feat: add MinCommissionRate param (#3)

* add MinCommissionRate param

* migrate store

* expose migrate13to14

* fix migrate

* set default MinCommissionRate to zero

* update rosetta data

CHANGELOG.md

@@ -37,6 +37,12 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 ## [Unreleased]
 
+## v0.45.14 - 2023-05-31
+
+### Improvements
+
+* (x/staking) [\#3](https://github.com/classic-terra/cosmos-sdk/pull/3) Add `MinCommissionRate` param to `x/staking` module.
+
 ### Bug Fixes
 
 * (x/feegrant) [#4](https://github.com/classic-terra/cosmos-sdk/pull/4) Fix infinite feegrant allowance bug.

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/migrations.go

@@ -3,6 +3,7 @@ package keeper
 import (
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	v043 "github.com/cosmos/cosmos-sdk/x/staking/legacy/v043"
+	v045 "github.com/cosmos/cosmos-sdk/x/staking/legacy/v045"
 )
 
 // Migrator is a struct for handling in-place store migrations.
@@ -19,3 +20,9 @@ func NewMigrator(keeper Keeper) Migrator {
 func (m Migrator) Migrate1to2(ctx sdk.Context) error {
 	return v043.MigrateStore(ctx, m.keeper.storeKey)
 }
+
+// Migrate13to14 migrates from version v0.45.13 to v0.45.14.
+// Only for this particular version, which do not use the version of module.
+func (m Migrator) Migrate13to14(ctx sdk.Context) {
+	v045.MigrateStore(ctx, m.keeper.storeKey, m.keeper.cdc, m.keeper.paramstore)
+}

x/staking/keeper/msg_server.go

@@ -63,6 +63,10 @@ func (k msgServer) CreateValidator(goCtx context.Context, msg *types.MsgCreateVa
 		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))
+	}
+
 	// check to see if the pubkey or sender has been registered before
 	if _, found := k.GetValidator(ctx, valAddr); found {
 		return nil, types.ErrValidatorOwnerExists

x/staking/keeper/params.go

@@ -47,6 +47,12 @@ func (k Keeper) PowerReduction(ctx sdk.Context) sdk.Int {
 	return sdk.DefaultPowerReduction
 }
 
+// MinCommissionRate - Minimum validator commission rate
+func (k Keeper) MinCommissionRate(ctx sdk.Context) (res sdk.Dec) {
+	k.paramstore.Get(ctx, types.KeyMinCommissionRate, &res)
+	return
+}
+
 // Get all parameteras as types.Params
 func (k Keeper) GetParams(ctx sdk.Context) types.Params {
 	return types.NewParams(
@@ -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 +1043,11 @@ func TestUpdateValidatorCommission(t *testing.T) {
 	app, ctx, _, addrVals := bootstrapValidatorTest(t, 1000, 20)
 	ctx = ctx.WithBlockHeader(tmproto.Header{Time: time.Now().UTC()})
 
+	// Set MinCommissionRate to 0.05
+	params := app.StakingKeeper.GetParams(ctx)
+	params.MinCommissionRate = sdk.NewDecWithPrec(5, 2)
+	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 +1072,7 @@ 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},
 		{val2, sdk.NewDecWithPrec(2, 1), false},
 	}
 

x/staking/legacy/v045/store.go

@@ -0,0 +1,49 @@
+package v045
+
+import (
+	"github.com/cosmos/cosmos-sdk/codec"
+	storetypes "github.com/cosmos/cosmos-sdk/store/types"
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	paramtypes "github.com/cosmos/cosmos-sdk/x/params/types"
+	"github.com/cosmos/cosmos-sdk/x/staking/types"
+)
+
+// MinCommissionRate is set to 5%
+var MinCommissionRate = sdk.NewDecWithPrec(5, 2)
+
+// Migrate performs in-place store migrations from v0.45.13 to v0.45.14.
+// The migration includes:
+//
+// - Adding MinCommissionRate param
+// - Setting validaotr commission rate and max commission rate to MinCommissionRate if they are lower
+func MigrateStore(ctx sdk.Context, storeKey storetypes.StoreKey, cdc codec.BinaryCodec, paramstore paramtypes.Subspace) {
+	migrateParamsStore(ctx, paramstore)
+	migrateValidators(ctx, storeKey, cdc)
+}
+
+func migrateParamsStore(ctx sdk.Context, paramstore paramtypes.Subspace) {
+	if paramstore.HasKeyTable() {
+		paramstore.Set(ctx, types.KeyMinCommissionRate, MinCommissionRate)
+	} else {
+		paramstore.WithKeyTable(types.ParamKeyTable())
+		paramstore.Set(ctx, types.KeyMinCommissionRate, MinCommissionRate)
+	}
+}
+
+func migrateValidators(ctx sdk.Context, storeKey storetypes.StoreKey, cdc codec.BinaryCodec) {
+	store := ctx.KVStore(storeKey)
+	iterator := sdk.KVStorePrefixIterator(store, types.ValidatorsKey)
+	defer iterator.Close()
+
+	for ; iterator.Valid(); iterator.Next() {
+		validator := types.MustUnmarshalValidator(cdc, iterator.Value())
+		if validator.Commission.CommissionRates.Rate.LT(MinCommissionRate) {
+			validator.Commission.CommissionRates.Rate = MinCommissionRate
+		}
+
+		if validator.Commission.CommissionRates.MaxRate.LT(MinCommissionRate) {
+			validator.Commission.CommissionRates.MaxRate = MinCommissionRate
+		}
+		store.Set(iterator.Key(), types.MustMarshalValidator(cdc, &validator))
+	}
+}

x/staking/legacy/v045/store_test.go

@@ -0,0 +1,120 @@
+package v045_test
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/cosmos/cosmos-sdk/simapp"
+	"github.com/cosmos/cosmos-sdk/testutil"
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	paramtypes "github.com/cosmos/cosmos-sdk/x/params/types"
+	v045staking "github.com/cosmos/cosmos-sdk/x/staking/legacy/v045"
+	"github.com/cosmos/cosmos-sdk/x/staking/types"
+)
+
+func TestMigrate(t *testing.T) {
+	encCfg := simapp.MakeTestEncodingConfig()
+	stakingKey := sdk.NewKVStoreKey("staking")
+	tStakingKey := sdk.NewTransientStoreKey("transient_test")
+	ctx := testutil.DefaultContext(stakingKey, tStakingKey)
+	paramstore := paramtypes.NewSubspace(encCfg.Marshaler, encCfg.Amino, stakingKey, tStakingKey, "staking")
+
+	testCases := []struct {
+		OldValidator types.Validator
+		NewValidator types.Validator
+	}{
+		{
+			OldValidator: types.Validator{
+				OperatorAddress: sdk.ValAddress{0x00}.String(),
+				Commission: types.Commission{
+					CommissionRates: types.CommissionRates{
+						Rate:    sdk.MustNewDecFromStr("0.01"),
+						MaxRate: sdk.MustNewDecFromStr("0.02"),
+					},
+				},
+			},
+			NewValidator: types.Validator{
+				OperatorAddress: sdk.ValAddress{0x00}.String(),
+				Commission: types.Commission{
+					CommissionRates: types.CommissionRates{
+						Rate:    sdk.MustNewDecFromStr("0.05"),
+						MaxRate: sdk.MustNewDecFromStr("0.05"),
+					},
+				},
+			},
+		},
+		{
+			OldValidator: types.Validator{
+				OperatorAddress: sdk.ValAddress{0x01}.String(),
+				Commission: types.Commission{
+					CommissionRates: types.CommissionRates{
+						Rate:    sdk.MustNewDecFromStr("0.05"),
+						MaxRate: sdk.MustNewDecFromStr("0.05"),
+					},
+				},
+			},
+			NewValidator: types.Validator{
+				OperatorAddress: sdk.ValAddress{0x01}.String(),
+				Commission: types.Commission{
+					CommissionRates: types.CommissionRates{
+						Rate:    sdk.MustNewDecFromStr("0.05"),
+						MaxRate: sdk.MustNewDecFromStr("0.05"),
+					},
+				},
+			},
+		},
+		{
+			OldValidator: types.Validator{
+				OperatorAddress: sdk.ValAddress{0x02}.String(),
+				Commission: types.Commission{
+					CommissionRates: types.CommissionRates{
+						Rate:    sdk.MustNewDecFromStr("0.1"),
+						MaxRate: sdk.MustNewDecFromStr("0.2"),
+					},
+				},
+			},
+			NewValidator: types.Validator{
+				OperatorAddress: sdk.ValAddress{0x02}.String(),
+				Commission: types.Commission{
+					CommissionRates: types.CommissionRates{
+						Rate:    sdk.MustNewDecFromStr("0.1"),
+						MaxRate: sdk.MustNewDecFromStr("0.2"),
+					},
+				},
+			},
+		},
+	}
+
+	store := ctx.KVStore(stakingKey)
+	for _, vs := range testCases {
+		bz := types.MustMarshalValidator(encCfg.Marshaler, &vs.OldValidator)
+		store.Set(types.GetValidatorKey(vs.OldValidator.GetOperator()), bz)
+	}
+
+	// Check no params
+	require.False(t, paramstore.Has(ctx, types.KeyMinCommissionRate))
+
+	// Run migrations.
+	v045staking.MigrateStore(ctx, stakingKey, encCfg.Marshaler, paramstore)
+
+	// Make sure the new params are set.
+	require.True(t, paramstore.Has(ctx, types.KeyMinCommissionRate))
+
+	minCommissionRate := sdk.Dec{}
+	paramstore.Get(ctx, types.KeyMinCommissionRate, &minCommissionRate)
+	require.Equal(t, v045staking.MinCommissionRate, minCommissionRate)
+
+	// Make sure the validators commission is set correctly.
+	iterator := sdk.KVStorePrefixIterator(store, types.ValidatorsKey)
+	defer iterator.Close()
+
+	i := int64(0)
+	for ; iterator.Valid(); iterator.Next() {
+		validator := types.MustUnmarshalValidator(encCfg.Marshaler, iterator.Value())
+		require.Equal(t, testCases[i].NewValidator.OperatorAddress, validator.GetOperator().String())
+		require.Equal(t, testCases[i].NewValidator.Commission.Rate, validator.Commission.Rate)
+		require.Equal(t, testCases[i].NewValidator.Commission.MaxRate, validator.Commission.MaxRate)
+		i++
+	}
+}

x/staking/simulation/genesis.go

@@ -40,9 +40,10 @@ func getHistEntries(r *rand.Rand) uint32 {
 func RandomizedGenState(simState *module.SimulationState) {
 	// params
 	var (
-		unbondTime  time.Duration
-		maxVals     uint32
-		histEntries uint32
+		unbondTime        time.Duration
+		maxVals           uint32
+		histEntries       uint32
+		minCommissionRate sdk.Dec
 	)
 
 	simState.AppParams.GetOrGenerate(
@@ -63,7 +64,7 @@ func RandomizedGenState(simState *module.SimulationState) {
 	// 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, minCommissionRate)
 
 	// validators & delegations
 	var (

x/staking/spec/08_params.md

@@ -6,11 +6,12 @@ order: 8
 
 The staking module contains the following parameters:
 
-| Key               | Type             | Example           |
-|-------------------|------------------|-------------------|
-| UnbondingTime     | string (time ns) | "259200000000000" |
-| MaxValidators     | uint16           | 100               |
-| KeyMaxEntries     | uint16           | 7                 |
-| HistoricalEntries | uint16           | 3                 |
-| BondDenom         | string           | "stake"           |
-| PowerReduction    | string           | "1000000"         |
+| Key               | Type             | Example                |
+| ----------------- | ---------------- | ---------------------- |
+| UnbondingTime     | string (time ns) | "259200000000000"      |
+| MaxValidators     | uint16           | 100                    |
+| KeyMaxEntries     | uint16           | 7                      |
+| HistoricalEntries | uint16           | 3                      |
+| BondDenom         | string           | "stake"                |
+| PowerReduction    | string           | "1000000"              |
+| MinCommissionRate | string           | "0.050000000000000000" |

x/staking/types/errors.go

@@ -50,4 +50,5 @@ var (
 	ErrNoHistoricalInfo                = sdkerrors.Register(ModuleName, 38, "no historical info found")
 	ErrEmptyValidatorPubKey            = sdkerrors.Register(ModuleName, 39, "empty validator public key")
 	ErrMsgNotSupported                 = sdkerrors.Register(ModuleName, 40, "message not supported")
+	ErrCommissionLTMinRate             = sdkerrors.Register(ModuleName, 41, "commission cannot be less than min rate")
 )