QA Report

[code423n4]

1. Use local variable for expression re-used multiple times

• uint256(orderHash) is used in 3 places inside fillOrder(), it's casted value can be saved into a local variable to reuse variable instead of multiple casting

• PuttyV2.sol#L303

• PuttyV2.sol#L312

• PuttyV2.sol#L316

// recommendation example 
uint tempOrderHash = uint256(orderHash)

2. 10_000 days can be saved in a constant varible

• use contants for numbers
• PuttyV2.sol#L287

3. Use bytes.concat instead of `abi.encodePacked

• ref: https://github.com/ethereum/solidity/issues/10903

4. No method to rescue stucked tokens

• Anyone accidentally sending any tokens into the contract have no way to rescue it.
• Create a skim() like method to withdraw stucked funds.

5 .Unused imported library

• Openzeppelin's string library is imported in PuttyV2Nft.sol is not used.
• PuttyV2Nft.sol#L5