followsLoEFrag now trims fragments

IntersectMBO · May 29, 2024 · 3957238 · 3957238
1 parent c6b1d22
commit 3957238
Showing 1 changed file with 11 additions and 8 deletions.
diff --git a/...os-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Storage/ChainDB/Impl/ChainSel.hs b/...os-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Storage/ChainDB/Impl/ChainSel.hs
@@ -35,7 +35,7 @@ import           Data.List.NonEmpty (NonEmpty)
 import qualified Data.List.NonEmpty as NE
 import           Data.Map.Strict (Map)
 import qualified Data.Map.Strict as Map
-import           Data.Maybe (isJust, isNothing)
+import           Data.Maybe (isJust, isNothing, mapMaybe)
 import           Data.Maybe.Strict (StrictMaybe (..), strictMaybeToMaybe)
 import           Data.Set (Set)
 import qualified Data.Set as Set
@@ -675,7 +675,7 @@ chainSelectionForBlock cdb@CDB{..} blockCache hdr punish = electric $ do
               return $ AF.fromOldestFirst curHead (hdr : hdrs)
 
         let chainDiffs = NE.nonEmpty
-              $ filter (followsLoEFrag loeFrag curChainAndLedger)
+              $ mapMaybe (followsLoEFrag loeFrag curChainAndLedger)
               $ map Diff.extend
               $ NE.filter (preferAnchoredCandidate (bcfg chainSelEnv) curChain)
                 candidates
@@ -718,14 +718,17 @@ chainSelectionForBlock cdb@CDB{..} blockCache hdr punish = electric $ do
     followsLoEFrag :: LoE (AnchoredFragment (Header blk))
                    -> ChainAndLedger blk
                    -> ChainDiff (Header blk)
-                   -> Bool
-    followsLoEFrag LoEDisabled _ _ = True
+                   -> Maybe (ChainDiff (Header blk))
+    followsLoEFrag LoEDisabled _ diff = Just diff
     followsLoEFrag (LoEEnabled loe) curChain diff =
       case Diff.apply (VF.validatedFragment curChain) diff of
-        Nothing -> False
+        Nothing -> Nothing
         Just frag ->
-             AF.withinFragmentBounds (AF.headPoint loe) frag
-          || AF.withinFragmentBounds (AF.headPoint frag) loe
+          if
+              AF.withinFragmentBounds (AF.headPoint loe) frag
+            || AF.withinFragmentBounds (AF.headPoint frag) loe
+            then Just diff
+            else Nothing
 
     -- | We have found a 'ChainDiff' through the VolatileDB connecting the new
     -- block to the current chain. We'll call the intersection/anchor @x@.
@@ -751,7 +754,7 @@ chainSelectionForBlock cdb@CDB{..} blockCache hdr punish = electric $ do
         -- times in case they're part of multiple forks that go through @b@.
         let initCache = Map.singleton (headerHash hdr) hdr
         chainDiffs <-
-            fmap (filter (followsLoEFrag loeFrag curChainAndLedger))
+            fmap (mapMaybe (followsLoEFrag loeFrag curChainAndLedger))
 
           -- 4. Filter out candidates that are not preferred over the current
           -- chain.