From ee6a927e1cc7303c9d7cab4112db2c654f70b7ba Mon Sep 17 00:00:00 2001
From: Christian Lohr <christian@volume.finance>
Date: Thu, 7 Mar 2024 14:43:21 +0100
Subject: [PATCH] feat: add gas limit multiplication (#358)

* feat: add gas limit multiplication

* fix: rotator test
---
 chain/evm/client.go          | 49 ++++++++++++++++++++++++++++++------
 chain/evm/client_test.go     |  2 +-
 util/rotator/rotator_test.go |  2 +-
 3 files changed, 44 insertions(+), 9 deletions(-)

diff --git a/chain/evm/client.go b/chain/evm/client.go
index 33a81e15..ea49fd9b 100644
--- a/chain/evm/client.go
+++ b/chain/evm/client.go
@@ -141,7 +141,7 @@ type mevClient interface {
 
 //go:generate mockery --name=ethClientConn --inpackage --testonly
 type ethClientConn interface {
-	bind.ContractBackend
+	ethClienter
 	TransactionByHash(ctx context.Context, hash common.Hash) (tx *etherumtypes.Transaction, isPending bool, err error)
 	HeaderByNumber(ctx context.Context, number *big.Int) (*etherumtypes.Header, error)
 	BlockByHash(ctx context.Context, hash common.Hash) (*etherumtypes.Block, error)
@@ -170,6 +170,11 @@ type CompassBindingFilterer interface {
 	WatchValsetUpdated(opts *bind.WatchOpts, sink chan<- *compassABI.CompassValsetUpdated) (event.Subscription, error)
 }
 
+//go:generate mockery --name=ethClienter --inpackage --testonly
+type ethClienter interface {
+	bind.ContractBackend
+}
+
 //go:generate mockery --name=CompassBinding
 type CompassBinding interface {
 	CompassBindingCaller
@@ -217,11 +222,6 @@ func (c *Client) newCompass(addr common.Address) (CompassBinding, error) {
 	return compassABI.NewCompass(addr, c.conn)
 }
 
-//go:generate mockery --name=ethClienter --inpackage --testonly
-type ethClienter interface {
-	bind.ContractBackend
-}
-
 type executeSmartContractIn struct {
 	ethClient ethClienter
 	mevClient mevClient
@@ -333,7 +333,14 @@ func callSmartContract(
 		txOpts.From = args.signingAddr
 
 		// https://github.com/VolumeFi/paloma/issues/1048
-		txOpts.GasLimit = uint64(float64(txOpts.GasLimit) * 1.1)
+		value := new(big.Int)
+		gasFeeCap := new(big.Int)
+		if args.txType == 2 {
+			gasFeeCap = gasPrice
+		}
+		gasLimit, err := estimateGasLimit(ctx, args.ethClient, txOpts, &args.contract, packedBytes, gasPrice, gasTipCap, gasFeeCap, value)
+		whoops.Assert(err)
+		txOpts.GasLimit = uint64(float64(gasLimit) * 1.2)
 
 		if args.txType == 2 {
 			txOpts.GasFeeCap = gasPrice
@@ -406,6 +413,34 @@ func callSmartContract(
 	})
 }
 
+// Copied from https://github.com/ethereum/go-ethereum/blob/e5d5e09faae48dac3723634e2b1813e4f2e89535/accounts/abi/bind/base.go#L357
+// since the original implementation is not exported, but we need access to the gas limit to multiply it
+// before we send the TX.
+// More detail: https://github.com/VolumeFi/paloma/issues/1048
+// And: https://github.com/VolumeFi/paloma/issues/1158#issuecomment-1896488916
+func estimateGasLimit(ctx context.Context, c ethClienter, opts *bind.TransactOpts, contract *ethcommon.Address, input []byte, gasPrice, gasTipCap, gasFeeCap, value *big.Int) (uint64, error) {
+	if contract != nil {
+		// Gas estimation cannot succeed without code for method invocations.
+		if code, err := c.PendingCodeAt(ctx, *contract); err != nil {
+			return 0, err
+		} else if len(code) == 0 {
+			return 0, bind.ErrNoCode
+		}
+	}
+
+	msg := ethereum.CallMsg{
+		From:      opts.From,
+		To:        contract,
+		GasPrice:  gasPrice,
+		GasTipCap: gasTipCap,
+		GasFeeCap: gasFeeCap,
+		Value:     value,
+		Data:      input,
+	}
+
+	return c.EstimateGas(ctx, msg)
+}
+
 func (c *Client) sign(ctx context.Context, bytes []byte) ([]byte, error) {
 	return c.keystore.SignHash(
 		accounts.Account{Address: c.addr},
diff --git a/chain/evm/client_test.go b/chain/evm/client_test.go
index 88e1fb20..e4a38633 100644
--- a/chain/evm/client_test.go
+++ b/chain/evm/client_test.go
@@ -135,7 +135,7 @@ func TestExecutingSmartContract(t *testing.T) {
 				ethMock.On("EstimateGas", mock.Anything, mock.Anything).Return(uint64(222), nil)
 
 				mevMock := newMockMevClient(t)
-				mevMock.On("Relay", mock.Anything, mock.Anything, mock.Anything).Return(common.HexToHash("0xb19cc052f5066cb445ea09461d99df913f6938fc825676e645f40d5d24abddda"), nil)
+				mevMock.On("Relay", mock.Anything, mock.Anything, mock.Anything).Return(common.HexToHash("0xde13fda4e25fc73f1d7f3b3e7652a56a0d0a8a6a361dcaec4c8c77f3720a05d1"), nil)
 
 				args.ethClient = ethMock
 				args.mevClient = mevMock
diff --git a/util/rotator/rotator_test.go b/util/rotator/rotator_test.go
index 0ef5f9e4..844c978b 100644
--- a/util/rotator/rotator_test.go
+++ b/util/rotator/rotator_test.go
@@ -23,8 +23,8 @@ func Test_Rotator_RotateKeys(t *testing.T) {
 	wg := &sync.WaitGroup{}
 
 	// Confirm rotator is concurrency safe
+	wg.Add(3 * 99)
 	for i := 0; i < 3; i++ {
-		wg.Add(1)
 		go func() {
 			for i := 1; i < 100; i++ {
 				r.RotateKeys(context.Background())