"""
Test for Python issue 2320 ("Race condition in subprocess using stdin")

Note that the name of the issue is over-specific.  As demonstrated below, one
need not use stdin to reproduce the problem.

To run:
    A) Create my_subprocess.py by copying the default subprocess.py and
       applying the patch below (exists only to encourage the race
       condition.  If simply adding a sleep reliably breaks it, then there
       is a race condition)
    B) Execute python subprocess_race_condition.py
    C) Observe that the thread that launches the "immediately terminate" child
       never returns from subprocess.Popen.__init__.  That is a bug.
    D) Set "do_close_fds" to True and observe that the parent does indeed
       terminate, leaving the child running in the background.

Tested on:
    Debian Lenny/Sid with Python 2.5.2-2
    Linux creechb-linux 2.6.25-2-686 #1 SMP Fri Jul 18 17:46:56 UTC 2008 i686 GNU/Linux

--- /usr/lib/python2.5/subprocess.py	2008-08-08 06:34:33.000000000 -0400
+++ my_subprocess.py	2008-10-24 17:43:00.000000000 -0400
@@ -1059,6 +1059,8 @@
             # The first char specifies the exception type: 0 means
             # OSError, 1 means some other error.
             errpipe_read, errpipe_write = os.pipe()
+            import time
+            time.sleep(5)
             self._set_cloexec_flag(errpipe_write)
 
             gc_was_enabled = gc.isenabled()
"""


import sys, os, threading, time

do_close_fds=False

def launchChild(mode):
    print 'Launching child in mode ' + mode
    s = my_subprocess.Popen(
        'python subprocess_race_condition.py ' + mode,
        shell=True,
        close_fds=do_close_fds)
    print 'Done launching child in mode ' + mode

if len(sys.argv) == 1:
    import my_subprocess
    
    threading.Thread(target=lambda: launchChild('never_terminate')).start()
    time.sleep(1)
    threading.Thread(target=lambda: launchChild('immediately_terminate')).start()

else:
    if sys.argv[1] == 'never_terminate':
        while 1:
            time.sleep(1)
            print 'hello from never-ending child process'
    else:
        time.sleep(1)
        print 'hello from immediately-ending child process'