INDEXING ERROR Error: failed to process trigger: block #34244323 (0x6c0e…9e1b), transaction

[decentralized-86]

ERROR

INDEXING ERROR
Error: failed to process trigger: block #34244323 (0x6c0e…9e1b), transaction a7247ed7255c7d92a07654eea43d200d7c89717691c2baa54baf5eaaadd510d5: Entity ActiveItem[0x00xc8d9dab212c7b19a5c4c9c566bb8b89f389d40e8]: missing value for non-nullable field `buyer` wasm backtrace: 0: 0x2cd8 - <unknown>!generated/schema/ActiveItem#save 1: 0x37d8 - <unknown>!src/marketplace/handleItemlisted

To view more details about this indexing error, please view the documentation.

I'm using The graph for the first time And As reading the error the bug is supposed to be in handleitemlisted function
**handleitelisted code **

export function handleItemlisted(event: ItemlistedEvent): void {
  /* Item Listed Handling */
  let Itemlisted = ItemListed.load(
    getIdFromEventParams(event.params.tokenId, event.params.nftAddress)
  );
  let activeItem = ActiveItem.load(
    getIdFromEventParams(event.params.tokenId, event.params.nftAddress)
  );
  if (!Itemlisted) {
    Itemlisted = new ItemListed(
      getIdFromEventParams(event.params.tokenId, event.params.nftAddress)
    );
  }
  if (!activeItem) {
    activeItem = new ActiveItem(
      getIdFromEventParams(event.params.tokenId, event.params.nftAddress)
    );
  }
  Itemlisted.seller = event.params.seller;
  Itemlisted.nftAddress = event.params.nftAddress;
  Itemlisted.tokenId = event.params.tokenId;
  Itemlisted.price = event.params.price;
  activeItem.nftcontractaddress = event.params.nftAddress;
  activeItem.seller = event.params.seller;
  activeItem.tokenId = event.params.tokenId;
  activeItem.price = event.params.price;

  activeItem.buyer = Address.fromString(
    "0x0000000000000000000000000000000000000000"
  );

  Itemlisted.save();
  activeItem.save();
}

Marketplace.ts

import { Address, BigInt } from "@graphprotocol/graph-ts";
import {
  Itembought as ItemboughtEvent,
  Itemcancelled as ItemcancelledEvent,
  Itemlisted as ItemlistedEvent,
  ListingUpdated as ListingUpdatedEvent,
} from "../generated/Marketplace/Marketplace";
import {
  ActiveItem,
  ItemBought,
  ItemCancelled,
  ItemListed,
  ListingUpdated,
} from "../generated/schema";

export function handleItembought(event: ItemboughtEvent): void {
  let Itembought = ItemBought.load(
    getIdFromEventParams(event.params.tokenId, event.params.nftcontractaddress)
  );
  let activeItem = ActiveItem.load(
    getIdFromEventParams(event.params.tokenId, event.params.nftcontractaddress)
  );

  if (!Itembought) {
    Itembought = new ItemBought(
      getIdFromEventParams(
        event.params.tokenId,
        event.params.nftcontractaddress
      )
    );
  }
  Itembought.soldto = event.params.soldto;
  Itembought.nftcontractaddress = event.params.nftcontractaddress;
  Itembought.tokenId = event.params.tokenId;
  activeItem!.buyer = event.params.soldto;

  Itembought.save();
  activeItem!.save();
}

export function handleItemcancelled(event: ItemcancelledEvent): void {
  /* Item Cancelled */
  let itemCancelled = ItemCancelled.load(
    getIdFromEventParams(event.params.tokenId, event.params.nftcontractaddress)
  );
  let activeItem = ActiveItem.load(
    getIdFromEventParams(event.params.tokenId, event.params.nftcontractaddress)
  );
  if (!itemCancelled) {
    itemCancelled = new ItemCancelled(
      getIdFromEventParams(
        event.params.tokenId,
        event.params.nftcontractaddress
      )
    );
  }
  itemCancelled.seller = event.params.seller;
  itemCancelled.nftcontractaddress = event.params.nftcontractaddress;
  itemCancelled.tokenId = event.params.tokenId;
  activeItem!.buyer = Address.fromString(
    "0x0000000000000000000000000000000000000000"
  );
  itemCancelled.save();
  activeItem!.save();
}

export function handleItemlisted(event: ItemlistedEvent): void {
  /* Item Listed Handling */
  let Itemlisted = ItemListed.load(
    getIdFromEventParams(event.params.tokenId, event.params.nftAddress)
  );
  let activeItem = ActiveItem.load(
    getIdFromEventParams(event.params.tokenId, event.params.nftAddress)
  );
  if (!Itemlisted) {
    Itemlisted = new ItemListed(
      getIdFromEventParams(event.params.tokenId, event.params.nftAddress)
    );
  }
  if (!activeItem) {
    activeItem = new ActiveItem(
      getIdFromEventParams(event.params.tokenId, event.params.nftAddress)
    );
  }
  Itemlisted.seller = event.params.seller;
  Itemlisted.nftAddress = event.params.nftAddress;
  Itemlisted.tokenId = event.params.tokenId;
  Itemlisted.price = event.params.price;
  activeItem.nftcontractaddress = event.params.nftAddress;
  activeItem.seller = event.params.seller;
  activeItem.tokenId = event.params.tokenId;
  activeItem.price = event.params.price;

  activeItem.buyer = Address.fromString(
    "0x0000000000000000000000000000000000000000"
  );

  Itemlisted.save();
  activeItem.save();
}

export function handleListingUpdated(event: ListingUpdatedEvent): void {
  /*  */
}

function getIdFromEventParams(tokenId: BigInt, nftAddress: Address): string {
  return tokenId.toHexString() + nftAddress.toHexString();
}

[alymurtazamemon]

@decentralized-86 Please check this #4324. Lots of errors are already answered you need to just search them throw search bar in the discussions tab.