
 		LastValidatorPowers:  newLastValidatorPowers,

x/staking/legacy/v040/migrate_test.go

@@ -55,6 +55,7 @@ func TestMigrate(t *testing.T) {
     "historical_entries": 0,
     "max_entries": 0,
     "max_validators": 0,
+    "min_commission_rate": "0.000000000000000000",
     "unbonding_time": "0s"
   },
   "redelegations": [],

x/staking/simulation/genesis.go

@@ -19,6 +19,7 @@ const (
 	unbondingTime     = "unbonding_time"
 	maxValidators     = "max_validators"
 	historicalEntries = "historical_entries"
+	minCommissionRate = "min_commission_rate"
 )
 
 // genUnbondingTime returns randomized UnbondingTime
@@ -43,6 +44,7 @@ func RandomizedGenState(simState *module.SimulationState) {
 		unbondTime  time.Duration
 		maxVals     uint32
 		histEntries uint32
+		minComRate  sdk.Dec
 	)
 
 	simState.AppParams.GetOrGenerate(
@@ -60,10 +62,15 @@ func RandomizedGenState(simState *module.SimulationState) {
 		func(r *rand.Rand) { histEntries = getHistEntries(r) },
 	)
 
+	simState.AppParams.GetOrGenerate(
+		simState.Cdc, minCommissionRate, &minComRate, simState.Rand,
+		func(r *rand.Rand) { minComRate = sdk.NewDec(0) },
+	)
+
 	// NOTE: the slashing module need to be defined after the staking module on the
 	// NewSimulationManager constructor for this to work
 	simState.UnbondTime = unbondTime
-	params := types.NewParams(simState.UnbondTime, maxVals, 7, histEntries, sdk.DefaultBondDenom)
+	params := types.NewParams(simState.UnbondTime, maxVals, 7, histEntries, sdk.DefaultBondDenom, minComRate)
 
 	// validators & delegations
 	var (
@@ -78,8 +85,9 @@ func RandomizedGenState(simState *module.SimulationState) {
 		valAddrs[i] = valAddr
 
 		maxCommission := sdk.NewDecWithPrec(int64(simulation.RandIntBetween(simState.Rand, 1, 100)), 2)
+		curCommissionRate := simulation.RandomDecAmount(simState.Rand, maxCommission.Sub(minComRate)).Add(minComRate)
 		commission := types.NewCommission(
-			simulation.RandomDecAmount(simState.Rand, maxCommission),
+			curCommissionRate,
 			maxCommission,
 			simulation.RandomDecAmount(simState.Rand, maxCommission),
 		)

x/staking/types/errors.go

@@ -49,4 +49,5 @@ var (
 	ErrInvalidHistoricalInfo           = sdkerrors.Register(ModuleName, 37, "invalid historical info")
 	ErrNoHistoricalInfo                = sdkerrors.Register(ModuleName, 38, "no historical info found")
 	ErrEmptyValidatorPubKey            = sdkerrors.Register(ModuleName, 39, "empty validator public key")
+	ErrCommissionLTMinRate             = sdkerrors.Register(ModuleName, 40, "commission cannot be less than min rate")
 )