Foundry Fundamentals: Section 4: Implement the Chainlink VRF

[DjiaaX]

I got an Error when i do forge build, here's my error#

[⠆] Compiling...
[⠊] Compiling 10 files with Solc 0.8.28
[⠒] Solc 0.8.28 finished in 1.70s
Error: Compiler run failed:
Error (9553): Invalid type for argument in function call. Invalid implicit conversion from struct VRFV2PlusClient.RandomWordsRequest memory to struct VRFV2PlusClient.RandomWordsRequest 
memory requested.
   --> src/Raffle.sol:101:65:
    |
101 |         uint256 requestId = s_vrfCoordinator.requestRandomWords(request);
    |   

I already ask gpt for this, but i still dunno how to solve this, HELP MEEEEE PLEASEEE!! MY BRAIN IS NOT BRAINING!!
here's my code:

// Layout of Contract:
// version
// imports
// errors
// interfaces, libraries, contracts
// Type declarations
// State variables
// Events
// Modifiers
// Functions

// Layout of Functions:
// constructor
// receive function (if exists)
// fallback function (if exists)
// external
// public
// internal
// private
// internal & private view & pure functions
// external & public view & pure functions

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.19;

import {VRFConsumerBaseV2Plus} from "@chainlink/contracts/src/v0.8/vrf/dev/VRFConsumerBaseV2Plus.sol";
import {VRFV2PlusClient} from "@chainlink/contracts/src/v0.8/dev/vrf/libraries/VRFV2PlusClient.sol";

/**
 * @title Sample for Raffle Smart Contract
 * @author Adji
 * @notice This contract is for creating a sample Raffle
 * @dev Implements ChainLink VRFv2.5
 */
contract Raffle is VRFConsumerBaseV2Plus {
    /* Errors */
    error Raffle__sendMoreToEnterRaffle();

    uint16 private constant REQUEST_CONFIRMATION = 3;
    uint32 private constant NUM_WORDS = 1;
    uint256 private immutable i_entranceFee;
    //@dev Duration of the Lottery in second 
    uint256 private immutable i_interval;
    bytes32 private immutable i_keyHash;
    uint256 private immutable i_subscriptionId;
    uint32 private immutable i_callbackGasLimit;
    address payable[] private s_players;
    uint256 private s_lastTimeStamp;

    /* Events */
    event RaffleEntered(address indexed player);

    constructor(uint256 entranceFee, uint256 interval, address vrfCoordinator, bytes32 gasLane, uint256 subscriptionId, uint32 callbackGasLimit) 
    VRFConsumerBaseV2Plus(vrfCoordinator) 
    {
        i_entranceFee = entranceFee;
        i_interval = interval;
        s_lastTimeStamp = block.timestamp;
        i_keyHash = gasLane;
        i_subscriptionId = subscriptionId;
        i_callbackGasLimit = callbackGasLimit;
    }

    function enterRaffle() external payable {
        // require(msg.value >= i_entranceFee, "Not enough eth")
        // require(msg.value >= i_entranceFee, sendMoreEthToEnterRaffle());
        /* Validation */
        if (msg.value < i_entranceFee) {
            revert Raffle__sendMoreToEnterRaffle();
        }
        /* Adding players to array */
        s_players.push(payable(msg.sender));

        /* Emit */
        emit RaffleEntered(msg.sender);
    }

    /*  1. Get a random number
        2. Use a random number to pick a player
        3. Be automatically called
    */
    function pickWinner() external {
        // Check to see if enough time who passed
        if ((block.timestamp - s_lastTimeStamp) < i_interval) {
            revert();
        }
        VRFV2PlusClient.RandomWordsRequest memory request = VRFV2PlusClient.RandomWordsRequest(
            {
                keyHash: i_keyHash,
                subId: i_subscriptionId,
                requestConfirmations: REQUEST_CONFIRMATION,
                callbackGasLimit: i_callbackGasLimit,
                numWords: NUM_WORDS,
                extraArgs: VRFV2PlusClient._argsToBytes(
                    // Set nativePayment to true to pay for VRF requests with Sepolia ETH instead of LINK
                    VRFV2PlusClient.ExtraArgsV1({nativePayment: false})
                )
        }
        );
        uint256 requestId = s_vrfCoordinator.requestRandomWords(request);
    }

    function fulfillRandomWords(uint256 requestId, uint256[] calldata randomWords) internal override {}

    /* Gather Function */
    function getEntranceFee() public view returns (uint256) {
        return i_entranceFee;
    }
}

[EngrPips]

Hello @DjiaaX, where did you declare s_vrfCoordinator in your code, I tried to find it but I did not see it.

[DjiaaX]

Umm..I guess I didn't declare it in my code, referring to the video I watched?, i think it declare in VRFConsumerBaseV2Plus.sol if IM not wrong..

[EngrPips]

Please show your VRFConsumerBaseV2Plus.sol file.

[DjiaaX]

here.. i copy the whole code XD

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.4;

import "../interfaces/IVRFCoordinatorV2Plus.sol";
import "../interfaces/IVRFMigratableConsumerV2Plus.sol";
import "../../shared/access/ConfirmedOwner.sol";

/** ****************************************************************************
 * @notice Interface for contracts using VRF randomness
 * *****************************************************************************
 * @dev PURPOSE
 *
 * @dev Reggie the Random Oracle (not his real job) wants to provide randomness
 * @dev to Vera the verifier in such a way that Vera can be sure he's not
 * @dev making his output up to suit himself. Reggie provides Vera a public key
 * @dev to which he knows the secret key. Each time Vera provides a seed to
 * @dev Reggie, he gives back a value which is computed completely
 * @dev deterministically from the seed and the secret key.
 *
 * @dev Reggie provides a proof by which Vera can verify that the output was
 * @dev correctly computed once Reggie tells it to her, but without that proof,
 * @dev the output is indistinguishable to her from a uniform random sample
 * @dev from the output space.
 *
 * @dev The purpose of this contract is to make it easy for unrelated contracts
 * @dev to talk to Vera the verifier about the work Reggie is doing, to provide
 * @dev simple access to a verifiable source of randomness. It ensures 2 things:
 * @dev 1. The fulfillment came from the VRFCoordinatorV2Plus.
 * @dev 2. The consumer contract implements fulfillRandomWords.
 * *****************************************************************************
 * @dev USAGE
 *
 * @dev Calling contracts must inherit from VRFConsumerBaseV2Plus, and can
 * @dev initialize VRFConsumerBaseV2Plus's attributes in their constructor as
 * @dev shown:
 *
 * @dev   contract VRFConsumerV2Plus is VRFConsumerBaseV2Plus {
 * @dev     constructor(<other arguments>, address _vrfCoordinator, address _subOwner)
 * @dev       VRFConsumerBaseV2Plus(_vrfCoordinator, _subOwner) public {
 * @dev         <initialization with other arguments goes here>
 * @dev       }
 * @dev   }
 *
 * @dev The oracle will have given you an ID for the VRF keypair they have
 * @dev committed to (let's call it keyHash). Create a subscription, fund it
 * @dev and your consumer contract as a consumer of it (see VRFCoordinatorInterface
 * @dev subscription management functions).
 * @dev Call requestRandomWords(keyHash, subId, minimumRequestConfirmations,
 * @dev callbackGasLimit, numWords, extraArgs),
 * @dev see (IVRFCoordinatorV2Plus for a description of the arguments).
 *
 * @dev Once the VRFCoordinatorV2Plus has received and validated the oracle's response
 * @dev to your request, it will call your contract's fulfillRandomWords method.
 *
 * @dev The randomness argument to fulfillRandomWords is a set of random words
 * @dev generated from your requestId and the blockHash of the request.
 *
 * @dev If your contract could have concurrent requests open, you can use the
 * @dev requestId returned from requestRandomWords to track which response is associated
 * @dev with which randomness request.
 * @dev See "SECURITY CONSIDERATIONS" for principles to keep in mind,
 * @dev if your contract could have multiple requests in flight simultaneously.
 *
 * @dev Colliding `requestId`s are cryptographically impossible as long as seeds
 * @dev differ.
 *
 * *****************************************************************************
 * @dev SECURITY CONSIDERATIONS
 *
 * @dev A method with the ability to call your fulfillRandomness method directly
 * @dev could spoof a VRF response with any random value, so it's critical that
 * @dev it cannot be directly called by anything other than this base contract
 * @dev (specifically, by the VRFConsumerBaseV2Plus.rawFulfillRandomness method).
 *
 * @dev For your users to trust that your contract's random behavior is free
 * @dev from malicious interference, it's best if you can write it so that all
 * @dev behaviors implied by a VRF response are executed *during* your
 * @dev fulfillRandomness method. If your contract must store the response (or
 * @dev anything derived from it) and use it later, you must ensure that any
 * @dev user-significant behavior which depends on that stored value cannot be
 * @dev manipulated by a subsequent VRF request.
 *
 * @dev Similarly, both miners and the VRF oracle itself have some influence
 * @dev over the order in which VRF responses appear on the blockchain, so if
 * @dev your contract could have multiple VRF requests in flight simultaneously,
 * @dev you must ensure that the order in which the VRF responses arrive cannot
 * @dev be used to manipulate your contract's user-significant behavior.
 *
 * @dev Since the block hash of the block which contains the requestRandomness
 * @dev call is mixed into the input to the VRF *last*, a sufficiently powerful
 * @dev miner could, in principle, fork the blockchain to evict the block
 * @dev containing the request, forcing the request to be included in a
 * @dev different block with a different hash, and therefore a different input
 * @dev to the VRF. However, such an attack would incur a substantial economic
 * @dev cost. This cost scales with the number of blocks the VRF oracle waits
 * @dev until it calls responds to a request. It is for this reason that
 * @dev that you can signal to an oracle you'd like them to wait longer before
 * @dev responding to the request (however this is not enforced in the contract
 * @dev and so remains effective only in the case of unmodified oracle software).
 */
abstract contract VRFConsumerBaseV2Plus is IVRFMigratableConsumerV2Plus, ConfirmedOwner {
  error OnlyCoordinatorCanFulfill(address have, address want);
  error OnlyOwnerOrCoordinator(address have, address owner, address coordinator);
  error ZeroAddress();

  IVRFCoordinatorV2Plus public s_vrfCoordinator;

  /**
   * @param _vrfCoordinator address of VRFCoordinator contract
   */
  constructor(address _vrfCoordinator) ConfirmedOwner(msg.sender) {
    s_vrfCoordinator = IVRFCoordinatorV2Plus(_vrfCoordinator);
  }

  /**
   * @notice fulfillRandomness handles the VRF response. Your contract must
   * @notice implement it. See "SECURITY CONSIDERATIONS" above for important
   * @notice principles to keep in mind when implementing your fulfillRandomness
   * @notice method.
   *
   * @dev VRFConsumerBaseV2Plus expects its subcontracts to have a method with this
   * @dev signature, and will call it once it has verified the proof
   * @dev associated with the randomness. (It is triggered via a call to
   * @dev rawFulfillRandomness, below.)
   *
   * @param requestId The Id initially returned by requestRandomness
   * @param randomWords the VRF output expanded to the requested number of words
   */
  function fulfillRandomWords(uint256 requestId, uint256[] memory randomWords) internal virtual;

  // rawFulfillRandomness is called by VRFCoordinator when it receives a valid VRF
  // proof. rawFulfillRandomness then calls fulfillRandomness, after validating
  // the origin of the call
  function rawFulfillRandomWords(uint256 requestId, uint256[] memory randomWords) external {
    if (msg.sender != address(s_vrfCoordinator)) {
      revert OnlyCoordinatorCanFulfill(msg.sender, address(s_vrfCoordinator));
    }
    fulfillRandomWords(requestId, randomWords);
  }

  /**
   * @inheritdoc IVRFMigratableConsumerV2Plus
   */
  function setCoordinator(address _vrfCoordinator) public override onlyOwnerOrCoordinator {
    s_vrfCoordinator = IVRFCoordinatorV2Plus(_vrfCoordinator);
  }

  modifier onlyOwnerOrCoordinator() {
    if (msg.sender != owner() && msg.sender != address(s_vrfCoordinator)) {
      revert OnlyOwnerOrCoordinator(msg.sender, owner(), address(s_vrfCoordinator));
    }
    _;
  }
}

[EngrPips]

This is the link https://github.com/Cyfrin/foundry-smart-contract-lottery-cu/blob/main/src/Raffle.sol to the final codebase of this Lottery section, and it is quite different from yours, So I will say continue with the tutorial and don't mind that compilation error for now as there will still be a lot of changes to the code and this current state of the code is not the final code.

[EngrPips]

@DjiaaX , Please use cltr + p [Windows] and command + p [Mac] and input VRFCoordinatorV2_5 in the search bar that appears. Like that vscode should show you the file, so open it and confirm if the path where the contract imports VRFV2PlusClient is the same as the path where your Raffle contract is importing VRFV2PlusClient

[DjiaaX]

Ty sir..im just worried that my problem will interrupted my proggress, and im confirmed that the path where the contract imports VRFV2PlusClient is the same as the path where my Raffle contract is importing VRFV2PlusClient, Thanks for your help!!

[EngrPips]

You are welcome, It won't block as the code will still change a lot, so just keep following the tutorial.