[GHC] #13660: Tail after and including `NUL` character in `FilePath`s silently truncated

[GHC]

#13660: Tail after and including `NUL` character in `FilePath`s silently truncated
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           Reporter:  hvr            |             Owner:  (none)
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:                 |           Version:  8.0.2
  libraries/base                     |
           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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 The current behaviour is imho not ideal as it masks invalid input
 arguments; consider e.g.

 {{{#!hs
 Prelude> readFile "foo"
 *** Exception: foo: openFile: does not exist (No such file or directory)
 Prelude> readFile "foo\NULbar"
 *** Exception: foobar: openFile: does not exist (No such file or
 directory)

 Prelude> writeFile "foo\NULbar" "contents"
 Prelude> readFile  "foo\NULbar"
 "contents"
 Prelude> readFile  "foo"
 "contents"
 }}}

 The reason for the surprising behaviour above is most likely (I haven't
 yet looked at the code), that `"foo\NULbar"` gets converted into a zero-
 terminated `CString` which is then passed to C functions such as
 `fopen(3)`, but to those C function, the C strings `"foo\0bar"` and
 `"foo"` are equivalent, as both are interpreted as `"foo"`.

 What I'd expect to happen on POSIX systems is that operations taking a
 `FilePath` such as `writeFile` or `readFile` should throw an exception
 when the `FilePath` gets encoded in such a way into a zero-terminated
 CString in such a way that a zero octet occurs (except for the intended
 zero-termination zero octet at the end).

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13660>
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