[Scummvm-devel] License FAQ draft

[Johannes Schickel]

On 01/01/2016 08:43 PM, Eugene Sandulenko wrote:
> Well, the official quiz (http://www.gnu.org/cgi-bin/license-quiz.cgi) 
> suggests that distributing just a URL to the source code does not 
> comply with GPL. Primarily reason for that is that internet sites do 
> change, and somebody could eventually remove the files from the server.
>
> While it is a gray area, I see no problem with that, but that is just 
> me. If somebody in the team feels otherwise, please speak up.
>

I don't really see an issue with it myself. However since we can't 
really ask all the copyright holders of our code, I would personally be 
conservative on the wiki page. This hopefully prevents any 
misunderstandings if someone has strong opinions about it.

> As of the GPLv3, my understanding is that if somebody goes and uses 
> ScummVM code in GPLv3 project, there are several pitaffls. Although we 
> are stating that we're "GPLv2 or later", licensing under GPLv3 will 
> remove 'v2' part, leaving only 'or later' from the clause. Thus, the 
> potential code user must keep both licenses and mark the borrowed 
> files as based on v2. Of course, any additions to those files will 
> taint the files with v3 license.
>
> In general RMS rightfully states 
> (http://www.gnu.org/licenses/rms-why-gplv3.en.html) that you cannot 
> mix the two in one distribution. So this is kind of confusing.
>
> Let me remind that unfortunately to us, we cannot relicense ScummVM 
> unless we rewrite some significant portions of our code. The reason is 
> simple: we cannot reach every contributor, particularly those who 
> passed away.
>

Using our code under GPLv3+ is allowed by our licensing terms. We use 
GPLv2+, i.e. we have the "or (at your option) any later version" clause. 
This gives everybody the permission to use our code under terms of GPL 
v2 or under any later version of the license, thus in particular GPLv3+.
The last two paragraphs of the article by RMS state that the "or any 
later version" allows to "upgrade" the license. Thus, if anybody chooses 
to distribute our code under GPLv3+, it's no issue and (personally) I 
don't think they need to keep a copy of the GPLv2+ license around.
That's also how I understand: 
https://www.gnu.org/licenses/gpl-faq.html#AllCompatibility (in 
particular footnote 3) which suggests if you take GPLv2+ code and 
combine it with GPLv3(+) code, the result is GPLv3(+).

// Johannes