Re: [eigen] Important: Relicensing Eigen to MPL2

[Gael Guennebaud <gael.guennebaud@xxxxxxxxx>]

On Sat, Jan 21, 2012 at 4:20 PM, Benoit Jacob <jacob.benoit.1@xxxxxxxxx> wrote:
> 2012/1/21 Rohit Garg <rpg.314@xxxxxxxxx>:
>> TL;DR
>>
>> I am not in favor of BSD/MIT/Apache etc.
>>
>> My criteria are
>>
>> a) Does MPL2 require redistribution of changes to Eigen itself?
>
> Yes, but specifically only for the files that come from the
> MPL2-licensed software. That's called file-level copyleft. So if you
> make an improvement to Eigen's own files, and distribute software
> based on that improved Eigen, you have to allow people to get these
> Eigen improvements. If on the other hand you improve Eigen from the
> outside (e.g. you add a new feature without modifying existing files)
> then there is no copyleft requirement. In the case of Eigen, that
> doesn't make much of a difference since my understanding of the LGPL3
> Section 3 is that things were already working that way. But at least
> it's much more explicit with MPL2, without room for corner cases.

I'd just like to emphasize that Eigen is not all about headers, we
also have blas and lapack interface libraries, and for them the MPL2
is a clear bonus where people won't have to bother wrt dynamic vs
static linking.

Since it is file based, the MPL2 also clarifies the situation with our
plugin mechanism, for which it  is still not clear to me whether the
LGPL3.0 is OK with our wills on this subject.

cheers,
gael