如何从硬件主干网叉修改Kyber池中的ETH价格？

Question

我正在编写一个安全帽测试，我用KyberSwap的主网叉在ETH上交换DAI，目的是改变Eth在池中的价格。交易是成功的，因为测试钱包收到DAI在最后，但不幸的是，ETH在池中的价格没有变化。

从我的测试结果来看：

Initial ETH price was:  2567000000000000000000
ETH price after was:  2567000000000000000000

考虑到在编写本报告时池中只有0.3 ETH，ETH应该足以改变价格。我甚至试着交换900 ETH，但还是没有改变。为什么ETH对Kyber的价格不受影响？

这是我的测试：

require('dotenv').config()
const { assert } = require("chai");
const { ethers } = require("hardhat");

// Contains ABi for balanceOf() method
const ERC20ABI = [{ "constant": true, "inputs": [{ "name": "_owner", "type": "address" }], "name": "balanceOf", "outputs": [{ "name": "balance", "type": "uint256" }], "payable": false, "stateMutability": "view", "type": "function" }]

// Contains ABI for Kyber's getExpectedRate() method
const kyberNetworkProxyABI = [{ "constant": true, "inputs": [{ "name": "src", "type": "address" }, { "name": "dest", "type": "address" }, { "name": "srcQty", "type": "uint256" }], "name": "getExpectedRate", "outputs": [{ "name": "expectedRate", "type": "uint256" }, { "name": "slippageRate", "type": "uint256" }], "payable": false, "stateMutability": "view", "type": "function" }]

const KYBER_NETWORK_PROXY_ADDRESS = "0x818E6FECD516Ecc3849DAf6845e3EC868087B755";
const KYBER_ETH_ADDRESS = "0xeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee";
const DAI_ADDRESS = "0x6b175474e89094c44da98b954eedeac495271d0f";

describe("kyber-eth-price-test", function () {
    it("Test that eth price is altered", async function () {
        const provider = ethers.provider;
        const [owner, addr1] = await ethers.getSigners();
        signer = await provider.getSigner(process.env.ETH_PUBLIC_KEY)

        // Get DAI contract
        const DAI = new ethers.Contract(DAI_ADDRESS, ERC20ABI, provider);

        // Get kyberNetworkProxy contract
        let kyberNetworkProxy = new ethers.Contract(
            KYBER_NETWORK_PROXY_ADDRESS,
            kyberNetworkProxyABI,
            signer,
        );

        // Deploy KyberTradeExample contract
        const kyberTradeExample =
            await ethers.getContractFactory("KyberTradeExample")
                .then(contract => contract.deploy(
                    KYBER_NETWORK_PROXY_ADDRESS,
                    DAI_ADDRESS
                ));
        await kyberTradeExample.deployed();

        // Assert addr1 DAI balance is initially 0
        addr1Dai = await DAI.balanceOf(addr1.address);
        assert(addr1Dai.isZero());

        // Get initial price from pegged block
        let ethPriceInitial
        const updateEthPrice = async () => {
            const results = await kyberNetworkProxy.getExpectedRate(
                KYBER_ETH_ADDRESS,
                DAI_ADDRESS,
                1 // 1 ETH
            )
            ethPriceInitial = results.expectedRate
        }
        await updateEthPrice()
        console.log("Initial ETH price was: ", ethPriceInitial.toString());

        // Swap 1 ETH for DAI
        await kyberTradeExample.connect(addr1).swapEthForDaiOnKyber(
            { value: ethers.utils.parseEther("999") }
        );

        // Assert DAI balance increased
        addr1Dai = await DAI.balanceOf(addr1.address);
        assert(addr1Dai.gt(ethers.BigNumber.from("0")));

        // Get Eth price after
        let ethPriceAfter
        const updateEthPrice2 = async () => {
            const results = await kyberNetworkProxy.getExpectedRate(
                KYBER_ETH_ADDRESS,
                DAI_ADDRESS,
                1 // 1 ETH
            )
            ethPriceAfter = results.expectedRate
        }
        await updateEthPrice2()
        console.log("ETH price after was: ", ethPriceAfter.toString());

        // Assert that Eth price has been altered
        assert.isFalse(ethPriceInitial.eq(ethPriceAfter), "Eth price did not change");
    });
});

这里是我用来从KyberSwap用ETH交换DAI的稳固契约：

pragma solidity ^0.5.0;

import { KyberNetworkProxy as IKyberNetworkProxy } from '@studydefi/money-legos/kyber/contracts/KyberNetworkProxy.sol';
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";

contract KyberTradeExample {
    IKyberNetworkProxy kyber;
    IERC20 dai;
    address constant KYBER_ETH_ADDRESS = 0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE;

    constructor(
        address kyberAddress,
        address daiAddress
    ) public {
      kyber = IKyberNetworkProxy(kyberAddress);
      dai = IERC20(daiAddress);
    }

    function swapEthForDaiOnKyber() external payable {
          (, uint minRate) = kyber.getExpectedRate(
            IERC20(KYBER_ETH_ADDRESS), 
            dai, 
            msg.value
          );

          // will send back tokens to this contract's address
          uint destAmount = kyber.swapEtherToToken.value(msg.value)(
            dai, 
            minRate
          );

          // send received tokens back to caller
          require(dai.transfer(msg.sender, destAmount));
    }

    function() external payable {}
}

在我的hardhat.config.js中，我使用炼金术创建了一个分叉，并将其与块#14368910挂钩。

module.exports = {
  solidity: "0.5.0",
  networks: {
    hardhat: {
      forking: {
        url: process.env.ALCHEMY_URL,
        blockNumber: 14368910
      }
    }
  }
};

更新

我现在相当肯定这是因为Kyber正在通过多个DEX进行交易，如果我用直接使用Kyber池的KNC来交换ETH，我的测试将成功地改变ETH的价格。

因此，我现在的问题是:我是否可以要求Kyber避免使用多个交换，并直接使用Kyber的ETH/DAI池？

Answer 1

经过一些阅读，我很确定这是不可能的，因为KyberSwap被设计成一个多DEX聚合器。从他们的医生那里：

KyberSwap交易通过不同的DEX进行最优分割和路由，在同一链/网络中以最佳价格进行交易。

除非我错过了一些文档中的内容，否则关闭多个DEX交易不是一种选择，因此我认为我无法通过执行掉期来修改KyberSwap令牌价格。