[Distutils] Some clarifications and/or corrections to PEP 376

[Antonio Cavallo]

Please consider a user scenario quite common: the use of DESTDIR while 
planning ahead for path resolution.

Linux distro use DESTDIR (and I believe autoconf-related things) uses 
this env variable to set an alternative "root", so:

  prefix=/usr
  sysconfdir=/etc
  DESTDIR=/foo/bar

  -> bindir (if DESTDIR is set) = /foo/bar/usr/bin
  -> bindir (if DESTDIR is *not* set) = /foo/bar/usr/bin

  -> bindir (if DESTDIR is set) = /foo/bar/etc
  -> bindir (if DESTDIR is *not* set) = /foo/bar/etc

The make install will write only under DESTDIR not requiring root 
permissions (generally regarded as best practice).

Generated rpm can be afterward installed as root (or as required).


Regards,
Antonio

PS. I'm generally against stand alone python "stacks" (isolated 
environment) because they're really a bad practice in respect to so many 
parameters (especially in highly regulated sectors).



Vinay Sajip wrote:
 >
 >
 >
 >> From: PJ Eby<pje at telecommunity.com>
 >
 >> FWIW, the original reason I argued for relative paths in PEP 376 is
 >> supporting installations that are shared across architectures for
 >> cross-platform development.  At OSAF, it was common to have a single
 >> installation directory shared by a Linux, Mac, *and* Windows machine
 >> simultaneously.  Absolute paths would break in such a scenario, as
 >> each accessing machine would see a different absolute path.  Some of
 >> setuptools' design is specifically mangled to handle this kind of
 >> thing.
 >
 >
 > Is this a mainstream use case, though? I'm not dead set against 
relative paths, but looking for simplicity if possible. Nowadays the 
thinking seems to be around using isolated environments even on a single 
platform, rather than trying to share across projects. After all, disk 
space is cheap. The other thing is that using *only* relative paths 
doesn't cut it - there are circumstances where you write files outside 
site-packages, so you would need absolute paths for those files (or 
incredibly convoluted relative ones), and that wouldn't work well in the 
OSAF scenario you described, anyway.
 >
 > Regards,
 >






Vinay Sajip wrote:
>
>
>
>> From: PJ Eby<pje at telecommunity.com>
>
>> FWIW, the original reason I argued for relative paths in PEP 376 is
>> supporting installations that are shared across architectures for
>> cross-platform development.  At OSAF, it was common to have a single
>> installation directory shared by a Linux, Mac, *and* Windows machine
>> simultaneously.  Absolute paths would break in such a scenario, as
>> each accessing machine would see a different absolute path.  Some of
>> setuptools' design is specifically mangled to handle this kind of
>> thing.
>
>
> Is this a mainstream use case, though? I'm not dead set against relative paths, but looking for simplicity if possible. Nowadays the thinking seems to be around using isolated environments even on a single platform, rather than trying to share across projects. After all, disk space is cheap. The other thing is that using *only* relative paths doesn't cut it - there are circumstances where you write files outside site-packages, so you would need absolute paths for those files (or incredibly convoluted relative ones), and that wouldn't work well in the OSAF scenario you described, anyway.
>
> Regards,
>
> Vinay Sajip
>
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