Re: Plugins, libraries, licenses and Debian

[Arnoud Engelfriet <galactus@stack.nl>]

M?ns Rullg?rd wrote:
> Arnoud Engelfriet <galactus@stack.nl> writes:
> > The original issue, as far as I understood is, was whether it
> > is allowed to bundle a GPL-licensed plugin with a host program
> > under a GPL-incompatible license. Or actually, a host that
> > also uses a second plugin which is under a GPL-incompatible license,
> > but that shouldn't make a difference.
> 
> In my opinion, there is a difference.  In the two plugins case, you
> don't need to use them at the same time.

Correct. However, if you do not use them at the same time, the
problem does not arise. So the issue is only relevant if you
do want to bundle both so that the host loads both at the same
time.

> > The host and the plugin can obviously be distributed separately
> > as they are original works created by different people.
> 
> What if they have the same author?  

Then you could make an argument that he intended both to work
together, so there must be an implicit exception to the GPL
license he applied to the plugin. 

> If the GPL tries to make
> restrictions on what independent works users of GPL'd software can
> create, I would definitely not call it a free license.  Would such a
> restriction even be valid under copyright law (or whatever law
> applies)?

The GPL does not impose restrictions on independent works.
Restrictions are imposed on works "based on" the GPL-licensed
work. So the host never "becomes" GPL, but a new work
consisting of host plus plugin seems to qualify as a
derivative of the plugin (and of the host, of course).

Then the question is, are you permitted to distribute this new
work? For that, you must comply with the licenses of both the
host and the plugin. Since the plugin is GPL, the host's license
must be GPL-compatible otherwise you cannot fulfill both
licenses at the same time.

Legally speaking I don't think there is much you can *not*
validly require in a license, if you write it as a condition
for being granted permission. M$ for example forbids you
to distribute their software in conjunction with GPL-licensed
software. 

Of course at some point other issues beyond copyright law
become relevant, such as abusing your dominant market position
or the "reasonableness" test for contracts (if licenses without
consideration qualify as contracts in your jurisdiction).

Arnoud

-- 
Arnoud Engelfriet, Dutch patent attorney - Speaking only for myself
Patents, copyright and IPR explained for techies: http://www.iusmentis.com/