CreateValidator self delegation must be at least one consensus power

CHANGELOG.md

@@ -77,6 +77,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 ### Improvements
 
+* (x/staking) [\#8909](https://github.com/cosmos/cosmos-sdk/pull/8909) Require self delegation in `MsgCreateValidator` to be at least one consensus power. 
 * (x/bank) [\#8614](https://github.com/cosmos/cosmos-sdk/issues/8614) Add `Name` and `Symbol` fields to denom metadata
 * (x/auth) [\#8522](https://github.com/cosmos/cosmos-sdk/pull/8522) Allow to query all stored accounts
 * (crypto/types) [\#8600](https://github.com/cosmos/cosmos-sdk/pull/8600) `CompactBitArray`: optimize the `NumTrueBitsBefore` method and add an `Equal` method.

x/staking/client/cli/cli_test.go

@@ -97,7 +97,7 @@ func (s *IntegrationTestSuite) TestNewCreateValidatorCmd() {
 		val.ClientCtx,
 		val.Address,
 		newAddr,
-		sdk.NewCoins(sdk.NewCoin(s.cfg.BondDenom, sdk.NewInt(200))), fmt.Sprintf("--%s=true", flags.FlagSkipConfirmation),
+		sdk.NewCoins(sdk.NewCoin(s.cfg.BondDenom, sdk.NewInt(10000000))), fmt.Sprintf("--%s=true", flags.FlagSkipConfirmation),
 		fmt.Sprintf("--%s=%s", flags.FlagBroadcastMode, flags.BroadcastBlock),
 		fmt.Sprintf("--%s=%s", flags.FlagFees, sdk.NewCoins(sdk.NewCoin(s.cfg.BondDenom, sdk.NewInt(10))).String()),
 	)
@@ -131,7 +131,7 @@ func (s *IntegrationTestSuite) TestNewCreateValidatorCmd() {
 		{
 			"invalid transaction (missing pubkey)",
 			[]string{
-				fmt.Sprintf("--%s=100stake", cli.FlagAmount),
+				fmt.Sprintf("--%s=%dstake", cli.FlagAmount, sdk.PowerReduction.Int64()),
 				fmt.Sprintf("--%s=AFAF00C4", cli.FlagIdentity),
 				fmt.Sprintf("--%s=https://newvalidator.io", cli.FlagWebsite),
 				fmt.Sprintf("--%[email protected]", cli.FlagSecurityContact),
@@ -151,7 +151,7 @@ func (s *IntegrationTestSuite) TestNewCreateValidatorCmd() {
 			"invalid transaction (missing moniker)",
 			[]string{
 				fmt.Sprintf("--%s=%s", cli.FlagPubKey, consPubKey),
-				fmt.Sprintf("--%s=100stake", cli.FlagAmount),
+				fmt.Sprintf("--%s=%dstake", cli.FlagAmount, sdk.PowerReduction.Int64()),
 				fmt.Sprintf("--%s=AFAF00C4", cli.FlagIdentity),
 				fmt.Sprintf("--%s=https://newvalidator.io", cli.FlagWebsite),
 				fmt.Sprintf("--%[email protected]", cli.FlagSecurityContact),
@@ -171,7 +171,7 @@ func (s *IntegrationTestSuite) TestNewCreateValidatorCmd() {
 			"valid transaction",
 			[]string{
 				fmt.Sprintf("--%s=%s", cli.FlagPubKey, consPubKey),
-				fmt.Sprintf("--%s=100stake", cli.FlagAmount),
+				fmt.Sprintf("--%s=%dstake", cli.FlagAmount, sdk.PowerReduction.Int64()),
 				fmt.Sprintf("--%s=NewValidator", cli.FlagMoniker),
 				fmt.Sprintf("--%s=AFAF00C4", cli.FlagIdentity),
 				fmt.Sprintf("--%s=https://newvalidator.io", cli.FlagWebsite),

x/staking/simulation/operations.go

@@ -112,11 +112,22 @@ func SimulateMsgCreateValidator(ak types.AccountKeeper, bk types.BankKeeper, k k
 			return simtypes.NoOpMsg(types.ModuleName, types.TypeMsgCreateValidator, "balance is negative"), nil, nil
 		}
 
-		amount, err := simtypes.RandPositiveInt(r, balance)
+		// A validator can only be created if it has at least one consensus power worth of tokens.
+		// Construct a maximum random value that is reduced by the PowerReduction, allowing
+		// for a minimum self delegation of the PowerReduction.
+		max := balance.Sub(sdk.PowerReduction)
+		if !max.IsPositive() {
+			return simtypes.NoOpMsg(types.ModuleName, types.TypeMsgCreateValidator, "balance doesn't have enough delegation amount"), nil, nil
+		}
+
+		amount, err := simtypes.RandPositiveInt(r, max)
 		if err != nil {
 			return simtypes.NoOpMsg(types.ModuleName, types.TypeMsgCreateValidator, "unable to generate positive amount"), nil, err
 		}
 
+		// ensure self delegation meets minimum requirement
+		amount = amount.Add(sdk.PowerReduction)
+
 		selfDelegation := sdk.NewCoin(denom, amount)
 
 		account := ak.GetAccount(ctx, simAccount.Address)

x/staking/types/msg.go

@@ -140,6 +140,11 @@ func (msg MsgCreateValidator) ValidateBasic() error {
 		return ErrMinSelfDelegationInvalid
 	}
 
+	// ensure delegation is at least one consensus power
+	if sdk.TokensToConsensusPower(msg.Value.Amount) <= 0 {
+		return sdkerrors.Wrapf(ErrBadDelegationAmount, "self delegation amount (%s) must be at least one consensus power (%s)", msg.Value.Amount, sdk.PowerReduction)
+	}
+
 	if msg.Value.Amount.LT(msg.MinSelfDelegation) {
 		return ErrSelfDelegationBelowMinimum
 	}

x/staking/types/msg_test.go

@@ -15,7 +15,7 @@ import (
 )
 
 var (
-	coinPos  = sdk.NewInt64Coin(sdk.DefaultBondDenom, 1000)
+	coinPos  = sdk.NewInt64Coin(sdk.DefaultBondDenom, sdk.PowerReduction.Int64())
 	coinZero = sdk.NewInt64Coin(sdk.DefaultBondDenom, 0)
 )
 
@@ -75,6 +75,7 @@ func TestMsgCreateValidator(t *testing.T) {
 		{"zero min self delegation", "a", "b", "c", "d", "e", commission1, sdk.ZeroInt(), valAddr1, pk1, coinPos, false},
 		{"negative min self delegation", "a", "b", "c", "d", "e", commission1, sdk.NewInt(-1), valAddr1, pk1, coinPos, false},
 		{"delegation less than min self delegation", "a", "b", "c", "d", "e", commission1, coinPos.Amount.Add(sdk.OneInt()), valAddr1, pk1, coinPos, false},
+		{"delegation less than one consensus power", "a", "b", "c", "d", "e", commission1, sdk.OneInt(), valAddr1, pk1, sdk.NewInt64Coin(sdk.DefaultBondDenom, 1000), false},
 	}
 
 	for _, tc := range tests {