refactor(evm): Remove unnecessary argument in the VerifyFee function, which returns the token payment required based on the effective fee from the tx data. Improve documentation.

CHANGELOG.md

@@ -47,6 +47,10 @@ that gas consumed during any send operation of the "NibiruBankKeeper" depends
 only on the "bankkeeper.BaseKeeper"'s gas consumption.
 - [#2120](https://github.com/NibiruChain/nibiru/pull/2120) - fix: Use canonical hexadecimal strings for Eip155 address encoding 
 - [#2122](https://github.com/NibiruChain/nibiru/pull/2122) - test(evm): more bank extension tests and EVM ABCI integration tests to prevent regressions
+- [#2124](https://github.com/NibiruChain/nibiru/pull/2124) - refactor(evm):
+Remove unnecessary argument in the `VerifyFee` function, which returns the token
+payment required based on the effective fee from the tx data. Improve
+documentation.
 
 #### Nibiru EVM | Before Audit 2 - 2024-12-06
 

app/evmante/evmante_gas_consume.go

@@ -99,7 +99,6 @@ func (anteDec AnteDecEthGasConsume) AnteHandle(
 
 		fees, err := keeper.VerifyFee(
 			txData,
-			evm.EVMBankDenom,
 			baseFeeMicronibiPerGas,
 			ctx.IsCheckTx(),
 		)

x/evm/keeper/gas_fees.go

@@ -140,13 +140,25 @@ func (k *Keeper) DeductTxCostsFromUserBalance(
 	return nil
 }
 
-// VerifyFee is used to return the fee for the given transaction data in
-// sdk.Coins. It checks that the gas limit is not reached, the gas limit is
-// higher than the intrinsic gas and that the base fee is lower than the gas fee
-// cap.
+// VerifyFee is used to return the fee, or token payment, for the given
+// transaction data in [sdk.Coin]s. It checks that the the gas limit and uses the
+// "effective fee" from the [evm.TxData].
+//
+//   - For [evm.DynamicFeeTx], the effective gas price is the minimum of
+//     (baseFee + tipCap) and the gas fee cap (feeCap).
+//   - For [evm.LegacyTx] and [evm.AccessListTx], the effective gas price is the
+//     max of the gas price and baseFee.
+//
+// Transactions where the baseFee exceeds the feeCap are priced out
+// under EIP-1559 and will not pass validation.
+//
+// Args:
+//   - txData: Tx data related to gas, effectie gas, nonce, and chain ID
+//     implemented by every Ethereum tx type.
+//   - baseFeeMicronibi:EIP1559 base fee in units of micronibi ("unibi").
+//   - isCheckTx: Comes from `[sdk.Context].isCheckTx()`
 func VerifyFee(
 	txData evm.TxData,
-	denom string,
 	baseFeeMicronibi *big.Int,
 	isCheckTx bool,
 ) (sdk.Coins, error) {
@@ -180,22 +192,13 @@ func VerifyFee(
 		baseFeeMicronibi = evm.BASE_FEE_MICRONIBI
 	}
 
-	// gasFeeCapMicronibi := evm.WeiToNative(txData.GetGasFeeCapWei())
-	// if baseFeeMicronibi != nil && gasFeeCapMicronibi.Cmp(baseFeeMicronibi) < 0 {
-	// 	baseFeeWei := evm.NativeToWei(baseFeeMicronibi)
-	// 	return nil, errors.Wrapf(errortypes.ErrInsufficientFee,
-	// 		"the tx gasfeecap is lower than the tx baseFee: %s (gasfeecap), %s (basefee) wei per gas",
-	// 		txData.GetGasFeeCapWei(),
-	// 		baseFeeWei,
-	// 	)
-	// }
-
 	baseFeeWei := evm.NativeToWei(baseFeeMicronibi)
 	feeAmtMicronibi := evm.WeiToNative(txData.EffectiveFeeWei(baseFeeWei))
+	bankDenom := evm.EVMBankDenom
 	if feeAmtMicronibi.Sign() == 0 {
 		// zero fee, no need to deduct
-		return sdk.Coins{{Denom: denom, Amount: sdkmath.ZeroInt()}}, nil
+		return sdk.Coins{{Denom: bankDenom, Amount: sdkmath.ZeroInt()}}, nil
 	}
 
-	return sdk.Coins{{Denom: denom, Amount: sdkmath.NewIntFromBigInt(feeAmtMicronibi)}}, nil
+	return sdk.Coins{{Denom: bankDenom, Amount: sdkmath.NewIntFromBigInt(feeAmtMicronibi)}}, nil
 }

x/evm/keeper/gas_fees_test.go

@@ -101,19 +101,18 @@ func (s *Suite) TestVerifyFee() {
 			}
 		},
 	} {
-		feeDenom := evm.EVMBankDenom
 		isCheckTx := true
 		tc := getTestCase()
 		s.Run(tc.name, func() {
 			gotCoins, err := evmkeeper.VerifyFee(
-				tc.txData, feeDenom, tc.baseFeeMicronibi, isCheckTx,
+				tc.txData, tc.baseFeeMicronibi, isCheckTx,
 			)
 			if tc.wantErr != "" {
 				s.Require().ErrorContains(err, tc.wantErr)
 				return
 			}
 			s.Require().NoError(err)
-			s.Equal(tc.wantCoinAmt, gotCoins.AmountOf(feeDenom).String())
+			s.Equal(tc.wantCoinAmt, gotCoins.AmountOf(evm.EVMBankDenom).String())
 		})
 	}
 }

x/evm/tx_data.go

@@ -32,6 +32,8 @@ var (
 // provide custom implementations for these methods without creating a new TxData
 // data structure. Thus, the current interface exists.
 type TxData interface {
+	// TxType returns a byte (uint8) identifying the tx as a [LegacyTx] (0),
+	// [AccessListTx] (1), or [DynamicFeeTx] (2).
 	TxType() byte
 	Copy() TxData
 	GetChainID() *big.Int
@@ -86,14 +88,24 @@ type TxData interface {
 	AsEthereumData() gethcore.TxData
 	Validate() error
 
-	// static fee
+	// Fee in units of wei := gasPrice (wei per gas)  * gasLimit (gas).
 	Fee() *big.Int
-	// Cost is the gas cost of the transaction in wei
+	// Cost in units of wei := Fee * Value. Cost is the gas cost of the
+	// transaction in wei, accounting for value transferred.
 	Cost() *big.Int
 
-	// effective gasPrice/fee/cost according to current base fee
+	// EffectiveGasPriceWeiPerGas is effective gas price in units of wei per gas.
+	// "Effective" means depending on the base fee of the network.
 	EffectiveGasPriceWeiPerGas(baseFeeWei *big.Int) *big.Int
+
+	// EffectiveFeeWei := effectiveGasPrice (wei per gas) * gasLimit (gas).
+	// "Effective" means depending on the base fee of the network.
 	EffectiveFeeWei(baseFeeWei *big.Int) *big.Int
+
+	// EffectiveCostWei is the same as cost, except it uses effective fee in wei
+	// rathen than fee. Effective cost is the gas cost of the transaction in wei,
+	// accounting for value (wei) transferred and using effective gas price (wei
+	// per gas).
 	EffectiveCostWei(baseFeeWei *big.Int) *big.Int
 }
 

x/evm/tx_data_access_list.go

@@ -101,7 +101,8 @@ func newAccessListTx(tx *gethcore.Transaction) (*AccessListTx, error) {
 	return txData, nil
 }
 
-// TxType returns the tx type
+// TxType returns a byte (uint8) identifying the tx as a [LegacyTx] (0),
+// [AccessListTx] (1), or [DynamicFeeTx] (2).
 func (tx *AccessListTx) TxType() uint8 {
 	return gethcore.AccessListTxType
 }
@@ -280,12 +281,12 @@ func (tx AccessListTx) Validate() error {
 	return nil
 }
 
-// Fee returns gasprice * gaslimit.
+// Fee returns gasPrice * gasLimit.
 func (tx AccessListTx) Fee() *big.Int {
 	return priceTimesGas(tx.GetGasPrice(), tx.GetGas())
 }
 
-// Cost returns amount + gasprice * gaslimit.
+// Cost returns amount + gasPrice * gasLimit.
 func (tx AccessListTx) Cost() *big.Int {
 	return cost(tx.Fee(), tx.GetValueWei())
 }

x/evm/tx_data_dynamic_fee.go

@@ -75,7 +75,8 @@ func NewDynamicFeeTx(tx *gethcore.Transaction) (*DynamicFeeTx, error) {
 	return txData, nil
 }
 
-// TxType returns the tx type
+// TxType returns a byte (uint8) identifying the tx as a [LegacyTx] (0),
+// [AccessListTx] (1), or [DynamicFeeTx] (2).
 func (tx *DynamicFeeTx) TxType() uint8 {
 	return gethcore.DynamicFeeTxType
 }
@@ -285,12 +286,12 @@ func (tx DynamicFeeTx) Validate() error {
 	return nil
 }
 
-// Fee returns gasprice * gaslimit.
+// Fee returns gasPrice * gasLimit.
 func (tx DynamicFeeTx) Fee() *big.Int {
 	return priceTimesGas(tx.GetGasFeeCapWei(), tx.GasLimit)
 }
 
-// Cost returns amount + gasprice * gaslimit.
+// Cost returns amount + gasPrice * gasLimit.
 func (tx DynamicFeeTx) Cost() *big.Int {
 	return cost(tx.Fee(), tx.GetValueWei())
 }
@@ -305,12 +306,12 @@ func (tx *DynamicFeeTx) EffectiveGasPriceWeiPerGas(baseFeeWei *big.Int) *big.Int
 	return BigIntMax(baseFeeWei, rawEffectiveGasPrice)
 }
 
-// EffectiveFeeWei returns effective_gasprice * gaslimit.
+// EffectiveFeeWei returns effective_gasPrice * gasLimit.
 func (tx DynamicFeeTx) EffectiveFeeWei(baseFeeWei *big.Int) *big.Int {
 	return priceTimesGas(tx.EffectiveGasPriceWeiPerGas(baseFeeWei), tx.GasLimit)
 }
 
-// EffectiveCostWei returns amount + effective_gasprice * gaslimit.
+// EffectiveCostWei returns amount + effective_gasPrice * gasLimit.
 func (tx DynamicFeeTx) EffectiveCostWei(baseFeeWei *big.Int) *big.Int {
 	return cost(tx.EffectiveFeeWei(baseFeeWei), tx.GetValueWei())
 }

x/evm/tx_data_legacy.go

@@ -43,7 +43,8 @@ func NewLegacyTx(tx *gethcore.Transaction) (*LegacyTx, error) {
 	return txData, nil
 }
 
-// TxType returns the tx type
+// TxType returns a byte (uint8) identifying the tx as a [LegacyTx] (0),
+// [AccessListTx] (1), or [DynamicFeeTx] (2).
 func (tx *LegacyTx) TxType() uint8 {
 	return gethcore.LegacyTxType
 }
@@ -184,12 +185,13 @@ func (tx LegacyTx) Validate() error {
 	return nil
 }
 
-// Fee returns gasprice * gaslimit.
+// Fee := gasPrice (wei per gas)  * gasLimit (gas). Thus, fee is in units of
+// wei.
 func (tx LegacyTx) Fee() *big.Int {
 	return priceTimesGas(tx.GetGasPrice(), tx.GetGas())
 }
 
-// Cost returns amount + gasprice * gaslimit.
+// Cost returns amount + gasPrice * gasLimit.
 func (tx LegacyTx) Cost() *big.Int {
 	return cost(tx.Fee(), tx.GetValueWei())
 }