Add ability to properly restrict languages when parsing cost models

Author: Lucsanszky

eras/alonzo/impl/src/Cardano/Ledger/Alonzo/Genesis.hs

@@ -112,7 +112,7 @@ instance FromJSON AlonzoExtraConfig where
   parseJSON = Aeson.withObject "Extra Config" $ \o ->
     o .:? "costModels" >>= \case
       Nothing -> pure $ AlonzoExtraConfig Nothing
-      Just val -> AlonzoExtraConfig . Just <$> parseCostModels True val
+      Just val -> AlonzoExtraConfig . Just <$> parseCostModels True [] val
 
 instance ToJSON AlonzoExtraConfig where
   toJSON (AlonzoExtraConfig cms) = Aeson.object ["costModels" .= cms]
@@ -221,7 +221,7 @@ instance ToCBOR AlonzoGenesis where
 instance FromJSON AlonzoGenesis where
   parseJSON = Aeson.withObject "Alonzo Genesis" $ \o -> do
     agCoinsPerUTxOWord <- o .: "lovelacePerUTxOWord"
-    cms <- parseCostModels False =<< o .: "costModels"
+    cms <- parseCostModels False [PlutusV1] =<< o .: "costModels"
     agPrices <- o .: "executionPrices"
     agMaxTxExUnits <- o .: "maxTxExUnits"
     agMaxBlockExUnits <- o .: "maxBlockExUnits"

libs/cardano-ledger-core/CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## 1.19.0.0
 
+* Changed type of `parseCostModels` by adding `[Language]` argument
 * Add `cddl` sub-library.
 * Limit `DecCBORGroup` decoding of `ProtVer` fields to `Word32` starting from protocol version `12`
 * Change `Relation` type to only be visible at the type level

libs/cardano-ledger-core/src/Cardano/Ledger/Plutus/CostModels.hs

@@ -134,17 +134,24 @@ instance NFData CostModel where
   rnf (CostModel lang cm ectx) = lang `deepseq` cm `deepseq` rnf ectx
 
 instance FromJSON CostModels where
-  parseJSON = parseCostModels True
+  parseJSON = parseCostModels True []
 
 parseCostModels ::
   -- | Do not restrict number of parameters to the initial count and allow parsing of cost models
   -- for unknown plutus versions.
   Bool ->
+  -- | Restrict parsable Plutus language versions to the given list.
+  -- If left empty, no restrictions are applied and all non-native languages
+  -- are parsed.
+  [Language] ->
   Value ->
   Parser CostModels
-parseCostModels isLenient =
+parseCostModels isLenient languages =
   withObject "CostModels" $ \o -> do
-    cms <- mapM (parseCostModel isLenient o) nonNativeLanguages
+    cms <-
+      if null languages
+        then mapM (parseCostModel isLenient o) nonNativeLanguages
+        else mapM (parseCostModel isLenient o) languages
     let cmsMap = Map.fromList [(cmLanguage cm, cm) | Just cm <- cms]
     unknownCostModels <-
       if isLenient