Re: draft for new Vim license

[Walter Landry <wlandry@ucsd.edu>]

tb@becket.net (Thomas Bushnell, BSG) wrote:
> Bram Moolenaar <Bram@moolenaar.net> writes:
> 
> > I have attempted to add the possibility to allow people to distribute a
> > modified Vim, under the condition that they include the source code.
> > This makes it possible to distribute it in a (more or less) closed group
> > of people and not having to provide a copy to the maintainer (that's
> > me).  For example, it would be possible to distribute a modified version
> > of Vim within a company, so long as the sources are also available to
> > the people using this modified version of Vim.  Thus it's possible that
> > the changes are kept as a secret within that company.
> 
> The new license you just posted, in my opinion, would be DFSG-free.
> It seems to me that it would also be GPL compatible, but I'm not
> certain and I'd want to hear what RMS has to say about that.

I agree that the license is DFSG-free.  However, I don't think that it
is GPL-compatible.  In the license, there are four options for
distributing modified copies.  The first option (3a) is just the old
Vim license and is GPL incompatible.  The second (3b) is permission to
distribute those modified versions even if you're not the one who
modified it.  The third (3c) is more tricky.  It reads

>        c) Provide the changes, including source code, with every
>	 copy of the modified Vim you distribute.  This may be done in the
>	 form of a context diff.  You can chose what license to use for new
>	 code you add, so long as it does not restrict present or future
>	 official Vim distributions in any way.

If the license were GPL-compatible, I could license my changes under
the GPL, and never talk to the Vim maintainer.  However, one of the
things that Bram wants to be able to do is relicense the whole thing
under a proprietary license.  This is exactly the sort of thing that
the GPL is designed to prevent.  So a GPL patch would restrict future
official Vim distributions.

I don't think that there is a way out of this quandary.  Relicensing
the code of contributors under a proprietary license is one of Bram's
goals with his license, and the GPL is just not compatible with it.

The fourth option (3d) is very similar to the GPL's option of allowing
written offers instead of actual source code.  It has an enforced
licensing problem that is very similar to the third part, but is
otherwise (I think) compatible with the GPL.

Regards,
Walter Landry
wlandry@ucsd.edu