[Python-Dev] [PEPs] Rebooting PEP 394 (aka Support the /usr/bin/python2 symlink upstream)

[Antoine Pitrou]

On Wed, 20 Jul 2011 01:53:09 -0500
Kerrick Staley <mail at kerrickstaley.com> wrote:
> On Mon, Jul 18, 2011 at 3:03 AM, Ned Deily <nad at acm.org> wrote:
> > I think adding the requirement to mandate hard link vs soft link usage
> > is an unnecessary and unwarranted attempt at optimization.  For
> > instance, IIRC, the OS X installers don't use any hard links: that may
> > complicate the install, plus hard links on OS X HFS* file systems are a
> > bit of a kludge and not necessarily more efficient than symlinks.   It's
> > not a big deal but perhaps the wording should be changed to make a
> > suggestion about hard links vs syminks rather than mandate which should
> > be used.
> 
> Ah, OK. The wording's been changed so that symbolic links will be
> installed on Mac OS X and hard links elsewhere (although maybe
> symbolic links are also better on certain other platforms; I'm not
> sure).
> 
> I do think that specific instructions must be given (rather than just
> a suggestion) because it's indicating what must be done to CPython.
> The instructions *should* be as close as possible to what the
> installer already does, but I'm not entirely sure what the installer
> does by default, and the hard-link recommendation was based off a
> cursory inspection of my own system, so further input from yourself
> and the rest of python-dev would be appreciated.

I think the recommendation should be symbolic links for all systems.
Hard links are generally harder to discover, while it is trivial to
find out that a given file is a symbolink link, and to which other file.
The optimization is probably not useful in the real world (our
executables are relatively small, and people worried about a couple of
megabytes can always go for the shared library option).

Regards

Antoine.