Float Capital contest - hrkrshnn's results

Handle

hrkrshnn

Vulnerability details

Variables that can be converted into immutable

Converting to immutable will decrease the cost of read from 2100 / 100 (depending on warm or cold) to just 3!

Warning: Variable declaration can be converted into an immutable.
  --> contracts/SyntheticToken.sol:18:3:
   |
18 |   address public longShort;
   |   ^^^^^^^^^^^^^^^^^^^^^^^^


Warning: Variable declaration can be converted into an immutable.
  --> contracts/SyntheticToken.sol:20:3:
   |
20 |   address public staker;
   |   ^^^^^^^^^^^^^^^^^^^^^


Warning: Variable declaration can be converted into an immutable.
  --> contracts/SyntheticToken.sol:22:3:
   |
22 |   uint32 public marketIndex;
   |   ^^^^^^^^^^^^^^^^^^^^^^^^^


Warning: Variable declaration can be converted into an immutable.
  --> contracts/SyntheticToken.sol:24:3:
   |
24 |   bool public isLong;
   |   ^^^^^^^^^^^^^^^^^^


Warning: Variable declaration can be converted into an immutable.
  --> contracts/TokenFactory.sol:16:3:
   |
16 |   address public longShort;
   |   ^^^^^^^^^^^^^^^^^^^^^^^^


Warning: Variable declaration can be converted into an immutable.
  --> contracts/YieldManagerAave.sol:25:3:
   |
25 |   address public longShort;
   |   ^^^^^^^^^^^^^^^^^^^^^^^^


Warning: Variable declaration can be converted into an immutable.
  --> contracts/YieldManagerAave.sol:27:3:
   |
27 |   address public treasury;
   |   ^^^^^^^^^^^^^^^^^^^^^^^


Warning: Variable declaration can be converted into an immutable.
  --> contracts/YieldManagerAave.sol:31:3:
   |
31 |   ERC20 public paymentToken;
   |   ^^^^^^^^^^^^^^^^^^^^^^^^^


Warning: Variable declaration can be converted into an immutable.
  --> contracts/YieldManagerAave.sol:34:3:
   |
34 |   IERC20Upgradeable public aToken;
   |   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^


Warning: Variable declaration can be converted into an immutable.
  --> contracts/YieldManagerAave.sol:36:3:
   |
36 |   ILendingPool public lendingPool;
   |   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^


Warning: Variable declaration can be converted into an immutable.
  --> contracts/YieldManagerAave.sol:38:3:
   |
38 |   IAaveIncentivesController public aaveIncentivesController;
   |   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^


Warning: Variable declaration can be converted into an immutable.
  --> contracts/YieldManagerAave.sol:41:3:
   |
41 |   uint16 referralCode;
   |   ^^^^^^^^^^^^^^^^^^^



Warning: Variable declaration can be converted into an immutable.
  --> contracts/oracles/OracleManagerBand.sol:17:3:
   |
17 |   IBandOracle public bandOracle;
   |   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^


Warning: Variable declaration can be converted into an immutable.
  --> contracts/oracles/OracleManagerChainlink.sol:16:3:
   |
16 |   AggregatorV3Interface public chainlinkOracle;
   |   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^


Warning: Variable declaration can be converted into an immutable.
  --> contracts/oracles/OracleManagerChainlink.sol:17:3:
   |
17 |   uint8 public oracleDecimals;
   |   ^^^^^^^^^^^^^^^^^^^^^^^^^^^


Warning: Variable declaration can be converted into an immutable.
  --> contracts/oracles/OracleManagerEthKiller.sol:22:3:
   |
22 |   IBandOracle public oracle;
   |   ^^^^^^^^^^^^^^^^^^^^^^^^^


Warning: Variable declaration can be converted into an immutable.
  --> contracts/oracles/OracleManagerEthKillerChainlink.sol:21:3:
   |
21 |   AggregatorV3Interface public tronOracle;
   |   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^


Warning: Variable declaration can be converted into an immutable.
  --> contracts/oracles/OracleManagerEthKillerChainlink.sol:22:3:
   |
22 |   AggregatorV3Interface public eosOracle;
   |   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^


Warning: Variable declaration can be converted into an immutable.
  --> contracts/oracles/OracleManagerEthKillerChainlink.sol:23:3:
   |
23 |   AggregatorV3Interface public xrpOracle;
   |   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^


Warning: Variable declaration can be converted into an immutable.
  --> contracts/oracles/OracleManagerEthVsBtc.sol:18:3:
   |
18 |   AggregatorV3Interface public btcOracle;
   |   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^


Warning: Variable declaration can be converted into an immutable.
  --> contracts/oracles/OracleManagerEthVsBtc.sol:19:3:
   |
19 |   AggregatorV3Interface public ethOracle;
   |   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^


Warning: Variable declaration can be converted into an immutable.
  --> contracts/oracles/OracleManagerFlippening_V0.sol:45:3:
   |
45 |   AggregatorV3Interface public btcOracle;
   |   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^


Warning: Variable declaration can be converted into an immutable.
  --> contracts/oracles/OracleManagerFlippening_V0.sol:46:3:
   |
46 |   AggregatorV3Interface public ethOracle;
   |   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Handle

hrkrshnn

Vulnerability details

Cache length in the for loop

modified   contracts/contracts/LongShort.sol
@@ -1059,7 +1059,8 @@ contract LongShort is ILongShort, Initializable {
   /// @param user The address of the user for whom to execute the function for.
   /// @param marketIndexes An array of int32s which each uniquely identify a market.
   function executeOutstandingNextPriceSettlementsUserMulti(address user, uint32[] memory marketIndexes) external {
-    for (uint256 i = 0; i < marketIndexes.length; i++) {
+    uint length = marketIndexes.length;
+    for (uint256 i = 0; i < length; i++) {
       _executeOutstandingNextPriceSettlements(user, marketIndexes[i]);
     }
   }

In the previous case, at each iteration of the loop, length is read from memory. something like mload(memory_offset). It takes 6 gas (3 for mload and 3 to place memory_offset) in the stack.

In the replacement, the value is placed in the stack only once and each iteration involves a dupN (3 gas). Saves around 3 gas per iteration.

Here are other places that can use this.

./contracts/contracts/LongShort.sol:776:    for (uint256 i = 0; i < marketIndexes.length; i++) {
./contracts/contracts/LongShort.sol:1063:    for (uint256 i = 0; i < length; i++) {
./contracts/contracts/Staker.sol:790:    for (uint256 i = 0; i < marketIndexes.length; i++) {
./contracts/contracts/mocks/BandOracleMock.sol:84:    for (uint256 i = 0; i < _bases.length; i++) {
./contracts/contracts/testing/LongShortInternalStateSetters.sol:34:    for (uint256 i = 0; i < marketIndexes.length; i++) {