Andy Green wrote:
Jerry Van Baren wrote:
If you have source code that is GPLv2 "or later", it is *your* option to exercise the "or later" clause on the source you hold. If the copyright
...
Downstream recipients cannot force *you* to exercise the "or later" clause and force you to GPLv3. It is their option to convert the source that they hold to GPLv3, but that change flows downstream, not upstream.
Well until the GPL V3 comes out, the "or later" protocol is completely untested, since this is the first chance to use it. Here is a hypothetical scenario a few months from now: that a recipient is told by the distributor that he may use the given software under V3 terms if he likes (this is the "or later" language in the license). The recipient says, "cool, I will modify the software you gave me under V3 terms then". Then the recipient points to section 1 of GPL V3
http://gplv3.fsf.org/gpl-draft-2006-07-27.html
''1. Source Code ... The Corresponding Source also includes any encryption or authorization keys necessary to install and/or execute modified versions from source code...''
and he says "well then, can I have your signing keys so I can install my version?" The distributor smiles and says, "oh no, I gave you that package under GPL v2 terms you see, there is no requirement on me to do that". The recipient says, "I don't know about that, nothing in writing about it is there? But what is in writing, on the license you gave me, it says I can 'modify' the code under GPL V2 'or later'. So I want to do that under V3 terms like I said, and you offered in writing. So your keys please!"
I don't know if that would fly or not, but distribution of signed GPL V2 "or later" code means the signing keys are hostage to the outcome of such an attempt, whereas GPL V2-only code is safe from it.
The distributor smiles and says "Sorry, you cannot take _my_ source code to GPLv3 since it is licensed GPLv2 _only_. You can take the source code that licensed GPLv2 "or later" to GPLv3, BUT THAT IS NOT A LICENSE BETWEEN YOU AND ME. Oh, and by the way, if you do that, you will not be able to use _my_ GPLv2 only code with it." (See GPLv2 Section 6, GPLv3 Section 2, and GPLv3 Section 10).
Lets say Dan Malek writes a whizzbang bootloader program named PPCBoot and licenses it GPLv2 "or later".
This gives you a license to use the said source code and add your "special sauce," as long as you abide by the rules of GPLv2 ("or later", but you choose to abide by GPLv2 only). You are free to license your "special sauce" GPLv2 _only_ because that is also compatible with Dan's code.
Say you sell your widget to Joe Schmuk. GPLv2 obligates you to provide both Dan's PPCBoot source code plus your "special sauce" source code to Joe. The critical item here is that you are *not* sublicensing Dan's source - Joe's only license to Dan's source is via GPLv2 "or later" directly with Dan, not via you (GPLv2 Section 6, quoted below). The way I read this, Joe force you abide by any GPLv3 licensing based on his license with Dan (PPCBoot) because you are not party to that licensing agreement. In particular, if he takes his PPCBoot code, which he has licensed from Dan directly (per GPLv2 Section 6) and takes it GPLv3, that is between him and Dan, you and not involved in any way and he cannot force you to convert _your_ copy of PPCBoot to GPLv3 because your copy is separately licensed between _you_ and Dan.
---------------------------------------------------------------- 6. Each time you redistribute the Program (or any work based on the Program), the recipient automatically receives a license from the original licensor to copy, distribute or modify the Program subject to these terms and conditions. You may not impose any further restrictions on the recipients' exercise of the rights granted herein. You are not responsible for enforcing compliance by third parties to this License. ----------------------------------------------------------------
In GPLv3, this is more explicit: ---------------------------------------------------------------- 2. Basic Permissions.
[snip] Propagation of covered works other than conveying is permitted without limitation. Sublicensing is not allowed; section 10 makes it unnecessary. Conveying is permitted under the conditions stated below. ---------------------------------------------------------------- FWIIW, GPLv3 Section 10 is the equivalent of GPLv2 Section 6, quoted previously, but is not a direct copy.
Joe's only license to your "special sauce" is your GPLv2 _only_ license, and that license is with you (Dan isn't involved). Joe can do what he likes with Dan's license and you are not involved in that licensing. To argue that you are involved since you conveyed the source would be to argue that Dell is party to the Microsoft EULA of every PC they sell since they were the distributor of that software.
FWIIW, the way I read GPLv2 and GPLv3, if Joe converts the source he licensed from Dan (PPCBoot) to GPLv3 (which he is free to do), he will no longer be able to use your "special sauce" code with it because the GPLv3 licensed code is no longer compatible with your GPLv2 "special sauce". The result is Joe's conversion of Dan's license to GPLv3 only "hurts" him in that it increases the limitations on what he can now do with his copy of Dan's code.
P.S. I deduce you don't care, but a big part of the consternation over Linus' GPLv2 _only_ stand is because it is impossible to convert the linux kernel to GPLv3 (you would have to get all copyright holders, starting with Linus, to convert their copyrights to GPLv2 "or later" or GPLv3 only). As a side effect of this, GPLv3 _only_ code will *not* be able to be linked with linux kernel code because GPLv3 puts more restrictions on the code than GPLv2, making it *incompatible* with GPLv2. Only GPLv2 or GPLv2 "or later" code will be legal in the kernel (and GPLv2 "or later" is frowned on and probably isn't accepted per the stated philosophies of Linus).
Well I would say that I do care about it, but that Linus' stance makes a lot of sense to me. An interesting consideration is that the FSF has a monopoly on creating GPL versions, and that if your project uses the "or later" language, it can mean you can see your project being distributed or modified under terms that you didn't want or ask for, depending on what the FSF (ie, RMS) decide to place in the next version which is out of your control. (Admittedly the old rules are still allowed too, so that should put a limit on how crazy it can get.) But only the FSF can generate a new version of the GPL which can be applied as an option to all existing GPL V2 "or later" projects by magic.
-Andy
gvb