subprocess.Popen pipeline bug?

[Marko Rauhamaa]

This tiny program hangs:

========================================================================
#!/usr/bin/env python
import subprocess
a = subprocess.Popen('cat',shell = True,stdin = subprocess.PIPE,
                     stdout = subprocess.PIPE)
b = subprocess.Popen('cat >/dev/null',shell = True,stdin = a.stdout)
a.stdin.close()
b.wait() # hangs
a.wait() # never reached
========================================================================

It shouldn't, should it?

Environment:
========================================================================
Python 2.5.1 (r251:54863, Jun 20 2007, 12:14:09) 
[GCC 4.1.2 20061115 (prerelease) (SUSE Linux)] on linux2
========================================================================


Marko

-- 
Marko Rauhamaa      mailto:marko at pacujo.net     http://pacujo.net/marko/