[Python-Dev] More optimisation ideas

[Stephen Hansen]

On Fri, Feb 5, 2016, at 10:33 AM, Emile van Sebille wrote:
> On 2/5/2016 9:37 AM, Alexander Walters wrote:
> >
> > On 2/5/2016 12:27, Emile van Sebille wrote:
> >> On 2/1/2016 9:20 AM, Ethan Furman wrote:
> >>> On 02/01/2016 08:40 AM, R. David Murray wrote:
> >> <snip>
> >>>> On the other hand, if the distros go the way Nick has (I think) been
> >>>> advocating, and have a separate 'system python for system scripts' that
> >>>> is independent of the one installed for user use, having the
> >>>> system-only
> >>>> python be frozen and sourceless would actually make sense on a
> >>>> couple of
> >>>> levels.
> >>>
> >>> Agreed.
> >>
> >> Except for that nasty licensing issue requiring source code.
> >>
> >> Emile
> > Licensing requires, in the GPL at least, that the *modified* sources be
> > made *available*, not that they be shipped with the product. Looking at
> > the Python license, and what tools already do, there is zero need to
> > ship the source to stay compliant.
> 
> Hmm, the annotated Open Source Definition explicitly states "The program 
> must include source code" -- how did I misinterpret that?

Couple things.

First, the OSD is not authoritative. Python's license establishes the
rules of its distribution: that Python's license is considered
compatible with the OSD doesn't actually mean your reading of anything
on the OSD page as having any binding meaning.

Second, OSD's Rule 2 means that those who are distributing Python -- the
PSF, originally -- must provide source code if they're distributing it
under Python's license, but it doesn't actually mean it must be packaged
with it in every download. In fact, its not today. The standard library
source is included in normal downloads, but the C source of Python
isn't. But you can download it readily though, so that's fine. Its fully
compliant with the OSD.

But! If Debian (pulling them out of a hat randomly) is distributing
Python, they aren't the PSF, and notably are not bound by the OSD rules,
only by Python's license terms. The PSF satisfied their requirements to
the licensing terms when releasing Python, but now Debian has Python,
and they are distributing it-- that's an entirely separate act, and you
must look at them as a separate actor in terms of the license. They
don't have to distribute it in the same license. They must be ABLE to
(as OSD's Rule 3 says), but they don't HAVE to. Some random person can
take Python, rename it Snakey, and release it under almost any license
they want and give no one the source code at all. 

Python has from the beginning allowed this:its actually in quite a few
closed source / proprietary products without ever advertising it and
providing no source, entirely legally and ethically -- Python's gone out
of its way to support this sort of use-case. 

As it happens, Debian usually distributes something very close to the
official release (sometimes they backport patches and such), and always
does so under the same license as Python (AFAICT), but they don't *have*
to. 

GPL is copyleft and requires its derivative works to be GPL'd (or at
least, no more restrictive then GPL)-- so in GPL, to distribute it you
MUST distribute it under GPL-compatible terms. Python is a permissive
license and allows anyone to do basically anything, INCLUDING produce
closed source releases if someone wanted to, or just release
modifications or modules that are available under different licenses. 

The OSD encompasses both ends of the spectrum: the GPL's mandate of
source access and the OSD's mandate of the receiver to be able to
distribute in the same terms they received (notably, NOT the same terms
it was originally released under).

-- 
Stephen Hansen
  m e @ i x o k a i  . i o