feat: nft bridge from l1 to optimism

.changeset/gentle-shrimps-hug.md

@@ -0,0 +1,5 @@
+---
+'@eth-optimism/contracts-periphery': patch
+---
+
+ERC721 bridge from Eth Mainnet to Optimism

integration-tests/contracts/FakeL2StandardERC721.sol

@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.9;
+
+import { ERC721 } from "@openzeppelin/contracts/token/ERC721/ERC721.sol";
+
+contract FakeL2StandardERC721 is ERC721 {
+
+    address public immutable l1Token;
+    address public immutable l2Bridge;
+
+    constructor(address _l1Token, address _l2Bridge) ERC721("FakeERC721", "FAKE") {
+        l1Token = _l1Token;
+        l2Bridge = _l2Bridge;
+    }
+
+    function mint(address to, uint256 tokenId) public {
+        _mint(to, tokenId);
+    }
+
+    // Burn will be called by the L2 Bridge to burn the NFT we are bridging to L1
+    function burn(address, uint256) external {}
+}

integration-tests/package.json

@@ -29,7 +29,8 @@
   },
   "devDependencies": {
     "@babel/eslint-parser": "^7.5.4",
-    "@eth-optimism/contracts": "0.5.27",
+    "@eth-optimism/contracts": "^0.5.26",
+    "@eth-optimism/contracts-periphery": "^0.1.1",
     "@eth-optimism/core-utils": "0.8.6",
     "@eth-optimism/sdk": "1.1.8",
     "@ethersproject/abstract-provider": "^5.6.1",

integration-tests/test/nft-bridge.spec.ts

@@ -0,0 +1,286 @@
+/* Imports: External */
+import { Contract, ContractFactory, utils, Wallet } from 'ethers'
+import { ethers } from 'hardhat'
+import { predeploys } from '@eth-optimism/contracts'
+import Artifact__TestERC721 from '@eth-optimism/contracts-periphery/artifacts/contracts/testing/helpers/TestERC721.sol/TestERC721.json'
+import Artifact__L1ERC721Bridge from '@eth-optimism/contracts-periphery/artifacts/contracts/L1/messaging/L1ERC721Bridge.sol/L1ERC721Bridge.json'
+import Artifact__L2ERC721Bridge from '@eth-optimism/contracts-periphery/artifacts/contracts/L2/messaging/L2ERC721Bridge.sol/L2ERC721Bridge.json'
+import Artifact__L2StandardERC721Factory from '@eth-optimism/contracts-periphery/artifacts/contracts/L2/messaging/L2StandardERC721Factory.sol/L2StandardERC721Factory.json'
+import Artifact__L2StandardERC721 from '@eth-optimism/contracts-periphery/artifacts/contracts/standards/L2StandardERC721.sol/L2StandardERC721.json'
+
+/* Imports: Internal */
+import { expect } from './shared/setup'
+import { OptimismEnv } from './shared/env'
+import { withdrawalTest } from './shared/utils'
+
+const TOKEN_ID: number = 1
+const FINALIZATION_GAS: number = 1_200_000
+const NON_NULL_BYTES: string = '0x1111'
+
+describe('ERC721 Bridge', () => {
+  let env: OptimismEnv
+  before(async () => {
+    env = await OptimismEnv.new()
+  })
+
+  let aliceWalletL1: Wallet
+  let aliceWalletL2: Wallet
+  let aliceAddress: string
+  let bobWalletL1: Wallet
+  let bobWalletL2: Wallet
+  let bobAddress: string
+  before(async () => {
+    const alice = Wallet.createRandom()
+    aliceWalletL1 = alice.connect(env.l1Wallet.provider)
+    aliceWalletL2 = alice.connect(env.l2Wallet.provider)
+    aliceAddress = aliceWalletL1.address
+
+    const tx = await env.l2Wallet.sendTransaction({
+      to: aliceAddress,
+      value: utils.parseEther('0.01'),
+    })
+    await tx.wait()
+
+    bobWalletL1 = env.l1Wallet
+    bobWalletL2 = env.l2Wallet
+    bobAddress = env.l1Wallet.address
+  })
+
+  let Factory__L1ERC721: ContractFactory
+  let Factory__L1ERC721Bridge: ContractFactory
+  let Factory__L2ERC721Bridge: ContractFactory
+  let Factory__L2StandardERC721Factory: ContractFactory
+  before(async () => {
+    Factory__L1ERC721 = await ethers.getContractFactory(
+      Artifact__TestERC721.abi,
+      Artifact__TestERC721.bytecode,
+      bobWalletL1
+    )
+    Factory__L1ERC721Bridge = await ethers.getContractFactory(
+      Artifact__L1ERC721Bridge.abi,
+      Artifact__L1ERC721Bridge.bytecode,
+      bobWalletL1
+    )
+    Factory__L2ERC721Bridge = await ethers.getContractFactory(
+      Artifact__L2ERC721Bridge.abi,
+      Artifact__L2ERC721Bridge.bytecode,
+      bobWalletL2
+    )
+    Factory__L2StandardERC721Factory = await ethers.getContractFactory(
+      Artifact__L2StandardERC721Factory.abi,
+      Artifact__L2StandardERC721Factory.bytecode,
+      bobWalletL2
+    )
+  })
+
+  let L1ERC721: Contract
+  let L1ERC721Bridge: Contract
+  let L2ERC721Bridge: Contract
+  let L2StandardERC721Factory: Contract
+  let L2StandardERC721: Contract
+  beforeEach(async () => {
+    L1ERC721 = await Factory__L1ERC721.deploy()
+    await L1ERC721.deployed()
+
+    L2ERC721Bridge = await Factory__L2ERC721Bridge.deploy(
+      predeploys.L2CrossDomainMessenger
+    )
+    await L2ERC721Bridge.deployed()
+
+    L1ERC721Bridge = await Factory__L1ERC721Bridge.deploy(
+      env.messenger.contracts.l1.L1CrossDomainMessenger.address,
+      L2ERC721Bridge.address
+    )
+    await L1ERC721Bridge.deployed()
+
+    L2StandardERC721Factory = await Factory__L2StandardERC721Factory.deploy(
+      L2ERC721Bridge.address
+    )
+    await L2StandardERC721Factory.deployed()
+
+    // Create a L2 Standard ERC721 with the Standard ERC721 Factory
+    const tx = await L2StandardERC721Factory.createStandardL2ERC721(
+      L1ERC721.address,
+      'L2ERC721',
+      'L2'
+    )
+    await tx.wait()
+
+    // Retrieve the deployed L2 Standard ERC721
+    const L2StandardERC721Address =
+      await L2StandardERC721Factory.standardERC721Mapping(L1ERC721.address)
+    L2StandardERC721 = await ethers.getContractAt(
+      Artifact__L2StandardERC721.abi,
+      L2StandardERC721Address
+    )
+    await L2StandardERC721.deployed()
+
+    // Initialize the L2 bridge contract
+    const tx1 = await L2ERC721Bridge.initialize(L1ERC721Bridge.address)
+    await tx1.wait()
+
+    // Mint an L1 ERC721 to Bob on L1
+    const tx2 = await L1ERC721.mint(bobAddress, TOKEN_ID)
+    await tx2.wait()
+
+    // Approve the L1 Bridge to operate the NFT
+    const tx3 = await L1ERC721.approve(L1ERC721Bridge.address, TOKEN_ID)
+    await tx3.wait()
+  })
+
+  it('depositERC721', async () => {
+    await env.messenger.waitForMessageReceipt(
+      await L1ERC721Bridge.depositERC721(
+        L1ERC721.address,
+        L2StandardERC721.address,
+        TOKEN_ID,
+        FINALIZATION_GAS,
+        NON_NULL_BYTES
+      )
+    )
+
+    // The L1 Bridge now owns the L1 NFT
+    expect(await L1ERC721.ownerOf(TOKEN_ID)).to.equal(L1ERC721Bridge.address)
+
+    // Bob owns the NFT on L2
+    expect(await L2StandardERC721.ownerOf(TOKEN_ID)).to.equal(bobAddress)
+  })
+
+  it('depositERC721To', async () => {
+    await env.messenger.waitForMessageReceipt(
+      await L1ERC721Bridge.depositERC721To(
+        L1ERC721.address,
+        L2StandardERC721.address,
+        aliceAddress,
+        TOKEN_ID,
+        FINALIZATION_GAS,
+        NON_NULL_BYTES
+      )
+    )
+
+    // The L1 Bridge now owns the L1 NFT
+    expect(await L1ERC721.ownerOf(TOKEN_ID)).to.equal(L1ERC721Bridge.address)
+
+    // Alice owns the NFT on L2
+    expect(await L2StandardERC721.ownerOf(TOKEN_ID)).to.equal(aliceAddress)
+  })
+
+  withdrawalTest('withdrawERC721', async () => {
+    // Deposit an NFT into L2 so that there's something to withdraw
+    await env.messenger.waitForMessageReceipt(
+      await L1ERC721Bridge.depositERC721(
+        L1ERC721.address,
+        L2StandardERC721.address,
+        TOKEN_ID,
+        FINALIZATION_GAS,
+        NON_NULL_BYTES
+      )
+    )
+
+    // First, check that the L1 Bridge now owns the L1 NFT
+    expect(await L1ERC721.ownerOf(TOKEN_ID)).to.equal(L1ERC721Bridge.address)
+
+    // Also check that Bob owns the NFT on L2 initially
+    expect(await L2StandardERC721.ownerOf(TOKEN_ID)).to.equal(bobAddress)
+
+    const tx = await L2ERC721Bridge.withdrawERC721(
+      L2StandardERC721.address,
+      TOKEN_ID,
+      0,
+      NON_NULL_BYTES
+    )
+    await tx.wait()
+    await env.relayXDomainMessages(tx)
+
+    // L1 NFT has been sent back to Bob
+    expect(await L1ERC721.ownerOf(TOKEN_ID)).to.equal(bobAddress)
+
+    // L2 NFT is burned
+    await expect(L2StandardERC721.ownerOf(TOKEN_ID)).to.be.reverted
+  })
+
+  withdrawalTest('withdrawERC721To', async () => {
+    // Deposit an NFT into L2 so that there's something to withdraw
+    await env.messenger.waitForMessageReceipt(
+      await L1ERC721Bridge.depositERC721(
+        L1ERC721.address,
+        L2StandardERC721.address,
+        TOKEN_ID,
+        FINALIZATION_GAS,
+        NON_NULL_BYTES
+      )
+    )
+
+    // First, check that the L1 Bridge now owns the L1 NFT
+    expect(await L1ERC721.ownerOf(TOKEN_ID)).to.equal(L1ERC721Bridge.address)
+
+    // Also check that Bob owns the NFT on L2 initially
+    expect(await L2StandardERC721.ownerOf(TOKEN_ID)).to.equal(bobAddress)
+
+    const tx = await L2ERC721Bridge.withdrawERC721To(
+      L2StandardERC721.address,
+      aliceAddress,
+      TOKEN_ID,
+      0,
+      NON_NULL_BYTES
+    )
+    await tx.wait()
+    await env.relayXDomainMessages(tx)
+
+    // L1 NFT has been sent to Alice
+    expect(await L1ERC721.ownerOf(TOKEN_ID)).to.equal(aliceAddress)
+
+    // L2 NFT is burned
+    await expect(L2StandardERC721.ownerOf(TOKEN_ID)).to.be.reverted
+  })
+
+  withdrawalTest(
+    'should not allow an arbitrary L2 NFT to be withdrawn in exchange for a legitimate L1 NFT',
+    async () => {
+      // First, deposit the legitimate L1 NFT.
+      await env.messenger.waitForMessageReceipt(
+        await L1ERC721Bridge.depositERC721(
+          L1ERC721.address,
+          L2StandardERC721.address,
+          TOKEN_ID,
+          FINALIZATION_GAS,
+          NON_NULL_BYTES
+        )
+      )
+      // Check that the L1 Bridge owns the L1 NFT initially
+      expect(await L1ERC721.ownerOf(TOKEN_ID)).to.equal(L1ERC721Bridge.address)
+
+      // Deploy a fake L2 ERC721, which:
+      // - Returns the address of the legitimate L1 token from its l1Token() getter.
+      // - Allows the L2 bridge to call its burn() function.
+      const FakeL2StandardERC721 = await (
+        await ethers.getContractFactory('FakeL2StandardERC721', bobWalletL2)
+      ).deploy(L1ERC721.address, L2ERC721Bridge.address)
+      await FakeL2StandardERC721.deployed()
+
+      // Use the fake contract to mint Alice an NFT with the same token ID
+      const tx = await FakeL2StandardERC721.mint(aliceAddress, TOKEN_ID)
+      await tx.wait()
+
+      // Check that Alice owns the NFT from the fake ERC721 contract
+      expect(await FakeL2StandardERC721.ownerOf(TOKEN_ID)).to.equal(
+        aliceAddress
+      )
+
+      // Alice withdraws the NFT from the fake contract to L1, hoping to receive the legitimate L1 NFT.
+      const withdrawalTx = await L2ERC721Bridge.connect(
+        aliceWalletL2
+      ).withdrawERC721(
+        FakeL2StandardERC721.address,
+        TOKEN_ID,
+        0,
+        NON_NULL_BYTES
+      )
+      await withdrawalTx.wait()
+      await env.relayXDomainMessages(withdrawalTx)
+
+      // The legitimate NFT on L1 is still held in the bridge.
+      expect(await L1ERC721.ownerOf(TOKEN_ID)).to.equal(L1ERC721Bridge.address)
+    }
+  )
+})