feat: custom denom for gas fees

app/ante/cosmos/fees.go

@@ -25,6 +25,7 @@ import (
 	errortypes "github.com/cosmos/cosmos-sdk/types/errors"
 	authante "github.com/cosmos/cosmos-sdk/x/auth/ante"
 	authtypes "github.com/cosmos/cosmos-sdk/x/auth/types"
+
 	anteutils "github.com/evmos/evmos/v12/app/ante/utils"
 )
 
@@ -38,6 +39,7 @@ import (
 type DeductFeeDecorator struct {
 	accountKeeper      authante.AccountKeeper
 	bankKeeper         BankKeeper
+	erc20Keeper        ERC20Keeper
 	distributionKeeper anteutils.DistributionKeeper
 	feegrantKeeper     authante.FeegrantKeeper
 	stakingKeeper      anteutils.StakingKeeper
@@ -48,6 +50,7 @@ type DeductFeeDecorator struct {
 func NewDeductFeeDecorator(
 	ak authante.AccountKeeper,
 	bk BankKeeper,
+	ek ERC20Keeper,
 	dk anteutils.DistributionKeeper,
 	fk authante.FeegrantKeeper,
 	sk anteutils.StakingKeeper,
@@ -60,6 +63,7 @@ func NewDeductFeeDecorator(
 	return DeductFeeDecorator{
 		accountKeeper:      ak,
 		bankKeeper:         bk,
+		erc20Keeper:        ek,
 		distributionKeeper: dk,
 		feegrantKeeper:     fk,
 		stakingKeeper:      sk,
@@ -140,9 +144,15 @@ func (dfd DeductFeeDecorator) deductFee(ctx sdk.Context, sdkTx sdk.Tx, fees sdk.
 		return errortypes.ErrUnknownAddress.Wrapf("fee payer address: %s does not exist", deductFeesFrom)
 	}
 
-	// deduct the fees
-	if err := deductFeesFromBalanceOrUnclaimedStakingRewards(ctx, dfd, deductFeesFromAcc, fees); err != nil {
-		return fmt.Errorf("insufficient funds and failed to claim sufficient staking rewards to pay for fees: %w", err)
+	// If the account balance is not sufficient, try to withdraw enough staking rewards
+	err := anteutils.ClaimStakingRewardsIfNecessary(ctx, dfd.bankKeeper, dfd.distributionKeeper, dfd.stakingKeeper, deductFeesFromAcc.GetAddress(), fees)
+	if err != nil {
+		return fmt.Errorf("insufficient funds and failed to claim sufficient staking rewards: %w", err)
+	}
+
+	err = anteutils.DeductFees(dfd.bankKeeper, dfd.erc20Keeper, ctx, deductFeesFromAcc, fees)
+	if err != nil {
+		return errorsmod.Wrapf(err, "failed to deduct transaction costs from user balance")
 	}
 
 	events := sdk.Events{
@@ -157,20 +167,6 @@ func (dfd DeductFeeDecorator) deductFee(ctx sdk.Context, sdkTx sdk.Tx, fees sdk.
 	return nil
 }
 
-// deductFeesFromBalanceOrUnclaimedStakingRewards tries to deduct the fees from the account balance.
-// If the account balance is not enough, it tries to claim enough staking rewards to cover the fees.
-func deductFeesFromBalanceOrUnclaimedStakingRewards(
-	ctx sdk.Context, dfd DeductFeeDecorator, deductFeesFromAcc authtypes.AccountI, fees sdk.Coins,
-) error {
-	if err := anteutils.ClaimStakingRewardsIfNecessary(
-		ctx, dfd.bankKeeper, dfd.distributionKeeper, dfd.stakingKeeper, deductFeesFromAcc.GetAddress(), fees,
-	); err != nil {
-		return err
-	}
-
-	return authante.DeductFees(dfd.bankKeeper, ctx, deductFeesFromAcc, fees)
-}
-
 // checkTxFeeWithValidatorMinGasPrices implements the default fee logic, where the minimum price per
 // unit of gas is fixed and set by each validator, and the tx priority is computed from the gas price.
 func checkTxFeeWithValidatorMinGasPrices(ctx sdk.Context, feeTx sdk.FeeTx) (sdk.Coins, int64, error) {

app/ante/cosmos/fees_test.go

@@ -2,18 +2,29 @@ package cosmos_test
 
 import (
 	"fmt"
+	"math/big"
 	"time"
 
 	"cosmossdk.io/math"
 	sdktestutil "github.com/cosmos/cosmos-sdk/testutil/testdata"
 	sdk "github.com/cosmos/cosmos-sdk/types"
+	authtypes "github.com/cosmos/cosmos-sdk/x/auth/types"
+	banktypes "github.com/cosmos/cosmos-sdk/x/bank/types"
 	"github.com/cosmos/cosmos-sdk/x/feegrant"
+	"github.com/ethereum/go-ethereum/common"
+
 	cosmosante "github.com/evmos/evmos/v12/app/ante/cosmos"
+	"github.com/evmos/evmos/v12/app/ante/evm"
+	"github.com/evmos/evmos/v12/contracts"
 	"github.com/evmos/evmos/v12/testutil"
 	testutiltx "github.com/evmos/evmos/v12/testutil/tx"
 	"github.com/evmos/evmos/v12/utils"
+	erc20types "github.com/evmos/evmos/v12/x/erc20/types"
+	inflationtypes "github.com/evmos/evmos/v12/x/inflation/types"
 )
 
+const ibcBase = "ibc/7B2A4F6E798182988D77B6B884919AF617A73503FDAC27C916CD7A69A69013CF"
+
 func (suite *AnteTestSuite) TestDeductFeeDecorator() {
 	var (
 		dfd cosmosante.DeductFeeDecorator
@@ -23,6 +34,7 @@ func (suite *AnteTestSuite) TestDeductFeeDecorator() {
 		fgAddr, _   = testutiltx.NewAccAddressAndKey()
 		initBalance = sdk.NewInt(1e18)
 		lowGasPrice = math.NewInt(1)
+		bigGasPrice = math.NewInt(1e12)
 		zero        = sdk.ZeroInt()
 	)
 
@@ -33,6 +45,7 @@ func (suite *AnteTestSuite) TestDeductFeeDecorator() {
 		rewards     math.Int
 		gas         uint64
 		gasPrice    *math.Int
+		gasDenom    string
 		feeGranter  sdk.AccAddress
 		checkTx     bool
 		simulate    bool
@@ -268,10 +281,181 @@ func (suite *AnteTestSuite) TestDeductFeeDecorator() {
 
 				// remove the feegrant keeper from the decorator
 				dfd = cosmosante.NewDeductFeeDecorator(
-					suite.app.AccountKeeper, suite.app.BankKeeper, suite.app.DistrKeeper, nil, suite.app.StakingKeeper, nil,
+					suite.app.AccountKeeper, suite.app.BankKeeper, suite.app.Erc20Keeper, suite.app.DistrKeeper, nil, suite.app.StakingKeeper, nil,
 				)
 			},
 		},
+		{
+			name:        "success - IBC gas denom",
+			balance:     zero,
+			rewards:     zero,
+			gas:         10_000,
+			gasPrice:    &bigGasPrice,
+			gasDenom:    ibcBase,
+			checkTx:     false,
+			simulate:    false,
+			expPass:     true,
+			errContains: "",
+			malleate: func() {
+				// update evm params to use IBC denom as gas denom
+				params := suite.app.EvmKeeper.GetParams(suite.ctx)
+				params.GasDenom = ibcBase
+				err := suite.app.EvmKeeper.SetParams(suite.ctx, params)
+				suite.Require().NoError(err)
+
+				// register IBC denom
+				metadataIbc := banktypes.Metadata{
+					Description: "ATOM IBC voucher (channel 14)",
+					Base:        ibcBase,
+					// NOTE: Denom units MUST be increasing
+					DenomUnits: []*banktypes.DenomUnit{
+						{
+							Denom:    ibcBase,
+							Exponent: 0,
+						},
+					},
+					Name:    "ATOM channel-14",
+					Symbol:  "ibcATOM-14",
+					Display: ibcBase,
+				}
+
+				// initial IBC denom
+				err = suite.app.BankKeeper.MintCoins(suite.ctx, inflationtypes.ModuleName, sdk.Coins{sdk.NewInt64Coin(metadataIbc.Base, 1)})
+				suite.Require().NoError(err)
+
+				// register ERC20 representation of IBC denom
+				_, err = suite.app.Erc20Keeper.RegisterCoin(suite.ctx, metadataIbc)
+				suite.Require().NoError(err)
+
+				// fund sender's SDK account: mint IBC coins and convert it to ERC20 tokens
+				coin := sdk.NewCoin(ibcBase, sdk.NewInt(1e18))
+				coins := sdk.NewCoins(coin)
+				sender := sdk.AccAddress(addr.Bytes())
+				err = testutil.FundAccount(suite.ctx, suite.app.BankKeeper, sender, coins)
+				suite.Require().NoError(err)
+
+				// check that SDK balance is funded with IBC coins
+				senderBalances := suite.app.BankKeeper.GetBalance(suite.ctx, sender, ibcBase)
+				suite.Require().True(senderBalances.IsPositive())
+
+				// unsure that the fee collector balance is empty initially
+				feeCollectorInitialBalance := suite.app.BankKeeper.GetBalance(suite.ctx, authtypes.NewModuleAddress(authtypes.FeeCollectorName), ibcBase)
+				suite.Require().True(feeCollectorInitialBalance.IsZero())
+
+				// for this case to work properly, we need to set a dynamic fee checker
+				dfd = cosmosante.NewDeductFeeDecorator(
+					suite.app.AccountKeeper,
+					suite.app.BankKeeper,
+					suite.app.Erc20Keeper,
+					suite.app.DistrKeeper,
+					suite.app.FeeGrantKeeper,
+					suite.app.StakingKeeper,
+					evm.NewDynamicFeeChecker(suite.app.EvmKeeper),
+				)
+			},
+			postCheck: func() {
+				// check the fee collector balance, it should be positive (initially it was empty)
+				balance := suite.app.BankKeeper.GetBalance(suite.ctx, authtypes.NewModuleAddress(authtypes.FeeCollectorName), ibcBase)
+				suite.Require().True(balance.IsPositive())
+			},
+		},
+		{
+			name:        "success - IBC gas denom, not enough SDK coins, enough ERC20 tokens",
+			balance:     zero,
+			rewards:     zero,
+			gas:         10_000,
+			gasPrice:    &bigGasPrice,
+			gasDenom:    ibcBase,
+			checkTx:     false,
+			simulate:    false,
+			expPass:     true,
+			errContains: "",
+			malleate: func() {
+				// update evm params to use IBC denom as gas denom
+				params := suite.app.EvmKeeper.GetParams(suite.ctx)
+				params.GasDenom = ibcBase
+				err := suite.app.EvmKeeper.SetParams(suite.ctx, params)
+				suite.Require().NoError(err)
+
+				// register IBC denom
+				metadataIbc := banktypes.Metadata{
+					Description: "ATOM IBC voucher (channel 14)",
+					Base:        ibcBase,
+					// NOTE: Denom units MUST be increasing
+					DenomUnits: []*banktypes.DenomUnit{
+						{
+							Denom:    ibcBase,
+							Exponent: 0,
+						},
+					},
+					Name:    "ATOM channel-14",
+					Symbol:  "ibcATOM-14",
+					Display: ibcBase,
+				}
+
+				// initial IBC denom
+				err = suite.app.BankKeeper.MintCoins(suite.ctx, inflationtypes.ModuleName, sdk.Coins{sdk.NewInt64Coin(metadataIbc.Base, 1)})
+				suite.Require().NoError(err)
+
+				// register ERC20 representation of IBC denom
+				tp, err := suite.app.Erc20Keeper.RegisterCoin(suite.ctx, metadataIbc)
+				suite.Require().NoError(err)
+
+				// fund sender's eth account: mint IBC coins and convert it to ERC20 tokens
+				coin := sdk.NewCoin(ibcBase, sdk.NewInt(1e16))
+				coins := sdk.NewCoins(coin)
+				sender := sdk.AccAddress(addr.Bytes())
+				err = testutil.FundAccount(suite.ctx, suite.app.BankKeeper, sender, coins)
+				suite.Require().NoError(err)
+				msg := erc20types.NewMsgConvertCoin(
+					coin,
+					common.BytesToAddress(sender.Bytes()),
+					sender,
+				)
+				_, err = suite.app.Erc20Keeper.ConvertCoin(sdk.WrapSDKContext(suite.ctx), msg)
+				suite.Require().NoError(err)
+
+				// now the sender's eth balance is funded with ERC20 tokens
+				senderBalance := suite.app.Erc20Keeper.BalanceOf(suite.ctx, contracts.ERC20MinterBurnerDecimalsContract.ABI, tp.GetERC20Contract(), common.BytesToAddress(addr.Bytes()))
+				suite.Require().NotNil(senderBalance)
+				suite.Require().Equal(senderBalance.Cmp(big.NewInt(1e16)), 0) // == 1e16
+
+				// while SDK balance is empty
+				senderBalances := suite.app.BankKeeper.GetAllBalances(suite.ctx, sender)
+				suite.Require().True(senderBalances.IsZero())
+
+				// ensure that the fee collector balance is empty initially
+				feeCollectorInitialBalance := suite.app.BankKeeper.GetBalance(suite.ctx, authtypes.NewModuleAddress(authtypes.FeeCollectorName), ibcBase)
+				suite.Require().True(feeCollectorInitialBalance.IsZero())
+
+				// for this case to work properly, we need to set a dynamic fee checker
+				dfd = cosmosante.NewDeductFeeDecorator(
+					suite.app.AccountKeeper,
+					suite.app.BankKeeper,
+					suite.app.Erc20Keeper,
+					suite.app.DistrKeeper,
+					suite.app.FeeGrantKeeper,
+					suite.app.StakingKeeper,
+					evm.NewDynamicFeeChecker(suite.app.EvmKeeper),
+				)
+			},
+			postCheck: func() {
+				// get the token pair for the IBC denom
+				tpID := suite.app.Erc20Keeper.GetTokenPairID(suite.ctx, ibcBase)
+				suite.Require().NotNil(tpID)
+				tp, found := suite.app.Erc20Keeper.GetTokenPair(suite.ctx, tpID)
+				suite.Require().True(found)
+
+				// check the sender's ERC20 balance, it should be less than the initial balance
+				senderBalance := suite.app.Erc20Keeper.BalanceOf(suite.ctx, contracts.ERC20MinterBurnerDecimalsContract.ABI, tp.GetERC20Contract(), common.BytesToAddress(addr.Bytes()))
+				suite.Require().NotNil(senderBalance)
+				suite.Require().Equal(senderBalance.Cmp(big.NewInt(1e16)), -1) // < 1e16
+
+				// check the fee collector balance, it should be positive (initially it was empty)
+				balance := suite.app.BankKeeper.GetBalance(suite.ctx, authtypes.NewModuleAddress(authtypes.FeeCollectorName), ibcBase)
+				suite.Require().True(balance.IsPositive())
+			},
+		},
 	}
 
 	// Test execution
@@ -281,7 +465,13 @@ func (suite *AnteTestSuite) TestDeductFeeDecorator() {
 
 			// Create a new DeductFeeDecorator
 			dfd = cosmosante.NewDeductFeeDecorator(
-				suite.app.AccountKeeper, suite.app.BankKeeper, suite.app.DistrKeeper, suite.app.FeeGrantKeeper, suite.app.StakingKeeper, nil,
+				suite.app.AccountKeeper,
+				suite.app.BankKeeper,
+				suite.app.Erc20Keeper,
+				suite.app.DistrKeeper,
+				suite.app.FeeGrantKeeper,
+				suite.app.StakingKeeper,
+				nil,
 			)
 
 			// prepare the testcase
@@ -302,6 +492,7 @@ func (suite *AnteTestSuite) TestDeductFeeDecorator() {
 				GasPrice:   tc.gasPrice,
 				FeeGranter: tc.feeGranter,
 				Msgs:       []sdk.Msg{msg},
+				GasDenom:   tc.gasDenom,
 			}
 
 			if tc.malleate != nil {

app/ante/cosmos/interfaces.go

@@ -16,12 +16,19 @@
 
 package cosmos
 
-import sdk "github.com/cosmos/cosmos-sdk/types"
+import (
+	"cosmossdk.io/math"
+	sdk "github.com/cosmos/cosmos-sdk/types"
+)
 
 // BankKeeper defines the exposed interface for using functionality of the bank keeper
 // in the context of the cosmos AnteHandler package.
 type BankKeeper interface {
 	GetBalance(ctx sdk.Context, addr sdk.AccAddress, denom string) sdk.Coin
-	SendCoins(ctx sdk.Context, from, to sdk.AccAddress, amt sdk.Coins) error
+	GetAllBalances(ctx sdk.Context, addr sdk.AccAddress) sdk.Coins
 	SendCoinsFromAccountToModule(ctx sdk.Context, senderAddr sdk.AccAddress, recipientModule string, amt sdk.Coins) error
 }
+
+type ERC20Keeper interface {
+	TryConvertErc20Sdk(ctx sdk.Context, sender, receiver sdk.AccAddress, denom string, amount math.Int) error
+}

app/ante/cosmos/min_price.go

@@ -21,6 +21,7 @@ import (
 	errorsmod "cosmossdk.io/errors"
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	errortypes "github.com/cosmos/cosmos-sdk/types/errors"
+
 	evmante "github.com/evmos/evmos/v12/app/ante/evm"
 )
 
@@ -52,11 +53,10 @@ func (mpd MinGasPriceDecorator) AnteHandle(ctx sdk.Context, tx sdk.Tx, simulate
 	if minGasPrice.IsZero() || simulate {
 		return next(ctx, tx, simulate)
 	}
-	evmParams := mpd.evmKeeper.GetParams(ctx)
-	evmDenom := evmParams.GetEvmDenom()
+	gasDenom := mpd.evmKeeper.GetParams(ctx).GasDenom
 	minGasPrices := sdk.DecCoins{
 		{
-			Denom:  evmDenom,
+			Denom:  gasDenom,
 			Amount: minGasPrice,
 		},
 	}