Fix handling empty lists

Author: Avi-D-coder

src/Hie/Cabal/Parser.hs

@@ -105,12 +105,12 @@ optSkipToNextLine i = do
   peekChar >>= \case
     Just c
       | isEndOfLine c ->
-        endOfLine *> indent i $> ()
+        endOfLine >> indent i $> ()
     _ -> pure ()
 
 -- | Comma or space separated list, with optional new lines.
 parseList :: Indent -> Parser [Text]
-parseList i = sepBy parseString (optSkipToNextLine i *> skipMany (char ',') *> optSkipToNextLine i)
+parseList i = sepBy parseString (optSkipToNextLine i >> skipMany (char ',') >> optSkipToNextLine i) <|> pure []
 
 pathMain :: Indent -> [Text] -> Text -> [Text] -> [Text] -> Parser [Text]
 pathMain i p m o a =

test/Spec.hs

@@ -116,6 +116,14 @@ spec = do
                         Comp Exe "gen-hie" "app/Hie/Executable/Helper.hs",
                         Comp Exe "gen-hie" "app/Hie/Executable/Utils.hs"
                       ]
+  describe "Should Succeed" $
+    it "succesfully parses single other-modules" $
+      ("other-modules: test\ndefault-language:   Haskell2011" :: Text) ~?> field 0 "other-modules" parseList
+        `leavesUnconsumed` "default-language:   Haskell2011"
+  describe "Should Succeed" $
+    it "succesfully parses empty other-modules" $
+      ("other-modules: test\ndefault-language:   Haskell2011" :: Text) ~?> field 0 "other-modules" parseList
+        `leavesUnconsumed` "default-language:   Haskell2011"
 
 exeSection :: Text
 exeSection =