MediaWiki reader: Fixed bug in certain nested lists.

The bug: If a level 2 list was followed by a level 1 list, the first
item of the level 1 list would be lost.

Closes #1213.

src/Text/Pandoc/Readers/MediaWiki.hs

@@ -438,7 +438,8 @@ listItem c = try $ do
        skipMany spaceChar
        first <- concat <$> manyTill listChunk newline
        rest <- many
-                (try $ string extras *> (concat <$> manyTill listChunk newline))
+                (try $ string extras *> lookAhead listStartChar *>
+                       (concat <$> manyTill listChunk newline))
        contents <- parseFromString (many1 $ listItem' c)
                           (unlines (first : rest))
        case c of

tests/mediawiki-reader.native

@@ -102,6 +102,10 @@ Pandoc (Meta {unMeta = fromList []})
    [[BulletList
      [[Plain [Str "But",Space,Str "jumping",Space,Str "levels",Space,Str "creates",Space,Str "empty",Space,Str "space."]]]]]]]
 ,Para [Str "Any",Space,Str "other",Space,Str "start",Space,Str "ends",Space,Str "the",Space,Str "list."]
+,BulletList
+ [[BulletList
+   [[Plain [Str "two"]]]]
+ ,[Plain [Str "one"]]]
 ,OrderedList (1,DefaultStyle,DefaultDelim)
  [[Plain [Str "Start",Space,Str "each",Space,Str "line"]]
  ,[Plain [Str "with",Space,Str "a",Space,Str "number",Space,Str "sign",Space,Str "(#)."]

tests/mediawiki-reader.wiki

@@ -185,6 +185,9 @@ http://johnmacfarlane.net/pandoc/
 *** But jumping levels creates empty space.
 Any other start ends the list.
 
+** two
+* one
+
 # Start each line
 # with a number sign (#).
 ## More number signs gives deeper