Debt DAO contest - exolorkistis's results

[1] USAGE OF UINTS/INTS SMALLER THAN 32 BYTES (256 BITS) INCURS OVERHEAD

When using elements that are smaller than 32 bytes, your contract’s gas usage may be higher. This is because the EVM operates on 32 bytes at a time. Therefore, if the element is smaller than that, the EVM must use more operations in order to reduce the size of the element from 32 bytes to the desired size.

https://docs.soliditylang.org/en/v0.8.11/internals/layout_in_storage.html Use a larger size then downcast where needed

There are 26 instances of this issue

File:  Line-of-Credit/contracts/modules/credit/LineOfCredit.sol

224:  uint128 drate,

225:  uint128 frate,

249:  uint128 drate,

250:  uint128 frate

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/modules/credit/LineOfCredit.sol#L224-225

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/modules/credit/LineOfCredit.sol#L249-250

File:  Line-of-Credit/contracts/modules/credit/SpigotedLine.sol

32:  uint8 public immutable defaultRevenueSplit;

60:   uint8 defaultRevenueSplit_

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/modules/credit/SpigotedLine.sol#L32

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/modules/credit/SpigotedLine.sol#L60

File:  Line-of-Credit/contracts/modules/credit/SecuredLine.sol

21:   uint8 defaultSplit_

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/modules/credit/SecuredLine.sol#L21

File:  Line-of-Credit/contracts/modules/spigot/Spigot.sol


146:  function updateOwnerSplit(address revenueContract, uint8 ownerSplit)

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/modules/spigot/Spigot.sol#L146

File:  Line-of-Credit/contracts/modules/escrow/Escrow.sol

24:  uint32 public immutable minimumCollateralRatio;

43:   uint32 _minimumCollateralRatio,

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/modules/escrow/Escrow.sol#L24

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/modules/escrow/Escrow.sol#L43

File:  Line-of-Credit/contracts/modules/factories/LineFactory.sol

12:  uint8 constant defaultRevenueSplit = 90;

13:  uint8 constant MAX_SPLIT = 100;

14:   uint32 constant defaultMinCRatio = 3000;

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/modules/factories/LineFactory.sol#L12-L14

File:  Line-of-Credit/contracts/utils/CreditLib.sol

112:  uint8 decimals

138:   uint8 decimals;

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/utils/CreditLib.sol#L112

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/utils/CreditLib.sol#L138

File:  Line-of-Credit/contracts/utils/SpigotLib.sol

25:  uint8 constant MAX_SPLIT = 100;

164:  function updateOwnerSplit(SpigotState storage self, address revenueContract, uint8 ownerSplit)

229:     returns(uint8, bytes4, bytes4)

252:    uint8 indexed split

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/utils/SpigotLib.sol#L25

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/utils/SpigotLib.sol#L164

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/utils/SpigotLib.sol#L229

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/utils/SpigotLib.sol#L252

File:  Line-of-Credit/contracts/utils/SpigotedLineLib.sol

13: uint8 constant MAX_SPLIT = 100;

169:  function updateSplit(address spigot, address revenueContract, LineLib.STATUS status, uint8 defaultSplit) external returns (bool) {

170:    (uint8 split,, bytes4 transferFunc) = ISpigot(spigot).getSetting(revenueContract);

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/utils/SpigotedLineLib.sol#L13

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/utils/SpigotedLineLib.sol#L169

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/utils/SpigotedLineLib.sol#L170

File:  Line-of-Credit/contracts/utils/LineFactoryLib.sol

13:  uint8 revenueSplit

25:   uint32 indexed minCRatio,

51:  uint8 split = SecuredLine(oldLine).defaultRevenueSplit();

85:   uint8 revenueSplit

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/utils/LineFactoryLib.sol#L13

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/utils/LineFactoryLib.sol#L25

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/utils/LineFactoryLib.sol#L51

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/utils/LineFactoryLib.sol#L85

[2] USING PRIVATE RATHER THAN PUBLIC FOR CONSTANTS, SAVES GAS

If needed, the value can be read from the verified contract source code. Savings are due to the compiler not having to create non-payable getter functions for deployment calldata, and not adding another entry to the method ID table

There are 10 instances of this issue:

File: Line-of-Credit/contracts/utils/SpigotedLineLib.sol

13: uint8 constant MAX_SPLIT = 100;

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/utils/SpigotedLineLib.sol#L13

File:  Line-of-Credit/contracts/utils/SpigotLib.sol

25:  uint8 constant MAX_SPLIT = 100;

27:   uint256 constant MAX_REVENUE = type(uint256).max / MAX_SPLIT;

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/utils/SpigotLib.sol#L25

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/utils/SpigotLib.sol#L27

File:  Line-of-Credit/contracts/utils/EscrowLib.sol

25-26:  uint256 constant MAX_INT =
        115792089237316195423570985008687907853269984665640564039457584007913129639935;

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/utils/EscrowLib.sol#L25-L26

File:  Line-of-Credit/contracts/modules/factories/LineFactory.sol

12:  uint8 constant defaultRevenueSplit = 90;

13:   uint8 constant MAX_SPLIT = 100;

14:     uint32 constant defaultMinCRatio = 3000;

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/modules/factories/LineFactory.sol#L12-L14

File: Line-of-Credit/contracts/modules/interest-rate/InterestRateCredit.sol

7: uint256 constant ONE_YEAR = 365.25 days;

9: uint256 constant BASE_DENOMINATOR = 10000;

11:   uint256 constant INTEREST_DENOMINATOR = ONE_YEAR * BASE_DENOMINATOR;

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/modules/interest-rate/InterestRateCredit.sol#L7

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/modules/interest-rate/InterestRateCredit.sol#L9

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/modules/interest-rate/InterestRateCredit.sol#L11

[3] FUNCTIONS GUARANTEED TO REVERT WHEN CALLED BY NORMAL USERS CAN BE MARKED PAYABLE

If a function modifier such as onlyOwner is used, the function will revert if a normal user tries to pay the function. Marking the function as payable will lower the gas cost for legitimate callers because the compiler will not include checks for whether a payment was provided. The extra opcodes avoided are CALLVALUE(2),DUP1(3),ISZERO(3),PUSH2(3),JUMPI(10),PUSH1(3),DUP1(3),REVERT(0),JUMPDEST(1),POP(2), which costs an average of about 21 gas per call to the function, in addition to the extra deployment cost

There are 4 instances of this issue:

File:  Line-of-Credit/contracts/modules/credit/LineOfCredit.sol

340-344:   function borrow(bytes32 id, uint256 amount)
        external
        override
        whileActive
        onlyBorrower

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/modules/credit/LineOfCredit.sol#L340-L344

File: Line-of-Credit/contracts/modules/credit/SecuredLine.sol

48-52:  function rollover(address newLine)
    external
    onlyBorrower
    override
    returns(bool)

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/modules/credit/SecuredLine.sol#L48-L52

File:  Line-of-Credit/contracts/modules/interest-rate/InterestRateCredit.sol

34-39:  function accrueInterest(
        bytes32 id,
        uint256 drawnBalance,
        uint256 facilityBalance
    ) external override onlyLineContract returns (uint256) {
        return _accrueInterest(id, drawnBalance, facilityBalance);


74-83:  function setRate(
        bytes32 id,
        uint128 dRate,
        uint128 fRate
    ) external onlyLineContract returns (bool) {
        rates[id] = Rate({
            dRate: dRate,
            fRate: fRate,
            lastAccrued: block.timestamp
        });

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/modules/interest-rate/InterestRateCredit.sol#L34-L39

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/modules/interest-rate/InterestRateCredit.sol#L74-L83

[4] ++I/I++ SHOULD BE UNCHECKED{++I}/UNCHECKED{I++} WHEN IT IS NOT POSSIBLE FOR THEM TO OVERFLOW, AS IS THE CASE WHEN USED IN FOR- AND WHILE-LOOPS

The unchecked keyword is new in solidity 0.8.0,so this only applies to that version or higher, which these instances are. This saves 30-40 gas PER LOOP

There are 5 instances of this issue:

File: Line-of-Credit/contracts/modules/credit/LineOfCredit.sol

179:  for (uint256 i; i < len; ++i) {

203:  for (uint256 i; i < len; ++i) {

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/modules/credit/LineOfCredit.sol#L179

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/modules/credit/LineOfCredit.sol#L203

File: Line-of-Credit/contracts/utils/EscrowLib.sol

57:  for (uint256 i; i < length; ++i) {

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/utils/EscrowLib.sol#L57

File:  Line-of-Credit/contracts/utils/CreditListLib.sol

23: for(uint256 i; i < len; ++i) {

51:  for(uint i = 1; i < len; ++i) {

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/utils/CreditListLib.sol#L23

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/utils/CreditListLib.sol#L51

[5] STATE VARIABLES ONLY SET IN THE CONSTRUCTOR SHOULD BE DECLARED IMMUTABLE

Avoids a Gsset (20000 gas) in the constructor, and replaces the first access in each transaction (Gcoldsload - 2100 gas) and each access thereafter (Gwarmacces - 100 gas) with a PUSH32 (3 gas).

There are 13 instances of this issue:

File:  Line-of-Credit/contracts/modules/credit/LineOfCredit.sol

51:  address arbiter_,

52:  address borrower_,

53:  uint256 ttl_

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/modules/credit/LineOfCredit.sol#L51-L53

File: Line-of-Credit/contracts/modules/credit/SpigotedLine.sol

55:   address arbiter_,

56:  address borrower_,

57:  address spigot_,

58:  address payable swapTarget_,

59:   uint256 ttl_,

60:    uint8 defaultRevenueSplit_

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/modules/credit/SpigotedLine.sol#L55-L60

File:  Line-of-Credit/contracts/modules/escrow/Escrow.sol

43:  uint32 _minimumCollateralRatio,

44:  address _oracle,

45:  address _line,

46:   address _borrower

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/modules/escrow/Escrow.sol#L43-L46

[6] ABI.ENCODE() IS LESS EFFICIENT THAN ABI.ENCODEPACKED()

There is 1 instance of this issue:

File:   Line-of-Credit/contracts/utils/CreditLib.sol

69:   return keccak256(abi.encode(line, lender, token));

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/utils/CreditLib.sol#L69

[7] USE ASSEMBLY TO CHECK FOR ADDRESS(0) to save gas.

There are 3 instances of this issue:

File:  Line-of-Credit/contracts/utils/SpigotLib.sol


180: require(newOwner != address(0));

189:   require(newOperator != address(0));

201:    require(newTreasury != address(0));

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/utils/SpigotLib.sol#L180

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/utils/SpigotLib.sol#L189

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/utils/SpigotLib.sol#L201

[8] DUPLICATED REQUIRE()/REVERT() CHECKS SHOULD BE REFACTORED TO A MODIFIER OR FUNCTION

Saves deployment cost

There are 5 instances of this issue:

File: Line-of-Credit/contracts/modules/credit/LineOfCredit.sol

241: require(interestRate.setRate(id, drate, frate));

259:   require(interestRate.setRate(id, drate, frate));

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/modules/credit/LineOfCredit.sol#L241

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/modules/credit/LineOfCredit.sol#L259

File: Line-of-Credit/contracts/utils/EscrowLib.sol

91:  require(amount > 0);

161:  require(amount > 0);

198:  require(amount > 0);

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/utils/EscrowLib.sol#L91

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/utils/EscrowLib.sol#L161

https://github.com/debtdao/Line-of-Credit/blob/master/contracts/utils/EscrowLib.sol#L198