Create directory if missing; some debug stuff and error handling.

src/Scion/Session.hs

@@ -217,11 +217,12 @@ startWorker start_worker homedir conf = do
    close_all (inp, out, err, _) =
      hClose inp >> hClose out >> hClose err
    wait_for_READY h = do
-     l <- S.hGetLine h
-     if l == str_READY then return () else do
-       -- ignore other lines
-       putStrLn $ "Worker: " ++ show l
-       wait_for_READY h
+     handle (\(_e :: IOError) -> putStrLn "Could not start worker.") $ do
+       l <- S.hGetLine h
+       if l == str_READY then return () else do
+         -- ignore other lines
+         putStrLn $ "Worker: " ++ show l
+         wait_for_READY h
 
    str_READY = S.pack (map (fromIntegral . ord) "READY")
    printFromHandle hdl =

src/Scion/Types/Session.hs

@@ -154,7 +154,7 @@ type WorkerStarter =
 defaultWorkerStarter :: String -> WorkerStarter
 defaultWorkerStarter workername homedir args = do
   worker <- do
-    bindir <- Info.getBinDir    
+    bindir <- Info.getBinDir
     has_inplace <- doesFileExist (bindir </> workername)
     if has_inplace then return (bindir </> workername)
      else do
@@ -164,6 +164,7 @@ defaultWorkerStarter workername homedir args = do
            throwIO $ CannotStartWorker $
              "Executable \"" ++ workername ++ "\" does not exist"
          Just w -> return w
+  --putStrLn $ "Starting worker process: " ++ worker
   runInteractiveProcess worker (homedir:args) Nothing Nothing
 
 data CannotStartWorker = CannotStartWorker String

src/Scion/Worker/Main.hs

@@ -78,6 +78,7 @@ import System.PosixCompat.Files ( getFileStatus, modificationTime )
 logfile :: Handle
 logfile = unsafePerformIO $ do
             path <- getAppUserDataDirectory "scion"
+            createDirectoryIfMissing True path
             openFile (path </> "worker-log") AppendMode
 
 debugMsg :: MonadIO m => String -> m ()