Introduce futurePParamsGovStateL:

And `futurePParamsShelleyGovStateL` and `sgsFuturePParams`

For now none of these are functional they are just placeholders

eras/allegra/impl/src/Cardano/Ledger/Allegra/PParams.hs

@@ -43,17 +43,14 @@ instance Crypto c => EraPParams (AllegraEra c) where
 
 instance Crypto c => EraGov (AllegraEra c) where
   type GovState (AllegraEra c) = ShelleyGovState (AllegraEra c)
-  emptyGovState =
-    ShelleyGovState
-      emptyPPPUpdates
-      emptyPPPUpdates
-      emptyPParams
-      emptyPParams
+  emptyGovState = emptyShelleyGovState
 
   getProposedPPUpdates = Just . sgsCurProposals
 
   curPParamsGovStateL = curPParamsShelleyGovStateL
 
   prevPParamsGovStateL = prevPParamsShelleyGovStateL
 
+  futurePParamsGovStateL = futurePParamsShelleyGovStateL
+
   obligationGovState = const mempty

eras/allegra/impl/src/Cardano/Ledger/Allegra/Translation.hs

@@ -100,6 +100,7 @@ instance Crypto c => TranslateEra (AllegraEra c) ShelleyGovState where
         , sgsFutureProposals = translateEra' ctxt $ sgsFutureProposals ps
         , sgsCurPParams = translateEra' ctxt $ sgsCurPParams ps
         , sgsPrevPParams = translateEra' ctxt $ sgsPrevPParams ps
+        , sgsFuturePParams = translateEra' ctxt <$> sgsFuturePParams ps
         }
 
 instance Crypto c => TranslateEra (AllegraEra c) ShelleyTxOut where

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

@@ -120,7 +120,6 @@ import Cardano.Ledger.Plutus.ExUnits (
 import Cardano.Ledger.Plutus.Language (Language (..))
 import Cardano.Ledger.Shelley.PParams (
   ShelleyPParams (..),
-  emptyPPPUpdates,
   shelleyCommonPParamsHKDPairs,
   shelleyCommonPParamsHKDPairsV6,
   shelleyCommonPParamsHKDPairsV8,
@@ -378,19 +377,16 @@ instance Crypto c => AlonzoEraPParams (AlonzoEra c) where
 
 instance Crypto c => EraGov (AlonzoEra c) where
   type GovState (AlonzoEra c) = ShelleyGovState (AlonzoEra c)
-  emptyGovState =
-    ShelleyGovState
-      emptyPPPUpdates
-      emptyPPPUpdates
-      emptyPParams
-      emptyPParams
+  emptyGovState = emptyShelleyGovState
 
   getProposedPPUpdates = Just . sgsCurProposals
 
   curPParamsGovStateL = curPParamsShelleyGovStateL
 
   prevPParamsGovStateL = prevPParamsShelleyGovStateL
 
+  futurePParamsGovStateL = futurePParamsShelleyGovStateL
+
   obligationGovState = const mempty
 
 instance Era era => EncCBOR (AlonzoPParams Identity era) where

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

@@ -152,6 +152,7 @@ instance Crypto c => TranslateEra (AlonzoEra c) ShelleyGovState where
         , sgsFutureProposals = translateEra' ctxt $ sgsFutureProposals ps
         , sgsCurPParams = translateEra' ctxt $ sgsCurPParams ps
         , sgsPrevPParams = translateEra' ctxt $ sgsPrevPParams ps
+        , sgsFuturePParams = translateEra' ctxt <$> sgsFuturePParams ps
         }
 
 instance Crypto c => TranslateEra (AlonzoEra c) ProposedPPUpdates where

eras/alonzo/impl/testlib/Test/Cardano/Ledger/Alonzo/Arbitrary.hs

@@ -337,7 +337,6 @@ instance Era era => Arbitrary (AlonzoContextError era) where
 
 instance
   ( EraTxOut era
-  , Era era
   , Arbitrary (Value era)
   , Arbitrary (TxOut era)
   , Arbitrary (PredicateFailure (EraRule "UTXOS" era))

eras/babbage/impl/src/Cardano/Ledger/Babbage/PParams.hs

@@ -95,7 +95,7 @@ import Cardano.Ledger.Core (EraPParams (..))
 import Cardano.Ledger.Crypto (Crypto)
 import Cardano.Ledger.HKD (HKD, HKDFunctor (..))
 import Cardano.Ledger.Orphans ()
-import Cardano.Ledger.Shelley.PParams (emptyPPPUpdates, shelleyCommonPParamsHKDPairsV8)
+import Cardano.Ledger.Shelley.PParams (shelleyCommonPParamsHKDPairsV8)
 import Control.DeepSeq (NFData)
 import Data.Aeson as Aeson (
   FromJSON (..),
@@ -263,19 +263,16 @@ instance Crypto c => BabbageEraPParams (BabbageEra c) where
 
 instance Crypto c => EraGov (BabbageEra c) where
   type GovState (BabbageEra c) = ShelleyGovState (BabbageEra c)
-  emptyGovState =
-    ShelleyGovState
-      emptyPPPUpdates
-      emptyPPPUpdates
-      emptyPParams
-      emptyPParams
+  emptyGovState = emptyShelleyGovState
 
   getProposedPPUpdates = Just . sgsCurProposals
 
   curPParamsGovStateL = curPParamsShelleyGovStateL
 
   prevPParamsGovStateL = prevPParamsShelleyGovStateL
 
+  futurePParamsGovStateL = futurePParamsShelleyGovStateL
+
   obligationGovState = const mempty
 
 instance Era era => EncCBOR (BabbagePParams Identity era) where

eras/babbage/impl/src/Cardano/Ledger/Babbage/Translation.hs

@@ -158,6 +158,7 @@ instance Crypto c => TranslateEra (BabbageEra c) ShelleyGovState where
         , sgsFutureProposals = translateEra' ctxt $ sgsFutureProposals ps
         , sgsCurPParams = translateEra' ctxt $ sgsCurPParams ps
         , sgsPrevPParams = translateEra' ctxt $ sgsPrevPParams ps
+        , sgsFuturePParams = translateEra' ctxt <$> sgsFuturePParams ps
         }
 
 instance Crypto c => TranslateEra (BabbageEra c) ProposedPPUpdates where

eras/mary/impl/src/Cardano/Ledger/Mary/PParams.hs

@@ -10,6 +10,8 @@ import Cardano.Ledger.Shelley.Governance (
   EraGov (..),
   ShelleyGovState (..),
   curPParamsShelleyGovStateL,
+  emptyShelleyGovState,
+  futurePParamsShelleyGovStateL,
   prevPParamsShelleyGovStateL,
  )
 import Cardano.Ledger.Shelley.PParams
@@ -48,17 +50,14 @@ instance Crypto c => EraPParams (MaryEra c) where
 
 instance Crypto c => EraGov (MaryEra c) where
   type GovState (MaryEra c) = ShelleyGovState (MaryEra c)
-  emptyGovState =
-    ShelleyGovState
-      emptyPPPUpdates
-      emptyPPPUpdates
-      emptyPParams
-      emptyPParams
+  emptyGovState = emptyShelleyGovState
 
   getProposedPPUpdates = Just . sgsCurProposals
 
   curPParamsGovStateL = curPParamsShelleyGovStateL
 
   prevPParamsGovStateL = prevPParamsShelleyGovStateL
 
+  futurePParamsGovStateL = futurePParamsShelleyGovStateL
+
   obligationGovState = const mempty

eras/mary/impl/src/Cardano/Ledger/Mary/Translation.hs

@@ -130,6 +130,7 @@ instance Crypto c => TranslateEra (MaryEra c) ShelleyGovState where
         , sgsFutureProposals = translateEra' ctxt $ sgsFutureProposals ps
         , sgsCurPParams = translateEra' ctxt $ sgsCurPParams ps
         , sgsPrevPParams = translateEra' ctxt $ sgsPrevPParams ps
+        , sgsFuturePParams = translateEra' ctxt <$> sgsFuturePParams ps
         }
 
 instance Crypto c => TranslateEra (MaryEra c) UTxOState where

eras/shelley/impl/CHANGELOG.md

@@ -2,7 +2,7 @@
 
 ## 1.10.1.0
 
-*
+* Introduce `futurePParamsGovStateL`, `futurePParamsShelleyGovStateL` and `sgsFuturePParams`
 
 ### `testlib`
 

eras/shelley/impl/src/Cardano/Ledger/Shelley/Governance.hs

@@ -13,11 +13,13 @@
 module Cardano.Ledger.Shelley.Governance (
   EraGov (..),
   ShelleyGovState (..),
+  emptyShelleyGovState,
   -- Lens
   proposalsL,
   futureProposalsL,
   curPParamsShelleyGovStateL,
   prevPParamsShelleyGovStateL,
+  futurePParamsShelleyGovStateL,
 
   -- * Deprecations
   proposals,
@@ -87,6 +89,9 @@ class
   -- | Lens for accessing the previous protocol parameters
   prevPParamsGovStateL :: Lens' (GovState era) (PParams era)
 
+  -- | Lens for accessing the previous protocol parameters
+  futurePParamsGovStateL :: Lens' (GovState era) (Maybe (PParams era))
+
   obligationGovState :: GovState era -> Obligations
 
 instance Crypto c => EraGov (ShelleyEra c) where
@@ -98,13 +103,19 @@ instance Crypto c => EraGov (ShelleyEra c) where
 
   prevPParamsGovStateL = prevPParamsShelleyGovStateL
 
+  futurePParamsGovStateL = futurePParamsShelleyGovStateL
+
   obligationGovState = const mempty -- No GovState obigations in ShelleyEra
 
 data ShelleyGovState era = ShelleyGovState
   { sgsCurProposals :: !(ProposedPPUpdates era)
   , sgsFutureProposals :: !(ProposedPPUpdates era)
   , sgsCurPParams :: !(PParams era)
   , sgsPrevPParams :: !(PParams era)
+  , sgsFuturePParams :: Maybe (PParams era)
+  -- ^ Prediction of any parameter changes that might happen on the epoch boundary. The
+  -- field is lazy on purpose, since we only need to compute this field only towards the
+  -- end of the epoch.
   }
   deriving (Generic)
 
@@ -133,6 +144,10 @@ curPParamsShelleyGovStateL = lens sgsCurPParams (\sps x -> sps {sgsCurPParams =
 prevPParamsShelleyGovStateL :: Lens' (ShelleyGovState era) (PParams era)
 prevPParamsShelleyGovStateL = lens sgsPrevPParams (\sps x -> sps {sgsPrevPParams = x})
 
+futurePParamsShelleyGovStateL :: Lens' (ShelleyGovState era) (Maybe (PParams era))
+futurePParamsShelleyGovStateL =
+  lens sgsFuturePParams (\sps x -> sps {sgsFuturePParams = x})
+
 deriving instance
   ( Show (PParamsUpdate era)
   , Show (PParams era)
@@ -164,13 +179,14 @@ instance
   ) =>
   EncCBOR (ShelleyGovState era)
   where
-  encCBOR (ShelleyGovState ppup fppup pp ppp) =
+  encCBOR (ShelleyGovState ppup fppup pp ppp fpp) =
     encode $
       Rec ShelleyGovState
         !> To ppup
         !> To fppup
         !> To pp
         !> To ppp
+        !> To fpp
 
 instance
   ( Era era
@@ -186,6 +202,7 @@ instance
         <! From
         <! From
         <! From
+        <! From
 
 instance
   ( Era era
@@ -227,9 +244,13 @@ toPPUPStatePairs ShelleyGovState {..} =
   ]
 
 instance EraPParams era => Default (ShelleyGovState era) where
-  def =
-    ShelleyGovState
-      emptyPPPUpdates
-      emptyPPPUpdates
-      emptyPParams
-      emptyPParams
+  def = emptyShelleyGovState
+
+emptyShelleyGovState :: EraPParams era => ShelleyGovState era
+emptyShelleyGovState =
+  ShelleyGovState
+    emptyPPPUpdates
+    emptyPPPUpdates
+    emptyPParams
+    emptyPParams
+    Nothing

eras/shelley/impl/testlib/Test/Cardano/Ledger/Shelley/Arbitrary.hs

@@ -306,7 +306,7 @@ instance
   ) =>
   Arbitrary (ShelleyGovState era)
   where
-  arbitrary = ShelleyGovState <$> arbitrary <*> arbitrary <*> arbitrary <*> arbitrary
+  arbitrary = ShelleyGovState <$> arbitrary <*> arbitrary <*> arbitrary <*> arbitrary <*> arbitrary
   shrink = genericShrink
 
 ------------------------------------------------------------------------------------------

libs/cardano-ledger-test/src/Test/Cardano/Ledger/Constrained/Vars.hs

@@ -407,6 +407,9 @@ futurePParamProposals p = Var (pV p "futurePParamProposals" (MapR GenHashR (PPar
 currPParams :: Era era => Proof era -> Term era (PParamsF era)
 currPParams p = Var (pV p "currPParams" (PParamsR p) No)
 
+futurePParams :: Era era => Proof era -> Term era (Maybe (PParamsF era))
+futurePParams p = Var (pV p "futurePParams" (MaybeR (PParamsR p)) No)
+
 prevPParams :: Gov.EraGov era => Proof era -> Term era (PParamsF era)
 prevPParams p =
   Var (V "prevPParams" (PParamsR p) (Yes NewEpochStateR (nesEsL . prevPParamsEpochStateL . ppFL p)))
@@ -424,13 +427,15 @@ ppupStateT p =
     :$ Lensed (futurePParamProposals p) (futureProposalsL . proposedMapL p)
     :$ Lensed (currPParams p) (Gov.curPParamsGovStateL . pparamsFL p)
     :$ Lensed (prevPParams p) (Gov.curPParamsGovStateL . pparamsFL p)
+    :$ Lensed (futurePParams p) (Gov.futurePParamsGovStateL . pparamsMaybeFL p)
   where
     ppupfun x y (PParamsF _ pp) (PParamsF _ prev) =
       ShelleyGovState
         (ProposedPPUpdates (Map.map unPParamsUpdate x))
         (ProposedPPUpdates (Map.map unPParamsUpdate y))
         pp
         prev
+        . fmap (\(PParamsF _ fpp) -> fpp)
 
 govL :: Lens' (GovState era) (Gov.GovState era)
 govL = lens f g
@@ -2139,6 +2144,12 @@ constitutionChildren = Var $ V "constitutionChildren" (SetR GovActionIdR) No
 pparamsFL :: Proof era -> Lens' (PParams era) (PParamsF era)
 pparamsFL p = lens (PParamsF p) (\_ (PParamsF _ x) -> x)
 
+pparamsMaybeFL :: Proof era -> Lens' (Maybe (PParams era)) (Maybe (PParamsF era))
+pparamsMaybeFL p =
+  lens
+    (fmap (PParamsF p))
+    (\_ -> fmap (\(PParamsF _ x) -> x))
+
 smCommL :: Lens' (StrictMaybe (Committee era)) (Committee era)
 smCommL = lens getter (\_ t -> SJust t)
   where

libs/cardano-ledger-test/src/Test/Cardano/Ledger/Generic/PrettyCore.hs

@@ -2805,14 +2805,15 @@ pcGovState p x = case whichGovState p of
   (GovStateConwayToConway) -> unReflect pcConwayGovState p x
 
 pcShelleyGovState :: Proof era -> ShelleyGovState era -> PDoc
-pcShelleyGovState p (ShelleyGovState _proposal _futproposal pp prevpp) =
+pcShelleyGovState p (ShelleyGovState _proposal _futproposal pp prevpp mfuturepp) =
   ppRecord
     "ShelleyGovState"
-    [ ("proposals", ppString "(Proposals ...)")
-    , ("futureProposals", ppString "(Proposals ...)")
-    , ("pparams", pcPParamsSynopsis p pp)
-    , ("prevParams", pcPParamsSynopsis p prevpp)
-    ]
+    $ [ ("proposals", ppString "(Proposals ...)")
+      , ("futureProposals", ppString "(Proposals ...)")
+      , ("pparams", pcPParamsSynopsis p pp)
+      , ("prevParams", pcPParamsSynopsis p prevpp)
+      ]
+      ++ [("futureParams", pcPParamsSynopsis p futurepp) | Just futurepp <- [mfuturepp]]
 
 instance Reflect era => PrettyA (ShelleyGovState era) where
   prettyA = pcShelleyGovState reify