epochSucc sucks

cardano-foundation · Nov 27, 2020 · 66f673c · 66f673c
1 parent 4a44023
commit 66f673c
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Showing 4 changed files with 6 additions and 71 deletions.
diff --git a/lib/core/src/Cardano/Wallet/Api/Server.hs b/lib/core/src/Cardano/Wallet/Api/Server.hs
@@ -283,7 +283,6 @@ import Cardano.Wallet.Primitive.Slotting
     , TimeInterpreter
     , currentEpoch
     , endTimeOfEpoch
-    , epochSucc
     , firstSlotInEpoch
     , ongoingSlotAt
     , startTime
@@ -384,7 +383,7 @@ import Data.List.NonEmpty
 import Data.Map.Strict
     ( Map )
 import Data.Maybe
-    ( catMaybes, fromMaybe, isJust )
+    ( catMaybes, isJust )
 import Data.Proxy
     ( Proxy (..) )
 import Data.Quantity
@@ -1801,8 +1800,8 @@ getNetworkInformation st nl = do
         let curEpoch = tip ^. #slotId . #epochNumber . #getApiT
         nextEpochStart <- lift $ ti $ endTimeOfEpoch curEpoch
         let nextEpoch = ApiEpochInfo
-                (ApiT $ unsafeEpochSucc curEpoch)
-                (nextEpochStart)
+                (ApiT $ succ curEpoch)
+                nextEpochStart
         return (tip, nextEpoch)
       where
         handlePastHorizonException
@@ -1811,12 +1810,6 @@ getNetworkInformation st nl = do
         handlePastHorizonException _ =
             MaybeT (pure Nothing)
 
-    -- Unsafe constructor for the next epoch. Chances to reach the last epoch
-    -- are quite unlikely in this context :)
-    unsafeEpochSucc :: HasCallStack => W.EpochNo -> W.EpochNo
-    unsafeEpochSucc = fromMaybe bomb . epochSucc
-      where bomb = error "reached final epoch of the Blockchain!?"
-
 getNetworkParameters
     :: (Block, NetworkParameters, SyncTolerance)
     -> NetworkLayer IO t Block

diff --git a/lib/core/src/Cardano/Wallet/Primitive/Slotting.hs b/lib/core/src/Cardano/Wallet/Primitive/Slotting.hs
@@ -40,8 +40,6 @@ module Cardano.Wallet.Primitive.Slotting
 
     -- ** Helpers
     , unsafeEpochNo
-    , epochPred
-    , epochSucc
 
       -- * Legacy api - Inaccurate with cardano-node, okay with Jörmungandr
     , SlotParameters (..)
@@ -379,20 +377,6 @@ slotParams t0 sp = SlotParameters
 epochStartTime :: SlotParameters -> EpochNo -> UTCTime
 epochStartTime sps e = slotStartTime sps $ SlotId e 0
 
--- | Return the epoch immediately before the given epoch, or 'Nothing' if there
---   is no representable epoch before the given epoch.
-epochPred :: EpochNo -> Maybe EpochNo
-epochPred (EpochNo e)
-    | e == minBound = Nothing
-    | otherwise = Just $ EpochNo $ pred e
-
--- | Return the epoch immediately after the given epoch, or 'Nothing' if there
---   is no representable epoch after the given epoch.
-epochSucc :: EpochNo -> Maybe EpochNo
-epochSucc (EpochNo e)
-    | e == maxBound = Nothing
-    | otherwise = Just $ EpochNo $ succ e
-
 -- | Convert a 'SlotId' to the number of slots since genesis.
 flatSlot :: EpochLength -> SlotId -> Word64
 flatSlot (EpochLength epochLength) (SlotId (EpochNo e) (SlotInEpoch s)) =

diff --git a/lib/core/test/unit/Cardano/Wallet/Primitive/TypesSpec.hs b/lib/core/test/unit/Cardano/Wallet/Primitive/TypesSpec.hs
@@ -32,11 +32,7 @@ import Cardano.Wallet.Primitive.AddressDerivation.Jormungandr
     ( JormungandrKey (..), generateKeyFromSeed )
 import Cardano.Wallet.Primitive.Slotting
     ( SlotParameters (..)
-    , epochPred
     , epochStartTime
-    , epochStartTime
-    , epochSucc
-    , epochSucc
     , flatSlot
     , fromFlatSlot
     , slotAt'
@@ -544,43 +540,6 @@ spec = do
                             "time point during the lifetime of the blockchain"
                     True
 
-    describe "Epoch arithmetic: predecessors and successors" $ do
-
-        let succN n = applyN n (epochSucc =<<)
-        let predN n = applyN n (epochPred =<<)
-
-        it "epochPred minBound == Nothing" $
-            epochPred minBound === Nothing
-
-        it "epochSucc maxBound == Nothing" $
-            epochSucc maxBound === Nothing
-
-        it "(applyN n epochSucc) . (applyN n epochPred) == id" $
-            withMaxSuccess 1000 $ property $
-                \(Small epochWord) (Small n) ->
-                    let epoch = EpochNo epochWord
-                        withinBounds = minBound + n <= unEpochNo epoch
-                        expectedResult =
-                            if withinBounds then Just epoch else Nothing
-                    in
-                    checkCoverage $
-                    cover 10      withinBounds  "within bounds" $
-                    cover 10 (not withinBounds) "out of bounds" $
-                    expectedResult === succN n (predN n $ Just epoch)
-
-        it "(applyN n epochPred) . (applyN n epochSucc) == id" $
-            withMaxSuccess 1000 $ property $
-                \(Small epochWord) (Small n) ->
-                    let epoch = EpochNo $ maxBound - epochWord
-                        withinBounds = maxBound - n >= unEpochNo epoch
-                        expectedResult =
-                            if withinBounds then Just epoch else Nothing
-                    in
-                    checkCoverage $
-                    cover 10      withinBounds  "within bounds" $
-                    cover 10 (not withinBounds) "out of bounds" $
-                    expectedResult === predN n (succN n $ Just epoch)
-
     describe "Slot arithmetic" $ do
 
         it "slotFloor (slotStartTime slotMinBound) == Just slotMinBound" $

diff --git a/lib/shelley/src/Cardano/Wallet/Shelley/Pools.hs b/lib/shelley/src/Cardano/Wallet/Shelley/Pools.hs
@@ -68,7 +68,6 @@ import Cardano.Wallet.Primitive.Slotting
     ( PastHorizonException (..)
     , TimeInterpreter
     , epochOf
-    , epochPred
     , firstSlotInEpoch
     , startTime
     )
@@ -122,7 +121,7 @@ import Control.Exception
     , try
     )
 import Control.Monad
-    ( forM, forM_, forever, void, when, (<=<) )
+    ( forM, forM_, forever, void, when )
 import Control.Monad.IO.Class
     ( liftIO )
 import Control.Monad.Trans.Except
@@ -692,9 +691,9 @@ monitorStakePools tr gp nl DBLayer{..} =
         -- #2196: We need the try. Arguably we shouldn't need it.
         liftIO (try @SomeException (timeInterpreter nl (epochOf currentSlot))) >>= \case
             Left _ -> return ()
+            Right currentEpoch | currentEpoch < 2 -> return ()
             Right currentEpoch -> do
-                let subtractTwoEpochs = epochPred <=< epochPred
-                forM_ (subtractTwoEpochs currentEpoch) $ \latestRetirementEpoch -> do
+                    let latestRetirementEpoch = currentEpoch - 2
                     latestGarbageCollectionEpoch <-
                         liftIO $ readIORef latestGarbageCollectionEpochRef
                     -- Only perform garbage collection once per epoch: