fix: minimal-gas-prices and baseFeePerGas conflicts (#916)

* Problem: minimal-gas-prices and baseFeePerGas conflicts

Closes: #915

Solution:
- Don't check min-gas-price for evm tx if london hardfork and feemarket enabled.

comments and cleanup

changelog

* fix zero fee coins

Co-authored-by: Federico Kunze Küllmer <31522760+fedekunze@users.noreply.github.com>

CHANGELOG.md

@@ -41,6 +41,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 * (ante) [\#866](https://github.com/tharsis/ethermint/pull/866) `NewAnteHandler` constructor now receives a `HandlerOptions` field.
 * (evm) [\#849](https://github.com/tharsis/ethermint/pull/849) `PostTxProcessing` hook now takes an Ethereum tx `Receipt` and a `from` `Address` as arguments.
+* (ante) [#916](https://github.com/tharsis/ethermint/pull/916) don't check min-gas-price for eth tx if london hardfork enabled and feemarket enabled.
 
 ### State Machine Breaking
 

app/ante/eth.go

@@ -222,14 +222,12 @@ func (egcd EthGasConsumeDecorator) AnteHandle(ctx sdk.Context, tx sdk.Tx, simula
 // context rules.
 type CanTransferDecorator struct {
 	evmKeeper EVMKeeper
-	feemarketKeeper evmtypes.FeeMarketKeeper
 }
 
 // NewCanTransferDecorator creates a new CanTransferDecorator instance.
-func NewCanTransferDecorator(evmKeeper EVMKeeper, fmk evmtypes.FeeMarketKeeper) CanTransferDecorator {
+func NewCanTransferDecorator(evmKeeper EVMKeeper) CanTransferDecorator {
 	return CanTransferDecorator{
 		evmKeeper: evmKeeper,
-		feemarketKeeper: fmk,
 	}
 }
 
@@ -477,13 +475,11 @@ func (esc EthSetupContextDecorator) AnteHandle(ctx sdk.Context, tx sdk.Tx, simul
 // If fee is high enough or not CheckTx, then call next AnteHandler
 // CONTRACT: Tx must implement FeeTx to use MempoolFeeDecorator
 type EthMempoolFeeDecorator struct {
-	feemarketKeeper evmtypes.FeeMarketKeeper
 	evmKeeper EVMKeeper
 }
 
-func NewEthMempoolFeeDecorator(ek EVMKeeper, fmk evmtypes.FeeMarketKeeper) EthMempoolFeeDecorator {
+func NewEthMempoolFeeDecorator(ek EVMKeeper) EthMempoolFeeDecorator {
 	return EthMempoolFeeDecorator{
-		feemarketKeeper: fmk,
 		evmKeeper: ek,
 	}
 }
@@ -491,27 +487,21 @@ func NewEthMempoolFeeDecorator(ek EVMKeeper, fmk evmtypes.FeeMarketKeeper) EthMe
 // AnteHandle ensures that the provided fees meet a minimum threshold for the validator,
 // if this is a CheckTx. This is only for local mempool purposes, and thus
 // is only ran on check tx.
+// It only do the check if london hardfork not enabled or feemarket not enabled, because in that case feemarket will take over the task.
 func (mfd EthMempoolFeeDecorator) AnteHandle(ctx sdk.Context, tx sdk.Tx, simulate bool, next sdk.AnteHandler) (newCtx sdk.Context, err error) {
 	if ctx.IsCheckTx() && !simulate {
+		params := mfd.evmKeeper.GetParams(ctx)
+		ethCfg := params.ChainConfig.EthereumConfig(mfd.evmKeeper.ChainID())
+		baseFee := mfd.evmKeeper.BaseFee(ctx, ethCfg)
+		if baseFee == nil {
 			for _, msg := range tx.GetMsgs() {
 				ethMsg, ok := msg.(*evmtypes.MsgEthereumTx)
 				if !ok {
 					return ctx, sdkerrors.Wrapf(sdkerrors.ErrUnknownRequest, "invalid message type %T, expected %T", msg, (*evmtypes.MsgEthereumTx)(nil))
 				}
 
-			var feeAmt *big.Int
-
-			params := mfd.evmKeeper.GetParams(ctx)
-			chainID := mfd.evmKeeper.ChainID()
-			ethCfg := params.ChainConfig.EthereumConfig(chainID)
 				evmDenom := params.EvmDenom
-			baseFee := mfd.evmKeeper.BaseFee(ctx, ethCfg)
-			if baseFee != nil {
-				feeAmt = ethMsg.GetEffectiveFee(baseFee)
-			} else {
-				feeAmt = ethMsg.GetFee()
-			}
-
+				feeAmt := ethMsg.GetFee()
 				glDec := sdk.NewDec(int64(ethMsg.GetGas()))
 				requiredFee := ctx.MinGasPrices().AmountOf(evmDenom).Mul(glDec)
 				if sdk.NewDecFromBigInt(feeAmt).LT(requiredFee) {
@@ -519,6 +509,7 @@ func (mfd EthMempoolFeeDecorator) AnteHandle(ctx sdk.Context, tx sdk.Tx, simulat
 				}
 			}
 		}
+	}
 
 	return next(ctx, tx, simulate)
 }

app/ante/eth_test.go

@@ -293,7 +293,7 @@ func (suite AnteTestSuite) TestEthGasConsumeDecorator() {
 }
 
 func (suite AnteTestSuite) TestCanTransferDecorator() {
-	dec := ante.NewCanTransferDecorator(suite.app.EvmKeeper, suite.app.FeeMarketKeeper)
+	dec := ante.NewCanTransferDecorator(suite.app.EvmKeeper)
 
 	addr, privKey := tests.NewAddrKey()
 

app/ante/handler_options.go

@@ -49,12 +49,12 @@ func (options HandlerOptions) Validate() error {
 func newEthAnteHandler(options HandlerOptions) sdk.AnteHandler {
 	return sdk.ChainAnteDecorators(
 		NewEthSetUpContextDecorator(options.EvmKeeper), // outermost AnteDecorator. SetUpContext must be called first
-		NewEthMempoolFeeDecorator(options.EvmKeeper, options.FeeMarketKeeper), // Check eth effective gas price against minimal-gas-prices
+		NewEthMempoolFeeDecorator(options.EvmKeeper),   // Check eth effective gas price against minimal-gas-prices
 		NewEthValidateBasicDecorator(options.EvmKeeper),
 		NewEthSigVerificationDecorator(options.EvmKeeper),
 		NewEthAccountVerificationDecorator(options.AccountKeeper, options.BankKeeper, options.EvmKeeper),
 		NewEthGasConsumeDecorator(options.EvmKeeper),
-		NewCanTransferDecorator(options.EvmKeeper, options.FeeMarketKeeper),
+		NewCanTransferDecorator(options.EvmKeeper),
 		NewEthIncrementSenderSequenceDecorator(options.AccountKeeper), // innermost AnteDecorator.
 	)
 }

rpc/ethereum/backend/backend.go

@@ -10,10 +10,8 @@ import (
 	"time"
 
 	"github.com/cosmos/cosmos-sdk/client/flags"
-	codectypes "github.com/cosmos/cosmos-sdk/codec/types"
 	"github.com/cosmos/cosmos-sdk/server"
 	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
-	authtx "github.com/cosmos/cosmos-sdk/x/auth/tx"
 	"github.com/ethereum/go-ethereum/accounts/keystore"
 	"github.com/ethereum/go-ethereum/params"
 	"github.com/ethereum/go-ethereum/rpc"
@@ -802,23 +800,6 @@ func (e *EVMBackend) SendTransaction(args evmtypes.TransactionArgs) (common.Hash
 		return common.Hash{}, err
 	}
 
-	// Assemble transaction from fields
-	builder, ok := e.clientCtx.TxConfig.NewTxBuilder().(authtx.ExtensionOptionsTxBuilder)
-	if !ok {
-		e.logger.Error("clientCtx.TxConfig.NewTxBuilder returns unsupported builder", "error", err.Error())
-	}
-
-	option, err := codectypes.NewAnyWithValue(&evmtypes.ExtensionOptionsEthereumTx{})
-	if err != nil {
-		e.logger.Error("codectypes.NewAnyWithValue failed to pack an obvious value", "error", err.Error())
-		return common.Hash{}, err
-	}
-
-	builder.SetExtensionOptions(option)
-	if err = builder.SetMsgs(msg); err != nil {
-		e.logger.Error("builder.SetMsgs failed", "error", err.Error())
-	}
-
 	// Query params to use the EVM denomination
 	res, err := e.queryClient.QueryClient.Params(e.ctx, &evmtypes.QueryParamsRequest{})
 	if err != nil {
@@ -826,19 +807,16 @@ func (e *EVMBackend) SendTransaction(args evmtypes.TransactionArgs) (common.Hash
 		return common.Hash{}, err
 	}
 
-	txData, err := evmtypes.UnpackTxData(msg.Data)
+	// Assemble transaction from fields
+	tx, err := msg.BuildTx(e.clientCtx.TxConfig.NewTxBuilder(), res.Params.EvmDenom)
 	if err != nil {
-		e.logger.Error("failed to unpack tx data", "error", err.Error())
+		e.logger.Error("build cosmos tx failed", "error", err.Error())
 		return common.Hash{}, err
 	}
 
-	fees := sdk.Coins{sdk.NewCoin(res.Params.EvmDenom, sdk.NewIntFromBigInt(txData.Fee()))}
-	builder.SetFeeAmount(fees)
-	builder.SetGasLimit(msg.GetGas())
-
 	// Encode transaction by default Tx encoder
 	txEncoder := e.clientCtx.TxConfig.TxEncoder()
-	txBytes, err := txEncoder(builder.GetTx())
+	txBytes, err := txEncoder(tx)
 	if err != nil {
 		e.logger.Error("failed to encode eth tx using default encoder", "error", err.Error())
 		return common.Hash{}, err
@@ -976,9 +954,9 @@ func (e *EVMBackend) ChainConfig() *params.ChainConfig {
 }
 
 // SuggestGasTipCap returns the suggested tip cap
+// always return zero since we don't support tx prioritization yet.
 func (e *EVMBackend) SuggestGasTipCap() (*big.Int, error) {
-	out := new(big.Int).SetInt64(e.RPCMinGasPrice())
-	return out, nil
+	return big.NewInt(0), nil
 }
 
 // BaseFee returns the base fee tracked by the Fee Market module. If the base fee is not enabled,

rpc/ethereum/namespaces/eth/api.go

@@ -193,16 +193,22 @@ func (e *PublicAPI) Hashrate() hexutil.Uint64 {
 // GasPrice returns the current gas price based on Ethermint's gas price oracle.
 func (e *PublicAPI) GasPrice() (*hexutil.Big, error) {
 	e.logger.Debug("eth_gasPrice")
-	tipcap, err := e.backend.SuggestGasTipCap()
+	var (
+		result *big.Int
+		err    error
+	)
+	if head := e.backend.CurrentHeader(); head.BaseFee != nil {
+		result, err = e.backend.SuggestGasTipCap()
 		if err != nil {
 			return nil, err
 		}
 
-	if head := e.backend.CurrentHeader(); head.BaseFee != nil {
-		tipcap.Add(tipcap, head.BaseFee)
+		result = result.Add(result, head.BaseFee)
+	} else {
+		result = big.NewInt(e.backend.RPCMinGasPrice())
 	}
 
-	return (*hexutil.Big)(tipcap), nil
+	return (*hexutil.Big)(result), nil
 }
 
 // MaxPriorityFeePerGas returns a suggestion for a gas tip cap for dynamic fee transactions.

x/evm/keeper/utils.go

@@ -66,6 +66,11 @@ func (k Keeper) DeductTxCostsFromUserBalance(
 		feeAmt = txData.Fee()
 	}
 
+	if feeAmt.Sign() == 0 {
+		// zero fee, no need to deduct
+		return sdk.NewCoins(), nil
+	}
+
 	fees := sdk.Coins{sdk.NewCoin(denom, sdk.NewIntFromBigInt(feeAmt))}
 
 	// deduct the full gas cost from the user balance

x/evm/types/msg.go

@@ -330,11 +330,10 @@ func (msg *MsgEthereumTx) BuildTx(b client.TxBuilder, evmDenom string) (signing.
 	if err != nil {
 		return nil, err
 	}
-	fees := sdk.Coins{
-		{
-			Denom:  evmDenom,
-			Amount: sdk.NewIntFromBigInt(txData.Fee()),
-		},
+	fees := make(sdk.Coins, 0)
+	feeAmt := sdk.NewIntFromBigInt(txData.Fee())
+	if feeAmt.Sign() > 0 {
+		fees = append(fees, sdk.NewCoin(evmDenom, feeAmt))
 	}
 
 	builder.SetExtensionOptions(option)