Markdown Reader: Req. " " after key in mmd title block

Require space after key-value delimiter colon in mmd title block.
Issue #2026
Amend: parsec's `spaces` include newlines, but we don't want that. Had
to make custom `spaceNoNewline` parser here

1 files changed, 4 insertions, 1 deletions

diff --git a/src/Text/Pandoc/Readers/Markdown.hs b/src/Text/Pandoc/Readers/Markdown.hs
index bd436da87..9d37808ee 100644
--- a/src/Text/Pandoc/Readers/Markdown.hs
+++ b/src/Text/Pandoc/Readers/Markdown.hs
@@ -35,7 +35,7 @@ import Data.List ( transpose, sortBy, intersperse, intercalate, elemIndex)
 import qualified Data.Map as M
 import Data.Scientific (coefficient, base10Exponent)
 import Data.Ord ( comparing )
-import Data.Char ( isAlphaNum, toLower )
+import Data.Char ( isSpace, isAlphaNum, toLower )
 import Data.Maybe
 import Text.Pandoc.Definition
 import qualified Data.Text as T
@@ -326,11 +326,14 @@ mmdTitleBlock = try $ do
 kvPair :: MarkdownParser (String, MetaValue)
 kvPair = try $ do
   key <- many1Till (alphaNum <|> oneOf "_- ") (char ':')
+  skipMany1 spaceNoNewline
   val <- manyTill anyChar
           (try $ newline >> lookAhead (blankline <|> nonspaceChar))
   let key' = concat $ words $ map toLower key
   let val' = MetaBlocks $ B.toList $ B.plain $ B.text $ trim val
   return (key',val')
+  where
+    spaceNoNewline = satisfy (\x -> isSpace x && (x/='\n') && (x/='\r'))
 
 parseMarkdown :: MarkdownParser Pandoc
 parseMarkdown = do