ValueError: Invalid mode ('rw')

[Denis Porfiryev]

Python 2.7.11 x64, Windows 7 x64.

Tested Rubber versions:
- 1.4
- preview revision 20a56ec761ecaf7aa900d5a35b0fc017fdd07aed

Commandline:
python2 -c "import sys,os;execfile(os.path.join(sys.exec_prefix,'scripts','rubber'))" -f -m xelatex document.tex

Rubber fails with this error message (first several lines have been skipped as they don't play a role):

  File "C:\tools\python2\lib\site-packages\rubber\converters\latex.py", line 1311, in run
    if not self.compile():
  File "C:\tools\python2\lib\site-packages\rubber\converters\latex.py", line 1228, in compile
    self.env.execute(cmd, env, kpse=1)
  File "C:\tools\python2\lib\site-packages\rubber\environment.py", line 172, in execute
    stdin = devnull(),
  File "C:\tools\python2\lib\site-packages\rubber\util.py", line 412, in devnull
    devnull_fp = open(os.devnull, 'rw')
  ValueError: Invalid mode ('rw')

After replacing 'rw' with 'r+' all works fine.

[Sebastian Kapfer (caci)]

Thanks, committed! Weirdly enough, Python2 on Linux accepts this mode. Python3 on Linux does not.