Lesson 9: Compile error - stack too deep

[RichardPalladino]

Lesson 9 was going great until I got to the point where we refactored the code and added "deployerKey". There were some other modifications with this, like grabbing the private key from my .env file with vm.envUint("SEPOLIA_PRIVATE_KEY"), but for the most part little else changed.

Yet when I tried to build after making the changes and clearing the code errors, I received the "Compile error - stack too deep" error.

I know to use the --via-ir switch option, but even that took literal minutes to compile.

Any idea of the root cause, or how I can keep this from happening in the future? I don't have any unused variables. I'm trying to figure out better optimizations. Stanzas don't seem too long. I just don't get how a simple change like that may have impacted the compiler so much.

[Naman1729]

Hey @RichardPalladino , Can you send you github repo . So, we can easily debug this error

[RichardPalladino]

https://github.com/RichardPalladino/f23-smartcontract-lottery

I'm going line-by-line of the key files now, comparing with what Patrick has done.

Thank you.

[sharonphiliplima]

Hey, even I am facing the same error. Please help me if you have found any fix.
My entire learning is halted rn.

[usmanfarooq91]

@RichardPalladino following line in your RaffleTest.t.sol file is causing this error. (entranceFee, interval, vrfCoordinator, gasHash, subscriptionId, callbackGasLimit, linkToken, deployerKey) = helperConfig.activeNetworkConfig(); try removing one variable from this tuple and your code will work fine. i.e. you can remove subscriptionId as you are not using it in this file. your line should look like this after removing this variable, (entranceFee, interval, vrfCoordinator, gasHash, , callbackGasLimit, linkToken, deployerKey) = helperConfig.activeNetworkConfig();. @sharonphiliplima I think you are facing the same issue, try this if it works. Otherwise, you can share your repo here so I can debug.

[sharonphiliplima]

function setUp() external {
        DeployRaffle deployer = new DeployRaffle();
        (raffle, helperConfig) = deployer.run();
        (
            entranceFee,
            interval,
            vrfCoordinator,
            gasLane,
            subscriptionId,
            callbackGasLimit,
            link,
            deployerKey
        ) = helperConfig.activeNetworkConfig(); //deconstructing basically!
        vm.deal(PLAYER, STARTING_USER_BALANCE);

        if (subscriptionId == 0) {
            CreateSubscription createSubscription = new CreateSubscription();
            subscriptionId = createSubscription.createSubscription(
                vrfCoordinator,
                deployerKey
            );
        }

I think that we are using subscriptionId in the RaffleTest.t.sol
so, I removed gasLane did I do right?

[sharonphiliplima]

Also, would it be viable to

struct RaffleState {
        Raffle raffle;
        HelperConfig helperConfig;
        address player;
        uint256 entranceFee;
        uint256 interval;
        address vrfCoordinator;
        bytes32 gasLane;
        uint64 subscriptionId;
        uint32 callbackGasLimit;
        address link;
        uint256 deployerKey;
    }

turn the state variables into a struct in the test file?

[RichardPalladino]

@sharonphiliplima I'm not sure that second approach - using a struct - would solve any issues since what @usmanfarooq91 calls out as the issue is referencing too many variables in the tuple receiving the return values.

It wouldn't matter if it was
(raffleState.entranceFee, raffleState.interval, raffleState.vrfCoordinator, raffleState.gasHash, raffleState.subscriptionId, raffleState.callbackGasLimit, raffleState.linkToken, raffleState.deployerKey) = helperConfig.activeNetworkConfig(); or
(entranceFee, interval, vrfCoordinator, gasHash, subscriptionId, callbackGasLimit, linkToken, deployerKey) = helperConfig.activeNetworkConfig();

It still probably would give a stack too deep error, either way.

The only other way I've solved the issue live on a chain is by using arrays, not structs, because those reduce the number of pointers.

I just now removed my two gas variables (gasHash and callbackgasLimit), ran forge test, and this fix solved the problem for me. Good luck, and excellent persistence.

[usmanfarooq91]

@sharonphiliplima Yes you can remove gasLane, it doesn't matter which variable you remove as long as you remove one.

[a1111198]

I solved my issuse by changing address(raffle) from stack to Memory and not removing any of the above varibale,

from

 addConsumer.addConsumer(
            vrfCoordinator,
            subscriptionId,
            address(raffle),
            deployerKey
        );

To

address raffleAddress = address(raffle);
        addConsumer.addConsumer(
            vrfCoordinator,
            subscriptionId,
            raffleAddress,
            deployerKey
        );