[Bf-committers] A practical proposal for the task of re-licensing Blender

[Campbell Barton]

On Wed, Nov 24, 2010 at 12:26 AM, Alex Combas <blenderwell at gmail.com> wrote:
> Hello developers,
>
> A common statement I've heard people make when talking about the
> possibility of a license change is: "Its a good idea, but in practical
> terms it is almost impossible".
>
> I do not think that is true. Here is my proposal for how it could be done:
>
> ~~~
> 1. Wait until Blender gets out of beta. A good first step.
>
> 2. Clarify the objective to re-license the code.
>
> There are several different proposals for re-licensing Blender. Before
> proceeding it would be necessary to pick one of them and make a
> clearly stated goal.
>
> For example: "Our goal is to re-license the entire Blender code base
> from GPL to LGPL for the purpose of keeping the code free and
> protected, while at the same time allowing developers to write
> extensions which link to Blender to use whatever license they wish for
> their own code."
>
> 3. After having clearly defined "the goal" it would be necessary to
> organize a census among the Blender developer community to determine
> if the majority support this idea.
>
> 4. If we reach a state where the majority (at least 60-70%) of the
> Blender developer community support this idea, then the idea should
> move forward. But wait! Would it be possible to move forward if there
> was less than 100% support? Yes.
>
> Next the Blender Foundation would need to make an announcement:
>
> "This is a notice to all past and present Blender developers:
> We are planning to change the license under which Blender is
> distributed from GPL to LGPL, this is for the purpose of keeping
> Blender free and protected, while at the same time allowing other
> developers to write extensions which link to Blender to use whatever
> license they wish for their own code.
>
> Important: If we have applied patches to the code from you, and you
> are opposed to this idea then please let us know and we will back out
> your changes."
>
> At this point people should wait for at least a month or two to give
> any developers who are opposed to the idea adequate time to go through
> the source and notify the Blender foundation of any sections which
> they claim they are the authors of and would like to have removed from
> Blender if the license is changed.
>
> Now depending upon how that goes will determine how the license change
> would proceed.
>
> Possibility #1: No developers contact the Blender Foundation and ask
> for their code to be removed. In this case, license Blender as LGPL
> and the job is done.
>
> Possibility #2: The Blender Foundation is notified by some developers
> that a few small trivial parts of Blender which they have written
> would need to be removed.
>
> In this case a separate branch could be created which does not contain
> their code, once the code has been reimplemented then it could be
> merged with trunk. Then license Blender as LGPL and the job is done.
>
> Possibility #3: The Blender Foundation is notified by some developers
> that one or more major sections of Blender which they have written
> will need to be removed.
>
> In this case it might be possible that their code could be completely
> removed from Blender and re-built as an extension.
>
> For example, lets just say that the compositor was made by a single
> developer and that this developer does not want his code to be
> relicensed as LGPL.
>
> Since we do not wish to lose the compositor, and it would be
> impractical to re-implement it, then the only option would be to
> rebuild the compositor as an extension. In this way the compositor
> extension would remain GPL in accordance with the authors wishes, and
> the rest of Blender could still be relicensed as LGPL.
>
> Once the code in contention has been reimplemented or modified to
> function as an extension then merge the branches, license Blender as
> LGPL, and the job is done.
>
> ~~
> So that is my proposal. Sorry if it is a bit long winded.
>
> It is probably full of many holes which I am blissfully unaware of,
> but hopefully this can help roll the ball a little further.
>
> Best regards,
> Alex Combas
> irc: blenderwell

Look at the simplest case for a LGPL switch:
  if all blender developers and all contributors agree to switch to LGPL.

We still have libraries that are GPL, these cant just be made into
extensions, they need to be replaced or removed/rewritten.

The likely-hood of convincing external projects from GPL to LGPL is much lower.

Quick grep reveals...
- intern/elbeem: Fluids, can be disabled now at build time.
- extern/lzo: Compression lib, can be disabled now at build time.
- extern/Eigen2: Math lib, can be disabled now at build time.
- intern/moto: Math lib, used for the BGE and IK's, could of course be
replaced but not trivial.

-- 
- Campbell