Brownie - Constructor Sequence has incorrect length, expected 1 but got 0

Question

I am trying to deploy a contract on Rinkeby by running brownie run scripts/deploy.py --network rinkeby but I get following error:

Constructor Sequence has incorrect length, expected 1 but got 0

I think the problem is that I do NOT specify the initial value of the constructor when I run my deploy.py script. Is it correct? If yes, how can I fix it?

deploy.py

from brownie import FundMe
from scripts.helpful_script import get_account


def deploy_fund_me():
    account = get_account()
    fund_me = FundMe.deploy({"from": account})
    print(f"Contract deployed to {fund_me.account}")

Solidity contract

pragma solidity ^0.6.6;

import "@chainlink/contracts/src/v0.6/interfaces/AggregatorV3Interface.sol";
import "@chainlink/contracts/src/v0.6/vendor/SafeMathChainlink.sol";

contract FundMe {
    using SafeMathChainlink for uint256;

    mapping(address => uint256) public addressToAmountFunded;
    address[] public funders;
    address public owner;
    AggregatorV3Interface public priceFeed;

    constructor(address _priceFeed) public {
        priceFeed = AggregatorV3Interface(_priceFeed);
        owner = msg.sender;
    }
    ...OTHER FUNCTIONS...
    }
}

Answer 1

Constructor Sequence has incorrect length means the number of parameters you're passing to the deploy function is off.

Your constructor is defined as:

constructor(address _priceFeed) public {

However, you don't pass it any parameters when you deploy it:

fund_me = FundMe.deploy({"from": account})

(the {"from": account} doesn't count as a constructor parameter)

So you could either:

1. Change the constructor

constructor() public {
        owner = msg.sender;
    }

Keep in mind, this means that you're not use the pricefeed anywhere. You can see a version of the refactored code here.

2. Change the deploy script

def deploy_fund_me():
    account = get_account()
    fund_me = FundMe.deploy( <PRICE_FEED_ADDRESS_HERE>, {"from": account})
    print(f"Contract deployed to {fund_me.account}")

You can see a refactored version of that here.

Answer 2

This can be a solution:

https://github.com/PatrickAlphaC/brownie_fund_me/issues/1

// SPDX-License-Identifier: MIT

pragma solidity ^0.6.6;

import "@chainlink/contracts/src/v0.6/interfaces/AggregatorV3Interface.sol";
import "@chainlink/contracts/src/v0.6/vendor/SafeMathChainlink.sol";

contract FundMe {
    using SafeMathChainlink for uint256;

    mapping(address => uint256) public addressToAmountFunded;
    address[] public funders;
    address public owner;

    constructor() public {
        owner = msg.sender;
    }

    function fund() public payable {
        uint256 mimimumUSD = 50 * 10**18;
        require(
            getConversionRate(msg.value) >= mimimumUSD,
            "You need to spend more ETH!"
        );
        addressToAmountFunded[msg.sender] += msg.value;
        funders.push(msg.sender);
    }

    function getVersion() public view returns (uint256) {
        AggregatorV3Interface priceFeed = AggregatorV3Interface(
            0x8A753747A1Fa494EC906cE90E9f37563A8AF630e
        );
        return priceFeed.version();
    }

    function getPrice() public view returns (uint256) {
        AggregatorV3Interface priceFeed = AggregatorV3Interface(
            0x8A753747A1Fa494EC906cE90E9f37563A8AF630e
        );
        (, int256 answer, , , ) = priceFeed.latestRoundData();
        return uint256(answer * 10000000000);
    }

    // 1000000000
    function getConversionRate(uint256 ethAmount)
        public
        view
        returns (uint256)
    {
        uint256 ethPrice = getPrice();
        uint256 ethAmountInUsd = (ethPrice * ethAmount) / 1000000000000000000;
        return ethAmountInUsd;
    }

    modifier onlyOwner() {
        require(msg.sender == owner);
        _;
    }

    function withdraw() public payable onlyOwner {
        msg.sender.transfer(address(this).balance);

        for (
            uint256 funderIndex = 0;
            funderIndex < funders.length;
            funderIndex++
        ) {
            address funder = funders[funderIndex];
            addressToAmountFunded[funder] = 0;
        }
        funders = new address[](0);
    }
}