[cc-community] CC-BY-SA 4.0 (and other CC-*** 4.0 licences) vs. computer game content

Rob Myers rob at robmyers.org
Mon Dec 19 14:51:29 EST 2011

On 19/12/11 19:03, drew Roberts wrote:
> On Monday 19 December 2011 12:54:31 Mike Linksvayer wrote:
>> Am I
>> still missing something?
> Perhaps. Since one of the things being considered for BY-SA this round is to 
> make its copyleft provisions stronger, we may not want to let it go into the 
> GPL where those copyleft provisions are currently being worked around in a 
> way that the AGPL does not allow.

The Mozilla Public Licence 2-B2, which I believe is being used as one
example of compatibility, defines a "Secondary Licence" as either the
GPL, LGPL or AGPL. I'd be against insisting on the AGPL, as desktop
software doesn't need to be AGPL and the source provision requirements
would be burdensome in that context.

I can see the value of AGPL-style disclosure requirements for meshes in
MMORPGs that don't send all the assets they render to the client, but
*forcing* this by BY-SA requiring that the AGPL be used would be
different to the MPL's allowing it. Depending on how it's formulated,
this could easily make BY-SA 4.0 nonfree.

There isn't a need for compatibility between BY-SA and the GPL in the
same way that there is between the MPL and the GPL. The MPL and GPL are
mutually exclusive code copylefts, so the MPL has to explicitly allow
including of MPL code in GPL works. In contrast, the GPL doesn't care
about BY-SA game assets (and I'm sorry but that includes level designs
and any other data that isn't expressed as executable code). This means
that there's no need for compatibility *as an end in itself*.

So my concerns are:

1. That BY-SA not end up nonfree by trying to dictate the free software
that it can be used with.

2. That BY-SA not confuse code and assets, as this *will* have
unintended consequences.

and additionally:

3. That "compatibility" not lead to derivatives of BY-SA work becoming
incompatible with their parents.

- Rob.

More information about the cc-community mailing list