HACK for translating ChainDepStates: set tip slot to bound slot

This prevents nonce mixing happening twice at era boundaries. This should also be done for PBft I think, but it doesn't seem to be strictly necessary.
IntersectMBO · Sep 12, 2023 · bf6c179 · bf6c179
1 parent 20d850e
commit bf6c179
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Showing 4 changed files with 12 additions and 8 deletions.
diff --git a/ouroboros-consensus-cardano/src/shelley/Ouroboros/Consensus/Shelley/ShelleyHFC.hs b/ouroboros-consensus-cardano/src/shelley/Ouroboros/Consensus/Shelley/ShelleyHFC.hs
@@ -291,11 +291,11 @@ translateChainDepStateAcrossShelley ::
        (ShelleyBlock protoTo eraTo)
 translateChainDepStateAcrossShelley =
     ignoringBoth $
-      Translate $ \_bound (Comp (WrapTickedChainDepState chainDepState)) ->
+      Translate $ \bound (Comp (WrapTickedChainDepState chainDepState)) ->
         -- Same protocol, same 'ChainDepState'. Note that we don't have to apply
         -- any changes related to an epoch transition, this is already done when
         -- ticking the state.
-        WrapChainDepState $ Proto.translateChainDepState @protoFrom @protoTo chainDepState
+        WrapChainDepState $ Proto.translateChainDepState @protoFrom @protoTo (boundSlot bound) chainDepState
 
 crossEraForecastAcrossShelley ::
      forall eraFrom eraTo protoFrom protoTo.

diff --git a/ouroboros-consensus-cardano/src/unstable-shelley-testlib/Test/Consensus/Shelley/Examples.hs b/ouroboros-consensus-cardano/src/unstable-shelley-testlib/Test/Consensus/Shelley/Examples.hs
@@ -231,6 +231,7 @@ fromShelleyLedgerExamplesPraos ShelleyLedgerExamples {
     , shelleyLedgerTransition = ShelleyTransitionInfo {shelleyAfterVoting = 0}
     }
     chainDepState = translateChainDepState @(TPraos (EraCrypto era)) @(Praos (EraCrypto era))
+      1
       TPraos.TickedChainDepState {
           TPraos.tickedTPraosStateChainDepState = \_lvExtraEntropy -> sleChainDepState
         , TPraos.untickedTPraosStateLastSlot    = NotOrigin 1

diff --git a/...protocol/src/ouroboros-consensus-protocol/Ouroboros/Consensus/Protocol/Praos/Translate.hs b/...protocol/src/ouroboros-consensus-protocol/Ouroboros/Consensus/Protocol/Praos/Translate.hs
@@ -19,6 +19,7 @@ import qualified Cardano.Protocol.TPraos.Rules.Prtcl as SL
 import qualified Cardano.Protocol.TPraos.Rules.Tickn as SL
 import           Data.Coerce (coerce)
 import qualified Data.Map.Strict as Map
+import           Ouroboros.Consensus.Block
 import           Ouroboros.Consensus.Protocol.Praos (ConsensusConfig (..),
                      Praos, PraosParams (..), PraosState (..),
                      Ticked (TickedPraosLedgerView),
@@ -37,16 +38,17 @@ import           Ouroboros.Consensus.Protocol.Translate (TranslateProto (..))
 instance (c1 ~ c2) => TranslateProto (TPraos c1) (TPraos c2) where
   translateConsensusConfig = id
   translateTickedLedgerView = id
-  translateChainDepState x = TPraos.TPraosState {
-      TPraos.tpraosStateLastSlot      = TPraos.untickedTPraosStateLastSlot x
+  translateChainDepState transSlot x = TPraos.TPraosState {
+      TPraos.tpraosStateLastSlot      = NotOrigin transSlot
     , TPraos.tpraosStateChainDepState =
         TPraos.tickedTPraosStateChainDepState x SL.NeutralNonce   -- TODO comment justifying NeutralNonce
     }
 
 instance (c1 ~ c2) => TranslateProto (Praos c1) (Praos c2) where
   translateConsensusConfig = id
   translateTickedLedgerView = id
-  translateChainDepState = tickedPraosStateChainDepState
+  translateChainDepState transSlot x =
+    (tickedPraosStateChainDepState x) { praosStateLastSlot = NotOrigin transSlot }
 
 -- | We can translate between TPraos and Praos, provided:
 --
@@ -100,9 +102,9 @@ instance
           coerceIndividualPoolStake (SL.IndividualPoolStake stake vrf) =
             SL.IndividualPoolStake stake $ coerce vrf
 
-  translateChainDepState tpState =
+  translateChainDepState transSlot tpState =
     PraosState
-      { praosStateLastSlot = TPraos.untickedTPraosStateLastSlot tpState,
+      { praosStateLastSlot = NotOrigin transSlot,
         praosStateOCertCounters = Map.mapKeysMonotonic coerce certCounters,
         praosStateEvolvingNonce = evolvingNonce,
         praosStateCandidateNonce = candidateNonce,

diff --git a/...ensus-protocol/src/ouroboros-consensus-protocol/Ouroboros/Consensus/Protocol/Translate.hs b/...ensus-protocol/src/ouroboros-consensus-protocol/Ouroboros/Consensus/Protocol/Translate.hs
@@ -4,6 +4,7 @@
 
 module Ouroboros.Consensus.Protocol.Translate (TranslateProto (..)) where
 
+import           Ouroboros.Consensus.Block
 import           Ouroboros.Consensus.Protocol.Abstract
 import           Ouroboros.Consensus.Ticked (Ticked)
 
@@ -16,4 +17,4 @@ class TranslateProto protoFrom protoTo
   translateTickedLedgerView ::
     Ticked (LedgerView protoFrom) -> Ticked (LedgerView protoTo)
   translateChainDepState ::
-    Ticked (ChainDepState protoFrom) -> ChainDepState protoTo
+    SlotNo -> Ticked (ChainDepState protoFrom) -> ChainDepState protoTo