[Python-Dev] PEP 433: Choose the default value of the new cloexec parameter (original) (raw)

Victor Stinner victor.stinner at gmail.com
Fri Jan 25 15:54:21 CET 2013

2013/1/25 Nick Coghlan <ncoghlan at gmail.com>:

I just realised I could be converted to a +0 if the runtime time switch could only be used to set the global default as "cloexec=True" and couldn't be used to switch it back again (for testing purposes, if you only want to switch it on temporarily, use a subprocess). (...)

Oh, I like this idea. It does simplify many things :-)

(And I agree that subprocess can be used to run a test which requires cloexec to be True by default.)

--

I tried to be future-proof. If we decide to enable close-on-exec flag globally by default, how do you disable the flag globally? We may add an inverse command line option and another environment variable (ex: PYTHONNOCLOEXEC), but what about sys.setdefaultcloexec()?

In a previous version, my implementation expected an argument for PYTHONCLOEXEC: PYTHONCLOEXEC=0 or PYTHONCLOEXEC=1. I realized that it's not how other options (like PYTHONDONTWRITEBYTECODE) are designed.

But do we really want to enable close-on-exec in the future? Charles François has really good arguments against such choice :-) It's maybe better to consider that the default at startup will always be False. So we should only provide different ways to set the default to True.

Victor

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