License compatibility

[jace]

I'd like to use Presentz in a BSD-licensed project, but I'm concerned this is incompatible with the GPLv3.

Could you clarify what conditions your license imposes on my code? Do I have to release my website under the GPLv3 as well (which is required as per my understanding of the GPLv3), or can I keep my website under BSD?

(The same issue affects anyone using MIT, Apache or any other permissive open source license.)

[ffissore]

Let's start with the usual IANAL: "I Am Not A Lawyer"

The GPL viral effect triggers only when you distribute your work. Web sites (and network servers in general) that provide your service are not distributing your software. That's a problem FSF has solved introducing the AGPL (see http://www.gnu.org/licenses/quick-guide-gplv3.html#new-compatible-licenses)

BSD is compatible with GPLv3 (according to the previous graph) and the latter does not require you to change the license of the former.

So: GPL does not imposes itself on your BSD licensed code. You don't have to release your website under the GPLv3, you can keep it BSD.

[jace]

Thanks for clarifying this. I haven't read the GPLv3 carefully, but my understanding is that the key difference from GPLv2 is with regard to binary linking.

GPLv2 required that if your code linked to a GPL-licensed library in a way that the library was a required dependency, your code was considered derivative and therefore had to be GPL-licensed as well. The GPLv2 defined a "link" as an explicit binary link, which doesn't apply to dynamic languages, and therefore made the GPLv2's "virality" ineffective for web-oriented languages.

My understanding is that GPLv3 amended this bit of legalese, bringing dynamic linking into the fold. This means if make a call to your JS function, my code must be GPLv3 as well. (This is different from the problem AGPL solves, which is with regard to distribution of modified versions.)

Maybe I should just read the GPLv3 carefully. Doing that now.

[ffissore]

I'm too reading it. For example this makes my first assumption wrong

To "convey" a work means any kind of propagation that enables other
parties to make or receive copies.  Mere interaction with a user through
a computer network, with no transfer of a copy, is not conveying.

As presentz.js doesn't run on the server, users do not "merely interact with it through a computer network" but are receiving a copy, so it's distribution (in the GPLv2 sense).

So, contrary to what I thought, probably you can't make something BSD with something GPL, even if is a js lib or a web site.

[ffissore]

After reading this http://www.pps.univ-paris-diderot.fr/~smimram/ocamlgpl.html ("If I make a program using a GPL library" paragraph) I realized that, despite the whole product being GPLed in the end, your source can still be BSD licensed, and people using your single files (that is: everything except what's GPL) are still subject to the BSD terms.

[jace]

From what I can make out:

1. GPLv3 no longer explicitly defines how linking works. It's up to a court of law to decide that.
2. The FAQ states in multiple locations that if a non-GPL program depends on a GPL-licensed library, the whole software becomes licensed under the GPL.

http://www.gnu.org/licenses/gpl-faq.html#GPLInProprietarySystem
http://www.gnu.org/licenses/gpl-faq.html#MereAggregation
http://www.gnu.org/licenses/gpl-faq.html#IfLibraryIsGPL
http://www.gnu.org/licenses/gpl-faq.html#LinkingWithGPL

The last FAQ entry is worrisome because I do not want to explicitly prohibit my code from being used to make proprietary derivates, but any dependency on Presentz.js will effectively enforce the GPL on downstream versions.

I urge you to consider licensing Presentz.js under the LGPL or a permissive open source license that will not cause such headaches. The LGPL especially will ensure Presentz.js itself remains open.

[jace]

I completely forgot that Presentz.js runs on the client, not the server. Now I'm confused over exactly what GPL licensing means in this case, since browsers only deal with source (even if minified).

[jace]

Incidentally, this is where I'm intending to use Presentz.js: https://github.com/hasgeek/hasgeek.tv

It's a website for videos from our conferences and should up in about a week at http://hasgeek.tv.

[ffissore]

I've just pushed version 1.1.1 that changes the license from GPL to LGPL

[jace]

Thank you!

[nanodeath]

What's the reason for not going with a BSD/MIT/liberal license? It's JavaScript...pretty uncommon to put restrictive licenses on JS, I think.