[Debichem-devel] LGPLv3+additional clauses and GPL-compatibility

[Michael Banck]

Dear FSF licensing,

The ELPA project is developping a library under a LGPLv3-like license
consisting of the LGPLv3 and two additional clauses (see below for their
full copyright statement):

|- 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.

The first question is: Is the LGPLv3 plus the above two addtional 
clauses still GPL-compatible, i.e. can the ELPA library be used by other
GPL'd projects?

The rationale for their addtional clauses is the possiblity of GPL
projects forking their code under the GPL, making it impossible for them
to use the modifications in their version of the code (as relicensing
from GPL to LGPL is not possible).

The second question is: If the ELPA license is not GPL-compatible and if
the above is a valid concern, could the Free Software Foundation propose
different language to add to the LGPLv3 in order to make GPLv3-only
forks usable by the original project, while retaining LGPL-like
licensing?

The third question is: If additional language to the LGPL is not
possible to accomodate the above issues, can the Free Software
Foundation recommend any other cause of action to the ELPA project?

The full version of the ELPA copyright statement is as follows:

|Licensing and copyright terms for the ELPA library:
|ELPA Consortium (2011)
|
|****
|
|Copyright of the original code rests with the authors inside the ELPA
|consortium. The copyright of any additional modifications shall rest
|with their original authors, but shall adhere to the licensing terms
|set forth below.
|
|****
|
|The code is distributed under ALMOST all of the the terms of the GNU
|Lesser General Public License version 3 (LGPL). The full text
|can be found in the file "lgpl.txt" in this repository. "lgpl.txt"
|makes reference to the GPL v3, which can also be found in this
|repository ("gpl.txt").
|
|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.
|
|****
|
|When in doubt, talk to us. What we would like to ensure is that the ELPA
|code can be used as needed, while providing a strong incentive for
|others to contribute their modifications back to the original
|development.
|
|****


Best regards,

Michael Banck