docs: add truffle example + ci (#666)

* docs: add truffle example

* fix: add gasPrice: 0 to all ctc calls and deploys

* chore(truffle-example): use correct truffle command

* fix: install missing packages

* style: fix missing newlines

* fix: attempt to fix yarn.lock (2)

* Update integration.yml

* specify truffle config and network

* correctly specify path and version

* relayer: logging cleanup (#807)

* relayer: don't log options at startup

* chore: add changeset

* relayer: log specifc config options

* config: message relayer (#809)

* relayer: migrate towards prefixed config w/ backwards compat

* chore: update relayer config parsing

* env: use start-offset instead of block offset

* lint: fix

* deps: add bcfg

* message-relayer: cleaner config parsing

* lint: fix

* Version Packages (#833)
Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

* fix: geth miner timestamp bug (#836)

* l2geth: use correct timestamp protection

* chore: add changeset

* Version Packages (#837)
Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

* style: require curly braces for if statements (#835)

* test[integration-tests]: l2geth call and creation OOG (#839)

* fix: WE DID IT
Co-authored-by: Georgios Konstantopoulos <me@gakonst.com>
Co-authored-by: Kelvin Fichter <kelvinfichter@gmail.com>
Co-authored-by: Mark Tyneway <mark.tyneway@gmail.com>
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: ben-chain <ben@pseudonym.party>

.github/workflows/integration.yml

@@ -62,8 +62,23 @@ jobs:
         run: |
           yarn compile
           yarn test:integration
+
       - name: Test & deploy waffle-example on Optimism
         working-directory: ./examples/waffle
         run: |
           yarn compile:ovm
           yarn test:integration:ovm
+
+      - name: Test & deploy truffle-example on truffle (regression)
+        working-directory: ./examples/truffle
+        run: |
+          yarn compile
+          yarn test:integration
+          yarn deploy
+
+      - name: Test & deploy truffle-example on Optimism
+        working-directory: ./examples/truffle
+        run: |
+          yarn compile:ovm
+          yarn test:integration:ovm
+          yarn deploy:ovm

examples/truffle/.gitignore

+# Project specific
+build 
+build-ovm
+
+# Logs
+logs
+*.log
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+lerna-debug.log*
+
+# Diagnostic reports (https://nodejs.org/api/report.html)
+report.[0-9]*.[0-9]*.[0-9]*.[0-9]*.json
+
+# Runtime data
+pids
+*.pid
+*.seed
+*.pid.lock
+
+# Directory for instrumented libs generated by jscoverage/JSCover
+lib-cov
+
+# Coverage directory used by tools like istanbul
+coverage
+*.lcov
+
+# nyc test coverage
+.nyc_output
+
+# Grunt intermediate storage (https://gruntjs.com/creating-plugins#storing-task-files)
+.grunt
+
+# Bower dependency directory (https://bower.io/)
+bower_components
+
+# node-waf configuration
+.lock-wscript
+
+# Compiled binary addons (https://nodejs.org/api/addons.html)
+build/Release
+
+# Dependency directories
+node_modules/
+jspm_packages/
+
+# TypeScript v1 declaration files
+typings/
+
+# TypeScript cache
+*.tsbuildinfo
+
+# Optional npm cache directory
+.npm
+
+# Optional eslint cache
+.eslintcache
+
+# Microbundle cache
+.rpt2_cache/
+.rts2_cache_cjs/
+.rts2_cache_es/
+.rts2_cache_umd/
+
+# Optional REPL history
+.node_repl_history
+
+# Output of 'npm pack'
+*.tgz
+
+# Yarn Integrity file
+.yarn-integrity
+
+# dotenv environment variables file
+.env
+.env.test
+
+# parcel-bundler cache (https://parceljs.org/)
+.cache
+
+# Next.js build output
+.next
+
+# Nuxt.js build / generate output
+.nuxt
+dist
+
+# Gatsby files
+.cache/
+# Comment in the public line in if your project uses Gatsby and *not* Next.js
+# https://nextjs.org/blog/next-9-1#public-directory-support
+# public
+
+# vuepress build output
+.vuepress/dist
+
+# Serverless directories
+.serverless/
+
+# FuseBox cache
+.fusebox/
+
+# DynamoDB Local files
+.dynamodb/
+
+# TernJS port file
+.tern-port
+
+.DS_Store
+
+build/

examples/truffle/README.md

+# Getting Started with Optimistic Ethereum: Simple ERC20 Token Truffle Tutorial
+
+### For the full README, please see the [guided repository, `Truffle-ER20-Example`](https://github.com/ethereum-optimism/Truffle-ERC20-Example)
\ No newline at end of file

examples/truffle/contracts/ERC20.sol

+// SPDX-License-Identifier: MIT LICENSE
+/* Implements ERC20 token standard: https://github.com/ethereum/EIPs/blob/master/EIPS/eip-20.md */
+pragma solidity ^0.7.6;
+
+import "./IERC20.sol";
+
+contract ERC20 is IERC20 {
+    uint256 private constant MAX_UINT256 = 2**256 - 1;
+    mapping(address => uint256) public balances;
+    mapping(address => mapping(address => uint256)) public allowed;
+    /*
+    NOTE:
+    The following variables are OPTIONAL vanities. One does not have to include them.
+    They allow one to customise the token contract & in no way influences the core functionality.
+    Some wallets/interfaces might not even bother to look at this information.
+    */
+    string public name;
+    uint8 public decimals;
+    string public symbol;
+    uint256 public totalSupply;
+
+    constructor(
+        uint256 _initialAmount,
+        string memory _tokenName,
+        uint8 _decimalUnits,
+        string memory _tokenSymbol
+    ) {
+        balances[msg.sender] = _initialAmount; // Give the creator all initial tokens
+        totalSupply = _initialAmount; // Update total supply
+        name = _tokenName; // Set the name for display purposes
+        decimals = _decimalUnits; // Amount of decimals for display purposes
+        symbol = _tokenSymbol; // Set the symbol for display purposes
+    }
+
+    function transfer(address _to, uint256 _value)
+        public
+        override
+        returns (bool success)
+    {
+        require(balances[msg.sender] >= _value);
+        balances[msg.sender] -= _value;
+        balances[_to] += _value;
+        emit Transfer(msg.sender, _to, _value); //solhint-disable-line indent, no-unused-vars
+        return true;
+    }
+
+    function transferFrom(
+        address _from,
+        address _to,
+        uint256 _value
+    ) public override returns (bool success) {
+        uint256 allowance_ = allowed[_from][msg.sender];
+        require(balances[_from] >= _value && allowance_ >= _value);
+        balances[_to] += _value;
+        balances[_from] -= _value;
+        if (allowance_ < MAX_UINT256) {
+            allowed[_from][msg.sender] -= _value;
+        }
+        emit Transfer(_from, _to, _value); //solhint-disable-line indent, no-unused-vars
+        return true;
+    }
+
+    function balanceOf(address _owner)
+        public
+        view
+        override
+        returns (uint256 balance)
+    {
+        return balances[_owner];
+    }
+
+    function approve(address _spender, uint256 _value)
+        public
+        override
+        returns (bool success)
+    {
+        allowed[msg.sender][_spender] = _value;
+        emit Approval(msg.sender, _spender, _value); //solhint-disable-line indent, no-unused-vars
+        return true;
+    }
+
+    function allowance(address _owner, address _spender)
+        public
+        view
+        override
+        returns (uint256 remaining)
+    {
+        return allowed[_owner][_spender];
+    }
+}

examples/truffle/contracts/IERC20.sol

+// SPDX-License-Identifier: MIT LICENSE
+// Abstract contract for the full ERC20 Token standard
+// https://github.com/ethereum/EIPs/blob/master/EIPS/eip-20.md
+pragma solidity ^0.7.6;
+
+interface IERC20 {
+    /// @param _owner The address from which the balance will be retrieved
+    /// @return balance The balance
+    function balanceOf(address _owner) external view returns (uint256 balance);
+
+    /// @notice send `_value` token to `_to` from `msg.sender`
+    /// @param _to The address of the recipient
+    /// @param _value The amount of token to be transferred
+    /// @return success Whether the transfer was successful or not
+    function transfer(address _to, uint256 _value)
+        external
+        returns (bool success);
+
+    /// @notice send `_value` token to `_to` from `_from` on the condition it is approved by `_from`
+    /// @param _from The address of the sender
+    /// @param _to The address of the recipient
+    /// @param _value The amount of token to be transferred
+    /// @return success Whether the transfer was successful or not
+    function transferFrom(
+        address _from,
+        address _to,
+        uint256 _value
+    ) external returns (bool success);
+
+    /// @notice `msg.sender` approves `_spender` to spend `_value` tokens
+    /// @param _spender The address of the account able to transfer the tokens
+    /// @param _value The amount of tokens to be approved for transfer
+    /// @return success Whether the approval was successful or not
+    function approve(address _spender, uint256 _value)
+        external
+        returns (bool success);
+
+    /// @param _owner The address of the account owning tokens
+    /// @param _spender The address of the account able to transfer the tokens
+    /// @return remaining Amount of remaining tokens allowed to spent
+    function allowance(address _owner, address _spender)
+        external
+        view
+        returns (uint256 remaining);
+
+    // solhint-disable-next-line no-simple-event-func-name
+    event Transfer(address indexed _from, address indexed _to, uint256 _value);
+    event Approval(
+        address indexed _owner,
+        address indexed _spender,
+        uint256 _value
+    );
+}

examples/truffle/migrations/1_deploy_ERC20_contract.js

+const ERC20 = artifacts.require('ERC20')
+
+module.exports = function (deployer, accounts) {
+  const tokenName = 'My Optimistic Coin'
+  const tokenSymbol = 'OPT'
+  const tokenDecimals = 1
+
+  // deployment steps
+  deployer.deploy(
+    ERC20,
+    10000,
+    tokenName,
+    tokenDecimals,
+    tokenSymbol,
+    { gasPrice: 0 }
+  )
+}

examples/truffle/package.json

+{
+  "name": "@ethereum-optimism/Truffle-ERC20-Example",
+  "private": true,
+  "version": "1.0.0-alpha.1",
+  "description": "Example of using Optimistic Ethereum compiler & local Optimistic Ethereum nodes with Truffle to run a full ERC20 test suite",
+  "scripts": {
+    "clean": "rimraf build build-ovm",
+    "compile": "truffle compile",
+    "compile:ovm": "truffle compile --config truffle-config-ovm.js",
+    "test:integration": "truffle test",
+    "test:integration:ovm": "truffle test --network optimism --config truffle-config-ovm.js",
+    "deploy": "truffle migrate --network ethereum --config truffle-config",
+    "deploy:ovm": "truffle migrate --network optimism --config truffle-config-ovm.js"
+  },
+  "keywords": [
+    "optimism",
+    "rollup",
+    "optimistic",
+    "ethereum",
+    "truffle",
+    "ovm",
+    "example",
+    "ERC20",
+    "token"
+  ],
+  "homepage": "https://github.com/ethereum-optimism/Truffle-ERC20-Example#readme",
+  "license": "MIT",
+  "author": "Optimism PBC",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/ethereum-optimism/Truffle-ERC20-Example.git"
+  },
+  "publishConfig": {
+    "access": "public"
+  },
+  "dependencies": {
+    "@eth-optimism/solc": "0.7.6-alpha.1",
+    "rimraf": "^3.0.2",
+    "truffle": "^5.3.6",
+    "@truffle/hdwallet-provider": "^1.4.0"
+  }
+}
\ No newline at end of file

examples/truffle/test/erc20.spec.js

+let token
+
+const ERC20 = artifacts.require('ERC20')
+
+contract('ERC20', (accounts) => {
+  const tokenName = 'My Optimistic Coin'
+  const tokenSymbol = 'OPT'
+  const tokenDecimals = 1
+
+  beforeEach(async () => {
+    token = await ERC20.new(10000, tokenName, tokenDecimals, tokenSymbol, { from: accounts[ 0 ], gasPrice: 0 })
+  })
+
+  it('creation: should create an initial balance of 10000 for the creator', async () => {
+    const balance = await token.balanceOf.call(accounts[ 0 ], {
+      gasPrice: 0
+    })
+    assert.strictEqual(balance.toNumber(), 10000)
+  })
+
+  it('creation: test correct setting of vanity information', async () => {
+    const name = await token.name.call()
+    assert.strictEqual(name, tokenName)
+
+    const decimals = await token.decimals.call()
+    assert.strictEqual(decimals.toNumber(), tokenDecimals)
+
+    const symbol = await token.symbol.call()
+    assert.strictEqual(symbol, tokenSymbol)
+  })
+
+  it('creation: should succeed in creating over 2^256 - 1 (max) tokens', async () => {
+    // 2^256 - 1
+    const token2 = await ERC20.new('115792089237316195423570985008687907853269984665640564039457584007913129639935', 'Simon Bucks', 1, 'SBX', { from: accounts[ 0 ], gasPrice: 0 })
+    const totalSupply = await token2.totalSupply()
+    assert.strictEqual(totalSupply.toString(), '115792089237316195423570985008687907853269984665640564039457584007913129639935')
+  })
+
+  // TRANSERS
+  // normal transfers without approvals
+  it('transfers: ether transfer should be reversed.', async () => {
+    const balanceBefore = await token.balanceOf.call(accounts[ 0 ])
+    assert.strictEqual(balanceBefore.toNumber(), 10000)
+
+    let threw = false
+    try {
+      await web3.eth.sendTransaction({ from: accounts[ 0 ], to: token.address, value: web3.utils.toWei('10', 'Ether'), gasPrice: 0 })
+    } catch (e) {
+      threw = true
+    }
+    assert.equal(threw, true)
+
+    const balanceAfter = await token.balanceOf.call(accounts[ 0 ])
+    assert.strictEqual(balanceAfter.toNumber(), 10000)
+  })
+
+  it('transfers: should transfer 10000 to accounts[1] with accounts[0] having 10000', async () => {
+    await token.transfer(accounts[ 1 ], 10000, { from: accounts[ 0 ], gasPrice: 0 })
+    const balance = await token.balanceOf.call(accounts[ 1 ])
+    assert.strictEqual(balance.toNumber(), 10000)
+  })
+
+  it('transfers: should fail when trying to transfer 10001 to accounts[1] with accounts[0] having 10000', async () => {
+    let threw = false
+    try {
+      await token.transfer.call(accounts[ 1 ], 10001, { from: accounts[ 0 ], gasPrice: 0 })
+    } catch (e) {
+      threw = true
+    }
+    assert.equal(threw, true)
+  })
+
+  it('transfers: should handle zero-transfers normally', async () => {
+    assert(await token.transfer.call(accounts[ 1 ], 0, { from: accounts[ 0 ], gasPrice: 0 }), 'zero-transfer has failed')
+  })
+
+  // NOTE: testing uint256 wrapping is impossible since you can't supply > 2^256 -1
+  // todo: transfer max amounts
+
+  // APPROVALS
+  it('approvals: msg.sender should approve 100 to accounts[1]', async () => {
+    await token.approve(accounts[ 1 ], 100, { from: accounts[ 0 ], gasPrice: 0 })
+    const allowance = await token.allowance.call(accounts[ 0 ], accounts[ 1 ])
+    assert.strictEqual(allowance.toNumber(), 100)
+  })
+
+  // bit overkill. But is for testing a bug
+  it('approvals: msg.sender approves accounts[1] of 100 & withdraws 20 once.', async () => {
+    const balance0 = await token.balanceOf.call(accounts[ 0 ])
+    assert.strictEqual(balance0.toNumber(), 10000)
+
+    await token.approve(accounts[ 1 ], 100, { from: accounts[ 0 ], gasPrice: 0 }) // 100
+    const balance2 = await token.balanceOf.call(accounts[ 2 ])
+    assert.strictEqual(balance2.toNumber(), 0, 'balance2 not correct')
+
+    await token.transferFrom.call(accounts[ 0 ], accounts[ 2 ], 20, { from: accounts[ 1 ], gasPrice: 0 })
+    await token.allowance.call(accounts[ 0 ], accounts[ 1 ])
+    await token.transferFrom(accounts[ 0 ], accounts[ 2 ], 20, { from: accounts[ 1 ], gasPrice: 0 }) // -20
+    const allowance01 = await token.allowance.call(accounts[ 0 ], accounts[ 1 ])
+    assert.strictEqual(allowance01.toNumber(), 80) // =80
+
+    const balance22 = await token.balanceOf.call(accounts[ 2 ])
+    assert.strictEqual(balance22.toNumber(), 20)
+
+    const balance02 = await token.balanceOf.call(accounts[ 0 ])
+    assert.strictEqual(balance02.toNumber(), 9980)
+  })
+
+  // should approve 100 of msg.sender & withdraw 50, twice. (should succeed)
+  it('approvals: msg.sender approves accounts[1] of 100 & withdraws 20 twice.', async () => {
+    await token.approve(accounts[ 1 ], 100, { from: accounts[ 0 ], gasPrice: 0 })
+    const allowance01 = await token.allowance.call(accounts[ 0 ], accounts[ 1 ])
+    assert.strictEqual(allowance01.toNumber(), 100)
+
+    await token.transferFrom(accounts[ 0 ], accounts[ 2 ], 20, { from: accounts[ 1 ], gasPrice: 0 })
+    const allowance012 = await token.allowance.call(accounts[ 0 ], accounts[ 1 ])
+    assert.strictEqual(allowance012.toNumber(), 80)
+
+    const balance2 = await token.balanceOf.call(accounts[ 2 ])
+    assert.strictEqual(balance2.toNumber(), 20)
+
+    const balance0 = await token.balanceOf.call(accounts[ 0 ])
+    assert.strictEqual(balance0.toNumber(), 9980)
+
+    // FIRST tx done.
+    // onto next.
+    await token.transferFrom(accounts[ 0 ], accounts[ 2 ], 20, { from: accounts[ 1 ], gasPrice: 0 })
+    const allowance013 = await token.allowance.call(accounts[ 0 ], accounts[ 1 ])
+    assert.strictEqual(allowance013.toNumber(), 60)
+
+    const balance22 = await token.balanceOf.call(accounts[ 2 ])
+    assert.strictEqual(balance22.toNumber(), 40)
+
+    const balance02 = await token.balanceOf.call(accounts[ 0 ])
+    assert.strictEqual(balance02.toNumber(), 9960)
+  })
+
+  // should approve 100 of msg.sender & withdraw 50 & 60 (should fail).
+  it('approvals: msg.sender approves accounts[1] of 100 & withdraws 50 & 60 (2nd tx should fail)', async () => {
+    await token.approve(accounts[ 1 ], 100, { from: accounts[ 0 ], gasPrice: 0 })
+    const allowance01 = await token.allowance.call(accounts[ 0 ], accounts[ 1 ])
+    assert.strictEqual(allowance01.toNumber(), 100)
+
+    await token.transferFrom(accounts[ 0 ], accounts[ 2 ], 50, { from: accounts[ 1 ], gasPrice: 0 })
+    const allowance012 = await token.allowance.call(accounts[ 0 ], accounts[ 1 ])
+    assert.strictEqual(allowance012.toNumber(), 50)
+
+    const balance2 = await token.balanceOf.call(accounts[ 2 ])
+    assert.strictEqual(balance2.toNumber(), 50)
+
+    const balance0 = await token.balanceOf.call(accounts[ 0 ])
+    assert.strictEqual(balance0.toNumber(), 9950)
+
+    // FIRST tx done.
+    // onto next.
+    let threw = false
+    try {
+      await token.transferFrom.call(accounts[ 0 ], accounts[ 2 ], 60, { from: accounts[ 1 ], gasPrice: 0 })
+    } catch (e) {
+      threw = true
+    }
+    assert.equal(threw, true)
+  })
+
+  it('approvals: attempt withdrawal from account with no allowance (should fail)', async () => {
+    let threw = false
+    try {
+      await token.transferFrom.call(accounts[ 0 ], accounts[ 2 ], 60, { from: accounts[ 1 ], gasPrice: 0 })
+    } catch (e) {
+      threw = true
+    }
+    assert.equal(threw, true)
+  })
+
+  it('approvals: allow accounts[1] 100 to withdraw from accounts[0]. Withdraw 60 and then approve 0 & attempt transfer.', async () => {
+    await token.approve(accounts[ 1 ], 100, { from: accounts[ 0 ], gasPrice: 0 })
+    await token.transferFrom(accounts[ 0 ], accounts[ 2 ], 60, { from: accounts[ 1 ], gasPrice: 0 })
+    await token.approve(accounts[ 1 ], 0, { from: accounts[ 0 ], gasPrice: 0 })
+    let threw = false
+    try {
+      await token.transferFrom.call(accounts[ 0 ], accounts[ 2 ], 10, { from: accounts[ 1 ], gasPrice: 0 })
+    } catch (e) {
+      threw = true
+    }
+    assert.equal(threw, true)
+  })
+
+  it('approvals: approve max (2^256 - 1)', async () => {
+    await token.approve(accounts[ 1 ], '115792089237316195423570985008687907853269984665640564039457584007913129639935', { from: accounts[ 0 ], gasPrice: 0 })
+    const allowance = await token.allowance(accounts[ 0 ], accounts[ 1 ])
+    assert.strictEqual(allowance.toString(), '115792089237316195423570985008687907853269984665640564039457584007913129639935')
+  })
+
+  // should approve max of msg.sender & withdraw 20 without changing allowance (should succeed).
+  it('approvals: msg.sender approves accounts[1] of max (2^256 - 1) & withdraws 20', async () => {
+    const balance0 = await token.balanceOf.call(accounts[ 0 ])
+    assert.strictEqual(balance0.toNumber(), 10000)
+
+    const max = '115792089237316195423570985008687907853269984665640564039457584007913129639935'
+    await token.approve(accounts[ 1 ], max, { from: accounts[ 0 ], gasPrice: 0 })
+    const balance2 = await token.balanceOf.call(accounts[ 2 ])
+    assert.strictEqual(balance2.toNumber(), 0, 'balance2 not correct')
+
+    await token.transferFrom(accounts[ 0 ], accounts[ 2 ], 20, { from: accounts[ 1 ], gasPrice: 0 })
+    const allowance01 = await token.allowance.call(accounts[ 0 ], accounts[ 1 ])
+    assert.strictEqual(allowance01.toString(), max)
+
+    const balance22 = await token.balanceOf.call(accounts[ 2 ])
+    assert.strictEqual(balance22.toNumber(), 20)
+
+    const balance02 = await token.balanceOf.call(accounts[ 0 ])
+    assert.strictEqual(balance02.toNumber(), 9980)
+  })
+
+  /* eslint-disable no-underscore-dangle */
+  it('events: should fire Transfer event properly', async () => {
+    const res = await token.transfer(accounts[ 1 ], '2666', { from: accounts[ 0 ], gasPrice: 0 })
+    const transferLog = res.logs.find(
+      element => element.event.match('Transfer') &&
+        element.address.match(token.address)
+    )
+    assert.strictEqual(transferLog.args._from, accounts[ 0 ])
+    // L2 ETH transfer also emits a transfer event
+    assert.strictEqual(transferLog.args._to, accounts[ 1 ])
+    assert.strictEqual(transferLog.args._value.toString(), '2666')
+  })
+
+  it('events: should fire Transfer event normally on a zero transfer', async () => {
+    const res = await token.transfer(accounts[ 1 ], '0', { from: accounts[ 0 ], gasPrice: 0 })
+    const transferLog = res.logs.find(
+      element => element.event.match('Transfer') &&
+        element.address.match(token.address)
+    )
+    assert.strictEqual(transferLog.args._from, accounts[ 0 ])
+    assert.strictEqual(transferLog.args._to, accounts[ 1 ])
+    assert.strictEqual(transferLog.args._value.toString(), '0')
+  })
+
+  it('events: should fire Approval event properly', async () => {
+    const res = await token.approve(accounts[ 1 ], '2666', { from: accounts[ 0 ], gasPrice: 0 })
+    const approvalLog = res.logs.find(element => element.event.match('Approval'))
+    assert.strictEqual(approvalLog.args._owner, accounts[ 0 ])
+    assert.strictEqual(approvalLog.args._spender, accounts[ 1 ])
+    assert.strictEqual(approvalLog.args._value.toString(), '2666')
+  })
+})

examples/truffle/truffle-config-ovm.js

+const mnemonicPhrase = "candy maple cake sugar pudding cream honey rich smooth crumble sweet treat"
+const HDWalletProvider = require('@truffle/hdwallet-provider')
+
+module.exports = {
+  contracts_build_directory: './build-ovm',
+  networks: {
+    optimism: {
+      provider: function () {
+        return new HDWalletProvider({
+          mnemonic: {
+            phrase: mnemonicPhrase
+          },
+          providerOrUrl: 'http://127.0.0.1:8545'
+        })
+      },
+      network_id: 420,
+      host: '127.0.0.1',
+      port: 8545,
+      gasPrice: 0,
+    }
+  },
+  compilers: {
+    solc: {
+      // Add path to the optimism solc fork
+      version: '../../node_modules/@eth-optimism/solc',
+      settings: {
+        optimizer: {
+          enabled: true,
+          runs: 1
+        },
+      }
+    }
+  }
+}
\ No newline at end of file

examples/truffle/truffle-config.js

+module.exports = {
+  contracts_build_directory: './build',
+  networks: {
+    ethereum: {
+      network_id: 31337,
+      host: '127.0.0.1',
+      port: 9545,
+      gasPrice: 0,
+    },
+  },
+  // Configure your compilers
+  compilers: {
+    solc: {
+      version: "0.7.6",    // Fetch exact version from solc-bin (default: truffle's version)
+    }
+  }
+}