Document fork number

Author: ninioArtillero

ouroboros-consensus-diffusion/test/consensus-test/Test/Consensus/Genesis/Setup/GenChains.hs

@@ -68,7 +68,7 @@ genHonestChainSchema = do
 
 -- | Random generator for one alternative chain schema forking off a given
 -- honest chain schema. The alternative chain schema is returned as the pair of
--- a slot number on the honest chain schema and a list of active slots.
+-- a block number on the honest chain schema and a list of active slots.
 --
 -- REVIEW: Use 'SlotNo' instead of 'Int'?
 genAlternativeChainSchema :: (H.HonestRecipe, H.ChainSchema base hon) -> QC.Gen (Int, [S])
@@ -153,6 +153,11 @@ genChainsWithExtraHonestPeers genNumExtraHonest genNumForks = do
     -- those values for individual tests?
     -- Also, we might want to generate these randomly.
     gtCSJParams = CSJParams $ fromIntegral scg,
+    -- The generated alternative chains (branches added to the @goodChain@)
+    -- can end up having the same @prefixCount@, meaning they fork at the same block. but are
+    -- The assigned fork number has no relation with the order in which the
+    -- branching happens, but is just a means to distinguish among then for
+    -- pretty printing.
     gtBlockTree = List.foldl' (flip BT.addBranch') (BT.mkTrunk goodChain) $ zipWith (genAdversarialFragment goodBlocks) [1..] alternativeChainSchemas,
     gtExtraHonestPeers,
     gtSchedule = ()
@@ -170,6 +175,9 @@ genChainsWithExtraHonestPeers genNumExtraHonest genNumForks = do
     mkTestFragment =
       AF.fromNewestFirst AF.AnchorGenesis
 
+    -- Cons new blocks acoording to the given active block schema
+    -- and mark the first with the corresponding fork number; the
+    -- next blocks get a zero fork number.
     mkTestBlocks :: [blk] -> [S] -> Int -> [blk]
     mkTestBlocks pre active forkNo =
       fst (List.foldl' folder ([], 0) active)

ouroboros-consensus-diffusion/test/consensus-test/Test/Consensus/PeerSimulator/StateDiagram.hs

@@ -405,8 +405,8 @@ hashForkNo bt hash =
         (Any False, _)    -> 0
 
 blockForkNo :: AF.HasHeader blk => BlockTree blk -> ChainHash blk -> Word64
-blockForkNo pxy = \case
-  BlockHash h -> hashForkNo pxy h
+blockForkNo bt = \case
+  BlockHash h -> hashForkNo bt h
   _ -> 0
 
 initBranch :: forall blk. (GetHeader blk, AF.HasHeader blk) => BlockTree blk -> Int -> Range -> AF.AnchoredFragment blk -> BranchSlots blk