PlutusV2: Error when spending script output

Question

This is how I spend script's utxos with the Emulator. This one from this example.

grab :: forall w s e. AsContractError e => Contract w s e ()  
grab = do
  utxos <- utxosAt scrAddress                                                                      
  let orefs   = fst <$> Map.toList utxos                                                           
    lookups = Constraints.unspentOutputs utxos <>                                           
              Constraints.plutusV1OtherScript validator                                          
    tx :: TxConstraints Void Void                                                            
    tx      = mconcat [mustSpendScriptOutput oref $ Redeemer $ Builtins.mkI 17 | oref <- orefs]  
                                                                                                 
  ledgerTx <- submitTxConstraintsWith @Void lookups tx                                             
  void $ awaitTxConfirmed $ getCardanoTxId ledgerTx                                                
  Plutus.Contract.logInfo @String $ "collected gifts"  

This is PlutusV1. This works as expected. But with PlutusV2, the lookups now is like:

    lookups = Constraints.unspentOutputs utxos <>                                           
              Constraints.plutusV2OtherScript validator  

Note the version difference in Constraints.plutusV2OtherScript validator.

The rest of the code is the same except that this time the package is plutus-apps v1.0.0.

The V2 script compiles but when grab is called I get this error:

*** CONTRACT STOPPED WITH ERROR: ""ConstraintResolutionContractError (DatumNotFound 03170a2e7597b7b7e3d84c05391d139a62b157e78786d8c082f29dcf4c111314)""

I try Constraints.otherScript (Versioned validator PlutusV2). Same error.

I try Plutus.Trace instead of Plutus.Trace.Emulator. Same error.

This is just one example. I see this "DatumNotFound" error in other projects when trying to work with plutus-apps v1.0.0.

How do I fix this. Or is it just a bug?

Answer 1

The cause is mustPayToOtherScript in the give endpoint where

give :: AsContractError e => Integer -> Contract w s e ()
give amount = do
  let tx = mustPayToOtherScript valHash (Datum $ Builtins.mkI 0) $ Ada.lovelaceValueOf amount 
  ledgerTx <- submitTx tx                                                                         
  void $ awaitTxConfirmed $ getCardanoTxId ledgerTx                                                
  Plutus.Contract.logInfo @String $ printf "made a gift of %d lovelace" amount 

The error is fixed by replacing mustPayToOtherScript with mustPayToOtherScriptWithDatumInTx.

Get the answer from mlabs-haskell/plutip. Thanks to their warning:

-- WARN: at the moment 'mustPayToOtherScript' causes 'DatumNotFound' error during constraints resolution