Guideline to linking in a multilicense situation

[Yaakov Nemoy]

On Fri, May 30, 2008 at 5:32 PM, Tom spot Callaway <tcallawa at redhat.com> wrote:
> On Fri, 2008-05-30 at 17:20 +0200, Yaakov Nemoy wrote:
>> Hi List,
>>
>> My mentor would like to use a library for part of his GSoC work that
>> is licensed partially under the BSD license and partially under the
>> Apache License.  The library is PlotKit and can be found here:
>>
>> http://www.liquidx.net/plotkit/
>>
>> As far as bundeling the library, we can always encourage him to create
>> a separate package for Fedora, so that we can ship Smolt as a GPL2
>> only package with a dependency.  In terms of GSoC related things, it's
>> one more way to encourage him to join the community, of course.  My
>> only question is though, are we allowed to link to this library?  I'm
>> afraid I don't quite understand the nuances of a mixed license
>> environment.  Or would we need to fork the library to match licenses?
>
> Off the cuff (I've not looked at plotkit, or what you want to link it
> to)...
>
> If plotkit is under both the BSD and the ASL 2.0 (yes, it does matter
> what version of the Apache license it uses), any linking would need to
> meet the terms of both licenses. ASL 2.0 is GPLv2 incompatible, but
> GPLv3 compatible. If Smolt would depend on PlotKit, this would be
> problematic (unless Smolt is GPLv2+, in which case, the complete work
> would likely be interpreted as GPLv3).
>
> Alternately, Smolt could add an exception permitting linking to code
> under the Apache 2.0 license, something like:
>
>  In addition, as a special exception, [the copyright holder] gives
>  permission to link the code of its release of Smolt with the
>  "PlotKit"  library (or with modified versions of it that use the same
>  license as the "PlotKit" library), and distribute the linked
>  executables. You must obey the GNU General Public License in all
>  respects for all of the code used other than "PlotKit". If you modify
>  this file, you may extend this exception to your version of the file,
>  but you are not obligated to do so. If you do not wish to do so,
>  delete this exception statement from your version.
>
> You'd need to get permission of the copyright holder to do this, which I
> suspect is Red Hat, Inc. If you want to go down this path, email Richard
> Fontana <rfontana at redhat.com> directly and CC me.

Luckily, the copyright holder is Mike McGrath.  I can take it up with
him.  An exception seems like a good idea to me though.

Thanks for the fast reply.

-Yaakov