Use rdptr instead of direct constructor

The redeemers are indexed to the input they apply to, assuming the
inputs are sorted by (TxId, TxIx), so we cannot naively use a counter
to build those. The rdptr function retrieves the correct index for the
pointer.

hydra-node/src/Hydra/Chain/Direct/Tx.hs

@@ -15,10 +15,10 @@ import Cardano.Binary (serialize)
 import Cardano.Ledger.Address (Addr (Addr))
 import Cardano.Ledger.Alonzo (AlonzoEra, Script)
 import Cardano.Ledger.Alonzo.Data (Data (Data), hashData)
-import Cardano.Ledger.Alonzo.Scripts (ExUnits (..), Script (PlutusScript), Tag (Spend))
-import Cardano.Ledger.Alonzo.Tx (IsValid (IsValid), ValidatedTx (..))
+import Cardano.Ledger.Alonzo.Scripts (ExUnits (..), Script (PlutusScript))
+import Cardano.Ledger.Alonzo.Tx (IsValid (IsValid), ScriptPurpose (Spending), ValidatedTx (..), rdptr)
 import Cardano.Ledger.Alonzo.TxBody (TxBody (..), TxOut (TxOut))
-import Cardano.Ledger.Alonzo.TxWitness (RdmrPtr (RdmrPtr), Redeemers (..), TxDats (..), TxWitness (..), unTxDats)
+import Cardano.Ledger.Alonzo.TxWitness (RdmrPtr, Redeemers (..), TxDats (..), TxWitness (..), unTxDats)
 import Cardano.Ledger.Crypto (StandardCrypto)
 import Cardano.Ledger.Era (hashScript)
 import qualified Cardano.Ledger.SafeHash as SafeHash
@@ -154,16 +154,20 @@ abortTx (txIn, token, HeadParameters{contestationPeriod, parties}) initInputs =
   -- TODO(SN): dummy exUnits, balancing overrides them?
   redeemers =
     Map.fromList $
-      (RdmrPtr Spend 0, (headRedeemer, ExUnits 0 0)) :
-      initialRedeemers
+      foldl' hasRdmrPtr [] $
+        (rdptr body (Spending txIn), (headRedeemer, ExUnits 0 0)) :
+        initialRedeemers
+
+  hasRdmrPtr acc = \case
+    (SNothing, _) -> acc
+    (SJust v, ex) -> (v, ex) : acc
 
   headRedeemer = Data $ toData Head.Abort
 
   initialRedeemers =
-    zipWith
-      (\rd n -> (RdmrPtr Spend n, (rd, ExUnits 0 0)))
-      (map (const $ Data $ toData ()) initInputs)
-      [1 ..]
+    map
+      (\(txin, _) -> (rdptr body (Spending txin), (Data $ toData (), ExUnits 0 0)))
+      initInputs
 
   scripts = Map.fromList $ map (\s -> (hashScript @Era s, s)) [initialScript, headScript]
 

hydra-node/test/Hydra/Chain/Direct/TxSpec.hs

@@ -101,7 +101,7 @@ spec =
             utxo = UTxO $ Map.fromList $ (txIn, txOut) : map toTxOut initials
 
             results = validateTxScriptsUnlimited tx utxo
-         in 1 == length (rights $ Map.elems results)
+         in 1 + length initials == length (rights $ Map.elems results)
               & counterexample ("Evaluation results: " <> show results)
               & counterexample ("Tx: " <> show tx)
               & counterexample ("Input utxo: " <> show utxo)