From 709b9a1e0448b7b2e9bbaba0c756acb7772e1b0f Mon Sep 17 00:00:00 2001
From: John Ky <john.ky@iohk.io>
Date: Fri, 16 Jun 2023 08:37:09 +1000
Subject: [PATCH 1/2] New requireShelleyBasedEra function

---
 cardano-api/internal/Cardano/Api/Eras.hs | 12 ++++++++++++
 cardano-api/src/Cardano/Api.hs           |  3 +++
 2 files changed, 15 insertions(+)

diff --git a/cardano-api/internal/Cardano/Api/Eras.hs b/cardano-api/internal/Cardano/Api/Eras.hs
index 7e2ccbef5a..4d181a1bc8 100644
--- a/cardano-api/internal/Cardano/Api/Eras.hs
+++ b/cardano-api/internal/Cardano/Api/Eras.hs
@@ -49,6 +49,9 @@ module Cardano.Api.Eras
     -- * Data family instances
   , AsType(AsByronEra, AsShelleyEra, AsAllegraEra, AsMaryEra, AsAlonzoEra, AsBabbageEra, AsConwayEra,
            AsByron,    AsShelley,    AsAllegra,    AsMary,    AsAlonzo,    AsBabbage, AsConway)
+
+    -- * Assertions on era
+  , requireShelleyBasedEra
   ) where
 
 import           Cardano.Api.HasTypeProxy
@@ -523,3 +526,12 @@ eraProtVerLow era =
     ShelleyBasedEraAlonzo  -> L.eraProtVerLow @L.Alonzo
     ShelleyBasedEraBabbage -> L.eraProtVerLow @L.Babbage
     ShelleyBasedEraConway  -> L.eraProtVerLow @L.Conway
+
+requireShelleyBasedEra :: ()
+  => Applicative m
+  => CardanoEra era
+  -> m (Maybe (ShelleyBasedEra era))
+requireShelleyBasedEra era =
+  case cardanoEraStyle era of
+    LegacyByronEra -> pure Nothing
+    ShelleyBasedEra sbe -> pure (Just sbe)
diff --git a/cardano-api/src/Cardano/Api.hs b/cardano-api/src/Cardano/Api.hs
index 757b1c1622..c26106dbad 100644
--- a/cardano-api/src/Cardano/Api.hs
+++ b/cardano-api/src/Cardano/Api.hs
@@ -34,6 +34,9 @@ module Cardano.Api (
     cardanoEraStyle,
     shelleyBasedToCardanoEra,
 
+    -- * Assertions on era
+    requireShelleyBasedEra,
+
     -- ** IO
     File(..),
     FileDirection(..),

From 62ab351626f14379cd08f8ab4102cf2ce37cfce2 Mon Sep 17 00:00:00 2001
From: John Ky <john.ky@iohk.io>
Date: Fri, 16 Jun 2023 10:28:49 +1000
Subject: [PATCH 2/2] Delete getSbe function.  Use requireShelleyBasedEra
 function instead

---
 .../internal/Cardano/Api/Convenience/Query.hs    | 16 ++++++----------
 1 file changed, 6 insertions(+), 10 deletions(-)

diff --git a/cardano-api/internal/Cardano/Api/Convenience/Query.hs b/cardano-api/internal/Cardano/Api/Convenience/Query.hs
index 6cd8e8831e..33d6f7c6e2 100644
--- a/cardano-api/internal/Cardano/Api/Convenience/Query.hs
+++ b/cardano-api/internal/Cardano/Api/Convenience/Query.hs
@@ -82,8 +82,8 @@ queryStateForBalancedTx :: ()
           , Set PoolId
           , Map StakeCredential Lovelace))
 queryStateForBalancedTx era allTxIns certs = runExceptT $ do
-  qSbe <- pure (getSbe $ cardanoEraStyle era)
-    & onLeft left
+  sbe <- requireShelleyBasedEra era
+    & onNothing (left ByronEraNotSupported)
 
   qeInMode <- pure (toEraInMode era CardanoMode)
     & onNothing (left (EraConsensusModeMismatch (AnyConsensusMode CardanoMode) (getIsCardanoEraConstraint era $ AnyCardanoEra era)))
@@ -93,11 +93,11 @@ queryStateForBalancedTx era allTxIns certs = runExceptT $ do
         _ -> Nothing
 
   -- Query execution
-  utxo <- lift (queryUtxo qeInMode qSbe (QueryUTxOByTxIn (Set.fromList allTxIns)))
+  utxo <- lift (queryUtxo qeInMode sbe (QueryUTxOByTxIn (Set.fromList allTxIns)))
     & onLeft (left . QceUnsupportedNtcVersion)
     & onLeft (left . QueryEraMismatch)
 
-  pparams <- lift (queryProtocolParameters qeInMode qSbe)
+  pparams <- lift (queryProtocolParameters qeInMode sbe)
     & onLeft (left . QceUnsupportedNtcVersion)
     & onLeft (left . QueryEraMismatch)
 
@@ -107,7 +107,7 @@ queryStateForBalancedTx era allTxIns certs = runExceptT $ do
   systemStart <- lift querySystemStart
     & onLeft (left . QceUnsupportedNtcVersion)
 
-  stakePools <- lift (queryStakePools qeInMode qSbe)
+  stakePools <- lift (queryStakePools qeInMode sbe)
     & onLeft (left . QceUnsupportedNtcVersion)
     & onLeft (left . QueryEraMismatch)
 
@@ -115,7 +115,7 @@ queryStateForBalancedTx era allTxIns certs = runExceptT $ do
     if null stakeCreds
       then pure mempty
       else do
-        lift (queryStakeDelegDeposits qeInMode qSbe stakeCreds)
+        lift (queryStakeDelegDeposits qeInMode sbe stakeCreds)
           & onLeft (left . QceUnsupportedNtcVersion)
           & onLeft (left . QueryEraMismatch)
 
@@ -134,10 +134,6 @@ determineEra cModeParams localNodeConnInfo =
       queryNodeLocalState localNodeConnInfo Nothing
         $ QueryCurrentEra CardanoModeIsMultiEra
 
-getSbe :: CardanoEraStyle era -> Either QueryConvenienceError (ShelleyBasedEra era)
-getSbe LegacyByronEra = Left ByronEraNotSupported
-getSbe (ShelleyBasedEra sbe) = return sbe
-
 -- | Execute a query against the local node. The local
 -- node must be in CardanoMode.
 executeQueryCardanoMode