[Qt-creator] Licensing of plugins

[Koehne Kai]

> -----Original Message-----
> From: qt-creator-bounces+kai.koehne=digia.com at qt-project.org [mailto:qt-
> creator-bounces+kai.koehne=digia.com at qt-project.org] On Behalf Of
> Mateusz Loskot
> Sent: Monday, November 11, 2013 11:49 PM
> To: qt-creator at qt-project.org
> Subject: [Qt-creator] Licensing of plugins
> 
> Hi,
> 
> What license is recommended for an open source plugin for Qt Creator?
> 
> Is it necessary to include the same licensing information as it is in the plugins
> included in the Qt Creator source tree? It is:
> 
> """
> Commercial License Usage
> Licensees...
> 
> GNU Lesser General Public License Usage
> Alternatively, ...
> """

That's only necessary if you want to contribute your plugin upstream to the Qt project.

> I'm reading the contribution guide [1] and I'm not completely clear about what
> exactly are "the licensing terms" in this statement:
> 
> "you can always write and distribute your own plug-ins separately, provided
> you follow the licensing terms"
> 
> IANAL, and, neither I have experience with Qt commercial licensing nor I have
> interest in learning it in very details.
> 
> What is the least restrictive, but sensible, license possible for a Qt Creator
> plugin?
> 
> Most of open source code I write is released under Boost Software License
> and I'm completely ignorant about how BSL interacts with (L)GPL.
> I don't know (L)GPL well, I admit.

For the usual reasons I can't give any legal advice. But a common interpretation of the LGPL is that you can 'depend' on LGPL libraries (e.g. Qt Creator plugins/libraries) in your code with a different license, provided that the user can easily change the LPGL libraries underneath (and that your license doesn't somehow 'infect' the LGPL ones). See e.g. the wikipedia article about LGPL. 

> I'd be thankful for any recommendation.

I'd just go for LGPL 2.1. It's probably the one given the least headaches in Qt Creator, since Qt Creator is available under this license, too.

Regards

Kai