From dea4cdc4c1a28524b9be9a0fd9f96d8fd5907196 Mon Sep 17 00:00:00 2001
From: Unique Divine <51418232+Unique-Divine@users.noreply.github.com>
Date: Thu, 22 Aug 2024 10:45:54 -0500
Subject: [PATCH] chore(evm): Set appropriate gas value for the required gas of
 the "IFunToken.sol" precompile. (#2013)

* chore(evm): Set appropriate gas value for the required gas of the "IFunToken.sol" precompile.

* typo
---
 CHANGELOG.md                 |  1 +
 x/evm/precompile/funtoken.go | 16 ++++++++++------
 2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index f6f536f43..b4103476e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -108,6 +108,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - [#2003](https://github.com/NibiruChain/nibiru/pull/2003) - fix(evm): fix FunToken conversions between Cosmos and EVM
 - [#2004](https://github.com/NibiruChain/nibiru/pull/2004) - refactor(evm)!: replace `HexAddr` with `EIP55Addr`
 - [#2008](https://github.com/NibiruChain/nibiru/pull/2008) - refactor(evm): clean up precompile setups
+- [#2013](https://github.com/NibiruChain/nibiru/pull/2013) - chore(evm): Set appropriate gas value for the required gas of the "IFunToken.sol" precompile.
 
 #### Dapp modules: perp, spot, oracle, etc
 
diff --git a/x/evm/precompile/funtoken.go b/x/evm/precompile/funtoken.go
index 4e1f131cd..365cac8e1 100644
--- a/x/evm/precompile/funtoken.go
+++ b/x/evm/precompile/funtoken.go
@@ -12,6 +12,7 @@ import (
 	gethabi "github.com/ethereum/go-ethereum/accounts/abi"
 	gethcommon "github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/core/vm"
+	gethparams "github.com/ethereum/go-ethereum/params"
 
 	"github.com/NibiruChain/nibiru/v2/app/keepers"
 	"github.com/NibiruChain/nibiru/v2/x/evm"
@@ -32,12 +33,15 @@ func (p precompileFunToken) Address() gethcommon.Address {
 }
 
 func (p precompileFunToken) RequiredGas(input []byte) (gasPrice uint64) {
-	// TODO: https://github.com/NibiruChain/nibiru/issues/1990
-	// We need to determine an appropriate gas value for the transaction to
-	// configure this function and add a assertions around the gas usage to
-	// the precompile's test suite. UD-DEBUG: not implemented yet. Currently
-	// set to 0 gasPrice
-	return 22
+	// Since [gethparams.TxGas] is the cost per (Ethereum) transaction that does not create
+	// a contract, it's value can be used to derive an appropriate value for the
+	// precompile call. The FunToken precompile performs 3 operations, labeld 1-3
+	// below:
+	// 0 | Call the precompile (already counted in gas calculation)
+	// 1 | Send ERC20 to EVM.
+	// 2 | Convert ERC20 to coin
+	// 3 | Send coin to recipient.
+	return gethparams.TxGas * 3
 }
 
 const (