[development] Modules that integrate non-GPL PHP apps violatethe GPL.

[FGM]

First, mandatory disclaimer: IANAL, so this is only an interpretation in
general terms, not advice to anyone, for which they'd have to consult a
lawyer. This being said...

The last "obviously" is not so obvious: since committers have had to agree
to only submitting code to be distributed by d.o. under GPLv2, everything
they commit will be distributed by d.o. under that license.

But it does not prevent *additional* licenses to be available for the same
code, as long as they are compatible with the GPLv2.

Case in point: my own modules are originally created and distributed under
the CeCILL 2.0, because the GPL has various issues under french law.
According to both the FSF and the CeCILL authors, both licenses are
compatible with each other, so no incompatibility arises.

Details at:
http://www.fsf.org/licensing/licenses#CeCILL
http://www.cecill.info/licences.en.html

Now, since I commit this code to d.o., I have to make it available from d.o.
under the GPLv2 (actually: licensing it to d.o. under the GPLv2), because
this is a prerequisite to be allowed to commit there. As a consequence, any
user obtaining the code from d.o. obtains it under both licenses, at his
choice: the GPLv2, available for everything downloaded from d.o. due the
requirement on committers, or CeCILLv2, because an *additional* compatible
license to GPLv2 has been specified in the module files.

This is only possible because the license are compatible, otherwise this
would be a violation of the GPL and possibly of the other license, but any
user will probably want to use the product under the CeCILL because it is
better for them. There's a rather good explanation on wikipedia, even better
than on the very site of the CeCILL:
http://en.wikipedia.org/wiki/CeCILL#CeCILL_version_2

The same dual (or even multiple) licensing mechanism would work with any
GPL-compatible license. Not there are that many available, actually...

So code released under a non-GPL license can be checked into Drupal's CVS
repository, as long as:
- it is also released under the GPL
- the other license does not prevent it.

FGM

----- Original Message ----- 
From: "Jeff Eaton" <jeff at viapositiva.net>
To: <development at drupal.org>
Sent: Thursday, August 30, 2007 4:32 PM
Subject: Re: [development] Modules that integrate non-GPL PHP apps
violatethe GPL.
[...]
> So, for
> example, it would be perfectly legal to create a Drupal theme that
> consists of nothing but images and CSS files (using drupal 6's
> new .info file format) and release it under a non-GPL license.
> Obviously, it couldn't be checked into Drupal's CVS repository in
> that case.
>
> --Jeff
>