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Submission Details
Severity: low
Invalid

Unnecessary double deleting element from feeDataArray

elolpuer

Summary

When manipulating feeDataArray in loop in the UpliftOnlyExample.sol:onAfterRemoveLiquidity() instead of just pop() current element it's also call delete on it which is unnecessary:

function onAfterRemoveLiquidity(
address router,
address pool,
RemoveLiquidityKind,
uint256 bptAmountIn,
uint256[] memory,
uint256[] memory amountsOutRaw,
uint256[] memory,
bytes memory userData
) public override onlySelfRouter(router) returns (bool, uint256[] memory hookAdjustedAmountsOutRaw) {
address userAddress = address(bytes20(userData));
​
AfterRemoveLiquidityData memory localData = AfterRemoveLiquidityData({...});
// We only allow removeLiquidity via the Router/Hook itself so that fee is applied correctly.
hookAdjustedAmountsOutRaw = amountsOutRaw;
​
//this rounding faxvours the LP
localData.lpTokenDepositValueNow = getPoolLPTokenValue(localData.prices, pool, MULDIRECTION.MULDOWN);
​
FeeData[] storage feeDataArray = poolsFeeData[pool][userAddress];
localData.feeDataArrayLength = feeDataArray.length;
localData.amountLeft = bptAmountIn;
for (uint256 i = localData.feeDataArrayLength - 1; i >= 0; --i) {
...
​
// if the deposit is less than the amount left to burn, burn the whole deposit and move on to the next
if (feeDataArray[i].amount <= localData.amountLeft) {
uint256 depositAmount = feeDataArray[i].amount;
localData.feeAmount += (depositAmount * feePerLP);
​
localData.amountLeft -= feeDataArray[i].amount;
​
lpNFT.burn(feeDataArray[i].tokenID);
​
//AUDIT ISSUE START
//delete doesn't make sense here because you pop() this element out of array
delete feeDataArray[i];
feeDataArray.pop();
//AUDIT ISSUE END
​
if (localData.amountLeft == 0) {
break;
}
} else {
feeDataArray[i].amount -= localData.amountLeft;
localData.feeAmount += (feePerLP * localData.amountLeft);
break;
}
}
}

Vulnerability Details

UpliftOnlyExample.sol:onAfterRemoveLiquidity() deletes element of the feeDataArray twice

Impact

The redundant delete operation increases gas usage without providing any functional benefit

Tools Used

Manual Review

Recommendations

Remove delete feeDataArray[i]; line

Updates

Lead Judging Commences

n0kto Lead Judge 10 months ago
Submission Judgement Published
Invalidated
Reason: Non-acceptable severity
Assigned finding tags:

Informational or Gas / Admin is trusted / Pool creation is trusted / User mistake / Suppositions

Please read the CodeHawks documentation to know which submissions are valid. If you disagree, provide a coded PoC and explain the real likelyhood and the detailed impact on the mainnet without any supposition (if, it could, etc) to prove your point.

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