feat: add adapter for mellow erc4626 (#141)

* feat: add adapter for mellow erc4626

* fix: change type function to constant

* chore: warnings cleanup

contracts/adapters/erc4626/ERC4626Adapter.sol

@@ -14,7 +14,6 @@ import {IERC4626Adapter} from "../../interfaces/erc4626/IERC4626Adapter.sol";
 /// @title ERC4626 Vault adapter
 /// @notice Implements logic allowing CAs to interact with any standard-compliant ERC4626 vault
 contract ERC4626Adapter is AbstractAdapter, IERC4626Adapter {
-    AdapterType public constant override _gearboxAdapterType = AdapterType.ERC4626_VAULT;
     uint16 public constant override _gearboxAdapterVersion = 3_00;
 
     /// @notice Address of the underlying asset of the vault
@@ -26,6 +25,10 @@ contract ERC4626Adapter is AbstractAdapter, IERC4626Adapter {
     /// @notice Mask of the ERC4626 vault shares
     uint256 public immutable override sharesMask;
 
+    function _gearboxAdapterType() external pure virtual override returns (AdapterType) {
+        return AdapterType.ERC4626_VAULT;
+    }
+
     /// @notice Constructor
     /// @param _creditManager Credit manager address
     /// @param _vault ERC4626 vault address
@@ -96,6 +99,7 @@ contract ERC4626Adapter is AbstractAdapter, IERC4626Adapter {
     /// @dev `receiver` and `owner` are ignored, since they are always set to the credit account address
     function withdraw(uint256 assets, address, address)
         external
+        virtual
         override
         creditFacadeOnly // U:[TV-2]
         returns (uint256 tokensToEnable, uint256 tokensToDisable)
@@ -110,6 +114,7 @@ contract ERC4626Adapter is AbstractAdapter, IERC4626Adapter {
     /// @dev `receiver` and `owner` are ignored, since they are always set to the credit account address
     function redeem(uint256 shares, address, address)
         external
+        virtual
         override
         creditFacadeOnly // U:[TV-2]
         returns (uint256 tokensToEnable, uint256 tokensToDisable)
@@ -122,6 +127,7 @@ contract ERC4626Adapter is AbstractAdapter, IERC4626Adapter {
     /// @param leftoverAmount Amount of vault token to keep on the account
     function redeemDiff(uint256 leftoverAmount)
         external
+        virtual
         override
         creditFacadeOnly // U:[TV-2]
         returns (uint256 tokensToEnable, uint256 tokensToDisable)

contracts/adapters/mellow/Mellow4626VaultAdapter.sol

@@ -0,0 +1,35 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+// Gearbox Protocol. Generalized leverage for DeFi protocols
+// (c) Gearbox Foundation, 2023.
+pragma solidity ^0.8.17;
+
+import {ERC4626Adapter} from "../erc4626/ERC4626Adapter.sol";
+import {AdapterType} from "@gearbox-protocol/sdk-gov/contracts/AdapterType.sol";
+import {NotImplementedException} from "@gearbox-protocol/core-v3/contracts/interfaces/IExceptions.sol";
+
+/// @title Mellow ERC4626 Vault adapter
+/// @notice Implements logic allowing CAs to interact with a ERC4626 vaults, but with `withdraw` / `redeem` restricted, to avoid
+///         CA's being exposed to Mellow's asynchronous withdrawals
+contract Mellow4626VaultAdapter is ERC4626Adapter {
+    AdapterType public constant override _gearboxAdapterType = AdapterType.MELLOW_ERC4626_VAULT;
+
+    /// @notice Constructor
+    /// @param _creditManager Credit manager address
+    /// @param _vault ERC4626 vault address
+    constructor(address _creditManager, address _vault) ERC4626Adapter(_creditManager, _vault) {}
+
+    /// @dev For Mellow ERC4626 vaults all withdrawals revert to avoid CA's interacting with Mellow's delayed withdrawals
+    function withdraw(uint256, address, address) external view override creditFacadeOnly returns (uint256, uint256) {
+        revert NotImplementedException();
+    }
+
+    /// @dev For Mellow ERC4626 vaults all withdrawals revert to avoid CA's interacting with Mellow's delayed withdrawals
+    function redeem(uint256, address, address) external view override creditFacadeOnly returns (uint256, uint256) {
+        revert NotImplementedException();
+    }
+
+    /// @dev For Mellow ERC4626 vaults all withdrawals revert to avoid CA's interacting with Mellow's delayed withdrawals
+    function redeemDiff(uint256) external view override creditFacadeOnly returns (uint256, uint256) {
+        revert NotImplementedException();
+    }
+}

contracts/test/unit/adapters/erc4626/ERC4626Adapter.unit.t.sol

@@ -5,7 +5,9 @@ pragma solidity ^0.8.17;
 
 import {IERC4626} from "@openzeppelin/contracts/interfaces/IERC4626.sol";
 import {ERC4626Adapter} from "../../../../adapters/erc4626/ERC4626Adapter.sol";
+import {Mellow4626VaultAdapter} from "../../../../adapters/mellow/Mellow4626VaultAdapter.sol";
 import {AdapterUnitTestHelper} from "../AdapterUnitTestHelper.sol";
+import {NotImplementedException} from "@gearbox-protocol/core-v3/contracts/interfaces/IExceptions.sol";
 
 /// @title ERC-4626 adapter unit test
 /// @notice U:[TV]: Unit tests for ERC-4626 tokenized vault adapter
@@ -168,4 +170,21 @@ contract ERC4626AdapterUnitTest is AdapterUnitTestHelper {
         assertEq(tokensToEnable, assetMask, "Incorrect tokensToEnable");
         assertEq(tokensToDisable, diffDisableTokenIn ? sharesMask : 0, "Incorrect tokensToDisable");
     }
+
+    /// @notice U:[TV-9]: withdrawal functions restricted for Mellow adapter
+    function test_U_TV_09_withdrawal_functions_restricted_for_mellow() public diffTestCases {
+        adapter = new Mellow4626VaultAdapter(address(creditManager), vault);
+
+        vm.expectRevert(NotImplementedException.selector);
+        vm.prank(creditFacade);
+        adapter.withdraw(1000, address(0), address(0));
+
+        vm.expectRevert(NotImplementedException.selector);
+        vm.prank(creditFacade);
+        adapter.redeem(1000, address(0), address(0));
+
+        vm.expectRevert(NotImplementedException.selector);
+        vm.prank(creditFacade);
+        adapter.redeemDiff(1000);
+    }
 }