In Windows XP, using CPython 3.1.1:

python -c "import os; os.spawnl( os.P_WAIT, 'blah' )"

Crashes the interpreter and Windows pops up the "tell us about it" box.


Python 2.6 is however happy and just reports invalid arg.

Confirmed on trunk, release31-maint, and py3k on Windows. OS X returns 127 in that case.

In case it matters, 3.0.1 does NOT crash.

2.6 and 3.0.1 used to disable the Microsoft CRT argument error handler: they return EINVAL, but newer versions don't, and should check their arguments before calling _spawnv.

FWIW, the checks are::
    pathname != NULL
    *pathname != '\0'
    argv != NULL
    *argv != NULL
    **argv != '\0'
The first and third checks are guaranteed by the implementation, but the other three should be done in posix_spawnv().
And the other calls to the various nt.spawn* functions probably suffer the same problem.

Why is the Microsoft CRT argument error handler no longer disabled?

Because this is a global setting for the whole process. This was discussed with issue4804.

Should this just be resolved as a "won't fix"?

No, the issue can be fixed by better checking the arguments.

Attached first attempt to close this issue. Are there enough checks? It passes:
os.spawnl(os.P_WAIT, '')
os.spawnl(os.P_WAIT, 'path')
os.spawnl(os.P_WAIT, 'path', '')

This came up on python-list with
os.spawnl (os.P_NOWAIT, r"c:\windows\notepad.exe")
Tim Golden confirmed crash with Win7 on 2.7.?
I did same with 3.2.2 in both interpreter and from IDLE (IDLE hangs and then restarts after closing the 'pythonw has stopped' error message box).
Above apparently works in XP, at least with Py2.2.

@nvetoshkin: Can you please also write tests (in Lib/test/test_os.py) for your patch?

against py3k branch?

Now we are using Mercurial, and what was called 'py3k' on SVN is now 'default'.  Since we now commit on older branches first and then merge with the most recent ones, the patch should either be against 3.2 or 2.7.
You can check the devguide for more informations.

added some tests (not sure if in appropriate place).