Error Applying Redeemer Lucid

Question

I get this error when trying to unlock funds from an UTXO in a contract address:

Uncaught (in promise) "Redeemer (Spend, 0): Attempted to apply a non-function:\n\nCon(\n    Unit,\n)\n\nExBudget {\n    mem: 12788611,\n    cpu: 9492522265,\n}\n\n"

is there any problem in the following code?

async function unlock(ref: OutRef, from: SpendingValidator): Promise<TxHash> {
  const [utxo] = await lucid.utxosByOutRef([ref]);

  const tx = await lucid
    .newTx()
    .collectFrom( [utxo], Data.to(new Constr(0,[])) )
    .addSigner(await lucid.wallet.address())
    .attachSpendingValidator(from)
    .complete();

  const signedTx = await tx
    .sign()
    .complete();
 
  return signedTx.submit();
}

here is how I take the validator:

const validator = await readValidator();

async function readValidator(): Promise<SpendingValidator> {
  const validator = JSON.parse(await Deno.readTextFile("plutus.json")).validators[0];
  return {
    type: "PlutusV2",
    script: toHex(cbor.encode(fromHex(validator.compiledCode))), 
    // some alchemy with Uint8Array and other codes that returns pretty much initial thing but a little different
  };
}

Answer 1

You probably already did, but check that you are actually passing the utxos to the tx, and check that the datum is the right one, the datum seems to be hash or its just a bytestring? how does quering the utxo on cli or looking for the datum in explorers look?

It seems no valid utxo is available for spending or the validator itself its wrong.

take a look at this post that seems to be dealing with a similar problem.

Lucid Error "End of input in bytes"

how are you importing your validators cbor into Lucid?, you can use Lucid blueprint parser examples, or if you where using a CLI ready json file (created with aiken blueprint convert) you can copy paste the cborhex, or import it and parse it.