Bug#740463: libelmersolver-6.1.so links with both GPL-licensed and GPL-incompatible libraries

[Francesco Poli (wintermute)]

Package: libelmersolver-6.1
Version: 6.1.0.svn.5396.dfsg2-2
Severity: serious
Justification: Policy 2.3
User: debian-science-maintainers at lists.alioth.debian.org
Usertags: scotch-license-issues

Hello,
it was previously [1] noticed that Elmer links with SCOTCH, which is
GPL-incompatible.

[1] https://bugs.debian.org/618696#34

Unfortunately, it seems to me that the issue is deeper than it appeared
to be.

Let's start from the beginning.
SCOTCH [2] is under the terms of the CeCILL-C license, which is
GPL-incompatible, since it includes some restrictions not
included in the GPL (at the very least, the choice of venue clause) and
has no explicit conversion-to-GPL clause.
An analysis of this license may be found on the debian-legal archives [3].

[2] http://packages.qa.debian.org/s/scotch.html
[3] https://lists.debian.org/debian-legal/2008/01/msg00171.html

The library /usr/lib/libelmersolver-6.1.so links with:

  => libdmumps_scotch-4.10.0.so, which is public domain, but is
     linked with the GPL-incompatible libscotch-5.1.so

  => libumfpack.so.5.6.2, which [4] is under the GNU GPL v2 or later

  => libcholmod.so.2.1.2, which [4] has parts under the GNU GPL v2 or later

[4] http://metadata.ftp-master.debian.org/changelogs/main/s/suitesparse/unstable_copyright

This seems to mean that package libelmersolver-6.1 includes a file
which links with both GPL-licensed and GPL-incompatible libraries.

I think the possible solutions to this licensing issue are, in
descending order of desirability:

 (A) SCOTCH copyright holders should be contacted and persuaded to
re-license (or dual-license) it under GPLv2-or-later-compatible terms

 (B) SCOTCH should be substituted with a GPLv2-or-later-compatible
replacement, if any is available

 (C) GPL-licensed library (such as UMFPACK and CHOLMOD) copyright
holders should be asked to relax the copyleft (for instance by switching
the LGPL v2.1) or add license exceptions that give permission to link
their works with code released under CeCILL-C v1.0


The best solution is (A): having SCOTCH re-licensed under
GPLv2-or-later-compatible terms would eliminate all the SCOTCH
license incompatibility issues.
Since SCOTCH used to be LGPL-licensed (before switching to CeCILL-C!
oh nooo!), I got in touch with the main author of SCOTCH
(François Pellegrini) and tried to persuade him that SCOTCH should
be re-licensed, in the hope that he would discuss the issue with
the actual copyright holders (INRIA) and obtain the necessary paperwork.
I talked to him in 2011, explaining the issue, but I apparently failed
to convince him that there indeed is an issue.
I have recently tried again to get in touch with him, but I haven't
succeeded.

Now I really need your help: please try hard to pursue solution (A).
Succeeding would solve the issue for elmerfem, but also really benefit 
several other packages which suffer from similar problems with SCOTCH.
I still have to file bug reports against those other packages, but
I'll do so sooner or later. I hope you are OK with the usertag
I set for this bug report: I intend to use it for the other similar
reports as well.

Thanks for your time and let's hope this issue may be solved for
the best real soon now!