fix: update user paid fee for cointype ZETA to use correct denomination (backport #4542)

e2e/e2etests/legacy/test_zeta_withdraw.go

@@ -6,6 +6,7 @@ import (
 	"github.com/zeta-chain/node/e2e/runner"
 	"github.com/zeta-chain/node/e2e/utils"
 	crosschaintypes "github.com/zeta-chain/node/x/crosschain/types"
+	observertypes "github.com/zeta-chain/node/x/observer/types"
 )
 
 func TestZetaWithdraw(r *runner.E2ERunner, args []string) {
@@ -14,10 +15,23 @@ func TestZetaWithdraw(r *runner.E2ERunner, args []string) {
 	// parse withdraw amount
 	amount := utils.ParseBigInt(r, args[0])
 
+	evmChainID, err := r.EVMClient.ChainID(r.Ctx)
+	require.NoError(r, err)
+
 	r.LegacyDepositAndApproveWZeta(amount)
 	tx := r.LegacyWithdrawZeta(amount, true)
 
 	cctx := utils.WaitCctxMinedByInboundHash(r.Ctx, tx.Hash().Hex(), r.CctxClient, r.Logger, r.CctxTimeout)
 	r.Logger.CCTX(*cctx, "zeta withdraw")
 	utils.RequireCCTXStatus(r, cctx, crosschaintypes.CctxStatus_OutboundMined)
+
+	// Get chain params for stability pool percentage
+	chainParams, err := r.ObserverClient.GetChainParamsForChain(
+		r.Ctx,
+		&observertypes.QueryGetChainParamsForChainRequest{ChainId: evmChainID.Int64()},
+	)
+	require.NoError(r, err)
+
+	// Verify gas accounting and log refund amounts
+	utils.VerifyOutboundGasAccounting(r, cctx, chainParams.ChainParams.StabilityPoolPercentage, r.Logger)
 }

e2e/e2etests/test_erc20_withdraw.go

@@ -9,13 +9,17 @@ import (
 	"github.com/zeta-chain/node/e2e/runner"
 	"github.com/zeta-chain/node/e2e/utils"
 	crosschaintypes "github.com/zeta-chain/node/x/crosschain/types"
+	observertypes "github.com/zeta-chain/node/x/observer/types"
 )
 
 func TestERC20Withdraw(r *runner.E2ERunner, args []string) {
 	require.Len(r, args, 1)
 
 	amount := utils.ParseBigInt(r, args[0])
 
+	evmChainID, err := r.EVMClient.ChainID(r.Ctx)
+	require.NoError(r, err)
+
 	r.ApproveERC20ZRC20(r.GatewayZEVMAddr)
 	r.ApproveETHZRC20(r.GatewayZEVMAddr)
 
@@ -26,4 +30,14 @@ func TestERC20Withdraw(r *runner.E2ERunner, args []string) {
 	cctx := utils.WaitCctxMinedByInboundHash(r.Ctx, tx.Hash().Hex(), r.CctxClient, r.Logger, r.CctxTimeout)
 	r.Logger.CCTX(*cctx, "withdraw")
 	utils.RequireCCTXStatus(r, cctx, crosschaintypes.CctxStatus_OutboundMined)
+
+	// Get chain params for stability pool percentage
+	chainParams, err := r.ObserverClient.GetChainParamsForChain(
+		r.Ctx,
+		&observertypes.QueryGetChainParamsForChainRequest{ChainId: evmChainID.Int64()},
+	)
+	require.NoError(r, err)
+
+	// Verify gas accounting and log refund amounts
+	utils.VerifyOutboundGasAccounting(r, cctx, chainParams.ChainParams.StabilityPoolPercentage, r.Logger)
 }

e2e/e2etests/test_eth_withdraw.go

@@ -9,13 +9,17 @@ import (
 	"github.com/zeta-chain/node/e2e/runner"
 	"github.com/zeta-chain/node/e2e/utils"
 	crosschaintypes "github.com/zeta-chain/node/x/crosschain/types"
+	observertypes "github.com/zeta-chain/node/x/observer/types"
 )
 
 func TestETHWithdraw(r *runner.E2ERunner, args []string) {
 	require.Len(r, args, 1)
 
 	amount := utils.ParseBigInt(r, args[0])
 
+	evmChainID, err := r.EVMClient.ChainID(r.Ctx)
+	require.NoError(r, err)
+
 	oldBalance, err := r.EVMClient.BalanceAt(r.Ctx, r.EVMAddress(), nil)
 	require.NoError(r, err)
 
@@ -29,6 +33,16 @@ func TestETHWithdraw(r *runner.E2ERunner, args []string) {
 	r.Logger.CCTX(*cctx, "withdraw")
 	utils.RequireCCTXStatus(r, cctx, crosschaintypes.CctxStatus_OutboundMined)
 
+	// Get chain params for stability pool percentage
+	chainParams, err := r.ObserverClient.GetChainParamsForChain(
+		r.Ctx,
+		&observertypes.QueryGetChainParamsForChainRequest{ChainId: evmChainID.Int64()},
+	)
+	require.NoError(r, err)
+
+	// Verify gas accounting and log refund amounts
+	utils.VerifyOutboundGasAccounting(r, cctx, chainParams.ChainParams.StabilityPoolPercentage, r.Logger)
+
 	// check the balance was updated, we just check newBalance is greater than oldBalance because of the gas fee
 	newBalance, err := r.EVMClient.BalanceAt(r.Ctx, r.EVMAddress(), nil)
 	require.NoError(r, err)

e2e/e2etests/test_zeta_withdraw.go

@@ -9,6 +9,7 @@ import (
 	"github.com/zeta-chain/node/e2e/runner"
 	"github.com/zeta-chain/node/e2e/utils"
 	crosschaintypes "github.com/zeta-chain/node/x/crosschain/types"
+	observertypes "github.com/zeta-chain/node/x/observer/types"
 )
 
 func TestZetaWithdraw(r *runner.E2ERunner, args []string) {
@@ -29,6 +30,16 @@ func TestZetaWithdraw(r *runner.E2ERunner, args []string) {
 		cctx := utils.WaitCctxMinedByInboundHash(r.Ctx, tx.Hash().Hex(), r.CctxClient, r.Logger, r.CctxTimeout)
 		r.Logger.CCTX(*cctx, "zeta_withdraw")
 		utils.RequireCCTXStatus(r, cctx, crosschaintypes.CctxStatus_OutboundMined)
+
+		// Get chain params for stability pool percentage
+		chainParams, err := r.ObserverClient.GetChainParamsForChain(
+			r.Ctx,
+			&observertypes.QueryGetChainParamsForChainRequest{ChainId: evmChainID.Int64()},
+		)
+		require.NoError(r, err)
+
+		// Verify gas accounting and log refund amounts
+		utils.VerifyOutboundGasAccounting(r, cctx, chainParams.ChainParams.StabilityPoolPercentage, r.Logger)
 	} else {
 		// V2 ZETA flows disabled: tx should revert on GatewayZEVM, no CCTX created
 		utils.EnsureNoCctxMinedByInboundHash(r.Ctx, tx.Hash().Hex(), r.CctxClient)

e2e/utils/zetacore.go

@@ -6,6 +6,7 @@ import (
 	"math/big"
 	"time"
 
+	"cosmossdk.io/math"
 	rpchttp "github.com/cometbft/cometbft/rpc/client/http"
 	"github.com/ethereum/go-ethereum/accounts/abi/bind"
 	"github.com/ethereum/go-ethereum/common"
@@ -17,6 +18,7 @@ import (
 	"google.golang.org/grpc/status"
 
 	"github.com/zeta-chain/node/pkg/constant"
+	crosschainkeeper "github.com/zeta-chain/node/x/crosschain/keeper"
 	crosschaintypes "github.com/zeta-chain/node/x/crosschain/types"
 )
 
@@ -498,3 +500,49 @@ func WaitAndVerifyZRC20BalanceChange(
 		return
 	}
 }
+
+// VerifyOutboundGasAccounting verifies the gas accounting for an outbound CCTX.
+// It asserts that UserGasFeePaid equals GasLimit * GasPrice (gas token denomination),
+// and logs the calculated refund amounts (stability pool and user refund).
+// stabilityPoolPercentage should be obtained from chain params (e.g., chainParams.ChainParams.StabilityPoolPercentage)
+func VerifyOutboundGasAccounting(
+	t require.TestingT,
+	cctx *crosschaintypes.CrossChainTx,
+	stabilityPoolPercentage uint64,
+	logger infoLogger,
+) {
+	outboundParams := cctx.GetCurrentOutboundParam()
+
+	// Verify UserGasFeePaid == GasLimit * GasPrice (gas token denomination)
+	gasLimit := ParseUint(t, fmt.Sprintf("%d", outboundParams.CallOptions.GasLimit))
+	gasPrice := ParseUint(t, outboundParams.GasPrice)
+	expectedUserGasFeePaid := gasLimit.Mul(gasPrice)
+	require.Equal(
+		t,
+		expectedUserGasFeePaid.String(),
+		outboundParams.UserGasFeePaid.String(),
+		"UserGasFeePaid should equal GasLimit * GasPrice (gas token denomination)",
+	)
+
+	outboundTxFeePaid := math.NewUint(outboundParams.GasUsed).
+		Mul(math.NewUintFromBigInt(outboundParams.EffectiveGasPrice.BigInt()))
+	userGasFeePaid := outboundParams.UserGasFeePaid
+
+	logger.Info("Gas accounting - UserGasFeePaid: %s, OutboundTxFeePaid: %s",
+		userGasFeePaid.String(), outboundTxFeePaid.String())
+
+	if outboundTxFeePaid.GTE(userGasFeePaid) {
+		logger.Info("No remaining fees to refund (outbound used all or more gas than paid)")
+		return
+	}
+
+	// Calculate refund amounts
+	totalRemainingFees := userGasFeePaid.Sub(outboundTxFeePaid)
+	usableRemainingFees := crosschainkeeper.PercentOf(totalRemainingFees, crosschaintypes.UsableRemainingFeesPercentage)
+	stabilityPoolAmount := crosschainkeeper.PercentOf(usableRemainingFees, stabilityPoolPercentage)
+	userRefundAmount := usableRemainingFees.Sub(stabilityPoolAmount)
+
+	logger.Info("Gas refund - TotalRemaining: %s, UsableRemaining: %s, StabilityPool: %s, UserRefund: %s",
+		totalRemainingFees.String(), usableRemainingFees.String(),
+		stabilityPoolAmount.String(), userRefundAmount.String())
+}

x/crosschain/keeper/gas_payment.go

@@ -457,8 +457,8 @@ func (k Keeper) PayGasInZetaAndUpdateCctx(
 		cctx.ZetaFees = cctx.ZetaFees.Add(feeInZeta)
 	}
 
-	// zeta token paid by the user is swapped for gas ZRC20 and burned to pay for fee.
-	cctx.GetCurrentOutboundParam().UserGasFeePaid = sdkmath.NewUintFromBigInt(outTxGasFeeInZeta)
+	// Gas fee paid by the user in gas token
+	cctx.GetCurrentOutboundParam().UserGasFeePaid = outTxGasFee
 
 	return nil
 }