[racket] Bug in path-replace-suffix?

Hello,

during the development of the PLaneT package for protocol buffers [1] a
likely bug in Racket's standard library function path-replace-suffix has
shown up [2].

When you apply path-replace-suffix to a path that is not native to the
platform on which Racket is running, the procedure strips all leading
directories from the path. For example on Linux:

  $ racket
  Welcome to Racket v5.3.6.
  > (path-replace-suffix
      (string->some-system-path "foo/bar.x" 'unix)
      ".y")
  #<path:foo/bar.y>
  > (path-replace-suffix
      (string->some-system-path "foo/bar.x" 'windows)
      ".y")
  #<windows-path:bar.y>
  > (path-replace-suffix
      (string->some-system-path "foo\\bar.x" 'windows)
      ".y")
  #<windows-path:bar.y>

Or on Windows:

  Microsoft Windows [Version 6.1.7601]
  [...]>racket
  Welcome to Racket v5.3.6.
  > (path-replace-suffix
      (string->some-system-path "foo/bar.x" 'unix)
      ".y")
  #<unix-path:bar.y>
  > (path-replace-suffix
      (string->some-system-path "foo/bar.x" 'windows)
      ".y")
  #<path:foo/bar.y>
  > (path-replace-suffix
      (string->some-system-path "foo\\bar.x" 'windows)
      ".y")
  #<path:foo\bar.y>

I think this behaviour contradicts the documentation which states that
place-replace-suffix should only touch the filename suffix, should leave
the rest of the path as is and should also work with paths for other
systems.

Ciao,
Thomas


--
[1] The package in question is

http://planet.racket-lang.org/display.ss?package=protobuf.plt&owner=murphy

[2] The relevant bug tracker entry for the package is
    http://planet.racket-lang.org/trac/ticket/1519


-- 
When C++ is your hammer, every problem looks like your thumb.