Proposal summary

This proposal upgrades the Compound III USDC and WETH markets on Linea and the USDC market on Scroll to a new Comet version that changes how the base supply index is capped in markets that have lenders but no borrowers.

Previously, accruedInterestIndices() applied a post-accrual clamp: whenever totalBorrowBase == 0, if presentValueSupply(totalSupplyBase) exceeded the Comet's base token balance, baseSupplyIndex was forced down to (balance * BASE_INDEX_SCALE) / totalSupplyBase. This protected lender withdrawals in reserve-funded markets with no borrowers, but only corrected the index after it had already been pushed too far.

The new version enforces the same cap earlier, in getSupplyRate(): when utilization is 0 and presentValueSupply(totalSupplyBase) >= balanceOf(this), the supply rate returns 0, so accrual stops before the index overshoots rather than being corrected after the fact. Because a single accrual step still applies one rate over the full timeElapsed, a long gap between accruals can still overshoot the cap by a few wei; after that, getSupplyRate() returns 0 and the supply index no longer increases.

Further detailed information can be found in the corresponding pull request.

Audit

The new Comet version has been audited by Certora and no issues were found.

Proposal Actions

The first action updates the Comet implementation version in V2 Factory on Linea and deploys and upgrades the USDC and WETH Comets to the new implementation.

The second action updates the Comet implementation version in V2 Factory on Scroll and deploys and upgrades the USDC Comet to the new implementation.