Problem: native fee handler don't respect DefaultPriorityReduction

app/ante/eip712.go

@@ -66,7 +66,7 @@ func NewLegacyCosmosAnteHandlerEip712(ctx sdk.Context, options HandlerOptions, e
 		NewMinGasPriceDecorator(options.FeeMarketKeeper, evmDenom),
 		authante.NewValidateMemoDecorator(options.AccountKeeper),
 		authante.NewConsumeGasForTxSizeDecorator(options.AccountKeeper),
-		authante.NewDeductFeeDecorator(options.AccountKeeper, options.BankKeeper, options.FeegrantKeeper, options.TxFeeChecker),
+		NewDeductFeeDecorator(options.AccountKeeper, options.BankKeeper, options.FeegrantKeeper, options.TxFeeChecker),
 		// SetPubKeyDecorator must be called before all signature verification decorators
 		authante.NewSetPubKeyDecorator(options.AccountKeeper),
 		authante.NewValidateSigCountDecorator(options.AccountKeeper),

app/ante/fee_checker.go

@@ -111,9 +111,14 @@
 
 // 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, tx sdk.FeeTx) (sdk.Coins, int64, error) {
-	feeCoins := tx.GetFee()
-	gas := tx.GetGas()
+func checkTxFeeWithValidatorMinGasPrices(ctx sdk.Context, tx sdk.Tx) (sdk.Coins, int64, error) {
+	feeTx, ok := tx.(sdk.FeeTx)
+	if !ok {
+		return nil, 0, errorsmod.Wrap(errortypes.ErrTxDecode, "Tx must be a FeeTx")
+	}
+
+	feeCoins := feeTx.GetFee()
+	gas := feeTx.GetGas()
 	minGasPrices := ctx.MinGasPrices()
 
 	// Ensure that the provided fees meet a minimum threshold for the validator,

app/ante/handler_options.go

@@ -108,7 +108,7 @@ func newCosmosAnteHandler(ctx sdk.Context, options HandlerOptions, extra ...sdk.
 		NewMinGasPriceDecorator(options.FeeMarketKeeper, evmDenom),
 		ante.NewValidateMemoDecorator(options.AccountKeeper),
 		ante.NewConsumeGasForTxSizeDecorator(options.AccountKeeper),
-		ante.NewDeductFeeDecorator(options.AccountKeeper, options.BankKeeper, options.FeegrantKeeper, options.TxFeeChecker),
+		NewDeductFeeDecorator(options.AccountKeeper, options.BankKeeper, options.FeegrantKeeper, options.TxFeeChecker),
 		// SetPubKeyDecorator must be called before all signature verification decorators
 		ante.NewSetPubKeyDecorator(options.AccountKeeper),
 		ante.NewValidateSigCountDecorator(options.AccountKeeper),

app/ante/nativefee.go

@@ -0,0 +1,122 @@
+package ante
+
+import (
+	"fmt"
+
+	"cosmossdk.io/errors"
+
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
+	"github.com/cosmos/cosmos-sdk/x/auth/ante"
+	"github.com/cosmos/cosmos-sdk/x/auth/types"
+	evmkeeper "github.com/evmos/ethermint/x/evm/keeper"
+)
+
+// DeductFeeDecorator deducts fees from the fee payer. The fee payer is the fee granter (if specified) or first signer of the tx.
+// If the fee payer does not have the funds to pay for the fees, return an InsufficientFunds error.
+// Call next AnteHandler if fees successfully deducted.
+// CONTRACT: Tx must implement FeeTx interface to use DeductFeeDecorator
+type DeductFeeDecorator struct {
+	accountKeeper  ante.AccountKeeper
+	bankKeeper     types.BankKeeper
+	feegrantKeeper ante.FeegrantKeeper
+	txFeeChecker   ante.TxFeeChecker
+}
+
+func NewDeductFeeDecorator(ak ante.AccountKeeper, bk types.BankKeeper, fk ante.FeegrantKeeper, tfc ante.TxFeeChecker) DeductFeeDecorator {
+	if tfc == nil {
+		tfc = checkTxFeeWithValidatorMinGasPrices
+	}
+
+	return DeductFeeDecorator{
+		accountKeeper:  ak,
+		bankKeeper:     bk,
+		feegrantKeeper: fk,
+		txFeeChecker:   tfc,
+	}
+}
+
+func (dfd DeductFeeDecorator) AnteHandle(ctx sdk.Context, tx sdk.Tx, simulate bool, next sdk.AnteHandler) (sdk.Context, error) {
+	feeTx, ok := tx.(sdk.FeeTx)
+	if !ok {
+		return ctx, errors.Wrap(sdkerrors.ErrTxDecode, "Tx must be a FeeTx")
+	}
+
+	if !simulate && ctx.BlockHeight() > 0 && feeTx.GetGas() == 0 {
+		return ctx, errors.Wrap(sdkerrors.ErrInvalidGasLimit, "must provide positive gas")
+	}
+
+	var (
+		priority int64
+		err      error
+	)
+
+	fee := feeTx.GetFee()
+	if !simulate {
+		fee, priority, err = dfd.txFeeChecker(ctx, tx)
+		if err != nil {
+			return ctx, err
+		}
+	}
+	if err := dfd.checkDeductFee(ctx, tx, fee); err != nil {
+		return ctx, err
+	}
+
+	newCtx := ctx.WithPriority(priority)
+
+	return next(newCtx, tx, simulate)
+}
+
+func (dfd DeductFeeDecorator) checkDeductFee(ctx sdk.Context, sdkTx sdk.Tx, fee sdk.Coins) error {
+	feeTx, ok := sdkTx.(sdk.FeeTx)
+	if !ok {
+		return errors.Wrap(sdkerrors.ErrTxDecode, "Tx must be a FeeTx")
+	}
+
+	if addr := dfd.accountKeeper.GetModuleAddress(types.FeeCollectorName); addr == nil {
+		return fmt.Errorf("fee collector module account (%s) has not been set", types.FeeCollectorName)
+	}
+
+	feePayer := feeTx.FeePayer()
+	feeGranter := feeTx.FeeGranter()
+	deductFeesFrom := feePayer
+
+	// if feegranter set deduct fee from feegranter account.
+	// this works with only when feegrant enabled.
+	if feeGranter != nil {
+		if dfd.feegrantKeeper == nil {
+			return sdkerrors.ErrInvalidRequest.Wrap("fee grants are not enabled")
+		} else if !feeGranter.Equals(feePayer) {
+			err := dfd.feegrantKeeper.UseGrantedFees(ctx, feeGranter, feePayer, fee, sdkTx.GetMsgs())
+			if err != nil {
+				return errors.Wrapf(err, "%s does not allow to pay fees for %s", feeGranter, feePayer)
+			}
+		}
+
+		deductFeesFrom = feeGranter
+	}
+
+	deductFeesFromAcc := dfd.accountKeeper.GetAccount(ctx, deductFeesFrom)
+	if deductFeesFromAcc == nil {
+		return sdkerrors.ErrUnknownAddress.Wrapf("fee payer address: %s does not exist", deductFeesFrom)
+	}
+
+	// deduct the fees
+	if !fee.IsZero() {
+		err := evmkeeper.DeductFees(dfd.bankKeeper, ctx, deductFeesFromAcc, fee)
+		if err != nil {
+			return err
+		}
+	}
+
+	events := sdk.Events{
+		sdk.NewEvent(
+			sdk.EventTypeTx,
+			sdk.NewAttribute(sdk.AttributeKeyFee, fee.String()),
+			sdk.NewAttribute(sdk.AttributeKeyFeePayer, deductFeesFrom.String()),
+		),
+	}
+	ctx.EventManager().EmitEvents(events)
+
+	return nil
+}

x/evm/keeper/benchmark_test.go

@@ -9,7 +9,6 @@ import (
 	"github.com/stretchr/testify/require"
 
 	sdk "github.com/cosmos/cosmos-sdk/types"
-	authante "github.com/cosmos/cosmos-sdk/x/auth/ante"
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/ethereum/go-ethereum/crypto"
@@ -18,6 +17,7 @@ import (
 	"github.com/evmos/ethermint/server/config"
 	"github.com/evmos/ethermint/testutil"
 	ethermint "github.com/evmos/ethermint/types"
+	evmkeeper "github.com/evmos/ethermint/x/evm/keeper"
 	"github.com/evmos/ethermint/x/evm/types"
 )
 
@@ -115,7 +115,7 @@ func doBenchmark(b *testing.B, txBuilder TxBuilder) {
 		require.NoError(b, err)
 
 		fees := sdk.Coins{sdk.NewCoin(suite.EvmDenom(), sdkmath.NewIntFromBigInt(txData.Fee()))}
-		err = authante.DeductFees(suite.App.BankKeeper, suite.Ctx, suite.App.AccountKeeper.GetAccount(ctx, msg.GetFrom()), fees)
+		err = evmkeeper.DeductFees(suite.App.BankKeeper, suite.Ctx, suite.App.AccountKeeper.GetAccount(ctx, msg.GetFrom()), fees)
 		require.NoError(b, err)
 
 		rsp, err := suite.App.EvmKeeper.EthereumTx(sdk.WrapSDKContext(ctx), msg)
@@ -182,7 +182,7 @@ func BenchmarkMessageCall(b *testing.B) {
 		require.NoError(b, err)
 
 		fees := sdk.Coins{sdk.NewCoin(suite.EvmDenom(), sdkmath.NewIntFromBigInt(txData.Fee()))}
-		err = authante.DeductFees(suite.App.BankKeeper, suite.Ctx, suite.App.AccountKeeper.GetAccount(ctx, msg.GetFrom()), fees)
+		err = evmkeeper.DeductFees(suite.App.BankKeeper, suite.Ctx, suite.App.AccountKeeper.GetAccount(ctx, msg.GetFrom()), fees)
 		require.NoError(b, err)
 
 		rsp, err := suite.App.EvmKeeper.EthereumTx(sdk.WrapSDKContext(ctx), msg)

x/evm/keeper/utils.go

@@ -27,6 +27,7 @@
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	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"
 	stakingtypes "github.com/cosmos/cosmos-sdk/x/staking/types"
 
 	"github.com/evmos/ethermint/x/evm/types"
@@ -69,7 +70,7 @@
 	}
 
 	// deduct the full gas cost from the user balance
-	if err := authante.DeductFees(k.bankKeeper, ctx, signerAcc, fees); err != nil {
+	if err := DeductFees(k.bankKeeper, ctx, signerAcc, fees); err != nil {
 		return errorsmod.Wrapf(err, "failed to deduct full gas cost %s from the user %s balance", fees, from)
 	}
 
@@ -150,3 +151,17 @@
 	}
 	return nil
 }
+
+// DeductFees deducts fees from the given account.
+func DeductFees(bankKeeper authtypes.BankKeeper, ctx sdk.Context, acc authtypes.AccountI, fees sdk.Coins) error {
+	if !fees.IsValid() {
+		return errorsmod.Wrapf(errortypes.ErrInsufficientFee, "invalid fee amount: %s", fees)
+	}
+
+	err := bankKeeper.SendCoinsFromAccountToModule(ctx, acc.GetAddress(), authtypes.FeeCollectorName, fees)
+	if err != nil {
+		return errorsmod.Wrapf(errortypes.ErrInsufficientFunds, err.Error())
+	}
+
+	return nil
+}