Error: call revert exception; VM Exception while processing transaction: reverted with panic code 50

Question

I am getting an unusual error. It would be great if someone can help me out with it.

This is the code of my user interface which sends a transaction to the smart contract.

const provider = new ethers.providers.JsonRpcProvider("https://matic-mumbai.chainstacklabs.com/")

const marketContract = new ethers.Contract(marketplace_mumbai, Marketplace.abi, provider);

const data = await marketContract.fetchMarketItems();

I have checked my arguments for setting up the contract instance are correct, but there is something wrong whenever I call the fetchMarketItems() of my smart contract:

 function fetchMarketItems() public view returns (MarketItem[] memory) {
    uint256 itemCount = itemIds.current();
    uint256 unsoldItemCount = itemIds.current() - itemsSold.current();
    uint256 currentIndex = 0;

    MarketItem[] memory items = new MarketItem[](unsoldItemCount);

    for (uint256 i = 0; i < itemCount; i++) {
        if (idToMarketItem[i + 1].owner == address(0)) {
            uint256 currentId = idToMarketItem[i + 1].itemId;
            MarketItem storage currentItem = idToMarketItem[currentId];
            items[currentIndex] = currentItem;
            currentIndex += 1;
        }
    }
    return items;
}

I get this error:

Uncaught (in promise) Error: call revert exception; VM Exception while processing transaction: reverted with panic code 50 [ See: https://links.ethers.org/v5-errors-CALL_EXCEPTION ] (method="fetchMarketItems()", data="0x4e487b710000000000000000000000000000000000000000000000000000000000000032", errorArgs=[{"type":"BigNumber","hex":"0x32"}], errorName="Panic", errorSignature="Panic(uint256)", reason=null, code=CALL_EXCEPTION, version=abi/5.7.0)
    at Logger.makeError (index.js?dd68:224:1)
    at Logger.throwError (index.js?dd68:233:1)
    at Interface.decodeFunctionResult (interface.js?1df7:345:1)
    at Contract.eval (index.js?b70c:293:1)
    at Generator.next (<anonymous>)
    at fulfilled (index.js?b70c:5:43)

Answer 1

idToMarketItem[i + 1].owner is out of bounds for the last item.

Solidity's array starts with index 0, you don't need to use idToMarketItem[i + 1]. Is your idToMarketItem array padded with some initial item?🤔