[Zope] Mixing Open Source licenses

Jim Penny jpenny@universal-fasteners.com
Tue, 23 Oct 2001 11:58:34 -0400


On Tue, Oct 23, 2001 at 05:35:14PM +0200, Bruno BORGHI wrote:
> Hello,
> 
> Is there any documentation somewhere on the impact of the mixing of
> licenses between ZPL and GPL, for a Zope site ?
> 
> For instance, suppose I develop for a customer a business application
> with Zope (ZPL) and MetaPublisher (MPL - Mozilla) , and that a very
> independant part of the application is just having Zwikis (GPL) for
> ordinar use without modification. What does apply to my application
> itself ?
> My understanding is that my application is not GPLed if it does not rely
> specifically on a GPL module. Do you agree ?
> 
> And what about GPL Python modules ? Python being an interpreted
> language, what is the impact of a GPL python module over the general
> license issue ?
> More. MySQLdb has a choice of license between GPL and the original
> license based on Python 1.5.2's license. It has a C module _mysql.c that
> is linked with the Python executable. What would be the status of my
> application using Zope and  MySQLdb,  if the only choice was GPL for
> _mysql.c ?
> 
> Although it is not of paramount importance, this license issue worry
> customers for which we develop applications, even if they do not plan to
> redistribute the application. I would like to give an answer that is
> generally accepted in the Zope community.
> 
> Thanks,
> Bruno Borghi
> http://www.akeirou.com

This is somewhat controversial -- largely due to how "linking" is 
to be interpreted and whether it occurs at all.

See http://lists.zope.org/pipermail/zope-dev/2001-June/thread.html#11792
Thread is "http://lists.zope.org/pipermail/zope-dev/2001-June/thread.html#11792"

>From the archives at
lists.zope.org/pipermail/zope-dev/2001-June/011881.html 

------------------------------------------------------------------

Date: Thu, 21 Jun 2001 16:43:05 -0600 (MDT)
From: Richard Stallman <rms@NO-SPAM.gnu.org>
To: morten@NO-SPAM.thingamy.net
Subject: Re: Mixing different licences
 
    Another question is whether or not it's legal to use GPL-ed Zope
products with Zope.
 
That is a hard question.  I don't know whether Zope is just an interpreter
or contains facilities that, in effect, the user program links with.
It makes a difference.
 
If the former, you can run programs on Zope regardless of their
licenses.
 
If the latter, then in general, you can't take someone's GPL-covered
code and combine it with Zope, because the Zope license is
GPL-incompatible.
 
If someone wrote a GPL-covered program specifically for Zope, you are
pretty safe taking that as implicit permission to combine it with
Zope.  But it would be better for them to give explicit permission.

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Also from the archives at
http://lists.zope.org/pipermail/zope-dev/2001-June/011882.html
(Simon is simon@joyful.com)

-----------------------------------------------------------------

Now here, I have to assume RMS is using "combine" above to mean
"combine and redistribute".

I hope I'm right ? If "combine" included "install zwiki on your zope
installation and use it" then everything I know is wrong..  I did
intend for that to be fairly danger-free.

-Simon

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There is a range of opinion.
If I had something releasable under GPL, _I_ would intend the license
to apply only to the code itself and code sub-classed from it.  (note
that GPL is silent on OO classing issues).

fog (Federico di Gregorio) opines:
"licensing a zope product under gpl is a non-sense
because you won't be able to use it (usually products inherit on zope
classes) and respect the gpl at the same time"  [fog interprets
sub-classing as equivalent to linking].

Jerome Alet has the strictest conditions I have ever seen:
He allows his code to be _called_ only from GPL'd code, or
as a specific condition from the Test tab.

If in doubt, contact the author and/or copyright owner (who is really the 
only one with standing to complain) and ask.

Jim Penny

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