Revert execution error when a transaction is performed

Question

I'm new in solidity and I'm triying to build a kind of DAO system.

The issue is that when I call the proposalCreation function (which has 2 input parameters of string type) the code crash and I do not understand the error message or why it's happening.

    // SPDX-License-Identifier: MIT

pragma solidity ^0.8.13;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/access/Ownable.sol";

contract VotationContract is Ownable {

    uint256 public proposalTime = 0;
    uint256 public votationStartTime = 0;
    IERC20 public governanceToken;
    address public governanceTokenAddress =
        0x3194cBDC3dbcd3E11a07892e7bA5c3394048Cc87;

    constructor() {
        governanceToken = IERC20(governanceTokenAddress);
    }

    // Mapping with title and proposal description
    mapping(string => string) public publishedProposals;

    struct VotationResult {
        string proposalTitle;
        uint256 approvedVotes;
        uint256 refusedVotes;
        uint256 abstentionVotes;
    }

    VotationResult votation_result = VotationResult("No proposal yet", 0, 0, 0);

    mapping(string => VotationResult) public proposalResults;

    enum Voting_state {
        Open,
        Closed,
        About_To_Start
    }

    Voting_state public state_voting = Voting_state.Closed;

    address[] public whiteList;

    // Proposal creation under 2 cases, the msg.sender has some tokens or is in the whiteList

    function proposalCreation(
        string memory proposalTitle,
        string memory proposalDescription
    ) public {

        // only 1 proposal at time because of state_voting

        // Verify that there are not ongoing votations during proposal creation

        require(
            state_voting == Voting_state.Closed,
            "Hay una votacion en curso"
        );
        if (
            governanceToken.balanceOf(msg.sender) >=
            (governanceToken.totalSupply() / 10)
        ) {
            // Publish proposal
            publishedProposals[proposalTitle] = proposalDescription;

            // Change votation state - only 1 proposal at time
            state_voting = Voting_state.About_To_Start;

            // We asure that votation results starts always empty
            votation_result = VotationResult(proposalTitle, 0, 0, 0);

            proposalTime = block.timestamp;
        }

        // Verify that sender account is in the whiteList
        bool whiteList_ok = false;
        for (uint256 i = 0; i == whiteList.length; i++) {
            if (msg.sender == whiteList[i]) {
                whiteList_ok = true;
            }
        }

        if (whiteList_ok == true) {

            publishedProposals[proposalTitle] = proposalDescription;

            state_voting = Voting_state.About_To_Start;

            votation_result = VotationResult(proposalTitle, 0, 0, 0);

            proposalTime = block.timestamp;
        }
    }

And the script to run that transaction is:

from brownie import VotationContract, GOVToken
from scripts.helpful_scripts import set_account


def test_creation_proposal_with_tokens():

    # Arrange
    account = set_account()
    votation_contract = VotationContract.deploy({"from": account})
    token_contract = GOVToken.deploy({"from": account})
    tx_mint = token_contract.mint(100, {"from": account, "value": 10000000000005000})
    tx_mint.wait(1)

    # Acting
    tx_proposal = votation_contract.proposalCreation(
        "Primera Propuesta",
        "Descripcion Primera propuesta",
        {"from": account},
    )
    tx_proposal.wait(1)

    # Assert

    assert (
        votation_contract.state_voting == votation_contract.Voting_state.About_To_start
    )

And the error is:

Anyone knows why I'm getting this error and the cause of it?

Thanks.

Answer 1

In the proposalCreation function there white list verification fails when whiteList is empty

// Verify that sender account is in the whiteList
bool whiteList_ok = false;
for (uint256 i = 0; i == whiteList.length; i++) {
    if (msg.sender == whiteList[i]) {
        whiteList_ok = true;
    }
}

When it is empty whiteList.length will be zero. Then when i = 0 the condition i == whiteList.length will be true and it will enter the for body. The if condition msg.sender == whiteList[i] will revert because i = 0 is not a valid array position.