feat: chainlink-like wsteth price feed

contracts/release/infrastructure/price-feeds/primitives/ChainlinkLikeWstethPriceFeed.sol

@@ -0,0 +1,71 @@
+// SPDX-License-Identifier: GPL-3.0
+
+/*
+    This file is part of the Enzyme Protocol.
+
+    (c) Enzyme Foundation <foundation@enzyme.finance>
+
+    For the full license information, please view the LICENSE
+    file that was distributed with this source code.
+*/
+
+pragma solidity 0.8.19;
+
+import {IChainlinkAggregator} from "../../../../external-interfaces/IChainlinkAggregator.sol";
+import {ILidoSteth} from "../../../../external-interfaces/ILidoSteth.sol";
+
+/// @title ChainlinkLikeWstethPriceFeed Contract
+/// @author Enzyme Foundation <security@enzyme.finance>
+/// @notice Price feed for Lido wrapped stETH (wstETH), wrapped in a Chainlink-like interface and quoted in ETH
+/// @dev Relies on a stETH/ETH feed with the Chainlink aggregator interface for the intermediary conversion step
+contract ChainlinkLikeWstethPriceFeed is IChainlinkAggregator {
+    uint8 private constant CHAINLINK_AGGREGATOR_ETH_QUOTE_DECIMALS = 18;
+    uint256 private constant STETH_UNIT = 10 ** 18;
+    uint256 private constant WSTETH_UNIT = 10 ** 18;
+
+    ILidoSteth private immutable STETH;
+    IChainlinkAggregator private immutable STETH_ETH_CHAINLINK_AGGREGATOR;
+
+    error ChainlinkLikeWstethPriceFeed__NegativeAnswer();
+
+    constructor(ILidoSteth _steth, IChainlinkAggregator _stethEthChainlinkAggregator) {
+        STETH = _steth;
+        STETH_ETH_CHAINLINK_AGGREGATOR = _stethEthChainlinkAggregator;
+    }
+
+    /// @notice The number of precision decimals in the aggregator answer
+    /// @return decimals_ The number of decimals
+    function decimals() external pure override returns (uint8 decimals_) {
+        return CHAINLINK_AGGREGATOR_ETH_QUOTE_DECIMALS;
+    }
+
+    /// @notice Returns Chainlink-like latest round data for the wstETH/ETH pair
+    /// @return roundId_ Unused
+    /// @return answer_ The price of wstETH quoted in ETH
+    /// @return startedAt_ The `startedAt_` value returned by the Chainlink stETH/ETH aggregator `latestRoundData()`
+    /// @return updatedAt_ The `updatedAt_` value returned by the Chainlink stETH/ETH aggregator `latestRoundData()`
+    /// @return answeredInRound_ Unused
+    /// @dev Does not pass through round-related values, to avoid misinterpretation
+    function latestRoundData()
+        external
+        view
+        override
+        returns (uint80, int256 answer_, uint256 startedAt_, uint256 updatedAt_, uint80)
+    {
+        // steth-per-wsteth rate
+        uint256 stethPerWsteth = STETH.getPooledEthByShares({_sharesAmount: WSTETH_UNIT});
+
+        // eth-per-steth rate
+        int256 ethPerStethAnswer;
+        (, ethPerStethAnswer, startedAt_, updatedAt_,) = STETH_ETH_CHAINLINK_AGGREGATOR.latestRoundData();
+
+        if (ethPerStethAnswer < 0) {
+            revert ChainlinkLikeWstethPriceFeed__NegativeAnswer();
+        }
+
+        // eth-per-wsteth rate
+        answer_ = int256(uint256(ethPerStethAnswer) * stethPerWsteth / STETH_UNIT);
+
+        return (uint80(0), answer_, startedAt_, updatedAt_, uint80(0));
+    }
+}

tests/bases/IntegrationTest.sol

@@ -169,7 +169,7 @@ abstract contract IntegrationTest is CoreUtils {
     }
 
     function setUpMainnetEnvironment(uint256 _forkBlock) internal {
-        vm.createSelectFork("mainnet", _forkBlock);
+        vm.createSelectFork({urlOrAlias: "mainnet", blockNumber: _forkBlock});
 
         v4ReleaseContracts = getV4MainnetReleaseContracts();
 

tests/interfaces/external/ILidoSteth.sol

@@ -2,5 +2,7 @@
 pragma solidity >=0.6.0 <0.9.0;
 
 interface ILidoSteth {
+    function getPooledEthByShares(uint256 _sharesAmount) external view returns (uint256 ethAmount_);
+
     function submit(address _referral) external payable;
 }

tests/tests/protocols/lido/ChainlinkLikeWstethPriceFeed.t.sol

@@ -0,0 +1,87 @@
+// SPDX-License-Identifier: GPL-3.0
+pragma solidity 0.8.19;
+
+import {IntegrationTest} from "tests/bases/IntegrationTest.sol";
+import {IChainlinkAggregator} from "tests/interfaces/external/IChainlinkAggregator.sol";
+import {IERC20} from "tests/interfaces/external/IERC20.sol";
+import {ILidoSteth} from "tests/interfaces/external/ILidoSteth.sol";
+
+contract ChainlinkLikeWstethPriceFeedTest is IntegrationTest {
+    IChainlinkAggregator wstethAggregator;
+    IChainlinkAggregator originalStethEthAggregator = IChainlinkAggregator(ETHEREUM_STETH_ETH_AGGREGATOR);
+
+    function setUp() public override {
+        vm.createSelectFork("mainnet", ETHEREUM_BLOCK_LATEST);
+
+        wstethAggregator = __deployWstethAggregator();
+    }
+
+    // DEPLOYMENT HELPERS
+
+    function __deployWstethAggregator() private returns (IChainlinkAggregator wstethAggregator_) {
+        bytes memory args = abi.encode(ETHEREUM_STETH, ETHEREUM_STETH_ETH_AGGREGATOR);
+
+        address addr = deployCode("ChainlinkLikeWstethPriceFeed.sol", args);
+
+        return IChainlinkAggregator(addr);
+    }
+
+    // TESTS
+
+    function test_decimals_success() public {
+        assertEq(wstethAggregator.decimals(), CHAINLINK_AGGREGATOR_DECIMALS_ETH, "Incorrect decimals");
+    }
+
+    function test_latestRoundData_successWithForkData() public {
+        // Query return data of stETH/ETH aggregator and the simulated wstETH/ETH aggregator
+        (,, uint256 originalStartedAt, uint256 originalUpdatedAt,) = originalStethEthAggregator.latestRoundData();
+        (
+            uint80 wstethRoundId,
+            int256 wstethAnswer,
+            uint256 wstethStartedAt,
+            uint256 wstethUpdatedAt,
+            uint80 wstethAnsweredInRound
+        ) = wstethAggregator.latestRoundData();
+
+        // startedAt and updatedAt should be passed-through as-is
+        assertEq(wstethStartedAt, originalStartedAt, "Incorrect startedAt");
+        assertEq(wstethUpdatedAt, originalUpdatedAt, "Incorrect updatedAt");
+
+        // Round values should be empty
+        assertEq(wstethRoundId, 0, "Non-zero roundId");
+        assertEq(wstethAnsweredInRound, 0, "Non-zero roundData");
+
+        // Rate: 1.17 ETH/wstETH, on June 24th, 2024
+        // https://www.coingecko.com/en/coins/wrapped-steth
+        uint256 expectedWstethEthRate = 1.17e18;
+        uint256 halfPercent = WEI_ONE_PERCENT / 2;
+        assertApproxEqRel(uint256(wstethAnswer), expectedWstethEthRate, halfPercent, "Incorrect rate");
+    }
+
+    function test_latestRoundData_successWithAlteredRates() public {
+        // Mock return values of stETH and wstETH sources to be:
+        // - eth-per-steth rate is 5e18
+        // - steth-per-wsteth rate is 2e18
+        // Expected eth-per-wsteth rate: 10e18
+        uint256 ethPerStethRate = 5e18;
+        uint256 stethPerWstethRate = 2e18;
+        uint256 expectedEthPerWstethRate = 10e18;
+
+        // Mock call on the Chainlink aggregator
+        vm.mockCall({
+            callee: address(originalStethEthAggregator),
+            data: abi.encodeWithSelector(IChainlinkAggregator.latestRoundData.selector),
+            returnData: abi.encode(1, ethPerStethRate, 345, 456, 2)
+        });
+
+        // Mock call in stETH
+        vm.mockCall({
+            callee: ETHEREUM_STETH,
+            data: abi.encodeWithSelector(ILidoSteth.getPooledEthByShares.selector, assetUnit(IERC20(ETHEREUM_WSTETH))),
+            returnData: abi.encode(stethPerWstethRate)
+        });
+
+        (, int256 wstethAnswer,,,) = wstethAggregator.latestRoundData();
+        assertEq(uint256(wstethAnswer), expectedEthPerWstethRate, "Incorrect rate");
+    }
+}

tests/tests/protocols/lido/WstethPriceFeed.t.sol

@@ -43,7 +43,7 @@ abstract contract WstethPriceFeedTestBase is IntegrationTest {
             _valueInterpreter: IValueInterpreter(getValueInterpreterAddressForVersion(version)),
             _tokenAddress: ETHEREUM_STETH,
             _skipIfRegistered: true,
-            _aggregatorAddress: ETHEREUM_STEH_ETH_AGGREGATOR,
+            _aggregatorAddress: ETHEREUM_STETH_ETH_AGGREGATOR,
             _rateAsset: IChainlinkPriceFeedMixinProd.RateAsset.ETH
         });
         addDerivative({

tests/utils/Constants.sol

@@ -96,7 +96,7 @@ abstract contract Constants {
     address internal constant ETHEREUM_DAI_ETH_AGGREGATOR = 0x773616E4d11A78F511299002da57A0a94577F1f4;
     address internal constant ETHEREUM_ETH_USD_AGGREGATOR = 0x5f4eC3Df9cbd43714FE2740f5E3616155c5b8419;
     address internal constant ETHEREUM_MLN_ETH_AGGREGATOR = 0xDaeA8386611A157B08829ED4997A8A62B557014C;
-    address internal constant ETHEREUM_STEH_ETH_AGGREGATOR = 0x86392dC19c0b719886221c78AB11eb8Cf5c52812;
+    address internal constant ETHEREUM_STETH_ETH_AGGREGATOR = 0x86392dC19c0b719886221c78AB11eb8Cf5c52812;
     address internal constant ETHEREUM_USDC_ETH_AGGREGATOR = 0x986b5E1e1755e3C2440e960477f25201B0a8bbD4;
     address internal constant ETHEREUM_USDT_ETH_AGGREGATOR = 0xEe9F2375b4bdF6387aa8265dD4FB8F16512A1d46;
     address internal constant ETHEREUM_WEETH_ETH_AGGREGATOR = 0x5c9C449BbC9a6075A2c061dF312a35fd1E05fF22;