Hi, thanks for your answer.
On Fri, Nov 02, 2012 at 04:49:08PM +0100, Francesco Poli wrote: > On Fri, 2 Nov 2012 16:13:10 +0100 Michael Banck wrote: > > The development version (not in testing/unstable for now) of cp2k, which > > is under the GPLv2+ itself has just added support for the ELPA library: > [...] > > they say ELPA is licensed > > under the LGPL with some additional clauses. > [...] > > It says this: > > > > --8<-- > [...] > > The code is distributed under ALMOST all of the the terms of the GNU > > Lesser General Public License version 3 (LGPL). > [...] > > While we are not allowed to alter the license texts as written in those > > files, IN ADDITION our own license prescribes two important > > modifications / clarifications to the original lgpl.txt: > > > > - In point 2., clause b) - stating that that you may redistribute > > under the terms of the plain GNU GPL - shall NOT apply. In other > > words, if you redistribute, you MUST keep the additional permissions > > of the LGPL v3 in place. > > > > - If you redistribute, you must redistribute under the terms of the > > LGPL version specified here. Using later or earlier versions > > published by anyone except the ELPA copyright holders is > > not allowed. > > > [...] > > --8<-- > > > > My main question would be whether the above can considered > > GPLv2+-compatible, i.e. whether cp2k can use this. > > Dear Michael, > first of all the GNU LGPL v3 is not compatible with the GNU GPL v2, but > only with the GNU GPL v3. > Hence, even a plainly LGPLv3-licensed work would be considered > compatible with a GPLv2+-licensed work, just because of that plus sign > (assuming that "v2+" means "v2 or later", as usual), but not with a > GPLv2only-licensed work. Right, that's why I explicitly mentioned that CP2K is under the GPLv2+. > However, this case is much more complicated, since there are two > additional clauses, with respect to the GNU LGPL v3. > > The first clause disables one clause of the GNU LGPL v3, dropping its > one-way convertibility to the ordinary GPL. > My own personal opinion is that such additional restriction (which I am > not even sure can actually be added this way to the GNU LGPL v3) makes > the result GPL-incompatible. > The reason is that the GNU GPL insists that the whole work be available > under the terms of the GNU GPL, but the above restriction makes this > impossible for the ELPA library. Now that you mention it I guess that clause was explicitly included in the LGPLv3 in order to maintain GPL-compatibility by design, right? In that case, I will bring it up with the CP2K maintainers. They do not distribute binaries though, only a source repository and sometimes release tarballs. Is this already an issue as they are shipping the ELPA source in their tree right now? > The second clause seems actually unnecessary to me: as specified by > Section 6 of the GNU LGPL v3, a library is not compelled to enable the > "or later" mechanism: > > [...] > | If the > | Library as you received it specifies that a certain numbered version > | of the GNU Lesser General Public License "or any later version" > | applies to it, you have the option of following the terms and > | conditions either of that published version or of any later version > | published by the Free Software Foundation. > [...] > > It says "*If* the Library [...] specifies [...]", so the Library may > specify otherwise (for instance "v3 only"). > The LGPL text even allow the licensor to elect a "proxy" that will > decide whether future versions shall apply... > Hence, I personally think that there's no need to add this second > clause to achieve this result. > I am under the impression that it should suffice to specify "v3 only", > which is already the case: Ok. Let's hope the ELPA people reconsider. It is pretty difficult for me to second guess why exactly they revoke the GPL compat clause (which would not be an "advantage" to anybody *less* Free Software happy than they are, AFAICT), maybe they are just confused about it and/or discarded the GPL due to their corporate (or rather publically funded organisation's) policies.. Cheers, Michael -- To UNSUBSCRIBE, email to [email protected] with a subject of "unsubscribe". Trouble? Contact [email protected] Archive: http://lists.debian.org/[email protected]
