diff --git a/src/Diffing.hs b/src/Diffing.hs
index 8166eeb89..2beda5514 100644
--- a/src/Diffing.hs
+++ b/src/Diffing.hs
@@ -87,7 +87,7 @@ diffFiles parser renderer sourceBlobs = do
   terms <- sequence $ parser <$> sources
 
   let replaceLeaves = breakDownLeavesByWord <$> sources
-  let areNullOids = runJoin $ (== nullOid) . oid <$> sourceBlobs
+  let areNullOids = runBothWith (\a b -> (oid a == nullOid || length (source a) == 0, oid b == nullOid || length (source b) == 0)) sourceBlobs
   let textDiff = case areNullOids of
         (True, False) -> pure $ Insert (snd terms)
         (False, True) -> pure $ Delete (fst terms)