[GHC] #10731: System.IO.openTempFile is not thread safe on Windows

3 Aug 2015

      #10731: System.IO.openTempFile is not thread safe on Windows
-------------------------------------+-------------------------------------
              Reporter:              |             Owner:
  NeilMitchell                       |
                  Type:  bug         |            Status:  new
              Priority:  normal      |         Milestone:
             Component:              |           Version:  7.10.1
  libraries/base                     |
              Keywords:              |  Operating System:  Windows
          Architecture:              |   Type of failure:  Runtime crash
  Unknown/Multiple                   |
             Test Case:              |        Blocked By:
              Blocking:              |   Related Tickets:
Differential Revisions:              |
-------------------------------------+-------------------------------------
 Given the test program:

 {{{#!hs
 import Control.Concurrent
 import System.IO
 import Control.Monad
 import System.Directory

 main = do
     putStrLn "Starting"
     var <- newEmptyMVar
     tdir <- getTemporaryDirectory
     xs <- replicateM 10 $ do
         var <- newEmptyMVar
         flip forkFinally (\s -> do print s; putMVar var ()) $ do
             replicateM_ 100000 $ do
                 (file, h) <- openTempFile tdir "test.txt"
                 hClose h
                 removeFile file
         return var
     mapM_ takeMVar xs
 }}}

 If I compile and run that with {{{ghc --make TmpFile.hs -threaded &&
 tmpfile +RTS -N5}}} I get:

 {{{
 Starting
 Left C:\Users\NDMIT_~1\AppData\Local\Temp\: openTempFile: permission
 denied (Permission denied)
 Left C:\Users\NDMIT_~1\AppData\Local\Temp\: openTempFile: permission
 denied (Permission denied)
 ...
 }}}

 I've reproduced this on GHC 7.8 and 7.10.1. We hit this in production
 about twice a day.

--
Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10731
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