Asymmetry contest - climber2002's results

Add require(_derivativeIndex < derivativeCount) validation in SafETH.adjustWeight

In SafETH.adjustWeight it doesn't make sense if _derivativeIndex >= derivativeCount. It's better to add such check in case of contract owner call this function with wrong params accidentally.

function adjustWeight(
        uint256 _derivativeIndex,
        uint256 _weight
    ) external onlyOwner {
  require(_derivativeIndex < derivativeCount, "Invalid _derivativeIndex");
  ...
}

When unstake user can lose funds if _safEthAmount is extremely small

In unstake it calculates derivativeAmount

uint256 derivativeAmount = (derivatives[i].balance() *
                _safEthAmount) / safEthTotalSupply;

if _safEthAmount is extremely small, then derivativeAmount could be 0 for all derivatives. For example, for 3 derivatives with equal weights, if _safETHAmount is 2wei, then derivativeAmount is 1 * 2 / 3 = 0 for all derivatives.

Recommendation

Revert if ethAmountToWithdraw is 0

Add a function previewUnstake

Currently unstake doesn't return the ETH amount that it's actually unstaked. It's better to have a function previewUnstake(uint256 _safEthAmount) external view returns (uint256) which can let the user know how much ETH he will receive for a given _safEthAmount before doing unstake