[Zope-dev] ZPL and GPL licensing issues

[Erik Enge]

On Wed, 20 Jun 2001, Gregor Hoffleit wrote:

> You're not allowed to distribute a derived work of GPL code with proprietary
> code incorporated.

Ok, this is the situation.  We in Thingamy usually create all our products
under the GPL.  Then we give the whole shebang to the client we have been
working for and they have all the lovely rights that they should have.  If
they want to redistribute, they can.

Then, we have the other clients, that's the clients that are scared
shitless from the GPL because if someone gets ahold of the code, that is
their business-processes, it could be devastating for their business.  It
is a semi-legitimate fear, but only if they have the intention of actually
redistributing the code (eg. becomming software-vendors, which some
actually want to do...).

If I have the proprietory program P (that is the clients business-process
workflow application *phew*) as a Zope Python Product and then we have
Morten's GUM under the GPL, which also is a Zope Python Product, can P
application utilise GUM without having to be relicensed as GPL?  (And I
realise that the word "utilise" is ambigous, that was intentional.)

To ask again, if it was unclear: can I use GPL Zope Python Products with
non-copylefted Zope Python Products without relicensing?  It is imperative
for me as a professional Zope-developer (ie, I charge for my services) to
know the answer to that question, and I should think it is vital to other
developers as well.

Surely someone from DC already as the answer?

Another question which I feel is very related, and to which I cannot get
any real clarification:  Can Zope run GPL Zope Python Products without
being relicensed as GPL?

All the GPL Zope Python Products I've writted as subclassed from
Persistent, for example.

> I. e. if you want to use that GPL code in your work, you'll have to
> make the proprietary code available under a GPL-compatible license as
> well (not necessarily the GPL itself).

"use [...] in your work", what does that mean?  Subclassing?  Interaction
between the products in a management-interface?
 
> The Zope license doesn't even get into the play here. It's all between
> the GPL and your proprietary license.

Hm.  What about a ZPL Zope Python Product and a GPL Zope Python
Product?  Isn't the problem exactly the same?