Encode version with serialized event.

  So that we know what version to use for decoding an event. This is necessary because events are encoded according to the version of the era they're emitted from; which may be different across the entire file even for similar events.

cardano-node/src/Cardano/Node/LedgerEvent.hs

@@ -35,8 +35,8 @@ module Cardano.Node.LedgerEvent (
 
 import           Cardano.Prelude hiding (All, Sum)
 
-import           Cardano.Ledger.Binary (DecCBOR(..), EncCBOR(..), Version, serialize',
-                                        unsafeDeserialize, toPlainDecoder)
+import           Cardano.Ledger.Binary (DecCBOR(..), EncCBOR(..), Version, fromCBOR,
+                   serialize', toCBOR, toPlainDecoder)
 import           Cardano.Ledger.Binary.Coders (Decode(..), Encode (..), encode, (!>),
                    (<!), decode)
 import           Cardano.Ledger.Coin (Coin (..), DeltaCoin (..))
@@ -53,10 +53,10 @@ import           Cardano.Ledger.Shelley.Rules (RupdEvent (..),
                      ShelleyNewEpochEvent, ShelleyPoolreapEvent (..),
                      ShelleyTickEvent (..))
 import           Cardano.Slotting.Slot (SlotNo, EpochNo (..))
+import qualified Codec.CBOR.Write as CBOR
 import           Codec.CBOR.Read(deserialiseFromBytes)
 import           Control.State.Transition (Event)
 import           Data.ByteString.Short(ShortByteString)
-import qualified Data.ByteString as BS
 import qualified Data.ByteString.Lazy as LBS
 import qualified Data.Map.Strict as Map
 import           Data.SOP.Strict (All, K (..), NS(..), hcmap, hcollapse)
@@ -67,7 +67,7 @@ import           Ouroboros.Consensus.Cardano.Block (AllegraEra, AlonzoEra,
                      BabbageEra, CardanoEras, ConwayEra, HardForkBlock,
                      MaryEra, ShelleyEra)
 import           Ouroboros.Consensus.HardFork.Combinator.AcrossEras
-                     (OneEraLedgerEvent(..), OneEraHash(..))
+                     (OneEraLedgerEvent(..))
 import           Ouroboros.Consensus.Ledger.Abstract (AuxLedgerEvent,
                      LedgerState)
 import           Ouroboros.Consensus.Shelley.Ledger (ShelleyBlock,
@@ -468,19 +468,21 @@ instance DecCBOR AnchoredEvent where
 
 serializeEvent :: Version -> AnchoredEvent -> ByteString
 serializeEvent codecVersion event =
-  serialize' codecVersion event
-
-deserializeEvent :: Version -> LBS.ByteString -> Maybe AnchoredEvent
-deserializeEvent codecVersion bytes =
-  case deserialiseFromBytes (toPlainDecoder codecVersion decCBOR) bytes of
-    Right (_, event) -> Just event
-    Left _ -> Nothing
-
+  CBOR.toStrictByteString (toCBOR codecVersion) <> serialize' codecVersion event
+
+deserializeEvent :: LBS.ByteString -> Maybe AnchoredEvent
+deserializeEvent bytes = do
+  case deserialiseFromBytes @Version fromCBOR bytes of
+    Right (rest, version) ->
+      case deserialiseFromBytes (toPlainDecoder version decCBOR) rest of
+        Right (_, event) -> Just event
+        Left{} -> Nothing
+    Left{} -> Nothing
+
 -- IO action to read ledger events in binary form
 tailEvent :: FilePath -> IO ()
 tailEvent eventsDb =
   withFile eventsDb ReadMode $ \ h -> LBS.hGetContents h >>= go
-
   where
     go bytes = do
      let version = maxBound

cardano-node/test/Test/Cardano/Node/LedgerEvent.hs

@@ -14,9 +14,10 @@ import qualified Hedgehog.Range as Range
 prop_roundtrip_LedgerEvent_CBOR :: Property
 prop_roundtrip_LedgerEvent_CBOR =
   Hedgehog.property $ do
+    version <- Hedgehog.forAll Gen.enumBounded
     event <- Hedgehog.forAll genEvent
-    footnote ("serialized event: " <> show (Hex.encode $ serializeEvent maxBound event))
-    Hedgehog.tripping event (serializeEvent maxBound) (deserializeEvent maxBound . fromStrict)
+    footnote ("serialized event: " <> show (Hex.encode $ serializeEvent version event))
+    Hedgehog.tripping event (serializeEvent version) (deserializeEvent . fromStrict)
 
 genEvent :: Hedgehog.Gen AnchoredEvent
 genEvent =