[kaffe] Relicensing the Verifier, and Turning it On

Chris Gray chris.gray at kiffer.be
Sat Jul 10 13:03:11 PDT 2004

On Saturday 10 July 2004 20:58, Dalibor Topic wrote:
> Hi Rob,
> rob at kaffe.org wrote:
> > Hi all,
> >
> > [The first part of this email is about licensing stuff, the last bit is
> > more interesting ;)]
> Yay, licensing, everyone's favorite ;(
> > There are a couple parties interested in using bits of Kaffe's verifier,
> > but the GPL is not compatible with their projects' licenses.  In the
> > past, I released an older version (of pass 3) for Chris Gray's WankaVM
> > under the MIT license, because I had done all of the development and so
> > had the copyright.  I would like to do a similar thing with the current
> > development snapshot, and would certainly like to release it under
> > multiple licenses when I'm pretty content that it's production-ready.
> Sounds cool. You will have to make sure that your non-GPLd version is a
> clearly separated work from the rest of kaffe, i.e. doesn't depend on
> other, GPLd code in kaffe, but I assume that you already know that. It'd
> be pointless for Wonka to depend on kaffe's internal data structures
> anyway ;)


Yes, in fact integrating Rob's code will be quite a major effort. Wonka has a 
different object layout (we don't use handles), different stack layout, and 
our data structures for classes, methods etc. don't resemble Kaffe's any more 
than coincidentally. So any Kaffe-dependent code in the version Rob gave me 
is just noise.

> > I believe that Helmer, Guilhem, and Dalibor have all done various things
> > to the verifier's code since my last relicensing, which means, I believe,
> > that I need their permission this time around.  I went through the
> > ChangeLogs and didn't find anyone else mentioned, but I wanted to make
> > sure on this list, as it's possible that I missed a small contribution
> > (the ChangeLogs are mighty long these days).
> I think you missed a few :) I used less and searched for 'verif' string
> in ChangeLog and ChangeLog.[5-9]. I found:
> [...]

Some of these (mainly Tim's) are clearly substantive, and indicate that the 
version I have now contains real-world bugs.

> > Anyway, I don't want to pressure anyone into doing anything contrary to
> > their convictions.  If you have contributed, and you feel strongly about
> > the GPL and so don't want to give permission to relicense, then I'm
> > content to continue working on Kaffe's verifier and not relicense it.
> > However, I think it ultimately benefits more people if I have the ability
> > to give what is mostly my work to whomever will find it useful.
> First of all, thanks for doing all that great work, and getting the
> ghastly verifier written :) No small feat, so I can understand why
> people are interested in getting access to the code base on more liberal
> terms, rather then rewriting another verifier from scratch.
> I like the GPL quite a bit, myself. With that out of the way, I'd be
> willing to relicense my own changes under a license that made sure that
> I'd be still able to re-merge improvements back into kaffe. While GPL
> guarantees that, that's unfortunately not helpful for Wonka. So, how
> about GPL+linking exception, a la GNU Classpath? Would that be ok for
> Chris?

In this case I think it would be OK. I have a query outstanding with the FSF 
about the Classpath licence, because I'm not too sure I know what constitutes 
an "independent module" in Java. The verifier is an easier case, in that we 
just have to agree amongst ourselves that other components of the VM (class 
loader, interpreter, ...) are to be regarded as "independent". This would 
need to be stated in the exception clause, as it's not obvious.

Looks like this will depend mainly on Tim...

Best wishes


Chris Gray                      /k/ Embedded Java Solutions
Embedded & Mobile Java, OSGi        http://www.kiffer.be/k/
chris.gray at kiffer.be                         +32 3 216 0369

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