From e53f83ea6ab057013c9cd425f22a58fd791406da Mon Sep 17 00:00:00 2001
From: joshvera <josh@joshvera.com>
Date: Mon, 3 Oct 2016 18:55:04 -0400
Subject: [PATCH] Alternate through both sides of the diff when in
 diffToDiffSummaries annotateWithCategory function

---
 src/Data/RandomWalkSimilarity.hs |  5 +++--
 src/DiffSummary.hs               | 24 ++++++++++++++----------
 2 files changed, 17 insertions(+), 12 deletions(-)

diff --git a/src/Data/RandomWalkSimilarity.hs b/src/Data/RandomWalkSimilarity.hs
index e188ba2e8..f77f8fd89 100644
--- a/src/Data/RandomWalkSimilarity.hs
+++ b/src/Data/RandomWalkSimilarity.hs
@@ -138,13 +138,14 @@ rws compare as bs
         insertDiff (i, mappedTerm) into)
         into
         diffs
-    -- Given a list of diffs, and unmapped terms in unmappedA, deletes
-    -- any terms that remain in umappedA.
+
+    -- Given a list of diffs, and unmapped terms, deletes any terms that remain in unmappedA.
     deleteRemaining diffs (_, unmappedA, _) = foldl' (\into (i, deletion) ->
         insertDiff (This i, deletion) into)
       diffs
       ((termIndex &&& deleting . term) <$> unmappedA)
 
+    -- Possibly replace terms in a diff.
     replaceIfEqual :: Term f (Record fields) -> Term f (Record fields) -> Maybe (Diff f (Record fields))
     replaceIfEqual a b
       | (category <$> a) == (category <$> b) = hylo wrap runCofree <$> zipTerms a b
diff --git a/src/DiffSummary.hs b/src/DiffSummary.hs
index b45466d8f..83367e40e 100644
--- a/src/DiffSummary.hs
+++ b/src/DiffSummary.hs
@@ -25,7 +25,7 @@ import Source
 data Identifiable a = Identifiable a | Unidentifiable a
 
 identifiable :: SyntaxTerm leaf fields -> Identifiable (SyntaxTerm leaf fields)
-identifiable term = isIdentifiable (unwrap term) $ term
+identifiable term = isIdentifiable (unwrap term) term
   where isIdentifiable = \case
           S.FunctionCall{} -> Identifiable
           S.MethodCall{} -> Identifiable
@@ -64,12 +64,16 @@ summaryToTexts DiffSummary{..} = runJoin . fmap (show . (<+> maybeParentContext
 -- Returns a list of 'DiffSummary' given two source blobs and a diff.
 diffToDiffSummaries :: (HasCategory leaf, HasField fields Category, HasField fields Range) => Both (Source Char) -> SyntaxDiff leaf fields -> [DiffSummary DiffInfo]
 diffToDiffSummaries sources = para $ \diff ->
-  let diff' = free (Prologue.fst <$> diff)
-      annotateWithCategory :: [(Diff leaf (Record fields), [DiffSummary DiffInfo])] -> [DiffSummary DiffInfo]
-      annotateWithCategory children = maybeToList (prependSummary (Both.snd sources) <$> (afterTerm diff')) <*> (children >>= snd) in
-  case diff of
+  let
+    diff' = free (Prologue.fst <$> diff)
+    annotateWithCategory :: [DiffSummary DiffInfo] -> [DiffSummary DiffInfo]
+    annotateWithCategory children = case (beforeTerm diff', afterTerm diff') of
+      (_, Just diff'') -> prependSummary (Both.snd sources) diff'' <$> children
+      (Just diff'', _) -> prependSummary (Both.fst sources) diff'' <$> children
+      (Nothing, Nothing) -> []
+  in case diff of
     -- Skip comments and leaves since they don't have any changes
-    (Free (_ :< syntax)) -> annotateWithCategory (toList syntax)
+    (Free (_ :< syntax)) -> annotateWithCategory (toList syntax >>= snd)
     (Pure patch) -> [ DiffSummary (mapPatch (termToDiffInfo beforeSource) (termToDiffInfo afterSource) patch) Nothing ]
   where
     (beforeSource, afterSource) = runJoin sources
@@ -124,13 +128,13 @@ toTermName source term = case unwrap term of
   Leaf leaf -> toCategoryName leaf
   S.Assignment identifier _ -> toTermName' identifier
   S.Function identifier _ _ -> toTermName' identifier
-  S.FunctionCall i args -> toTermName' i <> "(" <> (intercalate ", " (toArgName <$> args)) <> ")"
+  S.FunctionCall i args -> toTermName' i <> "(" <> intercalate ", " (toArgName <$> args) <> ")"
   S.MemberAccess base property -> case (unwrap base, unwrap property) of
     (S.FunctionCall{}, S.FunctionCall{}) -> toTermName' base <> "()." <> toTermName' property <> "()"
     (S.FunctionCall{}, _) -> toTermName' base <> "()." <> toTermName' property
     (_, S.FunctionCall{}) -> toTermName' base <> "." <> toTermName' property <> "()"
     (_, _) -> toTermName' base <> "." <> toTermName' property
-  S.MethodCall targetId methodId methodParams -> toTermName' targetId <> sep <> toTermName' methodId <> "(" <> (intercalate ", " (toArgName <$> methodParams)) <> ")"
+  S.MethodCall targetId methodId methodParams -> toTermName' targetId <> sep <> toTermName' methodId <> "(" <> intercalate ", " (toArgName <$> methodParams) <> ")"
     where sep = case unwrap targetId of
             S.FunctionCall{} -> "()."
             _ -> "."
@@ -207,7 +211,7 @@ prependSummary source term summary =
 
 isBranchInfo :: DiffInfo -> Bool
 isBranchInfo info = case info of
-  (BranchInfo _ _ _) -> True
+  BranchInfo{} -> True
   _ -> False
 
 hasErrorInfo :: DiffInfo -> Bool
@@ -290,6 +294,6 @@ instance Arbitrary a => Arbitrary (DiffSummary a) where
   shrink = genericShrink
 
 instance P.Pretty DiffInfo where
-  pretty LeafInfo{..} = squotes (string $ toSL termName) <+> (string $ toSL categoryName)
+  pretty LeafInfo{..} = squotes (string $ toSL termName) <+> string (toSL categoryName)
   pretty BranchInfo{..} = mconcat $ punctuate (string "," P.<> space) (pretty <$> branches)
   pretty ErrorInfo{..} = squotes (string $ toSL termName) <+> "at" <+> (string . toSL $ displayStartEndPos errorSpan) <+> "in" <+> (string . toSL $ spanName errorSpan)