Re: Overview of copyright issues

[Hans Aberg]

On 9 Sep 2009, at 20:30, Joseph Wakeling wrote:

> > I think that the formulation should be "GPL, v2 or latest", because
> > otherwise those that want to redistribute the code can choose which
> > version, which is not the intent - v3 is in fact more restrictive  
> > with
> > respect to tivoization. Only one GPL should be applicable. The
> > formulation "or later" is probably spilled usage when indicating  
> > which
> > version can be used - then it means one can choose version.
>
> The standard formulation, as advised in the GPL appendix which  
> describes
> how to apply the GPL to your programs, is
>
>    This program is free software; you can redistribute it and/or  
> modify
>    it under the terms of the GNU General Public License as published  
> by
>    the Free Software Foundation; either version 2 of the License, or
>    (at your option) any later version.
>
> The whole point of this formulation is to give users of the program  
> the
> option to choose which version of the license they want to be bound by
> if they redistribute or modify the code, and in particular to make it
> easy for a project to upgrade the license OR NOT.

You might check with the GNUers if it is the intention. It means that  
sources can be tivoized, even in the face of the new v3.

> > This formulation also means that the distribution conditions may  
> > change,
> > even though the copyright notice is not changed of a package, when  
> > new
> > version of the GPL are issued. I think that is fully legal.
>
> The problem with your formulation is that it is too restrictive.
> Consider this scenario: a program is being distributed as 'GPLv2 or
> latest' as you suggest.  Someone writes a GPLv3 program which links  
> with
> that code (as they are allowed to do at that point).  Now Version 4 of
> the GPL is released.  Suddenly the person with the second program  
> can no
> longer keep linking to new releases of the first one, because 'GPLv2  
> or
> latest' now means v2 or v4 and neither v2 nor v4 are compatible with  
> v3.

Linking is always allowed if you make sure the interfaces are provided  
and other linking info is provided - copyright only controls  
distribution of the parts that makes it creatively unique, and v3  
seemed to have changed over v2 to bring that out. There is no legal  
requirement that the parts should have the same license.

> It's a scenario that is completely undesirable.  'or later'  
> basically is
> about making sure that writers of programs using all future versions  
> of
> the GPL will have the right to link to or incorporate your code (as  
> well
> as being handy if, as a community, you decide you want to upgrade the
> license).

But it has the effect that sources that formerly have been OK to  
distribute may not be so. For example, if they are tivoized, then when  
the GPL v3 now has arrived, the old sources cannot be tivoized, even  
if the package itself has not been changed.

On the other hand, the formulation "or later" means that new sources  
can be tivoized even if the new version v3 has been released, unless  
they explicitly mention v3.

It is a choice: when a new license is issued, if it is more  
restrictive, do you want it to apply or not?

I just point this difference out - do what you prefer.

  Hans