FuelLabs/fuels-ts · error · FuelError

INVALID_TRANSACTION_INPUT

INVALID_TRANSACTION_INPUT

Error message

Contract input should be of type 'contract'.

What it means

Thrown by `getInputContract()` (transaction-summary/input.ts) when the input at the given `inputIndex` exists but its `type` is not `InputType.Contract`. The function is used during transaction summary assembly to resolve a contract input referenced by an output; if the slot holds a Coin or Message instead, the type contract is violated and decoding would be unsafe.

Source

Thrown at packages/account/src/providers/transaction-summary/input.ts:117

  return undefined;
}

/** @hidden */
export function getInputContractFromIndex(
  inputs: Input[],
  inputIndex: number
): InputContract | undefined {
  if (inputIndex == null) {
    return undefined;
  }

  const contractInput = inputs?.[inputIndex];

  if (!contractInput) {
    return undefined;
  }
  if (contractInput.type !== InputType.Contract) {
    throw new FuelError(
      ErrorCode.INVALID_TRANSACTION_INPUT,
      `Contract input should be of type 'contract'.`
    );
  }

  return contractInput as InputContract;
}

/** @hidden */
export function getInputAccountAddress(input: Input) {
  if (input.type === InputType.Coin) {
    return input.owner.toString();
  }

  if (input.type === InputType.Message) {
    return input.recipient.toString();
  }

View on GitHub (pinned to b3f37c91ac)

Solutions

1. Ensure contract outputs reference the correct `inputIndex` that points to a contract-type input.
2. Do not reorder inputs after building outputs; rebuild the transaction request if input order changes.
3. Validate input/output index consistency before submitting.

Example fix

// before (contract output points at a coin input slot)
request.inputs = [coinInput];
request.outputs = [{ type: OutputType.Contract, inputIndex: 0 }]; // wrong
// after
request.inputs = [contractInput, coinInput];
request.outputs = [{ type: OutputType.Contract, inputIndex: 0 }]; // points at contract

import { InputType } from '@fuel-ts/transactions';
function contractInputAt(inputs: any[], idx: number) {
  const inp = inputs[idx];
  return inp && inp.type === InputType.Contract ? inp : undefined;
}

function isInputContract(v: unknown): v is import('@fuel-ts/transactions').InputContract {
  return typeof v === 'object' && v !== null && (v as any).type === InputType.Contract;
}

null

When it happens

Trigger: Transaction summary assembly where a receipt/output references `inputIndex` pointing at a non-contract input. Typically reached internally from `getTransactionSummary` / `getTransactionSummaryFromRequest` when correlating contract outputs to their inputs.

Common situations: A malformed or corrupted transaction where input/output indices are inconsistent; a manually-constructed transaction with a contract output referencing a coin input index; decoding a transaction built by an incompatible tool that ordered inputs differently.

Related errors

• INVALID_TRANSACTION_INPUT
• UNSUPPORTED_TRANSACTION_TYPE
• INVALID_TRANSACTION_STATUS
• INVALID_RECEIPT_TYPE
• DECODE_ERROR

AI-assisted analysis of FuelLabs/fuels-ts@b3f37c91ac (2026-08-12). Data as JSON: /api/errors/964129f6541a9642. Report an issue: GitHub.