GPL Version for Plugins

[Randall Knutson]

On Drupal.org there is a policy that only external libraries that are GPL2 can be included in projects hosted there (And no, GPL3 is not allowed right now). CKEditor's licensing between GPL2 and GPL3 is a bit confusing. Currently in the license.md file it lists:

Licensed under the terms of any of the following licenses at your choice:

• GNU General Public License Version 2 or later (the "GPL"):
• GNU Lesser General Public License Version 2.1 or later (the "LGPL"):
• Mozilla Public License Version 1.1 or later (the "MPL"):

However, in the actual source code it has: /*

Copyright (c) 2003-2013, CKSource - Frederico Knabben. All rights reserved. For licensing, see LICENSE.md or ​http://ckeditor.com/license

*/

Which links to a page with links to the GPL3 and images with GPL3.

The problem then comes when we try to include plugins such as the awesome Widgets plugin into a distribution. Because the plugins only have a link to the ​http://ckeditor.com/license and the license section of the plugin page only has a link to GPL3, it isn't GPL2+ like the main ckeditor is (See: ​http://ckeditor.com/addon/widget).

In order to have plugins included in distributions on drupal.org, would it be possible to clarify (or change) so that the plugins are GPLV2 as well? Adding the license.md from ckeditor into the plugins would suffice (I believe) as it would clarify that it is compatible with GPL2.

For drupal.org discussions, see: ​https://drupal.org/node/1996750 ​https://drupal.org/comment/7737161#comment-7737161

[Wiktor Walc]

The following licenses are valid for both, CKEditor and all plugins, included in the ​ckeditor-dev repository:

• GNU General Public License Version 2 or later (the "GPL") ​http://www.gnu.org/licenses/gpl.html (See Appendix A)

• GNU Lesser General Public License Version 2.1 or later (the "LGPL") ​http://www.gnu.org/licenses/lgpl.html (See Appendix B)

• Mozilla Public License Version 1.1 or later (the "MPL") ​http://www.mozilla.org/MPL/MPL-1.1.html (See Appendix C)

as mentioned in ​https://github.com/ckeditor/ckeditor-dev/blob/master/LICENSE.md

The link and logos on ​http://ckeditor.com/license are quite unfortunate / confusing, we have this on our todo list. In any case, you may consider the information that I wrote here as 100% correct and official. So: the widget plugin (and its requirements) are GPL2+, you may safely add them to the Drupal.org Library Packaging Whitelist.

[Randall Knutson]

Thanks for the clarification!

[Kevin Reynen]

Did the CKEditor project get any legal advice about adding Apache2 code to a project you are distributing as GPLv2+?

We've whitelisted everything in ckeditor-dev on Drupal.org based on this thread, but I just came across ​https://github.com/ckeditor/ckeditor-dev/blob/latest/tests/plugins/mathjax/_assets/truncated-mathjax/LICENSE.

The mathjax plugin uses a cdn url (​https://github.com/ckeditor/ckeditor-dev/blob/master/plugins/mathjax/plugin.js#L14). IANAL, but I don't think that is really a work around for the fact that GPLv2 and Apache2 aren't compatible licenses and can't be used like this. The or later clause of CKEditor's license allows this under GPLv3, but Drupal's licensing requires GPLv2 compatibility.

If CKEditor is allowing Apache2 code to be used in plugins, we're going to have to remove that whitelist entry from Drupal.org.

[Frederico Caldeira Knabben]

@kreynen, thanks for pointing this out.

We're definitely making a mistake by distributing MathJax as part of our tests, even those are not included in releases. We gonna fix this asap here: ​http://dev.ckeditor.com/ticket/12930

As for the CDN issue, more research is needed to understand this situation, being this software that we're not distributing. I don't think that it depends on the software license anymore, but on the CDN rights of use. We'll keep you updated here.

[Kevin Reynen]

Thanks! As far as the CDN question, I've opened ​https://www.drupal.org/node/2425319 on our end to discuss since I haven't found a definitive answer on this.

[Frederico Caldeira Knabben]

From our side, I've opened a talk with MathJax to see what can be done in this sense. I'll keep this thread updated. Thanks!