[GHC] #9266: getDirectoryContents blow its stack in a huge directory

[GHC]

#9266: getDirectoryContents blow its stack in a huge directory
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       Reporter:  joeyhess                 |             Owner:
           Type:  bug                      |            Status:  new
       Priority:  normal                   |         Milestone:
      Component:  libraries/directory      |           Version:  7.8.2
       Keywords:                           |  Operating System:  Linux
   Architecture:  Unknown/Multiple         |   Type of failure:
     Difficulty:  Easy (less than 1 hour)  |  None/Unknown
     Blocked By:                           |         Test Case:
Related Tickets:                           |          Blocking:
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 Once a directory has around 2 million files in it, a lack of an
 accumulator in getDirectoryContents (unix version only; windows already
 has an acc) causes it to blow the stack:

 {{{
 joey at darkstar:‾/src/git-annex>cat test.hs
 import System.Directory
 main = do
         l <- getDirectoryContents "/tmp/big"
         print (null l)
 joey at darkstar:‾/src/git-annex>ghc --make -O2 test
 [1 of 1] Compiling Main             ( test.hs, test.o )
 Linking test ...
 joey at darkstar:‾/src/git-annex>./test
 Stack space overflow: current size 8388608 bytes.
 Use `+RTS -Ksize -RTS' to increase it.
 }}}

 I suggest the attached patch.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9266>
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