ValueError: VM Exception while processing transaction: revert:

[praxis-dev]

Hi!

I've encountered this type of error when trying to run fund and withdraw script as instructed in the video at 5:45. Any suggestions?

(BVE) praxis@Praxis:~/demos/brownie_fund_me$ brownie run scripts/fund_and_withdraw.py --network ganache-local
Brownie v1.18.2 - Python development framework for Ethereum

Compiling contracts...
  Solc version: 0.6.12
  Optimizer: Enabled  Runs: 200
  EVM Version: Istanbul
Generating build data...
 - smartcontractkit/[email protected]/AggregatorV3Interface
 - smartcontractkit/[email protected]/SafeMathChainlink
 - FundMe

BrownieFundMeProject is the active project.

Running 'scripts/fund_and_withdraw.py::main'...
  File "brownie/_cli/run.py", line 51, in main
    return_value, frame = run(
  File "brownie/project/scripts.py", line 110, in run
    return_value = f_locals[method_name](*args, **kwargs)
  File "./scripts/fund_and_withdraw.py", line 13, in main
    fund()
  File "./scripts/fund_and_withdraw.py", line 8, in fund
    entrance_fee = fund_me.getEntranceFee()
  File "brownie/network/multicall.py", line 115, in _proxy_call
    result = ContractCall.__call__(*args, **kwargs)  # type: ignore
  File "brownie/network/contract.py", line 1902, in __call__
    return self.call(*args, block_identifier=block_identifier, override=override)
  File "brownie/network/contract.py", line 1693, in call
    raise VirtualMachineError(e) from None
  File "brownie/exceptions.py", line 106, in __init__
    raise ValueError(f"{self.message}: {err_msg}") from None
ValueError: VM Exception while processing transaction: revert: 

My code:

fund_and_withdraw.py

from brownie import FundMe
from scripts.helpful_scripts import get_account


def fund():
    fund_me = FundMe[-1]
    account = get_account()
    entrance_fee = fund_me.getEntranceFee()
    print(entrance_fee)


def main():
    fund()

FundMe.sol 

// SPDX-Licence-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;
    AggregatorV3Interface public priceFeed;

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

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

    function getVersion() public view returns (uint256) {
        return priceFeed.version();
    }

    function getPrice() public view returns (uint256) {
        (, 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;
    }

    function getEntranceFee() public view returns (uint256) {
        // minimumUSD
        uint256 minimumUSD = 50 * 10**18;
        uint256 price = getPrice();
        uint256 precision = 1 * 10**18;
        return (minimumUSD * precision) / price;
    }

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

    function withraw() public payable onlyOwner {
        //require(msg.sender == owner);
        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);
    }
}

deploy.py

from brownie import FundMe, network, config, MockV3Aggregator
from scripts.helpful_scripts import (
    get_account,
    deploy_mocks,
    LOCAL_BLOCKCHAIN_ENVIRONMENTS,
)
from web3 import Web3
from brownie.network import gas_price
from brownie.network.gas.strategies import LinearScalingStrategy

gas_strategy = LinearScalingStrategy("60 gwei", "70 gwei", 1.1)

gas_price(gas_strategy)


def deploy_fund_me():
    account = get_account()
    if network.show_active() not in LOCAL_BLOCKCHAIN_ENVIRONMENTS:
        price_feed_address = config["networks"][network.show_active()][
            "eth_usd_price_feed"
        ]
    else:
        deploy_mocks()
        price_feed_address = MockV3Aggregator[-1].address

    fund_me = FundMe.deploy(
        "price_feed_address",
        {"from": account, "gas_price": gas_strategy},
        publish_source=config["networks"][network.show_active()].get("verify"),
    )
    print(f"Contract deployed to {fund_me.address}")


def main():
    deploy_fund_me()

[praxis-dev]

helpful_scripts.py

from brownie import network, config, accounts, MockV3Aggregator
from web3 import Web3

LOCAL_BLOCKCHAIN_ENVIRONMENTS = ["development", "ganache-local"]

DECIMALS = 8
STARTING_PRICE = 200000000000


def get_account():
    if network.show_active() in LOCAL_BLOCKCHAIN_ENVIRONMENTS:
        return accounts[0]
    else:
        return accounts.add(config["wallets"]["from_key"])


def deploy_mocks():
    print(f"The active network is {network.show_active()}")
    print("Deploying Mocks...")
    if len(MockV3Aggregator) <= 0:
        MockV3Aggregator.deploy(DECIMALS, STARTING_PRICE, {"from": get_account()})
    print("Mocks Deployed")

[praxis-dev]

Problem solved:

    fund_me = FundMe.deploy(
        "price_feed_address",
        {"from": account, "gas_price": gas_strategy},
        publish_source=config["networks"][network.show_active()].get("verify"),
    )
    print(f"Contract deployed to {fund_me.address}")

in this section of deploy.py - price_feed_address should be without quotes.

[cromewar]

Hello there @vaporm Sorry for the delay, I'm glad your problem is solved now !

[praxis-dev]

@cromewar it's no problem. Sometimes it prompts you to do an extra cycle of your own research :)