Submission Details
Severity:
Gas improvement for the resolveDispute()
Gas Issue Details
In the Escrow.resolveDispute(), we can improve the code in line 125 to save gas by deducting the totalFee from the tokenBalance instead (please refer to the Gas Improvements section below).
function resolveDispute(uint256 buyerAward) external onlyArbiter nonReentrant inState(State.Disputed) {
uint256 tokenBalance = i_tokenContract.balanceOf(address(this));
uint256 totalFee = buyerAward + i_arbiterFee; // Reverts on overflow
if (totalFee > tokenBalance) {
revert Escrow__TotalFeeExceedsBalance(tokenBalance, totalFee);
}
s_state = State.Resolved;
emit Resolved(i_buyer, i_seller);
if (buyerAward > 0) {
i_tokenContract.safeTransfer(i_buyer, buyerAward);
}
if (i_arbiterFee > 0) {
i_tokenContract.safeTransfer(i_arbiter, i_arbiterFee);
}
@> tokenBalance = i_tokenContract.balanceOf(address(this));
if (tokenBalance > 0) {
i_tokenContract.safeTransfer(i_seller, tokenBalance);
}
}
https://github.com/Cyfrin/2023-07-escrow/blob/65a60eb0773803fa0be4ba72defaec7d8567bccc/src/Escrow.sol#L125
Gas Improvements
I recommend applying the tokenBalance -= totalFee; statement instead of the tokenBalance = i_tokenContract.balanceOf(address(this)); statement, as shown below.
function resolveDispute(uint256 buyerAward) external onlyArbiter nonReentrant inState(State.Disputed) {
uint256 tokenBalance = i_tokenContract.balanceOf(address(this));
uint256 totalFee = buyerAward + i_arbiterFee; // Reverts on overflow
if (totalFee > tokenBalance) {
revert Escrow__TotalFeeExceedsBalance(tokenBalance, totalFee);
}
s_state = State.Resolved;
emit Resolved(i_buyer, i_seller);
if (buyerAward > 0) {
i_tokenContract.safeTransfer(i_buyer, buyerAward);
}
if (i_arbiterFee > 0) {
i_tokenContract.safeTransfer(i_arbiter, i_arbiterFee);
}
- tokenBalance = i_tokenContract.balanceOf(address(this));
+ tokenBalance -= totalFee;
if (tokenBalance > 0) {
i_tokenContract.safeTransfer(i_seller, tokenBalance);
}
}
Prize pool breakdown
Total prize
40,000 USDC
nSLOC
186215 USDC / LOC
37,000 USDC
3,000 USDC
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