Rahoz-G.md

Revert when update same variable can save gas

Some functions still executed with do nothing, we can revert to save gas

Proof of Concept

https://github.com/code-423n4/2022-10-zksync/blob/4db6c596931a291b17a4e0e2929adf810a4a0eed/ethereum/contracts/zksync/facets/Governance.sol#L19 https://github.com/code-423n4/2022-10-zksync/blob/4db6c596931a291b17a4e0e2929adf810a4a0eed/ethereum/contracts/zksync/facets/Governance.sol#L32 https://github.com/code-423n4/2022-10-zksync/blob/4db6c596931a291b17a4e0e2929adf810a4a0eed/ethereum/contracts/zksync/facets/Governance.sol#L46 https://github.com/code-423n4/2022-10-zksync/blob/4db6c596931a291b17a4e0e2929adf810a4a0eed/ethereum/contracts/zksync/facets/Governance.sol#L60 https://github.com/code-423n4/2022-10-zksync/blob/4db6c596931a291b17a4e0e2929adf810a4a0eed/ethereum/contracts/zksync/facets/Governance.sol#L75 https://github.com/code-423n4/2022-10-zksync/blob/4db6c596931a291b17a4e0e2929adf810a4a0eed/ethereum/contracts/zksync/facets/Governance.sol#L85 https://github.com/code-423n4/2022-10-zksync/blob/4db6c596931a291b17a4e0e2929adf810a4a0eed/ethereum/contracts/zksync/facets/Governance.sol#L96

Recommended Mitigation Steps

Add revert in else statement condition

Add unchecked{} to save gas

Because we transfer token from sender to contract, the balance can't decrease So balanceAfter alway >= balanceBefore

Proof of Concept

https://github.com/code-423n4/2022-10-zksync/blob/4db6c596931a291b17a4e0e2929adf810a4a0eed/ethereum/contracts/bridge/L1ERC20Bridge.sol#L145

Recommended Mitigation Steps

We can add unchecked to save check underflow gas.