Re: why is graphviz package non-free?

[Glenn Maynard <glenn@zewt.org>]

On Thu, Jan 13, 2005 at 04:43:57PM -0500, Raul Miller wrote:
> The same thing is possible with the GPL, with it's "any later version"
> clause.

You can release your modifications in a way that allows this, but by
contrast, you're not required to do so.  You can take a GPL-licensed
work with the "any later version" clause active, hack on it, and release
your modifications without that clause.

   http://lists.debian.org/debian-legal/2004/08/msg00821.html

> For that matter, the same thing is possible with the BSD license,
> because it makes no attempt to provide copyleft protection.

With BSD-licensed code, you're not required to grant permissions to your
modifications that the license doesn't grant you in the first place, which
is the issue Henning is concerned about.

Would you consider a license free that said:

   If you use this software in another work, you must include the text
   "includes code written by Glenn Maynard" in supporting documentation.
   You must grant Glenn Maynard a license to distribute your modifications
   without a similar acknowledgement (a bare copyright and license notice
   must be sufficient).

You're required to grant me permission to your modifications that he didn't
grant us.

This has come up in the past, under the argument that requiring this violates
the "under the same terms as the license of the original software" provision
of DFSG#3: you aren't allowed to distribute modifications under the same
terms you received them, but instead must grant extra permissions.

I'm not convinced it's a problem, and the argument doesn't work well in some
cases--there are many licenses which give special treatment to the upstream
author, which are generally considered very poor, obnoxious licenses, but
not quite non-free.  I do think it's worth thinking about, though.

-- 
Glenn Maynard