JPEG'd contest - Tomio's results

1. Using require instead of && can save gas

Proof of Concept: https://github.com/code-423n4/2022-04-jpegd/blob/main/contracts/vaults/FungibleAssetVaultForDAO.sol#L194 https://github.com/code-423n4/2022-04-jpegd/blob/main/contracts/escrow/NFTEscrow.sol#L86-L89 https://github.com/code-423n4/2022-04-jpegd/blob/main/contracts/staking/JPEGStaking.sol#L45-L48

Recommended Mitigation Steps: Change to:

require(amount > 0, "invalid_amount");
require(amount <= collateralAmount, "invalid_amount");

========================================================================

2. !=0 is more gas efficient than > 0

Proof of Concept: https://github.com/code-423n4/2022-04-jpegd/blob/main/contracts/farming/LPFarming.sol#L114 https://github.com/code-423n4/2022-04-jpegd/blob/main/contracts/farming/LPFarming.sol#L218 https://github.com/code-423n4/2022-04-jpegd/blob/main/contracts/farming/LPFarming.sol#L239 https://github.com/code-423n4/2022-04-jpegd/blob/main/contracts/farming/LPFarming.sol#L337

Recommended Mitigation Steps: Change > 0 or < 0 to != 0

========================================================================

3. Using > is cheaper than >=

Proof of Concept: https://github.com/code-423n4/2022-04-jpegd/blob/main/contracts/vaults/FungibleAssetVaultForDAO.sol#L197 https://github.com/code-423n4/2022-04-jpegd/blob/main/contracts/farming/LPFarming.sol#L112 https://github.com/code-423n4/2022-04-jpegd/blob/main/contracts/farming/LPFarming.sol#L243

Recommended Mitigation Steps: Change from >= to >

========================================================================

4. Using immutable which set once at constructor can save gas

Proof of Concept: https://github.com/code-423n4/2022-04-jpegd/blob/main/contracts/vaults/yVault/strategies/StrategyPUSDConvex.sol#L75-L78

Recommended Mitigation Steps: add immutable

========================================================================

5. unnecessary value set. the default value of uint is zero.

Proof of Concept: https://github.com/code-423n4/2022-04-jpegd/blob/main/contracts/farming/LPFarming.sol#L348 https://github.com/code-423n4/2022-04-jpegd/blob/main/contracts/vaults/NFTVault.sol#L181

Recommended Mitigation Steps: remove 0

========================================================================

6. Better increment

Proof of Concept: https://github.com/code-423n4/2022-04-jpegd/blob/main/contracts/farming/LPFarming.sol#L348 https://github.com/code-423n4/2022-04-jpegd/blob/main/contracts/vaults/NFTVault.sol#L181

Recommended Mitigation Steps: change i++ to ++i

========================================================================

7. Using calldata to store struct data type (Rate, NFTCategoryInitializer, Position.. ) can save gas

Proof of Concept: https://github.com/code-423n4/2022-04-jpegd/blob/main/contracts/vaults/NFTVault.sol#L182 https://github.com/code-423n4/2022-04-jpegd/blob/main/contracts/vaults/NFTVault.sol#L212 https://github.com/code-423n4/2022-04-jpegd/blob/main/contracts/vaults/NFTVault.sol#L222 https://github.com/code-423n4/2022-04-jpegd/blob/main/contracts/vaults/NFTVault.sol#L880 https://github.com/code-423n4/2022-04-jpegd/blob/main/contracts/vaults/NFTVault.sol#L923

Recommended Mitigation Steps: Change memory to calldata

========================================================================