[Python-Dev] Changing the licence of statistics.py

[Stephen J. Turnbull]

Please talk to the lawyers (IANAL TINLA).

Steven d'Aprano writes:

 > I now wish to change that and have it licenced under Python's
 > standard licence. Is there anything I need to do other than just
 > remove the Apache licence boilerplate from the file?

IMHO, no; in fact I would argue that its presence is a (cosmetic)
bug.[1]

Brett Cannon writes:

 > Are you the sole author of the statistics module prior to contributing it,
 > Steve?

AFAICT, this doesn't matter.  The only legally binding condition on
contributors in the CA is choice of contribution license.[2]  The CA
itself states that this allows the PSF to distribute the contributed
code under an open source license of the PSF's choice[3].

I interpret that to mean that any committer can remove language
referring to contributors' licenses, implicitly changing the license
to the "global" Python license.[4]  (Again, IANAL, TINLA, ask VanL!)
I don't see any ethical problem with this, as signing the CA implies
the contributor approves this action in advance.

Of course this is assuming that all authors signed the CA and
therefore chose one of the two approved contributor licenses, but if
they didn't there are bigger problems here.

Footnotes: 
[1]  I don't think there can be legal ramifications for the rest of
Python, there are no copyleft licenses in sight.  There could be a bit
of trouble for the file itself if other contributors chose the AFL but
there's no notice of the AFL -- AIUI legally the AFL allows you to do
that but ethically it's fishy.

[2]  I guess there's an implied warranty of provenance, ie, the
contributor has the right to contribute the code.

[3]  IIRC, "PSF's choice" means "Board-approved".

[4]  Of course these licenses allow *anybody* to sublicense with *any*
license.  Here the restriction to the Python license is due to the CA.
I'm pretty sure that anything in the public repos has to be considered
to be "distributed by the PSF" in the legal sense, and I believe that
although the contributor license allows the PSF to use *any* license,
the CA binds the PSF to distribute under a Board-approved open source
license, or the contributor's original license.