Open Source Newbie

[Richard Fontana]

On Tue, 2 Sep 2008 10:37:27 -0400
John Cowan <cowan at ccil.org> wrote:

> Tzeng, Nigel H. scripsit:
> 
> > I would not use LGPL 3.0 since it is incompatible with GPL v2 only
> > projects. Instead use "LGPL 2.1 or later".
> 
> That's just an urban legend, and in this case one that's peddled by
> the FSF itself.  The LGPL 3.0 plainly says in clause 4: "You may
> convey a Combined Work under terms of your choice"; "terms of your
> choice" would certainly include the GPLv2.   

The problem (if one wants to argue it is a problem) occurs because of
the clause in GPLv2 that prohibits imposition of "further restrictions"
on downstream recipients, coupled with the fact that there are certain
requirements in (L)GPLv3 that are (arguably) "further restrictions"
running with the 'Combined Work' -- notably, the limited Installation
Information requirement. The LGPLv3 licensor can solve this problem
through a grant of additional permission.  That, at any rate, is how I
believe the FSF would analyze it.  That is not to say that other
interpretations are impossible (though I think they'd have to call
the entirety of traditional GPL compatibility doctrine into question).

- RF