It's unclear under copyright law whether distributing the bundle of [code that calls GPL'd code + GPL'd code] makes the entire bundle fall under GPL [1].
It's pretty clear that if you modify some GPL'd code, you have to relicense that modified under GPL. It's not clear whether that holds when all you did was call the GPL code for a different product.
There're two main possibilities here:
1. The entire bundle is a derived work; under the terms of the GPL, derived works must be copylefted under GPL. This is the FSF's position as stated on their FAQ.
2. Wix's code + the GPL library is a 'mere aggregation', as defined by the license. Their only obligation is to distribute the library itself, along with modifications, under the terms of the GPL, but not their own code. For example, Linux distributions redistribute GPL + non-GPL code together, without making everything GPL.
None of these questions have really been tested in the courts.
> It's unclear under copyright law whether distributing the bundle of [code that calls GPL'd code + GPL'd code] makes the entire bundle fall under GPL [1].
My recollection was that GPLv3 made it so that if you included any GPL code, you had to opensource the entire. That freaked people out, so there was another GPL, LGPL meant mainly for libraries and other code that is linked into your code, so you won't have to release your code if you just linked against it. Of course, you'd have to release the modifications if you modified the LGPL'ed code to use it in your own.
It's pretty clear that if you modify some GPL'd code, you have to relicense that modified under GPL. It's not clear whether that holds when all you did was call the GPL code for a different product.
There're two main possibilities here:
1. The entire bundle is a derived work; under the terms of the GPL, derived works must be copylefted under GPL. This is the FSF's position as stated on their FAQ.
2. Wix's code + the GPL library is a 'mere aggregation', as defined by the license. Their only obligation is to distribute the library itself, along with modifications, under the terms of the GPL, but not their own code. For example, Linux distributions redistribute GPL + non-GPL code together, without making everything GPL.
None of these questions have really been tested in the courts.
[1] http://www.epiclaw.net/2012/01/31/combining-or-linking-propr...
PS: There's also a third possibility, which is that the whole thing is a derivative work, but calling the library falls under fair use.