Missing/ No Redeemer Error when spending 2 script outputs

Question

I am getting the following error, when I try to submit a transaction that spends 2 script outputs:

Error while submitting tx: ShelleyTxValidationError ShelleyBasedEraBabbage (ApplyTxError [UtxowFailure (FromAlonzoUtxowFail (MissingRedeemers [(Spending (TxIn (TxId {_unTxId = SafeHash "23e874d6549250c6d845031974212f87edb7f1b1d0f676afdf03cbddaf0ae9ad"}) (TxIx 0)),ScriptHash "d8feffeeee5fe079055719280d2a9603d93dc1289c2dff9912378d51")])),UtxowFailure (FromAlonzoUtxowFail (PPViewHashesDontMatch (SJust (SafeHash "0b672c4621917cc5ff6a62770cbd2841fa419603c43bb0d19d09b45ec184f995")) (SJust (SafeHash "72efce08bafc21afb779a47940e1866b53b4d33da32bc052f15ce80b2e49f5ce")))),UtxowFailure (UtxoFailure (FromAlonzoUtxoFail (UtxosFailure (CollectErrors [NoRedeemer (Spending (TxIn (TxId {_unTxId = SafeHash "23e874d6549250c6d845031974212f87edb7f1b1d0f676afdf03cbddaf0ae9ad"}) (TxIx 0)))]))))])

I am currently using the following code to create the Tx inputs:

for (let i = 0; i < sortedScriptTxInputs.length; i++) {
    const o = sortedScriptTxInputs[i];
    const txIn = TransactionInput.new(TransactionHash.from_bytes(Buffer.from(o.txId, 'hex')), o.idx);
    const redeemer = Redeemer.new(
      RedeemerTag.new_spend(),
      BigNum.from_str(`${i}`),     // NOT SURE IF THIS IS THE RIGHT WAY TO INDEX REDEEMERS ?!
      PlutusData.new_empty_constr_plutus_data(BigNum.zero()),
      ExUnits.new(
        BigNum.from_str("7000000"),
        BigNum.from_str("5000000000")
      )
    );
    const plutusWitness = PlutusWitness.new_with_ref(PlutusScriptSource.new(spendingContract), DatumSource.new_ref_input(txIn), redeemer);
    const amt = Value.new(BigNum.from_str(`${o.value.coins}`));
    txBuilder.add_plutus_script_input(plutusWitness, txIn, amt);
}

After adding collateral, I am creating the respective plutus-v2 CostModel and add it like so:

const costModel = TxBuilderConstants.plutus_vasil_cost_models().get(Language.new_plutus_v2());
if (!costModel)
    throw new Error('Missing cost model');
const costModels = Costmdls.new();
costModels.insert(Language.new_plutus_v2(), costModel);
txBuilder.calc_script_data_hash(costModels);

Observation:

If I inspect the redeemer witness set after building the Tx, I would expect to see 2 redeemers but the array only contains 1.

const tx = txBuilder.build_tx();
console.log('Witness Set before signing:');
console.log(tx.witness_set().redeemers()?.to_json());

Output

Witness Set before signing:
[
  {
    "tag": "Spend",
    "index": "1",
    "data": "{\"constructor\":0,\"fields\":[]}",
    "ex_units": {
      "mem": "7000000",
      "steps": "5000000000"
    }
  }
]

What am I missing or constructing wrongly? My suspicion is that I either create invalid indexed redeemers or that txBuilder.calc_script_data_hash or txBuilder.build_tx does not handle multiple redeemers correctly.

Thanks for any help!

Answer 1

There was a bug in the CSL lib for consuming multiple script outputs in one transaction which was resolved by https://github.com/Emurgo/cardano-serialization-lib/issues/536