From 50672f5e5ee52f91eddb8a310ba952543db821af Mon Sep 17 00:00:00 2001
From: Devin Lehmacher <lehmacdj@gmail.com>
Date: Sat, 5 Mar 2022 13:56:18 -0800
Subject: [PATCH 1/2] SourceRange.prettyRange: escape sourceName

---
 commonmark/src/Commonmark/Types.hs | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/commonmark/src/Commonmark/Types.hs b/commonmark/src/Commonmark/Types.hs
index a4d81ea..1516fe8 100644
--- a/commonmark/src/Commonmark/Types.hs
+++ b/commonmark/src/Commonmark/Types.hs
@@ -126,12 +126,12 @@ prettyRange (SourceRange xs) = go "" xs
     go _ [] = ""
     go curname ((p1,p2):rest)
       = (if sourceName p1 /= curname
-            then sourceName p1 ++ "@"
+            then escapeSourceName (sourceName p1) ++ "@"
             else "") ++
          show (sourceLine p1) ++ ":" ++
          show (sourceColumn p1) ++ "-" ++
          (if sourceName p2 /= sourceName p1
-             then sourceName p2 ++ "@"
+             then escapeSourceName (sourceName p2) ++ "@"
              else "") ++
          show (sourceLine p2) ++
          ":" ++ show (sourceColumn p2) ++
@@ -139,6 +139,17 @@ prettyRange (SourceRange xs) = go "" xs
             then ""
             else ";" ++ go (sourceName p2) rest
 
+-- if the source name contains special characters it can lead to ambiguity when
+-- a filename exactly matches a fragment of syntax of the range
+escapeSourceName :: String -> String
+escapeSourceName = concatMap escapeChar
+  where
+    escapeChar '-' = "%2D"
+    escapeChar '%' = "%25"
+    escapeChar ':' = "%3A"
+    escapeChar ';' = "%3B"
+    escapeChar x = [x]
+
 type Attribute = (Text, Text)
 
 type Attributes = [Attribute]

From 09b9ebb0a85c417be2afe779578adca6b77f035c Mon Sep 17 00:00:00 2001
From: Devin Lehmacher <lehmacdj@gmail.com>
Date: Sat, 12 Mar 2022 14:08:36 -0800
Subject: [PATCH 2/2] add benchmarks for SourceName escaping

---
 commonmark/benchmark/benchmark.hs | 26 +++++++++++++++++++++++++-
 1 file changed, 25 insertions(+), 1 deletion(-)

diff --git a/commonmark/benchmark/benchmark.hs b/commonmark/benchmark/benchmark.hs
index 44c9441..625ad99 100644
--- a/commonmark/benchmark/benchmark.hs
+++ b/commonmark/benchmark/benchmark.hs
@@ -1,6 +1,8 @@
 {-# LANGUAGE CPP                 #-}
 {-# LANGUAGE OverloadedStrings   #-}
 {-# LANGUAGE ScopedTypeVariables #-}
+{-# LANGUAGE TypeApplications #-}
+{-# LANGUAGE FlexibleContexts #-}
 import Test.Tasty.Bench
 import Data.Text (Text)
 import Data.Functor.Identity  -- base >= 4.8
@@ -19,6 +21,8 @@ main = do
       ]
     , bgroup "pathological"
       (map toPathBench pathtests)
+    , bgroup "name impact"
+      (map (toNameImpactBench sample) nameImpactTests)
     ]
 
 toPathBench :: (String, Int -> T.Text) -> Benchmark
@@ -88,11 +92,31 @@ pathtests =
     ("a" <> T.replicate num "<!A "))
   ]
 
+toNameImpactBench :: Text -> (String, String) -> Benchmark
+toNameImpactBench sample (testName, name) =
+  let benchArgs n = (show n, take (50 * n) (cycle name), sample)
+   in bgroup testName
+        (map (benchCommonmark' @SourceRange defaultSyntaxSpec . benchArgs)
+          [1, 5, 10, 20])
+
+nameImpactTests :: [(String, String)]
+nameImpactTests =
+  [ ("no special characters", "the quick brown fox jumps over the lazy dog")
+  , ("special characters", "\\-:-as;df-:d:%%-:\\;;;\\-:%%-:---:-sdf-:sa-\\;")
+  ]
+
 benchCommonmark :: SyntaxSpec Identity (Html ()) (Html ())
                 -> (String, Text)
                 -> Benchmark
 benchCommonmark spec (name, contents) =
-  bench name $
+  benchCommonmark' spec (name, name, contents)
+
+benchCommonmark' :: Rangeable (Html a)
+                => SyntaxSpec Identity (Html a) (Html a)
+                -> (String, String, Text)
+                -> Benchmark
+benchCommonmark' spec (testName, name, contents) =
+  bench testName $
     nf (either (error . show) renderHtml
         . runIdentity . parseCommonmarkWith spec . tokenize name)
     contents