VRFConsumerBaseV2Upgradeable Code Style Findings

VRF-01C: Potential Optimization of Variable Mutability

Type	Severity	Location
Gas Optimization		VRFConsumerBaseV2Upgradeable.sol:L101, L106-L108

Description:

The vrfCoordinator variable is assigned to only once during the contract's initialization flow via VRFConsumerBaseV2Upgradeable::__VRFConsumerBase_init.

Example:

Copy
101address public vrfCoordinator;
102
103/**
104 * @param _vrfCoordinator address of VRFCoordinator contract
105 */
106function __VRFConsumerBase_init(address _vrfCoordinator) internal onlyInitializing {
107  vrfCoordinator = _vrfCoordinator;
108}

Recommendation:

We advise the original VRFConsumerBaseV2 implementation of Chainlink to be utilized instead, as it is compatible with upgradeable contracts and makes use of an immutable variable that greatly optimizes read-access gas costs of the coordinator.

Alternatively, we advise the vrfCoordinator variable to be set as immutable and a VRFConsumerBaseV2Upgradeable::constructor to be introduced replacing the VRFConsumerBaseV2Upgradeable::__VRFConsumerBase_init function and thus mimicking the Chainlink implementation.

Alleviation (106fc61dcd38fe29a81d1984ccde9171f5f231af):

The Tangible team evaluated this exhibit but opted to acknowledge it in the current iteration of the codebase