Change the default logger to print to stderr

Author: pepeiborra

ghcide/exe/Main.hs

@@ -88,7 +88,7 @@ main = do
                 Typecheck x | not argLSP -> Just x
                 _                        -> Nothing
 
-            ,Main.argsLogger = logger
+            ,Main.argsLogger = pure logger
 
             ,Main.argsRules = do
                 -- install the main and ghcide-plugin rules

ghcide/src/Development/IDE/Main.hs

@@ -67,7 +67,7 @@ import           Data.Hashable                      (hashed)
 data Arguments = Arguments
     { argsOTMemoryProfiling :: Bool
     , argFiles :: Maybe [FilePath]   -- ^ Nothing: lsp server ;  Just: typecheck and exit
-    , argsLogger :: Logger
+    , argsLogger :: IO Logger
     , argsRules :: Rules ()
     , argsHlsPlugins :: IdePlugins IdeState
     , argsGhcidePlugin :: Plugin Config  -- ^ Deprecated
@@ -82,7 +82,7 @@ instance Default Arguments where
     def = Arguments
         { argsOTMemoryProfiling = False
         , argFiles = Nothing
-        , argsLogger = noLogging
+        , argsLogger = stderrLogger
         , argsRules = mainRule >> action kick
         , argsGhcidePlugin = mempty
         , argsHlsPlugins = pluginDescToIdePlugins Ghcide.descriptors
@@ -93,9 +93,18 @@ instance Default Arguments where
         , argsGetHieDbLoc = getHieDbLoc
         }
 
+-- | Cheap stderr logger that relies on LineBuffering
+stderrLogger :: IO Logger
+stderrLogger = do
+    lock <- newLock
+    return $ Logger $ \p m -> withLock lock $
+        T.hPutStrLn stderr $ "[" <> T.pack (show p) <> "] " <> m
+
 defaultMain :: Arguments -> IO ()
 defaultMain Arguments{..} = do
     pid <- T.pack . show <$> getProcessID
+    logger <- argsLogger
+    hSetBuffering stderr LineBuffering
 
     let hlsPlugin = asGhcIdePlugin argsDefaultHlsConfig argsHlsPlugins
         hlsCommands = allLspCmdIds' pid argsHlsPlugins
@@ -134,7 +143,7 @@ defaultMain Arguments{..} = do
                     argsDefaultHlsConfig
                     rules
                     (Just env)
-                    argsLogger
+                    logger
                     debouncer
                     options
                     vfs
@@ -171,7 +180,7 @@ defaultMain Arguments{..} = do
                         { optCheckParents = pure NeverCheck
                         , optCheckProject = pure False
                         }
-            ide <- initialise argsDefaultHlsConfig rules Nothing argsLogger debouncer options vfs hiedb hieChan
+            ide <- initialise argsDefaultHlsConfig rules Nothing logger debouncer options vfs hiedb hieChan
             registerIdeConfiguration (shakeExtras ide) $ IdeConfiguration mempty (hashed Nothing)
 
             putStrLn "\nStep 4/4: Type checking the files"
@@ -199,7 +208,7 @@ defaultMain Arguments{..} = do
                             Key GhcSessionDeps :
                             [k | (_, k) <- HashMap.keys values, k /= Key GhcSessionIO]
                             ++ [Key GhcSessionIO]
-                measureMemory argsLogger [keys] consoleObserver valuesRef
+                measureMemory logger [keys] consoleObserver valuesRef
 
             unless (null failed) (exitWith $ ExitFailure (length failed))
 {-# ANN defaultMain ("HLint: ignore Use nubOrd" :: String) #-}

src/Ide/Main.hs

@@ -94,7 +94,7 @@ runLspMode lspArgs@LspArguments{..} idePlugins = do
     Main.defaultMain def
       { Main.argFiles = if argLSP then Nothing else Just []
       , Main.argsHlsPlugins = idePlugins
-      , Main.argsLogger = hlsLogger
+      , Main.argsLogger = pure hlsLogger
       , Main.argsIdeOptions = \_config sessionLoader ->
         let defOptions = Ghcide.defaultIdeOptions sessionLoader
         in defOptions