[GHC] #14171: STM causes program to suddenly exit

30 Aug 2017

      #14171: STM causes program to suddenly exit
----------------------------------------+----------------------------------
           Reporter:  MichaelBurge      |             Owner:  (none)
               Type:  bug               |            Status:  new
           Priority:  normal            |         Milestone:
          Component:  libraries/stm     |           Version:  8.2.1
           Keywords:                    |  Operating System:  Linux
       Architecture:  Unknown/Multiple  |   Type of failure:  Runtime crash
          Test Case:                    |        Blocked By:
           Blocking:                    |   Related Tickets:
Differential Rev(s):                    |         Wiki Page:
----------------------------------------+----------------------------------
 Observed behavior:
 * The below program exits with return code 0 between the call to 'error
 "derp2"' and the call to 'error "derp"'
 * If the statement 'error "derp2"' is uncommented, the program will
 terminate with an exception.
 * The program only exits without output with -O. And in particular, with
 no-ignore-interface-pragmas.

 Expected behavior:
 * The program should terminate with an exception regardless of whether
 'error "derp2"' is commented out or not.

 {{{#!hs
 module Main where

 import Control.Concurrent.STM
 import Control.Concurrent.STM.TVar

 data A = A String deriving (Eq, Show)

 data E = E {
   a :: TVar [Int],
   b :: TVar A,
   c :: TVar [Int]
   }

 consistency_1 :: E -> STM Bool
 consistency_1 = \e -> do
   _ <- readTVar $ c e
   return True

 installSanityChecks :: E -> IO ()
 installSanityChecks e = do
   x e
   error "derp"

 x e = do
   atomically $ mapM_ installCheck [
     consistency_1
     ]
   -- error "derp2"
   where
     installCheck check = always $ check e

 main :: IO ()
 main = do
   state <- initialize
   installSanityChecks state

 initialize :: IO E
 initialize = E <$> newTVarIO [] <*> newTVarIO (A "USD") <*> newTVarIO []
 }}}

 Build options: (Remove -O and it will show the error)
 {{{
 /home/mburge/tmp/ghc/ghc-8.2.1/build/bin/ghc \
     -O \
     -package-id base-4.10.0.0 \
     -package-id stm-2.4.4.1-2iQ3ZIiQ6vc4AnCVcs8oMd \
     app/Main.hs \
     -package-db
 /home/mburge/.stack/snapshots/x86_64-linux/nightly-2017-08-24/8.2.1/pkgdb
 }}}

 I used a fresh copy of GHC installed from here:
 https://www.haskell.org/ghc/download.html

-- 
Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14171
GHC http://www.haskell.org/ghc/
The Glasgow Haskell Compiler