[Python-Dev] Licensing issue (?) for Frozen Python? [was: More optimisation ideas]

[Stephen J. Turnbull]

Executive summary:

There is no licensing issue because Python isn't copyleft.  Stick to
the pragmatic *technical* issue of how to reliably provide
corresponding source to those who want to look at that source (just
because that's how we do things in Python).

Emile van Sebille writes:

 > Except for that nasty licensing issue requiring source code.

CPython is not now and never has been copyleft.  CPython is
distributed by the PSF *as* open source with a license that *permits*
redistribution of original source and derivatives (including
executables), but legally need not *remain* open source downstream.

The remaining issue is the PSF's CLA which permits the PSF to
relicense/sublicense under any open source license.  However it's not
clear to me that the PSF is required by the CLA to distribute source!
It receives the code under very permissive licenses, and the CLA
merely names the contributor's chosen license.  I imagine those
licenses determine whether the PSF must distribute source.  If so, no,
not even the PSF is bound (legally) to distribute Python source.

Of course if *you* want to you can GPL Python (I think that's now
possible, at one time there was a issue with the CNRI license IIRC),
and then licensees of *your* distribution (but not you!) are required
to distribute source.

Of course our trust in the PSF is based on the moral principle of
reciprocity: we contribute to the PSF's distribution as open source
(according to the CLA) in large part because we expect to receive open
source back.  But if the PSF ever goes so wrong as to even think of
taking advantage of that loophole, we are well and truly hosed anyway.
(Among other things, that means a voting majority of the current PSF
Board -- many of them core developers -- fell under a bus.)  So don't
worry about it.