Errors encountered in param 0: Invalid value undefined supplied to : HardhatNetworkConfig

Question

My smart contract has to check balance of OpenSea OpenStore contract, so I need to be able to fork polygon mainnet. I want each test to start fresh with the same fork, so I'm invoking hardhat_reset in beforeEach. But I'm getting this incomprehensible error:

"before each" hook for "<very first 'it' under first 'describe'>":
     InvalidArgumentsError: Errors encountered in param 0: Invalid value undefined supplied to : HardhatNetworkConfig | undefined/forking: RpcForkConfig | undefined | undefined/jsonRpcUrl: string

My code looks like this (it's abridged, with ellipses filling in for standard boilerplate)

import ....
import * as helpers from "@nomicfoundation/hardhat-network-helpers"

....

  async function deployContract(addr=myAddr) {
    await ethers.provider.send("hardhat_impersonateAccount", [addr])
    helpers.setBalance(addr, "0x100000000000000000000")
    const signer = await ethers.getSigner(addr)
    const cf = await ethers.getContractFactory("MyContractName", signer)
    contract = await cf.deploy()
  }

  beforeEach(async () => {
    await network.provider.request({
      method: "hardhat_reset",
      params: [{
        forking: {
          url: "https://polygon-mainnet.g.alchemy.com/v2/" + apiKey,
          blockNumber: 31911877
        }
      }]
    })
    const wallets = waffle.provider.getWallets()
    wallet = wallets[0]
    await deployContract()
  })

Note that I don't get this issue if I move the forking param data to my hardhat.config.ts - in that case, the test executes fine except that because nothing is reset between tests, the actions done in the first test mess up the ones in later tests.

Thanks!

Answer 1

Under the forking params, replace url with jsonRpcUrl

I realized this after seeing https://stackoverflow.com/a/71811223/19350337