[Zope] Zope and the GPL poison pill

Magnus Alvestad magnus@websys.no
12 Sep 2000 23:05:46 +0200


Just to state my position, I have worked as a professional commercial
software developer since 1994.  I think the GPL is appropriate for
work I do outside customer contracts.

[Nils Kassube]

| The problem is not that a client who paid for custom development
| will get the source. It's the fact that you have to release the
| source code of an enhanced GPL'ed component (and possibly stuff
| built with it) for everyone else, too. 

(complete version at http://www.gnu.org/copyleft/gpl.html)

-- from the GPL 

3. You may copy and distribute the Program (or a work based on it,
under Section 2) in object code or executable form under the terms of
Sections 1 and 2 above provided that you also do one of the following:

     a) Accompany it with the complete corresponding machine-readable
     source code, which must be distributed under the terms of
     Sections 1 and 2 above on a medium customarily used for software
     interchange; or,

     b) Accompany it with a written offer, valid for at least three
     years, to give any third party, for a charge no more than your
     cost of physically performing source distribution, a complete
     machine-readable copy of the corresponding source code, to be
     distributed under the terms of Sections 1 and 2 above on a medium
     customarily used for software interchange; or,

--

These are the most relevant sections.  It's pretty clear that you are
only obligated to distribute source to the parties you've distributed
object code / executable form to.

| Another issue is that in a complex object oriented environment
| like Zope it's difficult to determine if you only used a GPL'ed 
| component or "embraced and extended" it. 

Actually the embrace and extension was a silly Microsoft-joke, the
definition in the license text is more verbose:

.. a "work based on the Program" means either the Program or any
derivative work under copyright law: that is to say, a work containing
the Program or a portion of it, either verbatim or with modifications
and/or translated into another language. ..

I don't think a zope site could be defined as a 'work'.

-Magnus