Nouns DAO contest - wagmi's results

Summary

1. Inconsistent coding style between safe32() and safe16()

In NounsDAOLogicV2, two function safe32() and safe16() even though have similar functionality but are implemented in different ways.

function safe32(uint256 n, string memory errorMessage) internal pure returns (uint32) {
    require(n <= type(uint32).max, errorMessage);
    return uint32(n);
}

function safe16(uint256 n) internal pure returns (uint16) {
    if (n > type(uint16).max) {
        revert UnsafeUint16Cast();
    }
    return uint16(n);
}

It should be consistent for better code quality

Affected Codes

• https://github.com/code-423n4/2022-08-nounsdao/blob/45411325ec14c6d747b999a40367d3c5109b5a89/contracts/governance/NounsDAOLogicV2.sol#L1018-L1028

Recommended Mitigation Steps

• Refactor to make them consistent

Summary

1. Should use memory variable when emiting events to save gas

In some function like _setProposalThresholdBPS(), we can use memory variable instead of storage variable with the same value when emiting events to save gas.

For example, in _setProposalThresholdBPS() function, we can use newProposalThresholdBPS instead of proposalThresholdBPS to save gas.

Affected Codes

• https://github.com/code-423n4/2022-08-nounsdao/blob/45411325ec14c6d747b999a40367d3c5109b5a89/contracts/governance/NounsDAOLogicV2.sol#L664
• https://github.com/code-423n4/2022-08-nounsdao/blob/45411325ec14c6d747b999a40367d3c5109b5a89/contracts/governance/NounsDAOLogicV2.sol#L646
• https://github.com/code-423n4/2022-08-nounsdao/blob/45411325ec14c6d747b999a40367d3c5109b5a89/contracts/governance/NounsDAOLogicV2.sol#L630

2. Cache length in the for loop and uncheck index

At each iteration of the loop, length is read from storage. We can cache the length and save gas per iteration.

Solidity 0.8.0 check safe math in every operation. Use uncheck to increase index can save gas.

For example

uint256 length = arr.length;
for (uint i; i < length; ) {
  // do stuff
  unchecked { ++i; }
}

Affected Codes

• https://github.com/code-423n4/2022-08-nounsdao/blob/45411325ec14c6d747b999a40367d3c5109b5a89/contracts/governance/NounsDAOLogicV2.sol#L292
• https://github.com/code-423n4/2022-08-nounsdao/blob/45411325ec14c6d747b999a40367d3c5109b5a89/contracts/governance/NounsDAOLogicV2.sol#L330
• https://github.com/code-423n4/2022-08-nounsdao/blob/45411325ec14c6d747b999a40367d3c5109b5a89/contracts/governance/NounsDAOLogicV2.sol#L357
• https://github.com/code-423n4/2022-08-nounsdao/blob/45411325ec14c6d747b999a40367d3c5109b5a89/contracts/governance/NounsDAOLogicV2.sol#L382