Description

The function fetchLiquidity is used to calculate value and error in the accumulator. The function could underflow if value - target is greater than ERROR_ZERO.

function fetchLiquidity(bytes memory data) internal view virtual override returns (uint112 value, uint112 err) {
    value = fetchValue(data);
    uint256 target = fetchTarget(data);

    if (target >= value) {
        err = (ERROR_ZERO + (target - value)).toUint112();
    } else {
        err = (ERROR_ZERO - (value - target)).toUint112();
    }
}

Impact

If value - target is greater than ERROR_ZERO, fetchLiquidity is reverted due to underflow protection implemented in solidity 8.0.0. This could cause the contract to not work as expected.

Recommendations

Consider adding a check to ensure that value - target is less than ERROR_ZERO.

Remediation

According to Adrastia, halting updates in this scenario is considered acceptable behavior. In the context of TrueFi's ALOCs, a reversion is appropriate since it would indicate a bug in the ALOC's utilization function.