Has the way to access public member variables in solidity through deployed contracts changed?

Question

I have a public contract member defined like this, which is later assigned a value in the constructor

AggregatorV3Interface public priceFeed;

I want to access this variable's value and I am trying like this

fundMe = await ethers.getContractAt("FundMe", deployer);
const response = await fundMe.priceFeed();

But I am getting error:

Error: could not decode result data (value="0x", info={ "method": "priceFeed", "signature": "priceFeed()" }, code=BAD_DATA, version=6.7.1)

I am getting this error when I am running the test which is defined below

const { assert } = require("chai");
const { deployments, ethers, getNamedAccounts } = require("hardhat");

describe("FundMe", async () => {
  let fundMe;
  let deployer;
  let MockV3Aggregator;
  beforeEach(async function () {
    deployer = (await getNamedAccounts()).deployer;
    await deployments.fixture("all");
    fundMe = await ethers.getContractAt("FundMe", deployer); // <-- change to getContract
    MockV3Aggregator = await ethers.getContractAt("MockV3Aggregator", deployer); // <-- same change here
  });

  describe("constructor", async function () {
    it("Sets the aggregator address correctly", async function () {
      const response = await fundMe.priceFeed(); //<-- error here
      console.log(response);

      assert.equal(response, MockV3Aggregator.target);
    });
  });
});

The fundMe contract is

contract FundMe {

    AggregatorV3Interface public priceFeed;

    constructor(address customPriceFeed) {
        i_owner = msg.sender;
        priceFeed = AggregatorV3Interface(customPriceFeed);
    }

hardhat.config.js file :

require("@nomicfoundation/hardhat-toolbox");
require("dotenv").config();
require("./tasks/block-number");
require("hardhat-deploy");
require("@nomiclabs/hardhat-ethers"); // <-- error solved by adding this

const SEPOLIA_URL = process.env.SEPOLIA_RPC_URL || "https://sepolia.com";
const PRIVATE_KEY = process.env.PRIVATE_KEY || "key";
const COINMARKETCAP_API_KEY = process.env.COINMARKETCAP_API_KEY || "key";

/** @type import('hardhat/config').HardhatUserConfig */
module.exports = {
  defaultNetwork: "hardhat",
  networks: {
    sepolia: {
      url: SEPOLIA_URL,
      accounts: [PRIVATE_KEY],
      chainId: 11155111,
    },
  },
  solidity: {
    compilers: [
      {
        version: "0.8.19",
      },
      {
        version: "0.6.6",
      },
    ],
  },
  gasReporter: {
    enabled: true,
    outputFile: "gas-reporter.txt",
    noColors: true,
    currency: "INR",
    coinmarketcap: COINMARKETCAP_API_KEY,
  },
  namedAccounts: {
    deployer: {
      default: 0,
    },
  },
};

Answer 1

• Change getContractAt by getContract
• in testing use MockV3Aggregator.address instead of MockV3Aggregator.target

Don't forget to import the hardhat ethers, and hardhat deploy modules in hardhat config file, this part was added in the question itself.

// hardhat.config.js
require("hardhat-deploy");
require("@nomiclabs/hardhat-ethers");