[GHC] #11180: A program writing to a read-only stdout should not succeed

[GHC]

#11180: A program writing to a read-only stdout should not succeed
-------------------------------------+-------------------------------------
           Reporter:  thomie         |             Owner:
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  Compiler       |           Version:  7.10.2
           Keywords:                 |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  None/Unknown
  Unknown/Multiple                   |
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
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 In the shell, redirection of file descriptors can be read-only (<), write-
 only (>), or read-write (<>).

 A program trying to write to stdout, while stdout is redirected read-only,
 currently exits with exit code 0.

 {{{
 $ cat hello.hs
 main = print "hello world"

 $ ghc hello.hs
 ...

 $ ./hello 1< /dev/null; echo Exit status: $?
 Exit status: 0
 }}}

 This should however show some error message, and return some non-zero
 error message, because the write never succeeds.

 Note that this example is different from `./hello 1> /dev/null`, which
 rightfully does succeed.

 As suggested by this [http://roscidus.com/blog/blog/2013/06/09/choosing-a
 -python-replacement-for-0install/ blog post]:

 >    "If you’re not sure why this is important, imagine the command is
 `dump-database > backup` and the filesystem is full."

 Supposedly OCaml gets this right.

 For reference, from my bash man page:

 >    *Redirecting Input*
 >
 >    Redirection of input causes the file whose name results from the
 expansion of word to be opened for reading on file descriptor n, or the
 standard input (file descriptor 0) if n is not specified.
 >
 >    The general format for redirecting input is:
 >
 >         [n]<word

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11180>
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