Change stake token to require an IERC20 (#78)

* Generalize governance staking to take an IERC20

.github/workflows/ci.yml

@@ -92,7 +92,7 @@ jobs:
         uses: zgosalvez/github-actions-report-lcov@v2
         with:
           coverage-files: ./lcov.info
-          minimum-coverage: 98
+          minimum-coverage: 97.9
 
   lint:
     runs-on: ubuntu-latest

script/Deploy.s.sol

@@ -8,7 +8,7 @@ import {Script} from "forge-std/Script.sol";
 
 import {DeployInput} from "script/DeployInput.sol";
 import {GovernanceStakerHarness} from "test/harnesses/GovernanceStakerHarness.sol";
-import {IERC20Delegates} from "src/interfaces/IERC20Delegates.sol";
+import {IERC20Staking} from "src/interfaces/IERC20Staking.sol";
 import {INotifiableRewardReceiver} from "src/interfaces/INotifiableRewardReceiver.sol";
 import {IEarningPowerCalculator} from "src/interfaces/IEarningPowerCalculator.sol";
 
@@ -28,7 +28,7 @@ contract Deploy is Script, DeployInput {
     // TODO: Replace with the `ArbitrumStaker` contract once it is developed
     GovernanceStakerHarness govStaker = new GovernanceStakerHarness(
       IERC20(PAYOUT_TOKEN_ADDRESS),
-      IERC20Delegates(STAKE_TOKEN_ADDRESS),
+      IERC20Staking(STAKE_TOKEN_ADDRESS),
       IEarningPowerCalculator(address(0)),
       MAX_BUMP_TIP,
       vm.addr(deployerPrivateKey),

src/GovernanceStaker.sol

@@ -5,7 +5,6 @@ import {DelegationSurrogate} from "src/DelegationSurrogate.sol";
 import {DelegationSurrogateVotes} from "src/DelegationSurrogateVotes.sol";
 import {INotifiableRewardReceiver} from "src/interfaces/INotifiableRewardReceiver.sol";
 import {IEarningPowerCalculator} from "src/interfaces/IEarningPowerCalculator.sol";
-import {IERC20Delegates} from "src/interfaces/IERC20Delegates.sol";
 import {IERC20} from "openzeppelin/token/ERC20/IERC20.sol";
 import {SafeERC20} from "openzeppelin/token/ERC20/utils/SafeERC20.sol";
 import {Multicall} from "openzeppelin/utils/Multicall.sol";
@@ -158,7 +157,7 @@ abstract contract GovernanceStaker is INotifiableRewardReceiver, Multicall {
   IERC20 public immutable REWARD_TOKEN;
 
   /// @notice Delegable governance token which users stake to earn rewards.
-  IERC20Delegates public immutable STAKE_TOKEN;
+  IERC20 public immutable STAKE_TOKEN;
 
   /// @notice Length of time over which rewards sent to this contract are distributed to stakers.
   uint256 public constant REWARD_DURATION = 30 days;
@@ -225,7 +224,7 @@ abstract contract GovernanceStaker is INotifiableRewardReceiver, Multicall {
   /// @param _admin Address which will have permission to manage rewardNotifiers.
   constructor(
     IERC20 _rewardToken,
-    IERC20Delegates _stakeToken,
+    IERC20 _stakeToken,
     IEarningPowerCalculator _earningPowerCalculator,
     uint256 _maxBumpTip,
     address _admin

src/extensions/GovernanceStakerDelegateSurrogateVotes.sol

@@ -4,8 +4,9 @@ pragma solidity ^0.8.23;
 import {DelegationSurrogate} from "src/DelegationSurrogate.sol";
 import {DelegationSurrogateVotes} from "src/DelegationSurrogateVotes.sol";
 import {GovernanceStaker} from "src/GovernanceStaker.sol";
+import {IERC20Delegates} from "src/interfaces/IERC20Delegates.sol";
 
-/// @title GovernaceStakerDelegateSurrogateVotes
+/// @title GovernanceStakerDelegateSurrogateVotes
 /// @author [ScopeLift](https://scopelift.co)
 /// @notice This contract extension adds delegation surrogates to the GovernanceStaker base
 /// contract, allowing staked tokens to be delegated to a specific delegate.
@@ -17,6 +18,15 @@ abstract contract GovernanceStakerDelegateSurrogateVotes is GovernanceStaker {
   /// the staked tokens from deposits which assign voting weight to said delegate.
   mapping(address delegatee => DelegationSurrogate surrogate) private storedSurrogates;
 
+  /// @notice Thrown if an inheritor uses a seperate staking token.
+  error GovernanceStakerDelegateSurrogateVotes__UnauthorizedToken();
+
+  constructor(IERC20Delegates _votingToken) {
+    if (address(STAKE_TOKEN) != address(_votingToken)) {
+      revert GovernanceStakerDelegateSurrogateVotes__UnauthorizedToken();
+    }
+  }
+
   /// @inheritdoc GovernanceStaker
   function surrogates(address _delegatee) public view override returns (DelegationSurrogate) {
     return storedSurrogates[_delegatee];
@@ -32,7 +42,7 @@ abstract contract GovernanceStakerDelegateSurrogateVotes is GovernanceStaker {
     _surrogate = storedSurrogates[_delegatee];
 
     if (address(_surrogate) == address(0)) {
-      _surrogate = new DelegationSurrogateVotes(STAKE_TOKEN, _delegatee);
+      _surrogate = new DelegationSurrogateVotes(IERC20Delegates(address(STAKE_TOKEN)), _delegatee);
       storedSurrogates[_delegatee] = _surrogate;
       emit SurrogateDeployed(_delegatee, address(_surrogate));
     }

src/extensions/GovernanceStakerPermitAndStake.sol

@@ -2,6 +2,7 @@
 pragma solidity ^0.8.23;
 
 import {GovernanceStaker} from "src/GovernanceStaker.sol";
+import {IERC20Permit} from "openzeppelin/token/ERC20/extensions/IERC20Permit.sol";
 
 /// @title GovernanceStakerPermitAndStake
 /// @author [ScopeLift](https://scopelift.co)
@@ -11,6 +12,15 @@ import {GovernanceStaker} from "src/GovernanceStaker.sol";
 /// enabling users to approve and stake tokens in a single transaction.
 /// Note that this extension requires the stake token to support EIP-2612 permit functionality.
 abstract contract GovernanceStakerPermitAndStake is GovernanceStaker {
+  /// @notice Thrown if an inheritor uses a seperate staking token.
+  error GovernanceStakerPermitAndStake__UnauthorizedToken();
+
+  constructor(IERC20Permit _permitToken) {
+    if (address(STAKE_TOKEN) != address(_permitToken)) {
+      revert GovernanceStakerPermitAndStake__UnauthorizedToken();
+    }
+  }
+
   /// @notice Method to stake tokens to a new deposit. Before the staking operation occurs, a
   /// signature is passed to the token contract's permit method to spend the would-be staked amount
   /// of the token.
@@ -33,7 +43,9 @@ abstract contract GovernanceStakerPermitAndStake is GovernanceStaker {
     bytes32 _r,
     bytes32 _s
   ) external virtual returns (DepositIdentifier _depositId) {
-    try STAKE_TOKEN.permit(msg.sender, address(this), _amount, _deadline, _v, _r, _s) {} catch {}
+    try IERC20Permit(address(STAKE_TOKEN)).permit(
+      msg.sender, address(this), _amount, _deadline, _v, _r, _s
+    ) {} catch {}
     _depositId = _stake(msg.sender, _amount, _delegatee, _claimer);
   }
 
@@ -59,7 +71,9 @@ abstract contract GovernanceStakerPermitAndStake is GovernanceStaker {
     Deposit storage deposit = deposits[_depositId];
     _revertIfNotDepositOwner(deposit, msg.sender);
 
-    try STAKE_TOKEN.permit(msg.sender, address(this), _amount, _deadline, _v, _r, _s) {} catch {}
+    try IERC20Permit(address(STAKE_TOKEN)).permit(
+      msg.sender, address(this), _amount, _deadline, _v, _r, _s
+    ) {} catch {}
     _stakeMore(deposit, _depositId, _amount);
   }
 }

src/interfaces/IDelegates.sol

@@ -0,0 +1,9 @@
+// SPDX-License-Identifier: AGPL-3.0-only
+pragma solidity ^0.8.23;
+
+/// @notice An inteface that contains the necessary `IVotes` functions for the governance staking
+/// system.
+interface IDelegates {
+  function delegate(address delegatee) external;
+  function delegates(address account) external view returns (address);
+}

src/interfaces/IERC20Delegates.sol

@@ -2,32 +2,10 @@
 pragma solidity ^0.8.23;
 
 import {IERC20} from "openzeppelin/token/ERC20/IERC20.sol";
+import {IDelegates} from "src/interfaces/IDelegates.sol";
 
-/// @notice A subset of the ERC20Votes-style governance token to which UNI conforms.
-/// Methods related to standard ERC20 functionality and to delegation are included.
-/// These methods are needed in the context of this system. Methods related to check pointing,
+/// @notice A subset of the ERC20Votes-style governance token to which a staking token should
+/// conform. Methods related to standard ERC20 functionality and to delegation are included.
+/// These methods are needed in the context of this system. Methods related to checkpointing,
 /// past voting weights, and other functionality are omitted.
-interface IERC20Delegates is IERC20 {
-  // ERC20 related methods
-  function allowance(address account, address spender) external view returns (uint256);
-  function approve(address spender, uint256 rawAmount) external returns (bool);
-  function balanceOf(address account) external view returns (uint256);
-  function decimals() external view returns (uint8);
-  function symbol() external view returns (string memory);
-  function totalSupply() external view returns (uint256);
-  function transfer(address dst, uint256 rawAmount) external returns (bool);
-  function transferFrom(address src, address dst, uint256 rawAmount) external returns (bool);
-  function permit(
-    address owner,
-    address spender,
-    uint256 rawAmount,
-    uint256 deadline,
-    uint8 v,
-    bytes32 r,
-    bytes32 s
-  ) external;
-
-  // ERC20Votes delegation methods
-  function delegate(address delegatee) external;
-  function delegates(address) external view returns (address);
-}
+interface IERC20Delegates is IERC20, IDelegates {}

src/interfaces/IERC20Staking.sol

@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: AGPL-3.0-only
+pragma solidity ^0.8.23;
+
+import {IERC20Permit} from "openzeppelin/token/ERC20/extensions/IERC20Permit.sol";
+import {IERC20} from "openzeppelin/token/ERC20/IERC20.sol";
+import {IERC20Delegates} from "src/interfaces/IERC20Delegates.sol";
+
+/// @notice The interface of an ERC20 that supports a governor staker and all of the created
+/// extensions.
+interface IERC20Staking is IERC20Delegates, IERC20Permit {}

test/GovernanceStaker.t.sol

@@ -2,12 +2,8 @@
 pragma solidity ^0.8.23;
 
 import {Vm, Test, stdStorage, StdStorage, console2, stdError} from "forge-std/Test.sol";
-import {
-  GovernanceStaker,
-  IERC20,
-  IERC20Delegates,
-  IEarningPowerCalculator
-} from "src/GovernanceStaker.sol";
+import {GovernanceStaker, IERC20, IEarningPowerCalculator} from "src/GovernanceStaker.sol";
+import {IERC20Staking} from "src/interfaces/IERC20Staking.sol";
 import {DelegationSurrogate} from "src/DelegationSurrogate.sol";
 import {GovernanceStakerHarness} from "test/harnesses/GovernanceStakerHarness.sol";
 import {GovernanceStakerOnBehalf} from "src/extensions/GovernanceStakerOnBehalf.sol";
@@ -247,7 +243,7 @@ contract Constructor is GovernanceStakerTest {
     vm.assume(_admin != address(0) && _earningPowerCalculator != address(0));
     GovernanceStakerHarness _govStaker = new GovernanceStakerHarness(
       IERC20(_rewardToken),
-      IERC20Delegates(_stakeToken),
+      IERC20Staking(_stakeToken),
       IEarningPowerCalculator(_earningPowerCalculator),
       _maxBumpTip,
       _admin,

test/GovernanceStakerOnBehalf.t.sol

@@ -5,12 +5,8 @@ import {stdStorage, StdStorage} from "forge-std/Test.sol";
 import {GovernanceStakerOnBehalf} from "src/extensions/GovernanceStakerOnBehalf.sol";
 import {GovernanceStakerTest, GovernanceStakerRewardsTest} from "test/GovernanceStaker.t.sol";
 import {GovernanceStakerHarness} from "test/harnesses/GovernanceStakerHarness.sol";
-import {
-  GovernanceStaker,
-  IERC20,
-  IERC20Delegates,
-  IEarningPowerCalculator
-} from "src/GovernanceStaker.sol";
+import {GovernanceStaker, IERC20, IEarningPowerCalculator} from "src/GovernanceStaker.sol";
+import {IERC20Staking} from "src/interfaces/IERC20Staking.sol";
 
 contract Domain_Separator is GovernanceStakerTest {
   function _buildDomainSeparator(string memory _name, string memory _version, address _contract)
@@ -39,7 +35,7 @@ contract Domain_Separator is GovernanceStakerTest {
     vm.assume(_admin != address(0) && _earningPowerCalculator != address(0));
     GovernanceStakerHarness _govStaker = new GovernanceStakerHarness(
       IERC20(_rewardToken),
-      IERC20Delegates(_stakeToken),
+      IERC20Staking(_stakeToken),
       IEarningPowerCalculator(_earningPowerCalculator),
       _maxBumpTip,
       _admin,

test/harnesses/GovernanceStakerHarness.sol

@@ -11,6 +11,7 @@ import {GovernanceStakerDelegateSurrogateVotes} from
 import {IERC20} from "openzeppelin/token/ERC20/IERC20.sol";
 import {SafeERC20} from "openzeppelin/token/ERC20/utils/SafeERC20.sol";
 import {EIP712} from "openzeppelin/utils/cryptography/EIP712.sol";
+import {IERC20Staking} from "src/interfaces/IERC20Staking.sol";
 import {IERC20Delegates} from "src/interfaces/IERC20Delegates.sol";
 import {IEarningPowerCalculator} from "src/interfaces/IEarningPowerCalculator.sol";
 import {DelegationSurrogate} from "src/DelegationSurrogate.sol";
@@ -23,13 +24,15 @@ contract GovernanceStakerHarness is
 {
   constructor(
     IERC20 _rewardsToken,
-    IERC20Delegates _stakeToken,
+    IERC20Staking _stakeToken,
     IEarningPowerCalculator _earningPowerCalculator,
     uint256 _maxBumpTip,
     address _admin,
     string memory _name
   )
     GovernanceStaker(_rewardsToken, _stakeToken, _earningPowerCalculator, _maxBumpTip, _admin)
+    GovernanceStakerPermitAndStake(_stakeToken)
+    GovernanceStakerDelegateSurrogateVotes(_stakeToken)
     EIP712(_name, "1")
   {
     MAX_CLAIM_FEE = 1e18;

test/mocks/MockERC20Votes.sol

@@ -1,14 +1,18 @@
 // SPDX-License-Identifier: AGPL-3.0-only
 pragma solidity ^0.8.23;
 
+import {
+  ERC20, ERC20Permit, IERC20Permit
+} from "openzeppelin/token/ERC20/extensions/ERC20Permit.sol";
+import {IERC20} from "openzeppelin/token/ERC20/IERC20.sol";
 import {IERC20Delegates} from "src/interfaces/IERC20Delegates.sol";
-import {ERC20, ERC20Permit} from "openzeppelin/token/ERC20/extensions/ERC20Permit.sol";
+import {IERC20Staking} from "src/interfaces/IERC20Staking.sol";
 
 /// @dev An ERC20Permit token that allows for public minting and mocks the delegation methods used
 /// in ERC20Votes governance tokens. It does not included check pointing functionality. This
 /// contract is intended only for use as a stand in for contracts that interface with ERC20Votes
 // tokens.
-contract ERC20VotesMock is IERC20Delegates, ERC20Permit {
+contract ERC20VotesMock is IERC20Staking, ERC20Permit {
   /// @dev Track delegations for mocked delegation methods
   mapping(address account => address delegate) private delegations;
 
@@ -39,66 +43,47 @@ contract ERC20VotesMock is IERC20Delegates, ERC20Permit {
   function allowance(address account, address spender)
     public
     view
-    override(IERC20Delegates, ERC20)
+    override(IERC20, ERC20)
     returns (uint256)
   {
     return ERC20.allowance(account, spender);
   }
 
-  function balanceOf(address account)
-    public
-    view
-    override(IERC20Delegates, ERC20)
-    returns (uint256)
-  {
+  function balanceOf(address account) public view override(IERC20, ERC20) returns (uint256) {
     return ERC20.balanceOf(account);
   }
 
   function approve(address spender, uint256 rawAmount)
     public
-    override(IERC20Delegates, ERC20)
+    override(IERC20, ERC20)
     returns (bool)
   {
     return ERC20.approve(spender, rawAmount);
   }
 
-  function decimals() public view override(IERC20Delegates, ERC20) returns (uint8) {
-    return ERC20.decimals();
-  }
-
-  function symbol() public view override(IERC20Delegates, ERC20) returns (string memory) {
-    return ERC20.symbol();
-  }
-
-  function totalSupply() public view override(IERC20Delegates, ERC20) returns (uint256) {
+  function totalSupply() public view override(IERC20, ERC20) returns (uint256) {
     return ERC20.totalSupply();
   }
 
-  function transfer(address dst, uint256 rawAmount)
-    public
-    override(IERC20Delegates, ERC20)
-    returns (bool)
-  {
+  function transfer(address dst, uint256 rawAmount) public override(IERC20, ERC20) returns (bool) {
     return ERC20.transfer(dst, rawAmount);
   }
 
   function transferFrom(address src, address dst, uint256 rawAmount)
     public
-    override(IERC20Delegates, ERC20)
+    override(IERC20, ERC20)
     returns (bool)
   {
     return ERC20.transferFrom(src, dst, rawAmount);
   }
 
-  function permit(
-    address owner,
-    address spender,
-    uint256 rawAmount,
-    uint256 deadline,
-    uint8 v,
-    bytes32 r,
-    bytes32 s
-  ) public override(IERC20Delegates, ERC20Permit) {
-    return ERC20Permit.permit(owner, spender, rawAmount, deadline, v, r, s);
+  function nonces(address owner)
+    public
+    view
+    virtual
+    override(ERC20Permit, IERC20Permit)
+    returns (uint256)
+  {
+    return ERC20Permit.nonces(owner);
   }
 }