Questions about copyleft-next

[Bradley M. Kuhn]

> On Mon, Jun 30, 2025 at 6:18 PM secureblueadmin asked about:

> > [this] is an interesting way of preventing (A)GPL/commercial dual
> > licensing:
> >     7. Nullification of Copyleft/Proprietary Dual Licensing
> >
> >     If I offer to license, for a fee, a Covered Work under terms other
> >     than a license that is OSI-Approved or FSF-Free as of the release
> >     date of this License or a numbered version of copyleft-next released
> >     by the Copyleft-Next Project, then the license I grant You under
> >     section 1 is no longer subject to the conditions in sections 3
> >     through 5.

Richard Fontana replied:
> In copyleft-next 0.3.1 the proprietary relicensing poison pill (isn't that
> what we sometimes used to call it?)

Shortly after you (Richard) invented §7, I dubbed it the “copyleft equality
clause”: https://sfconservancy.org/blog/2020/jan/06/copyleft-equality/

I remember because it marked the third time in my career [0] my only
contribution to something important was naming it.  Now that I'm active in
copyleft-next again, though, I hope to actually contribute more than names
for things again. 😆

I really dislike the term “poison pill” not only for its violence but also
because it's typically a tactic used by contracting parties who don't trust
each other.  IMO, the copyleft equality clause is a way that a licensor can
state “I won't engage in proprietary relicensing” and really mean it.  It
builds trust while poison pills typically erode trust.

secureblueadmin asked:
> > However, this license also says:
> >     If the Derived Work includes material licensed under the GPL, You may
> >     instead license the Derived Work under the GPL.
> >
> > As far as I can tell, it would seem that if there's some code under
> > copyleft-next that you want to include in your GPL/commercial dual
> > licensed software, you can just create a Derived work that combines
> > `copyleft-next` code with `GPL` code, and then use that derived work (now
> > under the GPL) in your GPL/commercial dual licensed software. Is this not
> > a loophole?
> >

secureblueadmin noted:
> > Anyhow, thanks for taking the time to read this and bear with my lack of
> > legal knowledge :)

Richard replied:
> No need to apologize for what you say is a lack of legal knowledge. I would
> think your question would be equally likely to be raised by a lawyer.

I agree.  IANAL either but I've been involved in copyleft policy for 30
years, and I still had to stare at the copyleft-next text and your question
for about 7 minutes to make sure I definitely agreed with Denver's and
Richard's analysis.

I think I do, for a third, slightly different reason: the copyleft equality
clause actually removes the §§3-5 requirements for everyone in the world all
at once and its binding once the Covered Work is distributed just once.

Remember the entity seeking to proprietary relicense *has* to have exclusive
rights to the code anyway, so they could always license the Covered Work a
new way (including under GPLv2, if they wanted) and didn't need copyleft-next
§3 to do it anyway.  Heck, §7 even lets them do it, too, without §§3-5.

The big flaw still remaining in the equality clause is that it may not fully
prevent entities in cahoots doing something nasty.

Meanwhile, on my “list” of conversations to reopen is a complete overhaul of
the approach in §3¶2 anyway.  But more on that much later; not first thing on
my list.

   -- bkuhn

[0] I named the Classpath and the Replicant projects but have contributed
    virtually nothing else to them other than the names and moral support to
    the developers.