Gas Optimizations

[code423n4]

https://github.com/pooltogether/aave-v3-yield-source/blob/e63d1b0e396a5bce89f093630c282ca1c6627e44/contracts/AaveV3YieldSource.sol#L127
https://github.com/pooltogether/aave-v3-yield-source/blob/e63d1b0e396a5bce89f093630c282ca1c6627e44/contracts/AaveV3YieldSource.sol#L130
https://github.com/pooltogether/aave-v3-yield-source/blob/e63d1b0e396a5bce89f093630c282ca1c6627e44/contracts/AaveV3YieldSource.sol#L133

The contract variables aToken, rewardsController, poolAddressesProviderRegistry must be immutable to save gas

IAToken public immutable aToken;
IRewardsController public immutable rewardsController;
IPoolAddressesProviderRegistry public immutable poolAddressesProviderRegistry;

extend this report:
If change the aToken should also change the constructor https://github.com/pooltogether/aave-v3-yield-source/blob/e63d1b0e396a5bce89f093630c282ca1c6627e44/contracts/AaveV3YieldSource.sol#L183

- IERC20(_tokenAddress()).safeApprove(address(_pool()), type(uint256).max);
+ IERC20(_aToken.UNDERLYING_ASSET_ADDRESS()).safeApprove(address(_pool()), type(uint256).max); 

extend 2:
https://github.com/pooltogether/aave-v3-yield-source/blob/e63d1b0e396a5bce89f093630c282ca1c6627e44/contracts/AaveV3YieldSource.sol#L183

-  IERC20(_tokenAddress()).safeApprove(address(_pool()), type(uint256).max);
+ IERC20(_aToken.UNDERLYING_ASSET_ADDRESS()).safeApprove(
      IPoolAddressesProvider(
        _poolAddressesProviderRegistry.getAddressesProvidersList()[ADDRESSES_PROVIDER_ID]
      ).getPool(),
      type(uint256).max
    );

[PierrickGT]

I have implemented the first suggestion (extend this report) proposed by the warden in the following PR: pooltogether/aave-v3-yield-source#2
I won't implement the second suggestion since it would indeed save a bit of gas while deploying but the code will be less legible.
So for this reason, I have acknowledged the issue.

[gititGoro]

I have implemented the first suggestion (extend this report) proposed by the warden in the following PR: pooltogether/aave-v3-yield-source#2 I won't implement the second suggestion since it would indeed save a bit of gas while deploying but the code will be less legible. So for this reason, I have acknowledged the issue.

Future wardens should pay attention to this response from the sponsor and determine whether the sponsor they're working with holds similar values. Clean, legible code is important enough that saving deployment gas is more than likely a lower priority. High level languages exist for a reason.

[gititGoro]

Duplicate of #2