feat: add contract for ERC20KavaWrappedNativeCoin (#1594)

* setup empty hardhat project for evm contract dev

* setup eslint

* setup prettier

* setup solhint

* ignore contracts dir in docker

* add ERC20KavaWrappedNativeCoin contract

* add unit tests for ERC20KavaWrappedNativeCoin

* use solidity 0.8.18

* configure solc with optimization and evm target

* compile ERC20KavaWrappedNativeCoin for evmutil

* setup script for deploying directly to a network

* fix burn test for ERC20KavaWrappedNativeCoin

Co-authored-by: drklee3 <derrick@dlee.dev>

---------

Co-authored-by: drklee3 <derrick@dlee.dev>

.dockerignore

@@ -3,6 +3,7 @@ out/
 .git/
 docs/
 tests/
+contracts/
 
 go.work
 go.work.sum

.tool-versions

@@ -1 +1,2 @@
 golang 1.20
+nodejs 18.16.0

contracts/.eslintignore

@@ -0,0 +1,4 @@
+node_modules
+artifacts
+cache
+coverage

contracts/.eslintrc.cjs

@@ -0,0 +1,10 @@
+module.exports = {
+  extends: [
+    "eslint:recommended",
+    "plugin:@typescript-eslint/recommended",
+    "plugin:prettier/recommended",
+  ],
+  parser: "@typescript-eslint/parser",
+  plugins: ["@typescript-eslint"],
+  root: true,
+};

contracts/.gitignore

@@ -0,0 +1,11 @@
+node_modules
+.env
+coverage
+coverage.json
+typechain
+typechain-types
+
+# Hardhat files
+cache
+artifacts
+

contracts/.prettierignore

@@ -0,0 +1,6 @@
+node_modules
+package-lock.json
+
+artifacts
+cache
+coverage*

contracts/.solhint.json

@@ -0,0 +1,7 @@
+{
+  "extends": "solhint:recommended",
+  "rules": {
+    "compiler-version": ["error", "^0.8.0"],
+    "func-visibility": ["warn", { "ignoreConstructors": true }]
+  }
+}

contracts/.solhintignore

@@ -0,0 +1 @@
+node_modules

contracts/README.md

@@ -0,0 +1,45 @@
+# Kava EVM contracts
+
+Contracts for the Kava EVM used by the Kava blockchain.
+Includes an ERC20 contract for wrapping native cosmos sdk.Coins.
+
+## Setup
+
+```
+npm install
+```
+
+## Test
+
+```
+npm test
+```
+
+## Development
+
+```
+# Watch contract + tests
+npm run dev
+
+# Watch tests only
+npm run test-watch
+```
+
+## Deploying contracts to test networks
+
+A deploy script is included in this hardhat project to deploy a contract directly to a network.
+To deploy the contracts to different networks:
+```
+npx hardhat run --network <network-name> scripts/deploy.ts
+```
+
+Configuration for various `<network-name>`s above are setup in the [hardhat config](./hardhat.config.ts).
+
+## Production compiling & Ethermint JSON
+
+Ethermint uses its own json format that includes the ABI and bytecode in a single file. The bytecode should have no `0x` prefix and should be under the property name `bin`. This structure is built from the compiled code with `npm ethermint-json`.
+
+The following compiles the contract, builds the ethermint json and copies the file to the evmutil:
+```
+npm build
+```

contracts/contracts/ERC20KavaWrappedNativeCoin.sol

@@ -0,0 +1,46 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.18;
+
+import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
+import "@openzeppelin/contracts/access/Ownable.sol";
+
+/// @title An ERC20 token contract owned and deployed by the evmutil module of Kava.
+///        Tokens are backed one-for-one by sdk coins held in the module account.
+/// @author Kava Labs, LLC
+/// @custom:security-contact security@kava.io
+contract ERC20KavaWrappedNativeCoin is ERC20, Ownable {
+    /// @notice The decimals places of the token. For display purposes only.
+    uint8 private immutable _decimals;
+
+    /// @notice Registers the ERC20 token with mint and burn permissions for the
+    ///         contract owner, by default the account that deploys this contract.
+    /// @param name The name of the ERC20 token.
+    /// @param symbol The symbol of the ERC20 token.
+    /// @param decimals_ The number of decimals of the ERC20 token.
+    constructor(
+        string memory name,
+        string memory symbol,
+        uint8 decimals_
+    ) ERC20(name, symbol) {
+        _decimals = decimals_;
+    }
+
+    /// @notice Query the decimal places of the token for display purposes.
+    function decimals() public view override returns (uint8) {
+        return _decimals;
+    }
+
+    /// @notice Mints new tokens to an address. Can only be called by token owner.
+    /// @param to Address to which new tokens are minted.
+    /// @param amount Number of tokens to mint.
+    function mint(address to, uint256 amount) public onlyOwner {
+        _mint(to, amount);
+    }
+
+    /// @notice Burns tokens from an address. Can only be called by token owner.
+    /// @param from Address from which tokens are burned.
+    /// @param amount Number of tokens to burn.
+    function burn(address from, uint256 amount) public onlyOwner {
+        _burn(from, amount);
+    }
+}

contracts/hardhat.config.ts

@@ -0,0 +1,41 @@
+import { HardhatUserConfig } from "hardhat/config";
+import "@nomicfoundation/hardhat-toolbox";
+
+const config: HardhatUserConfig = {
+  solidity: {
+    version: "0.8.18",
+    settings: {
+      // istanbul upgrade occurred before the london hardfork, so is compatible with kava's evm
+      evmVersion: "istanbul",
+      // optimize build for deployment to mainnet!
+      optimizer: {
+        enabled: true,
+        runs: 1000,
+      },
+    },
+  },
+  networks: {
+    // kvtool's local network
+    kava: {
+      url: "http://127.0.0.1:8545",
+      accounts: [
+        // kava keys unsafe-export-eth-key whale2
+        "AA50F4C6C15190D9E18BF8B14FC09BFBA0E7306331A4F232D10A77C2879E7966",
+      ],
+    },
+    protonet: {
+      url: "https://evm.app.protonet.us-east.production.kava.io:443",
+      accounts: [
+        "247069F0BC3A5914CB2FD41E4133BBDAA6DBED9F47A01B9F110B5602C6E4CDD9",
+      ],
+    },
+    internal_testnet: {
+      url: "https://evm.data.internal.testnet.us-east.production.kava.io:443",
+      accounts: [
+        "247069F0BC3A5914CB2FD41E4133BBDAA6DBED9F47A01B9F110B5602C6E4CDD9",
+      ],
+    },
+  },
+};
+
+export default config;

contracts/package.json

@@ -0,0 +1,39 @@
+{
+  "name": "kava-contracts",
+  "version": "0.0.1",
+  "author": "Kava Labs",
+  "private": true,
+  "description": "Solidity contracts for Kava Blockchain",
+  "engines": {
+    "node": ">=18.0.0"
+  },
+  "scripts": {
+    "build": "npm run clean && npm run compile && npm run ethermint-json",
+    "clean": "hardhat clean",
+    "compile": "hardhat compile",
+    "coverage": "hardhat coverage",
+    "ethermint-json": "jq '{ abi: .abi | tostring, bin: .bytecode | ltrimstr(\"0x\")}' artifacts/contracts/ERC20KavaWrappedNativeCoin.sol/ERC20KavaWrappedNativeCoin.json > ../x/evmutil/types/ethermint_json/ERC20KavaWrappedNativeCoin.json",
+    "gen-ts-types": "hardhat typechain",
+    "lint": "eslint '**/*.{js,ts}'",
+    "lint-fix": "eslint '**/*.{js,ts}' --fix",
+    "prettier": "prettier '**/*.{json,sol,md}' --check",
+    "prettier-fix": "prettier '**/*.{json,sol,md}' --write",
+    "solhint": "solhint 'contracts/**/*.sol' --max-warnings 0",
+    "solhint-fix": "solhint 'contracts/**/*.sol' --fix",
+    "test": "hardhat test"
+  },
+  "devDependencies": {
+    "@nomicfoundation/hardhat-toolbox": "^2.0.2",
+    "@openzeppelin/contracts": "4.8.3",
+    "@typescript-eslint/eslint-plugin": "^5.59.6",
+    "@typescript-eslint/parser": "^5.59.6",
+    "eslint": "^8.40.0",
+    "eslint-config-prettier": "8.8.0",
+    "eslint-plugin-prettier": "^4.2.1",
+    "hardhat": "^2.14.0",
+    "prettier": "2.8.8",
+    "prettier-plugin-solidity": "^1.1.3",
+    "solhint": "^3.4.1",
+    "typescript": "^5.0.4"
+  }
+}

contracts/scripts/deploy.ts

@@ -0,0 +1,27 @@
+import { ethers } from "hardhat";
+
+async function main() {
+  const tokenName = "Kava-wrapped ATOM";
+  const tokenSymbol = "kATOM";
+  const tokenDecimals = 6;
+
+  const ERC20KavaWrappedNativeCoin = await ethers.getContractFactory(
+    "ERC20KavaWrappedNativeCoin"
+  );
+  const token = await ERC20KavaWrappedNativeCoin.deploy(
+    tokenName,
+    tokenSymbol,
+    tokenDecimals
+  );
+
+  await token.deployed();
+
+  console.log(
+    `Token "${tokenName}" (${tokenSymbol}) with ${tokenDecimals} decimals is deployed to ${token.address}!`
+  );
+}
+
+main().catch((error) => {
+  console.error(error);
+  process.exitCode = 1;
+});

contracts/test/ERC20KavaWrappedNativeCoin.test.ts

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+import { expect } from "chai";
+import { Signer } from "ethers";
+import { ethers } from "hardhat";
+import {
+  ERC20KavaWrappedNativeCoin,
+  ERC20KavaWrappedNativeCoin__factory as ERC20KavaWrappedNativeCoinFactory,
+} from "../typechain-types";
+
+const decimals = 6n;
+
+describe("ERC20KavaWrappedNativeCoin", function () {
+  let erc20: ERC20KavaWrappedNativeCoin;
+  let erc20Factory: ERC20KavaWrappedNativeCoinFactory;
+  let owner: Signer;
+  let sender: Signer;
+
+  beforeEach(async function () {
+    erc20Factory = await ethers.getContractFactory(
+      "ERC20KavaWrappedNativeCoin"
+    );
+    erc20 = await erc20Factory.deploy("Wrapped ATOM", "ATOM", decimals);
+    [owner, sender] = await ethers.getSigners();
+  });
+
+  describe("decimals", function () {
+    it("should be the same as deployed", async function () {
+      expect(await erc20.decimals()).to.be.equal(decimals);
+    });
+  });
+
+  describe("mint", function () {
+    it("should reject non-owner", async function () {
+      const tx = erc20.connect(sender).mint(await sender.getAddress(), 10n);
+      await expect(tx).to.be.revertedWith("Ownable: caller is not the owner");
+    });
+
+    it("should be callable by owner", async function () {
+      const amount = 10n;
+
+      const tx = erc20.connect(owner).mint(await sender.getAddress(), amount);
+      await expect(tx).to.not.be.reverted;
+
+      const bal = await erc20.balanceOf(await sender.getAddress());
+      expect(bal).to.equal(amount);
+    });
+  });
+
+  describe("burn", function () {
+    it("should reject non-owner", async function () {
+      const tx = erc20.connect(sender).burn(await sender.getAddress(), 10n);
+      await expect(tx).to.be.revertedWith("Ownable: caller is not the owner");
+    });
+
+    it("should let owner burn some of the tokens", async function () {
+      const amount = 10n;
+
+      // give tokens to an account
+      const fundTx = erc20
+        .connect(owner)
+        .mint(await sender.getAddress(), amount);
+      await expect(fundTx).to.not.be.reverted;
+      const balBefore = await erc20.balanceOf(await sender.getAddress());
+      expect(balBefore).to.equal(amount);
+
+      // burn the tokens!
+      const burnTx = erc20
+        .connect(owner)
+        .burn(await sender.getAddress(), amount);
+      await expect(burnTx).to.not.be.reverted;
+      const balAfter = await erc20.balanceOf(await sender.getAddress());
+      expect(balAfter).to.equal(0);
+    });
+
+    it("should let owner burn all the tokens", async function () {
+      const amount = 10n;
+
+      // give tokens to an account
+      const fundTx = erc20
+        .connect(owner)
+        .mint(await sender.getAddress(), amount);
+      await expect(fundTx).to.not.be.reverted;
+      const balBefore = await erc20.balanceOf(await sender.getAddress());
+      expect(balBefore).to.equal(amount);
+
+      // burn the tokens!
+      const burnAmount = 7n;
+      const burnTx = erc20
+        .connect(owner)
+        .burn(await sender.getAddress(), burnAmount);
+      await expect(burnTx).to.not.be.reverted;
+      const balAfter = await erc20.balanceOf(await sender.getAddress());
+      expect(balAfter).to.equal(amount - burnAmount);
+    });
+
+    it("should error when trying to burn more than balance", async function () {
+      const amount = 10n;
+
+      // give tokens to an account
+      const fundTx = erc20
+        .connect(owner)
+        .mint(await sender.getAddress(), amount);
+      await expect(fundTx).to.not.be.reverted;
+      const balBefore = await erc20.balanceOf(await sender.getAddress());
+      expect(balBefore).to.equal(amount);
+
+      // burn the tokens!
+      const burnAmount = amount + 1n;
+      const burnTx = erc20
+        .connect(owner)
+        .burn(await sender.getAddress(), burnAmount);
+      await expect(burnTx).to.be.revertedWith(
+        "ERC20: burn amount exceeds balance"
+      );
+    });
+  });
+});

contracts/tsconfig.json

@@ -0,0 +1,11 @@
+{
+  "compilerOptions": {
+    "target": "es2020",
+    "module": "commonjs",
+    "esModuleInterop": true,
+    "forceConsistentCasingInFileNames": true,
+    "strict": true,
+    "skipLibCheck": true,
+    "resolveJsonModule": true
+  }
+}