Add HardHat compatibility and improve on use within Foundry

This commit makes it possible to use staker as a dependency in a HardHat Solidity project. It also makes using staker easier and more natural in the context of a Foundry project as well. Changes include:

* Adding a package.json with definitions for use in npm based environments like HardHat
* Change all imports in the project to relative imports, to avoid import issues in both Foundry and HardHat based projects
* Move the script directory into the src directory; in Foundry, this means the automatic remappings for staker will now switch to `staker/=lib/staker/src/` instead of just `staker/=/lib/staker/`, so imports do not have to include the `src/` extension
* Add a `remappings.txt` file that defines a `staker-test/=test/` remapping, making it easier for downstream Foundry projects to import test files they may want to extend from or leverage.
* Update the README to make it clearer how to use this repository as a dependency in various kinds of projects

---------

Co-authored-by: Ben DiFrancesco <ben@scopelift.co>

README.md

@@ -117,6 +117,96 @@ stateDiagram-v2
     PF --> Staker: Returns earning power to staking system
 ```
 
+## Usage
+
+The Staker repository is designed to be used as a library. Once added to your project, it can be used to assemble, configure, and deploy an instance of Staker appropriate for your project.
+
+### Installation
+
+#### Foundry
+
+Add Staker as a dependency:
+
+```bash
+forge install withtally/staker
+```
+
+#### Hardhat
+
+Staker is not currently distributed as a package on npm, but it can still be added to a HardHat project by referencing the github repository directly.
+
+Add the following lines to to your `package.json` in the `dependencies` key:
+
+```json
+"dependencies": {
+    "@openzeppelin/contracts": "^5.0.2",
+    "staker": "github:withtally/staker#v1.0.1"
+  }
+```
+
+Note that because the `staker` package is pinned to a version branch on GitHub. To upgrade to a new version of Staker in the future, you cannot expect an upgrade to a new version simply by running `npm upgrade`. Instead, you will have to update the tag referenced in the `pacakage.json` and re-run `npm install`.
+
+### Import and Assemble a Staker
+
+To create a concrete implementation, import Staker and the desired extensions. Create a new contract that inherits from Staker and the extensions of choice, and implement the constructor, along with any method overrides in accordance with your desired set of features and customizations.
+
+For example, here is a concrete implementation of the Staker that:
+
+* Uses an [ERC20Votes](https://docs.openzeppelin.com/contracts/5.x/api/token/erc20#ERC20Votes) style governance token as its staking token (via the `StakerDelegateSurrogateVotes` extension)
+* Uses a staking token that includes permit functionality, and provides convenience staking methods that use this functionality (via the `StakerPermitAndStake` extension)
+* Allows users to take actions via EIP712 signatures (via the `StakerOnBehalf` extension)
+* Allows a maximum claim fee of 1 (18 decimal) reward token, but configures the Staker with claim fees turned off to start
+
+```solidity
+pragma solidity 0.8.28;
+
+import {Staker} staker/Staker.sol;
+import {StakerDelegateSurrogateVotes} from "staker/extensions/StakerDelegateSurrogateVotes.sol";
+import {StakerPermitAndStake} from "staker/extensions/StakerPermitAndStake.sol";
+import {StakerOnBehalf} from "staker/extensions/StakerOnBehalf.sol";
+
+contract MyStaker is
+  Staker,
+  StakerDelegateSurrogateVotes,
+  StakerPermitAndStake
+  StakerOnBehalf
+{
+  constructor(
+    IERC20 _rewardsToken,
+    IERC20Staking _stakeToken,
+    IEarningPowerCalculator _earningPowerCalculator,
+    uint256 _maxBumpTip,
+    address _admin
+  )
+    Staker(_rewardsToken, _stakeToken, _earningPowerCalculator, _maxBumpTip, _admin)
+    StakerPermitAndStake(_stakeToken)
+    StakerDelegateSurrogateVotes(_stakeToken)
+    EIP712("MyStaker", "1")
+  {
+    // Override the maximum reward token fee for claiming rewards
+    MAX_CLAIM_FEE = 1e18;
+    // At deployment, there should be no reward claiming fee
+    _setClaimFeeParameters(ClaimFeeParameters({feeAmount: 0, feeCollector: address(0)}));
+  }
+}
+```
+
+### Testing
+
+Foundry users can also import test-related contracts into their own tests if desired:
+
+```solidity
+pragma solidity 0.8.28;
+
+import {StakerTestBase} from "staker-test/StakerTestBase.sol";
+
+contract MyStakerTest is StakerTestBase {
+    // ... Your test implementations
+}
+```
+
+Hardhat users cannot, by definition, import test contracts into their own tests. Any testing infrastructure for JavaScript tests must be written by the downstream consumer of the Staker package.
+
 ## Development
 
 These contracts were built and tested with care by the team at [ScopeLift](https://scopelift.co).

foundry.toml

@@ -5,7 +5,6 @@
   ]
   optimizer = true
   optimizer_runs = 10_000_000
-  remappings = ["openzeppelin/=lib/openzeppelin-contracts/contracts"]
   solc_version = "0.8.28"
   verbosity = 3
 

package.json

@@ -0,0 +1,21 @@
+{
+  "name": "staker",
+  "version": "1.0.1",
+  "description": "Staker is a flexible, configurable staking contract. Staker makes it easy to distribute onchain staking rewards for any ERC20 token, including DAO governance tokens. This file is included for compatibility with npm based development frameworks such as Hardhat.",
+  "author": "Contributors to https://github.com/ScopeLift/staker",
+  "files": [
+    "src/*"
+  ],
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/ScopeLift/staker.git"
+  },
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/ScopeLift/staker/issues"
+  },
+  "homepage": "https://github.com/ScopeLift/staker#readme",
+  "dependencies": {
+    "@openzeppelin/contracts": "^5.0.2"
+  }
+}

remappings.txt

@@ -0,0 +1 @@
+staker-test/=test/

src/DelegationSurrogate.sol

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: AGPL-3.0-only
 pragma solidity ^0.8.23;
 
-import {IERC20} from "openzeppelin/token/ERC20/IERC20.sol";
+import {IERC20} from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
 
 /// @title DelegationSurrogate
 /// @author [ScopeLift](https://scopelift.co)

src/DelegationSurrogateVotes.sol

@@ -1,8 +1,8 @@
 // SPDX-License-Identifier: AGPL-3.0-only
 pragma solidity ^0.8.23;
 
-import {DelegationSurrogate} from "src/DelegationSurrogate.sol";
-import {IERC20Delegates} from "src/interfaces/IERC20Delegates.sol";
+import {DelegationSurrogate} from "./DelegationSurrogate.sol";
+import {IERC20Delegates} from "./interfaces/IERC20Delegates.sol";
 
 /// @title DelegationSurrogateVotes
 /// @author [ScopeLift](https://scopelift.co)

src/Staker.sol

@@ -1,13 +1,13 @@
 // SPDX-License-Identifier: AGPL-3.0-only
 pragma solidity ^0.8.23;
 
-import {DelegationSurrogate} from "src/DelegationSurrogate.sol";
-import {INotifiableRewardReceiver} from "src/interfaces/INotifiableRewardReceiver.sol";
-import {IEarningPowerCalculator} from "src/interfaces/IEarningPowerCalculator.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";
-import {SafeCast} from "openzeppelin/utils/math/SafeCast.sol";
+import {DelegationSurrogate} from "./DelegationSurrogate.sol";
+import {INotifiableRewardReceiver} from "./interfaces/INotifiableRewardReceiver.sol";
+import {IEarningPowerCalculator} from "./interfaces/IEarningPowerCalculator.sol";
+import {IERC20} from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
+import {SafeERC20} from "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
+import {Multicall} from "@openzeppelin/contracts/utils/Multicall.sol";
+import {SafeCast} from "@openzeppelin/contracts/utils/math/SafeCast.sol";
 
 /// @title Staker
 /// @author [ScopeLift](https://scopelift.co)

src/calculators/BinaryEligibilityOracleEarningPowerCalculator.sol

@@ -2,7 +2,7 @@
 pragma solidity ^0.8.23;
 
 import {Ownable} from "@openzeppelin/contracts/access/Ownable.sol";
-import {IEarningPowerCalculator} from "src/interfaces/IEarningPowerCalculator.sol";
+import {IEarningPowerCalculator} from "../interfaces/IEarningPowerCalculator.sol";
 
 /// @title BinaryEligibilityOracleEarningPowerCalculator
 /// @author [ScopeLift](https://scopelift.co)

src/calculators/IdentityEarningPowerCalculator.sol

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: AGPL-3.0-only
 pragma solidity ^0.8.23;
 
-import {IEarningPowerCalculator} from "src/interfaces/IEarningPowerCalculator.sol";
+import {IEarningPowerCalculator} from "../interfaces/IEarningPowerCalculator.sol";
 
 /// @title IdentityEarningPowerCalculator
 /// @author [ScopeLift](https://scopelift.co)

src/extensions/StakerCapDeposits.sol

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: AGPL-3.0-only
 pragma solidity ^0.8.23;
 
-import {Staker} from "src/Staker.sol";
+import {Staker} from "../Staker.sol";
 
 /// @title StakerCapDeposits
 /// @author [ScopeLift](https://scopelift.co)

src/extensions/StakerDelegateSurrogateVotes.sol

@@ -1,10 +1,10 @@
 // SPDX-License-Identifier: AGPL-3.0-only
 pragma solidity ^0.8.23;
 
-import {DelegationSurrogate} from "src/DelegationSurrogate.sol";
-import {DelegationSurrogateVotes} from "src/DelegationSurrogateVotes.sol";
-import {Staker} from "src/Staker.sol";
-import {IERC20Delegates} from "src/interfaces/IERC20Delegates.sol";
+import {DelegationSurrogate} from "../DelegationSurrogate.sol";
+import {DelegationSurrogateVotes} from "../DelegationSurrogateVotes.sol";
+import {Staker} from "../Staker.sol";
+import {IERC20Delegates} from "../interfaces/IERC20Delegates.sol";
 
 /// @title StakerDelegateSurrogateVotes
 /// @author [ScopeLift](https://scopelift.co)

src/extensions/StakerOnBehalf.sol

@@ -1,10 +1,10 @@
 // SPDX-License-Identifier: AGPL-3.0-only
 pragma solidity ^0.8.23;
 
-import {Staker} from "src/Staker.sol";
-import {SignatureChecker} from "openzeppelin/utils/cryptography/SignatureChecker.sol";
-import {EIP712} from "openzeppelin/utils/cryptography/EIP712.sol";
-import {Nonces} from "openzeppelin/utils/Nonces.sol";
+import {Staker} from "../Staker.sol";
+import {SignatureChecker} from "@openzeppelin/contracts/utils/cryptography/SignatureChecker.sol";
+import {Nonces} from "@openzeppelin/contracts/utils/Nonces.sol";
+import {EIP712} from "@openzeppelin/contracts/utils/cryptography/EIP712.sol";
 
 /// @title StakerOnBehalf
 /// @author [ScopeLift](https://scopelift.co)

src/extensions/StakerPermitAndStake.sol

@@ -1,8 +1,8 @@
 // SPDX-License-Identifier: AGPL-3.0-only
 pragma solidity ^0.8.23;
 
-import {Staker} from "src/Staker.sol";
-import {IERC20Permit} from "openzeppelin/token/ERC20/extensions/IERC20Permit.sol";
+import {Staker} from "../Staker.sol";
+import {IERC20Permit} from "@openzeppelin/contracts/token/ERC20/extensions/IERC20Permit.sol";
 
 /// @title StakerPermitAndStake
 /// @author [ScopeLift](https://scopelift.co)

src/interfaces/IERC20Delegates.sol

@@ -1,8 +1,8 @@
 // SPDX-License-Identifier: AGPL-3.0-only
 pragma solidity ^0.8.23;
 
-import {IERC20} from "openzeppelin/token/ERC20/IERC20.sol";
-import {IDelegates} from "src/interfaces/IDelegates.sol";
+import {IERC20} from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
+import {IDelegates} from "./IDelegates.sol";
 
 /// @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.

src/interfaces/IERC20Staking.sol

@@ -1,8 +1,8 @@
 // SPDX-License-Identifier: AGPL-3.0-only
 pragma solidity ^0.8.23;
 
-import {IERC20Permit} from "openzeppelin/token/ERC20/extensions/IERC20Permit.sol";
-import {IERC20Delegates} from "src/interfaces/IERC20Delegates.sol";
+import {IERC20Permit} from "@openzeppelin/contracts/token/ERC20/extensions/IERC20Permit.sol";
+import {IERC20Delegates} from "./IERC20Delegates.sol";
 
 /// @notice The interface of an ERC20 that supports a governor staker and all of the created
 /// extensions.

src/interfaces/INotifiableRewardReceiver.sol

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: AGPL-3.0-only
 pragma solidity ^0.8.23;
 
-import {IERC20} from "openzeppelin/token/ERC20/IERC20.sol";
+import {IERC20} from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
 
 /// @title INotifiableRewardReceiver
 /// @author [ScopeLift](https://scopelift.co)

src/notifiers/MintRewardNotifier.sol

@@ -1,10 +1,10 @@
 // SPDX-License-Identifier: AGPL-3.0-only
 pragma solidity ^0.8.23;
 
-import {INotifiableRewardReceiver} from "src/interfaces/INotifiableRewardReceiver.sol";
-import {IMintable} from "src/interfaces/IMintable.sol";
-import {RewardTokenNotifierBase} from "src/notifiers/RewardTokenNotifierBase.sol";
-import {Ownable} from "openzeppelin/access/Ownable.sol";
+import {INotifiableRewardReceiver} from "../interfaces/INotifiableRewardReceiver.sol";
+import {IMintable} from "../interfaces/IMintable.sol";
+import {RewardTokenNotifierBase} from "./RewardTokenNotifierBase.sol";
+import {Ownable} from "@openzeppelin/contracts/access/Ownable.sol";
 
 /// @title MintRewardNotifier
 /// @author [ScopeLift](https://scopelift.co)

src/notifiers/RewardTokenNotifierBase.sol

@@ -1,8 +1,8 @@
 // SPDX-License-Identifier: AGPL-3.0-only
 pragma solidity ^0.8.23;
 
-import {INotifiableRewardReceiver, IERC20} from "src/interfaces/INotifiableRewardReceiver.sol";
-import {Ownable} from "openzeppelin/access/Ownable.sol";
+import {INotifiableRewardReceiver, IERC20} from "../interfaces/INotifiableRewardReceiver.sol";
+import {Ownable} from "@openzeppelin/contracts/access/Ownable.sol";
 
 /// @title RewardTokenNotifierBase
 /// @author [ScopeLift](https://scopelift.co)

src/notifiers/TransferFromRewardNotifier.sol

@@ -1,10 +1,10 @@
 // SPDX-License-Identifier: AGPL-3.0-only
 pragma solidity ^0.8.23;
 
-import {INotifiableRewardReceiver, IERC20} from "src/interfaces/INotifiableRewardReceiver.sol";
-import {RewardTokenNotifierBase} from "src/notifiers/RewardTokenNotifierBase.sol";
-import {Ownable} from "openzeppelin/access/Ownable.sol";
-import {SafeERC20} from "openzeppelin/token/ERC20/utils/SafeERC20.sol";
+import {INotifiableRewardReceiver, IERC20} from "../interfaces/INotifiableRewardReceiver.sol";
+import {RewardTokenNotifierBase} from "../notifiers/RewardTokenNotifierBase.sol";
+import {Ownable} from "@openzeppelin/contracts/access/Ownable.sol";
+import {SafeERC20} from "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
 
 /// @title TransferFromRewardNotifier
 /// @author [ScopeLift](https://scopelift.co)

src/notifiers/TransferRewardNotifier.sol

@@ -1,10 +1,10 @@
 // SPDX-License-Identifier: AGPL-3.0-only
 pragma solidity ^0.8.23;
 
-import {INotifiableRewardReceiver, IERC20} from "src/interfaces/INotifiableRewardReceiver.sol";
-import {RewardTokenNotifierBase} from "src/notifiers/RewardTokenNotifierBase.sol";
-import {Ownable} from "openzeppelin/access/Ownable.sol";
-import {SafeERC20} from "openzeppelin/token/ERC20/utils/SafeERC20.sol";
+import {INotifiableRewardReceiver, IERC20} from "../interfaces/INotifiableRewardReceiver.sol";
+import {RewardTokenNotifierBase} from "../notifiers/RewardTokenNotifierBase.sol";
+import {Ownable} from "@openzeppelin/contracts/access/Ownable.sol";
+import {SafeERC20} from "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
 
 /// @title TransferRewardNotifier
 /// @author [ScopeLift](https://scopelift.co)

script/Deploy.s.sol → src/script/Deploy.s.sol

@@ -3,14 +3,13 @@
 
 pragma solidity ^0.8.23;
 
-import {IERC20} from "openzeppelin/token/ERC20/IERC20.sol";
+import {IERC20} from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
 import {Script} from "forge-std/Script.sol";
 
-import {DeployInput} from "script/DeployInput.sol";
-import {StakerHarness} from "test/harnesses/StakerHarness.sol";
-import {IERC20Staking} from "src/interfaces/IERC20Staking.sol";
-import {INotifiableRewardReceiver} from "src/interfaces/INotifiableRewardReceiver.sol";
-import {IEarningPowerCalculator} from "src/interfaces/IEarningPowerCalculator.sol";
+import {DeployInput} from "./DeployInput.sol";
+import {StakerHarness} from "../../test/harnesses/StakerHarness.sol";
+import {IERC20Staking} from "../interfaces/IERC20Staking.sol";
+import {IEarningPowerCalculator} from "../interfaces/IEarningPowerCalculator.sol";
 
 contract Deploy is Script, DeployInput {
   uint256 deployerPrivateKey;

test/BinaryEligibilityOracleEarningPowerCalculator.t.sol

@@ -5,7 +5,7 @@ import {Test, console2} from "forge-std/Test.sol";
 import {
   BinaryEligibilityOracleEarningPowerCalculator as EarningPowerCalculator,
   Ownable
-} from "src/calculators/BinaryEligibilityOracleEarningPowerCalculator.sol";
+} from "../src/calculators/BinaryEligibilityOracleEarningPowerCalculator.sol";
 
 contract EarningPowerCalculatorTest is Test {
   address public owner;

test/DelegationSurrogate.t.sol

@@ -2,8 +2,8 @@
 pragma solidity ^0.8.23;
 
 import {Test, console2} from "forge-std/Test.sol";
-import {DelegationSurrogateVotes} from "src/DelegationSurrogateVotes.sol";
-import {ERC20VotesMock} from "test/mocks/MockERC20Votes.sol";
+import {DelegationSurrogateVotes} from "../src/DelegationSurrogateVotes.sol";
+import {ERC20VotesMock} from "./mocks/MockERC20Votes.sol";
 
 contract DelegationSurrogateVotesTest is Test {
   ERC20VotesMock govToken;

test/IdentityEarningPowerCalculator.t.sol

@@ -2,7 +2,7 @@
 pragma solidity ^0.8.23;
 
 import {Test} from "forge-std/Test.sol";
-import {IdentityEarningPowerCalculator} from "src/calculators/IdentityEarningPowerCalculator.sol";
+import {IdentityEarningPowerCalculator} from "../src/calculators/IdentityEarningPowerCalculator.sol";
 
 contract IdentityEarningPowerCalculatorTest is Test {
   IdentityEarningPowerCalculator calculator;

test/MintRewardNotifier.t.sol

@@ -2,14 +2,14 @@
 pragma solidity ^0.8.23;
 
 import {Vm, Test, stdStorage, StdStorage, console2, console, stdError} from "forge-std/Test.sol";
-import {MintRewardNotifier, IMintable} from "src/notifiers/MintRewardNotifier.sol";
-import {RewardTokenNotifierBase} from "src/notifiers/RewardTokenNotifierBase.sol";
-import {INotifiableRewardReceiver} from "src/interfaces/INotifiableRewardReceiver.sol";
-import {MockNotifiableRewardReceiver} from "test/mocks/MockNotifiableRewardReceiver.sol";
-import {ERC20VotesMock} from "test/mocks/MockERC20Votes.sol";
-import {FakeMinter} from "test/fakes/FakeMinter.sol";
-import {TestHelpers} from "test/helpers/TestHelpers.sol";
-import {Ownable} from "openzeppelin/access/Ownable.sol";
+import {MintRewardNotifier, IMintable} from "../src/notifiers/MintRewardNotifier.sol";
+import {RewardTokenNotifierBase} from "../src/notifiers/RewardTokenNotifierBase.sol";
+import {INotifiableRewardReceiver} from "../src/interfaces/INotifiableRewardReceiver.sol";
+import {MockNotifiableRewardReceiver} from "./mocks/MockNotifiableRewardReceiver.sol";
+import {ERC20VotesMock} from "./mocks/MockERC20Votes.sol";
+import {FakeMinter} from "./fakes/FakeMinter.sol";
+import {TestHelpers} from "./helpers/TestHelpers.sol";
+import {Ownable} from "@openzeppelin/contracts/access/Ownable.sol";
 
 contract MintRewardNotifierTest is Test, TestHelpers {
   ERC20VotesMock token;