On Thu, 2011-01-27 at 00:45 -0500, wren ng thornton wrote:
On 1/26/11 5:51 AM, Maciej Piechotka wrote:
Some projects (like Linux) remove this clause and I'm not sure how many projects are marked on hackage as GPL2 being GPL2-only.
Technically GPLx and GPLy are incompatible for all x and y such that x /= y.The problem is that *technically* the phrasing of the viral clause prohibits dual licensing, despite the obvious intention.
Could you elaborate? I cannot see any problem why author, having all rights, cannot publish code under GPL-2 and MPL. Sure GPL-2 allows someone to fork it into single-licence fork.
This is why the recommended verbiage states that that the work is "licensed under GPLx or any later version". That disjunction isn't saying that you're allowing for revisions of refinements to the license, it's a disjunction of licenses so that others can choose the license that's compatible with their needs. Which is also why, if the "or any later version" part is omitted then the GPLx code can't be combined with GPLy (for y > x).
Aka, "GPL2-only" stuff cannot depend on "GPL3(or later)" stuff. The only time this really matters is when dealing with the linux kernel (and few other projects) since they have specific objections to the GPL3 and intentionally sought to disallow licensing of kernel code under it.
Hmm. By GPL I understend FSF version which allows relicensing. I'm not sure about the interpretation (and IANAL) but I'm not entirely sure if GPLx+ and GPLx-only are compatible at all. Regards