[Zope-dev] ZPL and GPL licensing issues

[Jim Penny]

> > > err, no. if you write an external module using only python code, as long
> > > as you use a gpl-compatible python to run zope, you can call your
> > > external code from zope. if you write a product suclassing dc code,
> > > you're effectively 'linking' and gpl limitations apply. 
> > 
> > GPL limitations apply to whom:  To you, the developer?  To a
> > downstream user invoking the product via dtml-call or dtml-var or their
> > pythonish equivalents?  To a downstream developer who modifies your
> > product and redistibutes the modified product?  To a downstream
> > developer who writes a component that invokes the GPL component?
> > 
> > In my mind the only sensible answers are developer - no,
> > user - no (but see Jerome Alet's codacil), downstream modifier - yes,
> > downstream developer who uses - no.
> > 
> > The only other sensible option is that, indeed, no one may distribute
> > GPL components for Zope, including the original developer.
> 
> as i said before, writing gpl code subclassing zope is a non-sense. even
> the author cannot, imho, redistribute its work with a plain gpl attached
> to it. the gpl says that if you link with gpl code *all* the code should
> be gpl or gpl-compatible (major os components like clibs, compilers, etc
> are an exception). so even the author cannot do that without licensing
> under gpl plus some exception ("as a special exception you're allowed to
> link this code with zope or any other zope product distributed under the
> zpl".) see the (in)famous gpl vs. qt thread in the debian mailing lists
> for an in-depth analisys of this problem.
> 
> ciao,
> federico

OK, this is essentially what I wanted.  Now the problem is completely
distilled.

DC and FSF somehow have to come to some understandings of the following
questions.

Can a GPL (unmodified) component be distributed for Zope (at all)?
Can a GPL (modified per fog) component be distributed for Zope?
If yes to either, may the component be invoked (dtml-var, dtml-call,
or equivalent) from a non-GPL component?
If yes to either, may the component be subclassed by a non-GPL component?

Jim

> 
> -- 
> Federico Di Gregorio
> MIXAD LIVE Chief of Research & Technology              fog@mixadlive.com
> Debian GNU/Linux Developer & Italian Press Contact        fog@debian.org
>                       The number of the beast: vi vi vi. -- Delexa Jones
>