Subgraph indexing error, mapping aborted with ethereum value is not an address

Question

Subgraph indexing failing due to mapping abortion with reason - ethereum value is not an address, from one of the handlers. I understand the issue if from the handlePaymentExpenseCreated() function but I'm unable to pinpoint the issue. Everything seems right. Thank you in advance. Here's the image of the logs.

The subgraph schema

type ActiveExpense @entity {
  id: ID!
  payer: Bytes!
  to: Bytes!
  splitBy: [Bytes!]!
  splitAmounts: [BigInt!]!
  expenseIndex: BigInt!
  blockTimestamp: BigInt!
  transactionHash: Bytes!
}

The mapping handler function

export function handlePaymentExpenseCreated(
  event: PaymentExpenseCreatedEvent
): void {
  const id: string = getIdFromParams(event.params.param0, event.params.param4);
  let activeExpense = ActiveExpense.load(id);
  let newExpense = new PaymentExpenseCreated(id);

  if (!activeExpense) {
    activeExpense = new ActiveExpense(id);
  }

  newExpense.payer = event.params.param0;
  activeExpense.payer = event.params.param0;

  newExpense.to = event.params.param1;
  activeExpense.to = event.params.param1;

  // two different methods of assinging type Address[] to type Bytes[]
  const splitAddresses = event.params.param2.map<Bytes>(
    (address: Bytes) => address
  );
  newExpense.splitBy = splitAddresses;
  activeExpense.splitBy = changetype<Bytes[]>(event.params.param2);

  newExpense.splitAmounts = event.params.param3;
  activeExpense.splitAmounts = event.params.param3;

  newExpense.expenseIndex = event.params.param4;
  activeExpense.expenseIndex = event.params.param4;

  newExpense.blockTimestamp = event.block.timestamp;
  activeExpense.blockTimestamp = event.block.timestamp;

  newExpense.transactionHash = event.transaction.hash;
  activeExpense.transactionHash = event.transaction.hash;

  newExpense.save();
  activeExpense.save();
}

Subgraph yaml file

specVersion: 0.0.5
schema:
  file: ./schema.graphql
dataSources:
  - kind: ethereum
    name: DeSplit
    network: goerli
    source:
      address: "0xA74c0C03A05B94a67FDc09351b312f122308335d"
      abi: DeSplit
      startBlock: 8402740
    mapping:
      kind: ethereum/events
      apiVersion: 0.0.7
      language: wasm/assemblyscript
      entities:
        - ExpenseSettled
        - PaymentExpenseCreated
      abis:
        - name: DeSplit
          file: ./abis/DeSplit.json
      eventHandlers:
        - event: ExpenseSettled(address,address,uint256,uint256)
          handler: handleExpenseSettled
        - event: PaymentExpenseCreated(address,address,address[],uint256[],uint256)
          handler: handlePaymentExpenseCreated
      file: ./src/de-split.ts

The event emitted from the contract and link to the contract

emit PaymentExpenseCreated(
            msg.sender,
            _to, //address
            _splitBy, //address[]
            _splitAmount, // uint256[]
            expenses.length - 1 //uint256
        );

https://goerli.etherscan.io/address/0xA74c0C03A05B94a67FDc09351b312f122308335d

Answer 1

It took me two days to solve the same error. First of all, the event on your contract has no parameter name, which makes it impossible for the subgraph to map accurately. If you can't change the contract, you can try another method, manually mapping it to your subgraph event by modifying the abi in the abis/ folder.