#7743: GHCI segfaults with Data.Binary instances -----------------------------+---------------------------------------------- Reporter: BigEndian | Owner: Type: bug | Status: new Priority: normal | Component: Compiler Version: 7.6.2 | Keywords: Os: Unknown/Multiple | Architecture: Unknown/Multiple Failure: GHCi crash | Blockedby: Blocking: | Related: -----------------------------+---------------------------------------------- The following code seems to crash GHCi I apologize for the long test case, but I'll need to rebuild ghc with symbols first before I can reduce the test case. GHCi's output is {{{ eric@sagacity ~/prog/haskell/tasks master > ghci GHCi, version 7.6.2: http://www.haskell.org/ghc/ :? for help Loading package ghc-prim ... linking ... done. Loading package integer-gmp ... linking ... done. Loading package base ... linking ... done. Prelude> :l Segfault.hs [1 of 1] Compiling Main ( Segfault.hs, interpreted ) Ok, modules loaded: Main. *Main> main Loading package array-0.4.0.1 ... linking ... done. Loading package deepseq-1.3.0.1 ... linking ... done. Loading package bytestring-0.10.0.2 ... linking ... done. Loading package containers-0.5.0.0 ... linking ... done. Loading package binary-0.5.1.1 ... linking ... done. "zsh: segmentation fault ghci }}} Related code is {{{ module Main where import qualified Data.ByteString as BW import Data.Word(Word8(..)) import Data.Binary import Control.Monad import Data.Char convertWord8ToChar :: Word8 -> Char convertWord8ToChar = chr . fromIntegral convertCharToWord8 :: Char -> Word8 convertCharToWord8 = fromIntegral . ord stringToWByteString :: String -> BW.ByteString stringToWByteString = BW.pack . map convertCharToWord8 wByteStringToString :: BW.ByteString -> String wByteStringToString = map convertWord8ToChar . BW.unpack newtype TaskString = TaskString BW.ByteString deriving (Read, Show) stringToTaskString :: String -> TaskString stringToTaskString = TaskString . stringToWByteString word8sToTaskString :: [Word8] -> TaskString word8sToTaskString = TaskString . BW.pack instance Binary TaskString where get = do (return . word8sToTaskString . init) =<< readWord8sUntil 0 where readWord8sUntil :: Word8 -> Get [Word8] readWord8sUntil val = do w8 <- getWord8 if w8 == val then return $ [w8] else (return . (w8:)) =<< (readWord8sUntil val) put (TaskString bws) = mapM_ putWord8 $ (BW.unpack bws) ++ [0] data Task = Task { taskTitle :: TaskString, taskNotes :: TaskString, taskPriority :: Int } deriving (Read, Show) instance Binary Task where get = do tt <- get :: Get TaskString tn <- get :: Get TaskString tp <- get :: Get Int return Task { taskTitle = tt, taskNotes = tn, taskPriority = tp } put t = do put $ taskTitle t put $ taskNotes t put $ taskPriority t exTaskTitle = stringToTaskString "Do the dishes" exTaskNotes = stringToTaskString "Must be done by 12:00 today" exTaskPriority = 0 encTaskTitle = encode exTaskTitle decTaskTitle = decode encTaskTitle :: TaskString exTask = Task { taskTitle = exTaskTitle, taskNotes = exTaskNotes, taskPriority = exTaskPriority } encTask = encode exTask decTask = decode encTask :: Task main = do putStrLn $ show encTask -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/7743 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler