🏛️ 第21课：DAO治理

治理与未来 阶段五 ✅ 验证通过

📖 一、什么是DAO？

DAO = Decentralized Autonomous Organization（去中心化自治组织）

📖 二、治理流程

📖 三、使用OpenZeppelin Governor

// contracts/MyGovernor.sol
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.24;

import "@openzeppelin/contracts/governance/Governor.sol";
import "@openzeppelin/contracts/governance/extensions/GovernorSettings.sol";
import "@openzeppelin/contracts/governance/extensions/GovernorCountingSimple.sol";
import "@openzeppelin/contracts/governance/extensions/GovernorVotes.sol";
import "@openzeppelin/contracts/governance/extensions/GovernorVotesQuorumFraction.sol";
import "@openzeppelin/contracts/governance/extensions/GovernorTimelockControl.sol";

/**
 * @title MyGovernor
 * @dev 完整的链上治理合约
 * 
 * 治理参数：
 * - 投票延迟: 1个区块（提案创建后1个区块才能投票）
 * - 投票期: 50400个区块（约1周）
 * - 提案门槛: 100个代币才能创建提案
 * - 法定人数: 总供应量的4%
 * - 时间锁: 2天（执行前等待期）
 */
contract MyGovernor is
    Governor,
    GovernorSettings,
    GovernorCountingSimple,
    GovernorVotes,
    GovernorVotesQuorumFraction,
    GovernorTimelockControl
{
    constructor(
        IVotes _token,
        TimelockController _timelock
    )
        Governor("MyDAO")
        GovernorSettings(
            1,       // votingDelay: 1个区块
            50400,   // votingPeriod: ~1周
            100e18   // proposalThreshold: 100代币
        )
        GovernorVotes(_token)
        GovernorVotesQuorumFraction(4) // 4%法定人数
        GovernorTimelockControl(_timelock)
    {}

    // 以下函数必须重写以解决多继承冲突
    function quorum(uint256 blockNumber)
        public view
        override(Governor, GovernorVotesQuorumFraction)
        returns (uint256)
    {
        return super.quorum(blockNumber);
    }

    function state(uint256 proposalId)
        public view
        override(Governor, GovernorTimelockControl)
        returns (ProposalState)
    {
        return super.state(proposalId);
    }

    function proposalThreshold()
        public view
        override(Governor, GovernorSettings)
        returns (uint256)
    {
        return super.proposalThreshold();
    }

    function supportsInterface(bytes4 interfaceId)
        public view
        override(Governor, GovernorTimelockControl)
        returns (bool)
    {
        return super.supportsInterface(interfaceId);
    }
}

3.1 部署治理系统

// scripts/deploy-governance.js
async function main() {
  // 1. 部署治理代币（必须实现IVotes/ERC20Votes）
  const GovToken = await hre.ethers.getContractFactory("GovToken");
  const token = await GovToken.deploy();
  console.log("GovToken:", await token.getAddress());

  // 2. 部署时间锁控制器
  const minDelay = 2 * 24 * 60 * 60; // 2天
  const Timelock = await hre.ethers.getContractFactory("TimelockController");
  const timelock = await Timelock.deploy(
    minDelay,
    [],    // proposers: 初始为空，由Governor管理
    [],    // executors: 初始为空
    owner.address
  );
  console.log("Timelock:", await timelock.getAddress());

  // 3. 部署Governor
  const Governor = await hre.ethers.getContractFactory("MyGovernor");
  const governor = await Governor.deploy(token.getAddress(), timelock.getAddress());
  console.log("Governor:", await governor.getAddress());

  // 4. 设置时间锁角色
  const proposerRole = await timelock.PROPOSER_ROLE();
  const executorRole = await timelock.EXECUTOR_ROLE();
  await timelock.grantRole(proposerRole, await governor.getAddress());
  await timelock.grantRole(executorRole, hre.ethers.ZeroAddress); // 任何人可执行
  await timelock.revokeRole(await timelock.TIMELOCK_ADMIN_ROLE(), owner.address);

  console.log("✅ 治理系统部署完成！");
}

📖 四、提案与投票实战

// 创建提案：修改协议参数
async function createProposal(governor, targetContract, newFeeRate) {
  // 编码要调用的函数
  const encodedFunction = targetContract.interface.encodeFunctionData(
    "setFeeRate",
    [newFeeRate]
  );

  // 创建提案
  const tx = await governor.propose(
    [await targetContract.getAddress()],  // 目标合约地址
    [0],                                    // 发送的ETH（0）
    [encodedFunction],                      // 调用数据
    "Proposal: 将手续费率从0.3%降低到0.2%"  // 提案描述
  );

  const receipt = await tx.wait();
  const proposalId = receipt.logs[0].args.proposalId;
  console.log("提案已创建，ID:", proposalId);

  return proposalId;
}

// 投票
async function castVote(governor, proposalId, support) {
  // support: 0=反对, 1=赞成, 2=弃权
  const tx = await governor.castVote(proposalId, support);
  await tx.wait();
  console.log(support === 1 ? "赞成票已投出" : "反对票已投出");
}

// 执行提案
async function executeProposal(governor, targetContract, newFeeRate, description) {
  const encodedFunction = targetContract.interface.encodeFunctionData(
    "setFeeRate",
    [newFeeRate]
  );

  const tx = await governor.execute(
    [await targetContract.getAddress()],
    [0],
    [encodedFunction],
    hre.ethers.id(description) // 描述的哈希
  );

  await tx.wait();
  console.log("✅ 提案已执行！手续费率已更新");
}

📖 五、治理攻击与防御

🧪 练习