Add mETH as collateral to WETH market on Mainnet

contracts/pricefeeds/METHExchangeRatePriceFeed.sol

@@ -0,0 +1,98 @@
+// SPDX-License-Identifier: BUSL-1.1
+pragma solidity 0.8.15;
+
+import "../vendor/mantle/IRateProvider.sol";
+import "../IPriceFeed.sol";
+
+/**
+ * @title mETH Scaling price feed
+ * @notice A custom price feed that scales up or down the price received from an underlying Mantle mETH / ETH exchange rate price feed and returns the result
+ * @author Compound
+ */
+contract METHExchangeRatePriceFeed is IPriceFeed {
+    /** Custom errors **/
+    error InvalidInt256();
+    error BadDecimals();
+
+    /// @notice Version of the price feed
+    uint internal constant VERSION = 1;
+
+    /// @notice Description of the price feed
+    string public description;
+
+    /// @notice Number of decimals for returned prices
+    uint8 public immutable override decimals;
+
+    /// @notice mETH price feed where prices are fetched from
+    address public immutable underlyingPriceFeed;
+
+    /// @notice Whether or not the price should be upscaled
+    bool internal immutable shouldUpscale;
+
+    /// @notice The amount to upscale or downscale the price by
+    int256 internal immutable rescaleFactor;
+
+    /**
+     * @notice Construct a new mETH scaling price feed
+     * @param mETHRateProvider The address of the underlying price feed to fetch prices from
+     * @param decimals_ The number of decimals for the returned prices
+     **/
+    constructor(address mETHRateProvider, uint8 decimals_, string memory description_) {
+        underlyingPriceFeed = mETHRateProvider;
+        if (decimals_ > 18) revert BadDecimals();
+        decimals = decimals_;
+        description = description_;
+
+        uint8 mETHRateProviderDecimals = 18;
+        // Note: Solidity does not allow setting immutables in if/else statements
+        shouldUpscale = mETHRateProviderDecimals < decimals_ ? true : false;
+        rescaleFactor = (shouldUpscale
+            ? signed256(10 ** (decimals_ - mETHRateProviderDecimals))
+            : signed256(10 ** (mETHRateProviderDecimals - decimals_))
+        );
+    }
+
+    /**
+     * @notice Price for the latest round
+     * @return roundId Round id from the underlying price feed
+     * @return answer Latest price for the asset in terms of ETH
+     * @return startedAt Timestamp when the round was started; passed on from underlying price feed
+     * @return updatedAt Timestamp when the round was last updated; passed on from underlying price feed
+     * @return answeredInRound Round id in which the answer was computed; passed on from underlying price feed
+     **/
+    function latestRoundData() override external view returns (
+        uint80 roundId,
+        int256 answer,
+        uint256 startedAt,
+        uint256 updatedAt,
+        uint80 answeredInRound
+    ) {
+        // rate = 1 mETH in ETH
+        uint256 rate = IRateProvider(underlyingPriceFeed).mETHToETH(1e18);
+        // protocol uses only the answer value. Other data fields are not provided by the underlying pricefeed and are not used in Comet protocol
+        return (1, scalePrice(signed256(rate)), block.timestamp, block.timestamp, 1);
+    }
+
+    function signed256(uint256 n) internal pure returns (int256) {
+        if (n > uint256(type(int256).max)) revert InvalidInt256();
+        return int256(n);
+    }
+
+    function scalePrice(int256 price) internal view returns (int256) {
+        int256 scaledPrice;
+        if (shouldUpscale) {
+            scaledPrice = price * rescaleFactor;
+        } else {
+            scaledPrice = price / rescaleFactor;
+        }
+        return scaledPrice;
+    }
+
+    /**
+     * @notice Get the version of the price feed contract
+     * @return The version of the price feed contract
+     **/
+    function version() external pure returns (uint256) {
+        return VERSION;
+    }
+}

contracts/vendor/mantle/IRateProvider.sol

@@ -0,0 +1,6 @@
+// SPDX-License-Identifier: BUSL-1.1
+pragma solidity 0.8.15;
+
+interface IRateProvider {
+    function mETHToETH(uint256) external view returns (uint256);
+} 

deployments/mainnet/weth/migrations/1731429132_add_meth_collateral.ts

@@ -0,0 +1,133 @@
+import { expect } from 'chai';
+import { DeploymentManager } from '../../../../plugins/deployment_manager/DeploymentManager';
+import { migration } from '../../../../plugins/deployment_manager/Migration';
+import { exp, proposal } from '../../../../src/deploy';
+
+const METH_ADDRESS = '0xd5F7838F5C461fefF7FE49ea5ebaF7728bB0ADfa';
+const METH_EXCHANGE_RATE_PROVIDER_ADDRESS = '0xe3cBd06D7dadB3F4e6557bAb7EdD924CD1489E8f';
+let newPriceFeedAddress: string;
+
+export default migration('1731429132_add_meth_collateral', {
+  async prepare(deploymentManager: DeploymentManager) {
+    const _mETHScalingPriceFeed = await deploymentManager.deploy(
+      'mETH:priceFeed',
+      'pricefeeds/METHExchangeRatePriceFeed.sol',
+      [
+        METH_EXCHANGE_RATE_PROVIDER_ADDRESS, // mETH / ETH price feed
+        8,                                   // decimals
+        'mETH/ETH exchange rate',            // description
+      ]
+    );
+    return { mETHScalingPriceFeed: _mETHScalingPriceFeed.address };
+  },
+
+  async enact(deploymentManager: DeploymentManager, _, { mETHScalingPriceFeed }) {
+
+    const trace = deploymentManager.tracer();
+
+    const mETH = await deploymentManager.existing(
+      'mETH',
+      METH_ADDRESS,
+      'mainnet',
+      'contracts/ERC20.sol:ERC20'
+    );
+    const mEthPriceFeed = await deploymentManager.existing(
+      'mETH:priceFeed',
+      mETHScalingPriceFeed,
+      'mainnet'
+    );
+
+    newPriceFeedAddress = mEthPriceFeed.address;
+
+    const {
+      governor,
+      comet,
+      cometAdmin,
+      configurator,
+    } = await deploymentManager.getContracts();
+
+    const mETHAssetConfig = {
+      asset: mETH.address,
+      priceFeed: mEthPriceFeed.address,
+      decimals: await mETH.decimals(),
+      borrowCollateralFactor: exp(0.88, 18),
+      liquidateCollateralFactor: exp(0.9, 18),
+      liquidationFactor: exp(0.95, 18),
+      supplyCap: exp(5000, 18),
+    };
+
+    const mainnetActions = [
+      // 1. Add mETH as asset
+      {
+        contract: configurator,
+        signature: 'addAsset(address,(address,address,uint8,uint64,uint64,uint64,uint128))',
+        args: [comet.address, mETHAssetConfig],
+      },
+      // 2. Deploy and upgrade to a new version of Comet
+      {
+        contract: cometAdmin,
+        signature: 'deployAndUpgradeTo(address,address)',
+        args: [configurator.address, comet.address],
+      },
+    ];
+
+    const description = '# Add mETH as collateral into cWETHv3 on Mainnet\n\n## Proposal summary\n\nCompound Growth Program [AlphaGrowth] proposes to add mETH into cWETHv3 on Ethereum network. This proposal takes the governance steps recommended and necessary to update a Compound III WETH market on Ethereum. Simulations have confirmed the market’s readiness, as much as possible, using the [Comet scenario suite](https://github.com/compound-finance/comet/tree/main/scenario). The new parameters include setting the risk parameters based on the [recommendations from Gauntlet](https://www.comp.xyz/t/add-meth-market-on-ethereum/5647/5).\n\nFurther detailed information can be found on the corresponding [proposal pull request](https://github.com/compound-finance/comet/pull/919) and [forum discussion](https://www.comp.xyz/t/add-meth-market-on-ethereum/5647).\n\n\n## Proposal Actions\n\nThe first action adds mETH asset as collateral with corresponding configurations.\n\nThe second action deploys and upgrades Comet to a new version.';
+    const txn = await deploymentManager.retry(async () =>
+      trace(
+        await governor.propose(...(await proposal(mainnetActions, description)))
+      )
+    );
+
+    const event = txn.events.find(
+      (event) => event.event === 'ProposalCreated'
+    );
+    const [proposalId] = event.args;
+    trace(`Created proposal ${proposalId}.`);
+  },
+
+  async enacted(): Promise<boolean> {
+    return false;
+  },
+
+  async verify(deploymentManager: DeploymentManager) {
+    const { comet, configurator } = await deploymentManager.getContracts();
+
+    const mETHAssetIndex = Number(await comet.numAssets()) - 1;
+
+    const mETH = await deploymentManager.existing(
+      'mETH',
+      METH_ADDRESS,
+      'mainnet',
+      'contracts/ERC20.sol:ERC20'
+    );
+    const mETHAssetConfig = {
+      asset: mETH.address,
+      priceFeed: newPriceFeedAddress,
+      decimals: await mETH.decimals(),
+      borrowCollateralFactor: exp(0.88, 18),
+      liquidateCollateralFactor: exp(0.9, 18),
+      liquidationFactor: exp(0.95, 18),
+      supplyCap: exp(5000, 18),
+    };
+
+    // 1. Compare mETH asset config with Comet and Configurator asset info
+    const cometMETHAssetInfo = await comet.getAssetInfoByAddress(METH_ADDRESS);
+    expect(mETHAssetIndex).to.be.equal(cometMETHAssetInfo.offset);
+    expect(mETHAssetConfig.asset).to.be.equal(cometMETHAssetInfo.asset);
+    expect(mETHAssetConfig.priceFeed).to.be.equal(cometMETHAssetInfo.priceFeed);
+    expect(exp(1, mETHAssetConfig.decimals)).to.be.equal(cometMETHAssetInfo.scale);
+    expect(mETHAssetConfig.borrowCollateralFactor).to.be.equal(cometMETHAssetInfo.borrowCollateralFactor);
+    expect(mETHAssetConfig.liquidateCollateralFactor).to.be.equal(cometMETHAssetInfo.liquidateCollateralFactor);
+    expect(mETHAssetConfig.liquidationFactor).to.be.equal(cometMETHAssetInfo.liquidationFactor);
+    expect(mETHAssetConfig.supplyCap).to.be.equal(cometMETHAssetInfo.supplyCap);
+
+    const configuratorMETHAssetConfig = (await configurator.getConfiguration(comet.address)).assetConfigs[mETHAssetIndex];
+    expect(mETHAssetConfig.asset).to.be.equal(configuratorMETHAssetConfig.asset);
+    expect(mETHAssetConfig.priceFeed).to.be.equal(configuratorMETHAssetConfig.priceFeed);
+    expect(mETHAssetConfig.decimals).to.be.equal(configuratorMETHAssetConfig.decimals);
+    expect(mETHAssetConfig.borrowCollateralFactor).to.be.equal(configuratorMETHAssetConfig.borrowCollateralFactor);
+    expect(mETHAssetConfig.liquidateCollateralFactor).to.be.equal(configuratorMETHAssetConfig.liquidateCollateralFactor);
+    expect(mETHAssetConfig.liquidationFactor).to.be.equal(configuratorMETHAssetConfig.liquidationFactor);
+    expect(mETHAssetConfig.supplyCap).to.be.equal(configuratorMETHAssetConfig.supplyCap);
+  },
+});

scenario/constraints/ProposalConstraint.ts

@@ -61,13 +61,6 @@ export class ProposalConstraint<T extends CometContext> implements StaticConstra
             migrationData => migrationData.lastProposal === proposal.id.toNumber()
           );
         }
-
-        // temporary hack to skip proposal 348
-        if (proposal.id.eq(348)) {
-          console.log('Skipping proposal 348');
-          continue;
-        }
-
         // temporary hack to skip proposal 349
         if (proposal.id.eq(349)) {
           console.log('Skipping proposal 349');