Cleanup errors and logging a bit

Language/Haskell/GhcMod/Error.hs

@@ -35,7 +35,7 @@ module Language.Haskell.GhcMod.Error (
 
 import Control.Arrow
 import Control.Exception
-import Control.Monad.Error
+import Control.Monad.Error hiding (MonadIO, liftIO)
 import qualified Data.Set as Set
 import Data.List
 import Data.Version
@@ -49,9 +49,9 @@ import Config (cProjectVersion, cHostPlatformString)
 import Paths_ghc_mod (version)
 
 import Language.Haskell.GhcMod.Types
+import Language.Haskell.GhcMod.Monad.Types
 import Language.Haskell.GhcMod.Pretty
 
-
 type GmError m = MonadError GhcModError m
 
 gmCsfeDoc :: GMConfigStateFileError -> Doc
@@ -101,10 +101,15 @@ gmeDoc e = case e of
     GMECabalCompAssignment ctx ->
         text "Could not find a consistent component assignment for modules:" $$
           (nest 4 $ foldr ($+$) empty $ map ctxDoc ctx) $$
-        empty $$
-        text "Try this and that"
+        text "" $$
+        text "- Are you sure all these modules exist?" $$
+        text "- Maybe try enabling test suites and or benchmarks:" $$
+            nest 4 (backticks $ text "cabal configure --enable-tests --enable-benchmarks") $$
+        text "- To find out which components ghc-mod knows about try:" $$
+            nest 4 (backticks $ text "ghc-mod debug")
 
       where
+        backticks d = char '`' <> d <> char '`'
         ctxDoc = moduleDoc *** compsDoc
                  >>> first (<> colon) >>> uncurry (flip hang 4)
 
@@ -177,10 +182,11 @@ tryFix action f = do
 
 data GHandler m a = forall e . Exception e => GHandler (e -> m a)
 
-gcatches :: ExceptionMonad m => m a -> [GHandler m a] -> m a
+gcatches :: (MonadIO m, ExceptionMonad m) => m a -> [GHandler m a] -> m a
 gcatches io handlers = io `gcatch` gcatchesHandler handlers
 
-gcatchesHandler :: ExceptionMonad m => [GHandler m a] -> SomeException -> m a
+gcatchesHandler :: (MonadIO m, ExceptionMonad m)
+    => [GHandler m a] -> SomeException -> m a
 gcatchesHandler handlers e = foldr tryHandler (liftIO $ throw e) handlers
     where tryHandler (GHandler handler) res
               = case fromException e of

Language/Haskell/GhcMod/Logging.hs

@@ -54,5 +54,5 @@ gmLog level loc' doc = do
       msg = gmRenderDoc $ gmLogLevelDoc level <+> loc <+> doc
 
   when (Just level <= level') $
-       liftIO $ hPutStrLn stderr msg
+       liftIO $ hPutStr stderr msg
   gmlJournal (GhcModLog Nothing [(level, render loc, msg)])

Language/Haskell/GhcMod/PathsAndFiles.hs

@@ -29,6 +29,7 @@ import System.FilePath
 import System.IO.Unsafe
 
 import Language.Haskell.GhcMod.Types
+import Language.Haskell.GhcMod.Monad.Types
 import Language.Haskell.GhcMod.Error
 import Language.Haskell.GhcMod.Read
 import Language.Haskell.GhcMod.Utils hiding (dropWhileEnd)

Language/Haskell/GhcMod/Pretty.hs

@@ -17,6 +17,8 @@
 module Language.Haskell.GhcMod.Pretty where
 
 import Control.Arrow hiding ((<+>))
+import Data.Char
+import Data.List
 import Text.PrettyPrint
 
 import Language.Haskell.GhcMod.Types
@@ -56,7 +58,7 @@ warnDoc :: Doc -> Doc
 warnDoc d = text "Warning" <+>: d
 
 strDoc :: String -> Doc
-strDoc str = doc str
+strDoc str = doc (dropWhileEnd isSpace str)
  where
    doc :: String -> Doc
    doc = lines

Language/Haskell/GhcMod/Types.hs

@@ -68,7 +68,7 @@ defaultOptions :: Options
 defaultOptions = Options {
     outputStyle   = PlainStyle
   , lineSeparator = LineSeparator "\0"
-  , logLevel      = GmPanic
+  , logLevel      = GmException
 --  , ghcProgram    = "ghc"
   , cabalProgram  = "cabal"
   , ghcUserOptions= []

Language/Haskell/GhcMod/Utils.hs

@@ -25,6 +25,7 @@ import Control.Arrow
 import Control.Applicative
 import Data.Char
 import Language.Haskell.GhcMod.Error
+import Language.Haskell.GhcMod.Monad.Types
 import Exception
 import System.Directory (getCurrentDirectory, setCurrentDirectory, doesFileExist)
 import System.Process (readProcess)