Lesson 9 - Error: Calling performUpkeep(zeroBytes) results in 'function returned an unexpected amount of data'

[r-bytes]

Hi there,

I'm stuck at my unit test in lesson 9 and after reading a lot of discussions I cannot come to a solution.
Can somebody please help me? :)

The issue is that I'm unable to successfully call the performUpkeep() method on my smart contract Raffle.sol.
I'm using:

• hardhat 2.17.1
• ethers 6.7.1 and
• typescript

I have a test file where I manipulate the time and block mined and call the performUpkeep() method like this:

1.         describe("enterRaffle", async () => {
2.             it("should not allow entrance when the raffle state is set to calculating", async () => {
3.                 await raffle.enterRaffle({ value: raffleEntranceFee })
4.                 const increasedInterval = Number(interval) + 10
5.   
6.                 // manipulate time on evm
7.                 await network.provider.send("evm_increaseTime", [increasedInterval])
8.                 await network.provider.send("evm_mine", []);
9.                 
10.                 // calling chainlink keeper
11.                 const zeroBytes = new Uint8Array()
12.                 await raffle.performUpkeep(zeroBytes)
13. 
14.                 await expect(raffle.enterRaffle({ value: raffleEntranceFee })).to.be.revertedWithCustomError(raffle, "Raffle__NotOpen")
15. 
16.             })
17.         })

Line 11 results in the following error:

Error: Transaction reverted: function returned an unexpected amount of data

Interval is coming from my hardhat-helper-config.ts files that looks something like this:

    "31337": {
        name: "hardhat",
        entranceFee: ethers.parseEther("0.01"),
        gasLane: "0x474e34a077df58807dbe9c96d3c009b23b3c6d0cce433e59bbf5b34f823bc56c", // doesn't matter on hh
        subscriptionId: "0",
        callbackGasLimit: "500000",
        interval: 30
    },

My 01-deploy-raffle.ts file looks like this:

1. const deployRaffle: DeployFunction = async ({ getNamedAccounts, deployments, network }) => {
2.     const { deploy, log } = deployments;
3.     const { deployer, player } = await getNamedAccounts();
4.     const chainId: number = network.config.chainId!;
5. 
6.     let vrfCoordinatorV2Adress: (string | Addressable) | (string | undefined),
7.         subscriptionId: number | string | undefined,
8.         vrfCoordinatorV2Mock;
9. 
10.     if (developmentChains.includes(network.name)) {
11.         vrfCoordinatorV2Mock = await ethers.getContractAt("VRFCoordinatorV2Mock", deployer);
12.         
13.         vrfCoordinatorV2Adress = vrfCoordinatorV2Mock.target;
14.         
15.         // create a subscription programmatically
16.         const transactionResponse: ContractTransactionResponse = await vrfCoordinatorV2Mock.createSubscription();
18.         const transactionReceipt: ContractTransactionReceipt = (await transactionResponse.wait()) as ContractTransactionReceipt;
19.         
20.         // NOT WORKING => transactionReceipt.events[0].args.subId;
21.         subscriptionId = 1;
22.         
23.         // fund the subscription
24.         await vrfCoordinatorV2Mock.fundSubscription(subscriptionId, FUND_AMOUNT);
25. 
26.     } else {
27.         vrfCoordinatorV2Adress = networkConfig[chainId].vrfCoordinatorV2;
28.         subscriptionId = networkConfig[chainId].subscriptionId;
29.     }
30.     
31. 
32.     // constructer arguments
33.     const args = [
34.         vrfCoordinatorV2Adress,
35.         networkConfig[chainId].entranceFee,
36.         networkConfig[chainId].gasLane,
37.         subscriptionId,
38.         networkConfig[chainId].callbackGasLimit,
39.         networkConfig[chainId].interval,
40.     ];
41. 
42.     const deployOptions = {
43.         from: deployer,
44.         args: args,
45.         log: true,
46.         waitConfirmations: 1,
47.     };
48.     const raffle: DeployResult = await deploy("Raffle", deployOptions);
49. 
50.     if (!developmentChains.includes(network.name) && process.env.ETHERSCAN_API_KEY) {
51.         log("[deploy script] verifying contract...");
52.         await verify(raffle.address, args);
53.     }
54. };
55. 
56. export default deployRaffle;
57. deployRaffle.tags = ["all", "raffle"];

Note: I had some trouble earlier with line 20 but found out about the hard coded solution in an other discussion, which seems to work. Because I'm using hardhat locally transactionReceipt.events[0] does not exist on the ContractTransactionReceipt also no transactionReceipt.logs[0].args !

My solidity contract Raffle.sol looks something like this (it's a stripped down version):
The full file is on my github: https://github.com/r-bytes/blockchain/tree/main/hardhat-smartcontract-lottery

1. // SPDX-License-Identifier: MIT
2. pragma solidity ^0.8.19;
3. 
4. import "@chainlink/contracts/src/v0.8/interfaces/VRFCoordinatorV2Interface.sol";
5. import "@chainlink/contracts/src/v0.8/VRFConsumerBaseV2.sol";
6. import "@chainlink/contracts/src/v0.8/AutomationCompatible.sol";
7. 
8. // * errors
9. error Raffle__NotOpen();
10. error Raffle__UpkeepNotNeeded(uint256 currentBalance, uint256 numPlayers, uint256 raffleState);
11. 
12. contract Raffle is VRFConsumerBaseV2, AutomationCompatible {
13.     // * type declarations
14.     enum RaffleState {
15.         OPEN,
16.         CALCULATING
17.     }
18. 
19.     // * state variables
20.     uint256 private immutable i_entranceFee;
21.     address payable[] private s_players;
22.     VRFCoordinatorV2Interface private immutable i_vrfCoordinator;
23.     bytes32 private immutable i_gasLane;
24.     uint64 private immutable i_subscriptionId;
25.     uint16 private constant REQUEST_CONFIRMATIONS = 3;
26.     uint32 private immutable i_callbackGasLimit;
27.     uint32 private constant NUM_WORDS = 1;
28.     uint256 private s_lastTimestamp;
29.     uint256 private immutable i_interval;
30. 
31.     // * lottery variables
32.     RaffleState private s_raffleState;
33. 
34.     // * functions
35.     constructor(
36.         address vrfCoordinatorV2, //contract
37.         uint256 entranceFee,
38.         bytes32 gasLane,
39.         uint64 subscriptionId,
40.         uint32 callbackGasLimit,
41.         uint256 interval
42.     ) VRFConsumerBaseV2(vrfCoordinatorV2) {
43.         i_entranceFee = entranceFee;
44.         i_vrfCoordinator = VRFCoordinatorV2Interface(vrfCoordinatorV2);
45.         i_gasLane = gasLane;
46.         i_subscriptionId = subscriptionId;
47.         i_callbackGasLimit = callbackGasLimit;
48.         s_raffleState = RaffleState.OPEN;
49.         s_lastTimestamp = block.timestamp;
50.         i_interval = interval;
51.     }
52. 
53.     function checkUpkeep(
54.         bytes memory /* checkData */
55.     ) public view override returns (bool upkeepNeeded, bytes memory /* performData */) {
56.         bool isOpen = (RaffleState.OPEN == s_raffleState);
58.         // (block.timestamp - lastBlockTimestamp) > interval
59.         bool timePassed = ((block.timestamp - s_lastTimestamp) > i_interval);
60.         bool hasPlayers = (s_players.length > 0);
61.         bool hasBalance = address(this).balance > 0;
62.         upkeepNeeded = (isOpen && timePassed && hasPlayers && hasBalance && hasPlayers);
63.         return (upkeepNeeded, "0x0");
64.     }
65. 
66.     function performUpkeep(bytes calldata) external override /* performData */ {
67.         // check if upkeep is needed
68.         (bool upkeepNeeded, ) = checkUpkeep("");
69. 
70.         if (!upkeepNeeded) {
71.             revert Raffle__UpkeepNotNeeded(
72.                 address(this).balance,
73.                 s_players.length,
74.                 uint256(s_raffleState)
75.             );
76.         }
77. 
78.         // request random number
79.         // revert if subscription is not set and funded.
80.         s_raffleState = RaffleState.CALCULATING;
81.         uint256 requestId = i_vrfCoordinator.requestRandomWords(
82.             i_gasLane, // gasLane
83.             i_subscriptionId,
84.             REQUEST_CONFIRMATIONS,
85.             i_callbackGasLimit,
86.             NUM_WORDS
87.         );
88. 
89.         // once we get it, do something with it
90.         emit RequestedRaffleWinner(requestId);
91.     }
92. 
93.     // * view, pure functions
94.     function getInterval() public view returns (uint256) {
95.         return i_interval;
96.     }
97. }

The error points to line 80 but I cannot figure out what's wrong.
Is it because I don't have a valid subscriptionId from ChainLink Keepers because I'm working locally with hardhat?

Looking forward to suggestions! :)

[Nlferu]

Hi @r-bytes

The problem might be in ethers v6 as for v5 I know that both of below methods works when passing empty bytes array:

raffle.performUpkeep([])
raffle.performUpkeep("0x")

For ethers v6 I belive only raffle.performUpkeep([]) works

Same this with below:

await network.provider.send("evm_increaseTime", [interval.toNumber() + 1])
await network.provider.send("evm_mine", [])

// or you can call it like below:

await network.provider.request({ method: "evm_mine", params: [] })

// Only one method works in ethers v6

[r-bytes]

Thanks for your reply @Neftyr !
The issue was indeed in the network.provider methods.

In ethers 6 apparently only this works:

await network.provider.request({ method: "evm_increaseTime", params: [Number(interval) + 10] })
await network.provider.request({ method: "evm_mine", params: [] })

The method

interval.toNumber()

is also not working because interval is of type bigint

Thanks alot man!

[Nlferu]

@r-bytes

Glad I could help ;)

[r-bytes]

@Neftyr

Sorry but your aswer doesn't seems to be the actual answer to the issue.

I've already tried to install ethers 5 but it has to many dependencies and for the purpose of moving forward and learning I want to make it work on ethers 6 and keep this question open.

What I did so far is:
I created a new function in my Raffle.sol to doublecheck if upkeep is needed:

    function checkUpkeepNeeded() public view returns (bool) {
        (bool upkeepNeeded,) = checkUpkeep("");
        return upkeepNeeded; 
    }

In my test file Raffle.test.ts I perform some checks before and after skipping time on the evm, it looks like this:

describe("enterRaffle", async () => {
    it("should not allow entrance when the raffle state is set to calculating", async () => {
        await raffle.enterRaffle({ value: raffleEntranceFee });
        console.log("entered raffle");

        const upkeepNeededBefore = await raffle.checkUpkeepNeeded();
        console.log('upkeepNeeded:', upkeepNeededBefore)

        await network.provider.request({
            method: "evm_increaseTime",
            params: [Number(interval) + 10],
        });
        console.log("skipped time on evm");
        
        await network.provider.request({ 
            method: "evm_mine", 
            params: [] 
        });
        console.log("mined a block on evm");

        const upkeepNeededAfter = await raffle.checkUpkeepNeeded();
        console.log('upkeepNeeded:', upkeepNeededAfter)

        // pretend to be a chainlink keeper
        await raffle.performUpkeep("0x");
        console.log("state changed to calculating");

        await expect(
            raffle.enterRaffle({ value: raffleEntranceFee }),
        ).to.be.revertedWithCustomError(raffle, "Raffle__NotOpen");
    });
});

The console shows exactly what we want to see:

  Raffle Unit Tests
    enterRaffle
entered raffle
upkeepNeeded: false
skipped time on evm
mined a block on evm
upkeepNeeded: true

But the outcome unfortunately stays the same:

  1) Raffle Unit Tests
       enterRaffle
         should not allow entrance when the raffle state is set to calculating:

Error: Transaction reverted: function returned an unexpected amount of data
    at Raffle.performUpkeep (contracts/Raffle.sol:132)
    at processTicksAndRejections (node:internal/process/task_queues:95:5)
    at async HardhatNode._mineBlockWithPendingTxs (node_modules/hardhat/src/internal/hardhat-network/provider/node.ts:1854:23)
    at async HardhatNode.mineBlock (node_modules/hardhat/src/internal/hardhat-network/provider/node.ts:524:16)
    at async EthModule._sendTransactionAndReturnHash (node_modules/hardhat/src/internal/hardhat-network/provider/modules/eth.ts:1546:18)
    at async HardhatNetworkProvider.request (node_modules/hardhat/src/internal/hardhat-network/provider/provider.ts:124:18)
    at async HardhatEthersSigner.sendTransaction (node_modules/@nomicfoundation/hardhat-ethers/src/signers.ts:125:18)
    at async send (node_modules/ethers/src.ts/contract/contract.ts:299:20)

Do you have any more suggestions? They would be very welcome :)

I'm testing this locally with hardhat and I hardcoded my subscriptionId = 1
I've already check my arguments and compared the order to the constructor arguments..

[Nlferu]

Hi @r-bytes

The answer is still the same, in your script you are using below:

await raffle.performUpkeep("0x");

And as you said you are using ethers v6, so it should be like this:

await raffle.performUpkeep([]);

If you would be using ethers v5 both would work

[r-bytes]

@Neftyr, thanks again for the response, I appreciate it.
It's actually exactly the opposite, code below will only work in ethers v6 the other one will not:

await raffle.performUpkeep("0x")

But after some deeper trouble shooting I found my issue..
For some reason the method below is not working properly in ethers v6

await vrfCoordinatorV2Mock.createSubscription()

So the subscription is never created not matter what I do, I learned a lot with this troubleshooting and that's nice.
For now I decided to just downgrade to continue with the course :)

[r-bytes]

Update: I was not able to fix this issue with ethers v6.

I found out that my subscription simply wasn't created, no matter what I did.

For some reason I'm unable to successfully create a subscription using this piece of code:

await vrfCoordinatorV2Mock.createSubscription()

With ethers v5 I was able to create the subscription but got an other error:
reverted with custom error 'InvalidConsumer()'

For everybody reading this: just use ethers v5 and make sure to add your smart contract as a consumer at the bottom of your 01-deploy-raffle.ts script, right after you deploy the contract.

Like this:

const deployOptions = {
    from: deployer,
    args: args,
    log: true,
    waitConfirmations: 1,
  };

const raffle: DeployResult = await deploy("Raffle", deployOptions);

if(developmentChains.includes(network.name)) {
    console.log("adding raffle contract as consumer");
    await vrfCoordinatorV2Mock?.addConsumer(subscriptionId.toNumber(), raffle.address)
    console.log("consumer added!");
}

If anyone managed to get it to work with ethers v6 I'm very curious, please let me know! :)
Happy coding fellas!

[Nlferu]

Hi @r-bytes

Here is Raffle made on ethers v6 link thanks to @shikhar229169