LaTeX reader: Added code to handleIncludes to avoid inf loops.

e.g. when one file includes another which includes it.

1 files changed, 14 insertions, 8 deletions

diff --git a/src/Text/Pandoc/Readers/LaTeX.hs b/src/Text/Pandoc/Readers/LaTeX.hs
index 22d9b237a..4dce1726e 100644
--- a/src/Text/Pandoc/Readers/LaTeX.hs
+++ b/src/Text/Pandoc/Readers/LaTeX.hs
@@ -681,16 +681,22 @@ rawEnv name = do
 
 -- | Replace "include" commands with file contents.
 handleIncludes :: String -> IO String
-handleIncludes [] = return []
-handleIncludes ('\\':xs) =
+handleIncludes = handleIncludes' []
+
+-- parents parameter prevents infinite include loops
+handleIncludes' :: [FilePath] -> String -> IO String
+handleIncludes' _ [] = return []
+handleIncludes' parents ('\\':xs) =
   case runParser include defaultParserState "input" ('\\':xs) of
-       Right (fs, rest) -> do yss <- mapM readTeXFile fs
-                              handleIncludes $ intercalate "\n" yss ++ rest
+       Right (fs, rest) -> do yss <- mapM readTeXFile
+                                        [f | f <- fs, f `notElem` parents]
+                              handleIncludes' (parents ++ fs) $
+                                 intercalate "\n" yss ++ rest
        _  -> case runParser (verbCmd <|> verbatimEnv) defaultParserState
-                   "input" ('\\':xs) of
-                    Right (r, rest) -> (r ++) `fmap` handleIncludes rest
-                    _               -> ('\\':) `fmap` handleIncludes xs
-handleIncludes (x:xs) = (x:) `fmap` handleIncludes xs
+                  "input" ('\\':xs) of
+                   Right (r, rest) -> (r ++) `fmap` handleIncludes' parents rest
+                   _               -> ('\\':) `fmap` handleIncludes' parents xs
+handleIncludes' parents (x:xs) = (x:) `fmap` handleIncludes' parents xs
 
 readTeXFile :: FilePath -> IO String
 readTeXFile f = do