[sword-devel] GPL restrictions (was Re: using a zText module)

[Chris Little]

On 08/12/2012 05:51 PM, Daniel Hughes wrote:
> OK here is the issue for me. My application (Wide Margin) is GPL 3. It
> has been all it's life. I want to use libsword. But libsword is GPL2.

The license employed by The SWORD Project is presented in the LICENSE 
file in the root of the source tree. Most if not all of the source files 
identify themselves as being GPLv2 licensed. It was never a secret that 
Sword is GPLv2.

We would certainly encourage adoption of Sword in additional Bible 
software, but the same license and rules apply to GPLv3-licensed open 
source projects as apply to closed source software that might want to 
incorporate Sword. Using Sword requires adoption of GPLv2.

Peter's description of the options available to front-end authors was 
precisely correct. If you want to incorporate Sword, you'll have to 
adopt GPLv2. You can also license your code under other licenses, 
excluding those parts that actually interface with Sword. So you can 
license your work as 'version 2 or later', which would include 3, 
excluding those parts that specifically interface Sword. Binaries that 
include the Sword-interface code would obligatorily be GPLv2. If you 
build a binary without the Sword-interface code, such as your current 
non-Sword-interfacing builds, it can be under some other license, such 
as GPLv3.

> GPL 3 is a later version of GPL 2. The FSF want people to use GPL 3.

CrossWire is not the FSF. The terms of GPLv2 are agreeable to us, and 
allowing "version 2 or later" licensing would fundamentally permit the 
FSF to relicense Sword in the future. I wouldn't trust the FSF to 
arbitrarily change the terms of the GPL in version 4 or 5 or 25.

> What would it take for the sword project to re-licence to: GPL 2 or
> later. I'm sure that the libsword contributors would have no problem
> with allowing GPL 3 applications use the library.
>
> How many contributors do you have, how hard would it be for you to
> contact them and get permission for this licence change. Otherwise you
> are going to be preventing more and more libraries who are following
> FSF recommendations and licencing as GPL3.

I expect we'll follow Linux's lead. When Linux goes GPLv3, so will Sword.

> Xiphos uses GPL2 or later. This would make Xiphos non-compliant.
>
> Bible time uses GPL2 but contains this text:
> 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.
>
> This would make BibleTime also non-compliant
>
> Looks like you guys have a bit of a problem on your hands. What are you
> planning to do about it?

Xiphos & BibleTime can be GPLv2 or later, but only to the extent that 
their code can be dis-interfaced from Sword. Those applications could, 
for example, have all Sword-ness removed and be desktop interfaces to 
the Biblia.com API, and the result could be GPLv3 (or 4 or 5 ...). (I 
don't know about licensing terms on the Biblia.com API, but from the 
technical & Xiphos/BibleTime-licensing perspective this is accurate.)

--Chris