On Thu, Oct 11, 2012 at 10:45 PM, Bradley M. Kuhn <bkuhn(a)ebb.org> wrote:
Mike Linksvayer wrote on 9 August:
> there are cases where unambiguously MPL code could be included in a
> copyleft-next project, if only copyleft-next allowed for it.
Honestly, I'm not convinced that a truly strong copyleft can allow
unilaterally inclusion of other copylefted code -- even weak -- without
bilateral compatibility clauses.
I don't see why not, when the weaker copyleft's scope is unambiguously
a subset of the stronger one's. MPL and copyleft-next seem such a
case. One can comply with MPL's file-scoped copyleft by keeping MPL'd
files under MPL. These could be incorporated in a copyleft-next
project if copyleft-next permitted it. Maybe (wild speculation!) they
can be even if not explicitly permitted, just as permissively licensed
files can be.
We have to consider that such
provisions while seemly safe on the surface may actually be manipulated
to undermine the stronger copyleft by enterprising defense attorneys.
Ok, I now see "truly" as an important qualifier to "strong copyleft
can allow...". Additionally, added complexity may not be worth it.
and
Richard Fontana wrote on 2 September:
> This proposal might make the most sense for licenses that are
> generally considered non-copyleft but GPL-incompatible (the proposed
> language seems modeled on things like the [I believe FSF-recommended]
> OpenSSL GPL linking exception). For copyleft licenses, it raises the
> same problem on a more general level that we dealt with when thinking
> about a clause that would achieve EPL compatibility.
Exactly. I think anyone who wants this kind of compatibility has
to prove that it can't be used by the nefarious to circumenvent copyleft.
Note that the ways copyleft is subverted are subtle and complicated. Most
people don't see that because they rarely get the rather horrible experience
of regularly dealing with people who are trying. You may have to take
my word for it that this happens, but if folks want to raise specific
questions, I'm happy to talk about it in detail. There's enough of it
and it's common enough that it's difficult to generalize.
I'm curious about how one would exploit (as in undermine strong
copyleft) permission to add MPL licensed files to a copyleft-next
project, files remaining under MPL. I guess that one would start by
contributing MPL files, and eventually rewrite copyleft-next portions,
such that the whole project consists of nothing but MPL files. In some
case I guess this could make
avoid-strong-copyleft-through-reimplementation more feasible by
providing a bridge to such. But I'm guessing you have one or more
nefarious strategies in mind?
Mike