PoolTogether Aave v3 contest - 0xf15ers's results

1. Change function mutability of balanceOfToken() to view:

• https://github.com/pooltogether/aave-v3-yield-source/blob/e63d1b0e396a5bce89f093630c282ca1c6627e44/contracts/AaveV3YieldSource.sol#L203-L205

2. Add Reentrancy Guard (nonReentrant)to transferERC20()

• Although the call is restricted to only owner or Manager, using reentrancy guard is a good practice

1. Use custom error for gas optimisation

require(address(_aToken) != address(0), "AaveV3YS/aToken-not-zero-address");
require(address(_rewardsController) != address(0), "AaveV3YS/RC-not-zero-address");
require(address(_poolAddressesProviderRegistry) != address(0), "AaveV3YS/PR-not-zero-address");
require(_owner != address(0), "AaveV3YS/owner-not-zero-address");
require(decimals_ > 0, "AaveV3YS/decimals-gt-zero");
require(_shares > 0, "AaveV3YS/shares-gt-zero");
.....

• Use of custom error above 0.8.4 is recommended (https://blog.soliditylang.org/2021/04/21/custom-errors/)

2. >0 is less gas efficient than != 0 for uints

• https://github.com/pooltogether/aave-v3-yield-source/blob/e63d1b0e396a5bce89f093630c282ca1c6627e44/contracts/AaveV3YieldSource.sol#L179
• https://github.com/pooltogether/aave-v3-yield-source/blob/e63d1b0e396a5bce89f093630c282ca1c6627e44/contracts/AaveV3YieldSource.sol#L233
• use of !=0 is recommended

3. Reduce gas using modifiers instead of internal function (requiretoken())

• https://github.com/pooltogether/aave-v3-yield-source/blob/e63d1b0e396a5bce89f093630c282ca1c6627e44/contracts/AaveV3YieldSource.sol#L348

modifier requireNotAToken(address _token) {
  require(_token != address(aToken), "AaveV3YS/forbid-aToken-allowance");
  _;
}

Before:

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|  AaveV3YieldSourceHarness  ·  decreaseERC20Allowance  ·       40154  ·      42359  ·      41620  ·            3  ·      11.59  │
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|  AaveV3YieldSourceHarness  ·  increaseERC20Allowance  ·       61935  ·      64452  ·      64041  ·            7  ·      17.84  │
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After:

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|  AaveV3YieldSourceHarness  ·  decreaseERC20Allowance  ·       40130  ·      42335  ·      41596  ·            3  ·      11.58  │
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|  AaveV3YieldSourceHarness  ·  increaseERC20Allowance  ·       61911  ·      64428  ·      64017  ·            7  ·      17.82  │
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