Y2k Finance contest - malinariy's results

Gas Optimization Report

1. State variables only set in the constructor should be declared immutable

https://github.com/code-423n4/2022-09-y2k-finance/blob/ac3e86f07bc2f1f51148d2265cc897e8b494adf7/src/rewards/RewardsFactory.sol#L9-L11

2. Public functions not called by the contract should be declared external instead Calls to external functions are cheaper than public functions. Thus, if a function is not used internally in any contract, it should be set to external to save gas and improve code readability.

https://github.com/code-423n4/2022-09-y2k-finance/blob/ac3e86f07bc2f1f51148d2265cc897e8b494adf7/src/rewards/RewardsFactory.sol#L145-L148 https://github.com/code-423n4/2022-09-y2k-finance/blob/ac3e86f07bc2f1f51148d2265cc897e8b494adf7/src/VaultFactory.sol#L178-L186 https://github.com/code-423n4/2022-09-y2k-finance/blob/ac3e86f07bc2f1f51148d2265cc897e8b494adf7/src/VaultFactory.sol#L248-L253 https://github.com/code-423n4/2022-09-y2k-finance/blob/ac3e86f07bc2f1f51148d2265cc897e8b494adf7/src/VaultFactory.sol#L295 https://github.com/code-423n4/2022-09-y2k-finance/blob/ac3e86f07bc2f1f51148d2265cc897e8b494adf7/src/VaultFactory.sol#L366 https://github.com/code-423n4/2022-09-y2k-finance/blob/ac3e86f07bc2f1f51148d2265cc897e8b494adf7/src/VaultFactory.sol#L385-L388 https://github.com/code-423n4/2022-09-y2k-finance/blob/ac3e86f07bc2f1f51148d2265cc897e8b494adf7/src/Controller.sol#L148-L150 https://github.com/code-423n4/2022-09-y2k-finance/blob/ac3e86f07bc2f1f51148d2265cc897e8b494adf7/src/Controller.sol#L198 https://github.com/code-423n4/2022-09-y2k-finance/blob/ac3e86f07bc2f1f51148d2265cc897e8b494adf7/src/Vault.sol#L438-L441 https://github.com/code-423n4/2022-09-y2k-finance/blob/ac3e86f07bc2f1f51148d2265cc897e8b494adf7/src/SemiFungibleVault.sol#L221-L225 https://github.com/code-423n4/2022-09-y2k-finance/blob/ac3e86f07bc2f1f51148d2265cc897e8b494adf7/src/SemiFungibleVault.sol#L237 https://github.com/code-423n4/2022-09-y2k-finance/blob/ac3e86f07bc2f1f51148d2265cc897e8b494adf7/src/SemiFungibleVault.sol#L244 https://github.com/code-423n4/2022-09-y2k-finance/blob/ac3e86f07bc2f1f51148d2265cc897e8b494adf7/src/SemiFungibleVault.sol#L251-L255 https://github.com/code-423n4/2022-09-y2k-finance/blob/ac3e86f07bc2f1f51148d2265cc897e8b494adf7/src/SemiFungibleVault.sol#L263-L267

3. Use abi.encodePacked() not abi.encode() abi.encode pads extra null bytes at the end of the call data which is normally unnecessary. In general, abi.encodePacked is more gas-efficient.

https://github.com/code-423n4/2022-09-y2k-finance/blob/ac3e86f07bc2f1f51148d2265cc897e8b494adf7/src/rewards/RewardsFactory.sol#L118 https://github.com/code-423n4/2022-09-y2k-finance/blob/ac3e86f07bc2f1f51148d2265cc897e8b494adf7/src/rewards/RewardsFactory.sol#L150

4. Comparison operators In the EVM, there is no opcode for >= or <=. When using greater than or equal, two operations are performed: > and =. Replace <= with <, and >= with >. Do not forget to increment/decrement the compared variable. However, when 1 is negligible compared to the variable.

https://github.com/code-423n4/2022-09-y2k-finance/blob/ac3e86f07bc2f1f51148d2265cc897e8b494adf7/src/Controller.sol#L302

5. It costs more gas to initialize variables with their default value than letting the default value be applied

https://github.com/code-423n4/2022-09-y2k-finance/blob/ac3e86f07bc2f1f51148d2265cc897e8b494adf7/src/Vault.sol#L443

6. ++i costs less gas compared to i++ or i += 1 (same for --i vs i-- or i -= 1)

https://github.com/code-423n4/2022-09-y2k-finance/blob/ac3e86f07bc2f1f51148d2265cc897e8b494adf7/src/Vault.sol#L443

7. require()/revert() strings longer than 32 bytes cost extra gas

https://github.com/code-423n4/2022-09-y2k-finance/blob/ac3e86f07bc2f1f51148d2265cc897e8b494adf7/src/SemiFungibleVault.sol#L118