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

[Nick Coghlan]

On Sun, Jan 27, 2013 at 9:29 PM, Antoine Pitrou <solipsis at pitrou.net> wrote:
> I don't think such limitations are very useful in practice. Users
> calling sys.setdefaultexec() will have to be sufficiently knowledgeable
> to understand the implications, anyway.

I've yet to hear a use case for being able to turn it off globally if
the application developer has indicated they want it on. A global flag
that can be turned off programmatically is worse than no global flag
at all.

If we're never going to migrate to cloexec-on-by-default, then there
simply shouldn't be a global flag - the option should just default to
False.

If we're going to migrate to cloexec-on-by-default some day, then the
global flag should purely be a transition strategy to allow people to
try out that future behaviour and adjust their application
appropriately (by clearing the flag on descriptors that really need to
be inherited). The typical default that should be assumed by library
code will still be cloexec-off-by-default.

A completely flexible global flag is just a plain bad idea for all the
reasons Charles-François gave.

Regards,
Nick.

-- 
Nick Coghlan   |   ncoghlan at gmail.com   |   Brisbane, Australia