Does the GPL license contaminate?

Question

Quick Question.

I am doing a conversion of JavaScript code licensed by GPL (and not created by me) into PHP. Does the original GPL stand or can i put any license on the converted code?

I found this on SO, but wondering if it applies.

Answer 1

If you are the original copyright owner, then you can release a copy or a modified work under any license you like. That doesn't change the license of the previously released software of course.

Answer 2

Translation won't remove copyright. Think about decompiling binary code of Windows to Pascal for example and then recompiling it. You think Microsoft wouldn't come after you? :)

I think the correct way is to either:

• Study the code and produce a technical specification of it. Then use this spec to rewrite the code. If you are paranoid, these tasks can be done by different people. (Companies have been known to do this)
• Or credit the original author and keep the license. (Your code is a derivative work)

These suggestions may not be absolutely correct, but they are suggestions that don't get you into trouble. Before considering anything controversial you should at least read:

http://www.gnu.org/licenses/gpl-faq.html

Answer 3

IANAL, but if you are not the original author, then your PHP version will need to be GPL.

To “modify” a work means to copy from or adapt all or part of the work in a fashion requiring copyright permission, other than the making of an exact copy. The resulting work is called a “modified version” of the earlier work or a work “based on” the earlier work.

So porting a js library to php would count as a modification of the original, and then you are bound by the license to release the modified code under GPL.

Copyright may be dumb and apply only to the text, but if you have loaded the original into your computer to view it, you've copied it (at least under UK law, copyright applies to digital copies).

That act of copying was done under license and if you don't keep within terms of the license you are already in breach of copyright, whether or not you make further derivative copies.

Answer 4

You embed the GPL into an LGPL application or module, that is not just a wrapper++; This new module will be LGPL and you can cleanly use an LGPL module without spreading out. That's what our License Lawyer told us.

I trust my Lawyer, but that doesn't mean you should blindly trust my Lawyer :)

Answer 5

This really should never be considered as a legal question. It's really about doing the right thing.

Before looking at the legal side of things, first think common sense and politeness to the original author. Legal aspect should really come as a second thought.

Licensing the work resulting from your "translation" under the GPL would certainly be the best way to handle that.

The JavaScript software you are using as a starting point was "given" to you by its author under the GPL, and the best way to thank him/her for the gift is to give your own contribution under the GPL license.

Now if for some reason the GPL is not possible for you, then you really have two options:

1. Contact the original author and get his/her approval for your plan and the license you want to use on your own code. The original copyright holder could even allow you to either make a proprietary derivative of this original work or to license it under both GPL and another open-source license of your choice to work-around any GPL restriction you may have.
2. Do not start from that code, and create your own PHP software independently from the JavaScript implementation but re-using the idea you've learned from reading the JavaScript code. Re-using ideas from GPL code is a valid way to thank the original author whatever license you use.