Bug#617613: freecad: links with both GPL-licensed and GPL-incompatible libraries

[Francesco Poli (wintermute)]

Package: freecad
Version: 0.10.3247.dfsg-2
Severity: serious
Justification: Policy 2.2.1


Hello Debian Science Maintainers,
thanks for maintaining freecad.

This package is mainly released under the terms of the GNU LGPL v2 or
later, but includes some files released under the terms of the GNU GPL
v2 or later, and, above all, links with libcoin60, which is released
under the terms of the GNU GPL v2 (only) [1].

[1] http://packages.debian.org/changelogs/pool/main/c/coin3/coin3_3.1.3-1/libcoin60.copyright

On the other hand, freecad links with libopencascade-*-6.3.0, which
is released under the terms of the OCTPL v6.3: this license is itself
acceptable [2] (from a DFSG point of view), but is GPLv2-incompatible,
since it implements a copyleft mechanism and has no explicit
GPL-compatibility clause.
The GPL-incompatibility is acknowledged in Open CASCADE S.A.S.
FAQ [3]:

| 1) Is Open CASCADE Technology license GPL-compatible?
|
| No, it is not. OPEN CASCADE Company uses its own custom license.
| However, it follows LGPL license in terms of its purpose and intent.

[2] http://lists.debian.org/debian-legal/2007/12/msg00077.html
[3] http://www.opencascade.org/occt/faq/

As a consequence, I would say that freecad (the binary package) is
currently undistributable, as it links with both a GPLv2-licensed
library and a GPLv2-incompatible one.


AFAICT, there are three possible ways to fix this issue, in descending
order of desirability.

 (A) Open CASCADE S.A.S. should be contacted and persuaded to
re-license Open CASCADE Technology under GPLv2-compatible terms.

 (B) Open CASCADE Technology should be substituted with a
GPLv2-compatible replacement, if any is available.

 (C) Coin3D copyright holder should contacted and asked to add a
license exception to give permission to link Coin3D with code released under
the OCTPL; this additional permission should be drafted along the
lines of the template [4] suggested by the FSF. A similar exception
is needed for GPL-licensed files in FreeCAD itself and should be asked
to the corresponding copyright holders.

[4] http://www.gnu.org/licenses/gpl-faq.html#GPLIncompatibleLibs


Now, the half-good news.

It seems that there's some possibility [5] that Open CASCADE Technology
could be re-licensed under the terms of the LGPLv2.1: this would make it
GPLv2-compatible (solution (A) above).

[5] http://www.opencascade.org/org/forum/thread_15859/

I got in touch with upstream (Open CASCADE S.A.S.) via their web
contact form [6] and got a somewhat encouraging reply.

[6] http://www.opencascade.org/about/contacts/

This happened on April 2009, though.

There has been no progress on the re-licensing of Open CASCADE since
then: the management (of Open CASCADE S.A.S.) has not yet taken a
decision on the matter.
I have been going on contacting them periodically and asking them
whether there's any progress, but, apparently, I am not persuasive
enough...  :-(
I reported this on the debian-legal list [7][8].

[7] http://lists.debian.org/debian-legal/2009/10/msg00000.html
[8] http://lists.debian.org/debian-legal/2010/02/msg00007.html

Please note that Open CASCADE Technology version 6.5 has been recently
released, but v6.5 of the license, despite having a much more accurate
preamble, is substantially unchanged in its legally binding text.


If nobody else helps me by contacting Open CASCADE S.A.S. and
persuading them to re-license Open CASCADE Technology under the
LGPLv2.1, I am afraid that the above-mentioned solution (A) will
not be a viable option...   :-(

So, please, pretty please, help me in persuading Open CASCADE S.A.S.
to switch to the GNU LGPL v2.1!
I recommend involving FreeCAD upstream too in this persuasion effort.
The more people get in touch with Open CASCADE S.A.S. and try to
persuade them, the better.

Thanks for any help you can provide.