Merge remote-tracking branch 'origin/feat/wsteth-oracle' into feat/vault-quote

Author: MathisGD

src/wsteth-exchange-rate-adapter/WstEthEthExchangeRateChainlinkAdapter.sol

@@ -0,0 +1,30 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+pragma solidity 0.8.21;
+
+import {IStEth} from "./interfaces/IStEth.sol";
+import {MinimalAggregatorV3Interface} from "./interfaces/MinimalAggregatorV3Interface.sol";
+
+/// @title WstEthStEthExchangeRateChainlinkAdapter
+/// @author Morpho Labs
+/// @custom:contact security@morpho.org
+/// @notice wstETH/stETH exchange rate price feed.
+/// @dev This contract should only be deployed on Ethereum and used as a price feed for Morpho oracles.
+contract WstEthStEthExchangeRateChainlinkAdapter is MinimalAggregatorV3Interface {
+    /// @inheritdoc MinimalAggregatorV3Interface
+    // @dev The calculated price has 18 decimals precision, whatever the value of `decimals`.
+    uint8 public constant decimals = 18;
+
+    /// @notice The description of the price feed.
+    string public constant description = "wstETH/stETH exchange rate";
+
+    /// @notice The address of stETH on Ethereum.
+    IStEth public constant ST_ETH = IStEth(0xae7ab96520DE3A18E5e111B5EaAb095312D7fE84);
+
+    /// @inheritdoc MinimalAggregatorV3Interface
+    /// @dev Returns zero for roundId, startedAt, updatedAt and answeredInRound.
+    /// @dev Silently overflows if `getPooledEthByShares`'s return value is greater than `type(int256).max`.
+    function latestRoundData() external view returns (uint80, int256, uint256, uint256, uint80) {
+        // It is assumed that `getPooledEthByShares` returns a price with 18 decimals precision.
+        return (0, int256(ST_ETH.getPooledEthByShares(1 ether)), 0, 0, 0);
+    }
+}

src/wsteth-exchange-rate-adapter/WstEthStEthExchangeRateChainlinkAdapter.sol

@@ -0,0 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+pragma solidity >=0.5.0;
+
+interface IStEth {
+    function getPooledEthByShares(uint256) external view returns (uint256);
+}

src/wsteth-exchange-rate-adapter/interfaces/IStEth.sol

@@ -3,9 +3,13 @@ pragma solidity >=0.5.0;
 
 /// @dev Inspired by
 /// https://github.com/smartcontractkit/chainlink/blob/master/contracts/src/v0.8/shared/interfaces/AggregatorV3Interface.sol
+/// @dev This is the minimal feed interface required by `MorphoChainlinkOracleV2`.
 interface MinimalAggregatorV3Interface {
+    /// @notice Returns the precision of the feed.
     function decimals() external view returns (uint8);
 
+    /// @notice Returns Chainlink's `latestRoundData` return values.
+    /// @notice Only the `answer` field is used by `MorphoChainlinkOracleV2`.
     function latestRoundData()
         external
         view

src/wsteth-exchange-rate-adapter/interfaces/IWstEth.sol

@@ -4,17 +4,17 @@ pragma solidity ^0.8.0;
 import "./helpers/Constants.sol";
 import "../lib/forge-std/src/Test.sol";
 import {MorphoChainlinkOracleV2} from "../src/morpho-chainlink/MorphoChainlinkOracleV2.sol";
-import "../src/wsteth-exchange-rate-adapter/WstEthEthExchangeRateChainlinkAdapter.sol";
+import "../src/wsteth-exchange-rate-adapter/WstEthStEthExchangeRateChainlinkAdapter.sol";
 
-contract WstEthEthExchangeRateChainlinkAdapterTest is Test {
-    IWstEth internal constant WST_ETH = IWstEth(0x7f39C581F595B53c5cb19bD0b3f8dA6c935E2Ca0);
+contract WstEthStEthExchangeRateChainlinkAdapterTest is Test {
+    IStEth internal constant ST_ETH = IStEth(0xae7ab96520DE3A18E5e111B5EaAb095312D7fE84);
 
-    WstEthEthExchangeRateChainlinkAdapter internal adapter;
+    WstEthStEthExchangeRateChainlinkAdapter internal adapter;
     MorphoChainlinkOracleV2 internal morphoOracle;
 
     function setUp() public {
         vm.createSelectFork(vm.envString("ETH_RPC_URL"));
-        adapter = new WstEthEthExchangeRateChainlinkAdapter(address(WST_ETH));
+        adapter = new WstEthStEthExchangeRateChainlinkAdapter();
         morphoOracle = new MorphoChainlinkOracleV2(
             vaultZero, 1, AggregatorV3Interface(address(adapter)), feedZero, 18, vaultZero, 1, feedZero, feedZero, 18
         );
@@ -25,19 +25,14 @@ contract WstEthEthExchangeRateChainlinkAdapterTest is Test {
     }
 
     function testDescription() public {
-        assertEq(adapter.description(), "wstETH/ETH exchange rate");
-    }
-
-    function testDeployZeroAddress() public {
-        vm.expectRevert(bytes(ErrorsLib.ZERO_ADDRESS));
-        new WstEthEthExchangeRateChainlinkAdapter(address(0));
+        assertEq(adapter.description(), "wstETH/stETH exchange rate");
     }
 
     function testLatestRoundData() public {
         (uint80 roundId, int256 answer, uint256 startedAt, uint256 updatedAt, uint80 answeredInRound) =
             adapter.latestRoundData();
         assertEq(roundId, 0);
-        assertEq(uint256(answer), WST_ETH.stEthPerToken());
+        assertEq(uint256(answer), ST_ETH.getPooledEthByShares(1 ether));
         assertEq(startedAt, 0);
         assertEq(updatedAt, 0);
         assertEq(answeredInRound, 0);
@@ -49,7 +44,7 @@ contract WstEthEthExchangeRateChainlinkAdapterTest is Test {
         assertLe(uint256(answer), 1.5e18); // Max bounds of the exchange rate. Should work for a long enough time.
     }
 
-    function testOracleWstEthEthExchangeRate() public {
+    function testOracleWstEthStEthExchangeRate() public {
         (, int256 expectedPrice,,,) = adapter.latestRoundData();
         assertEq(morphoOracle.price(), uint256(expectedPrice) * 10 ** (36 + 18 - 18 - 18));
     }