Bug #45998 for Math-Random-MT: License/Copyright Information

Tue May 12 12:27:29 2009 frequency [...] cpan.org - Ticket created

Hi there: Thanks for Perl-izing such a great algorithm and maintaining this module. I've been in the process of getting a Debian package ready, and an important part of this is exploring licensing arrangements. The licensing information for a couple files is pretty dubious. Your module is distributed under the Artistic License, but the files _mt.c and mt.h were (to my knowledge) licensed under the GPL. Matsumoto's web site says: "Until 2001/4/6, MT had been distributed under GNU Public License, but after 2001/4/6, we decided to let MT be used for any purpose, including commercial use. 2002-versions mt19937ar.c, mt19937ar-cok.c are considered to be usable freely." (See: http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/MT2002/elicense.html) Now, as far as I know, GPL doesn't allow explicit relicensing of its code like that. It looks as if the new one is entirely public domain, in which case you can include the new version in your module without modifying your license. However I'm not entirely sure about the intentions of the author, and while he says that it can be used freely, that doesn't exactly mean that it's public domain, and doesn't say what to do for jurisdictions that do not permit authors to release their work to the public domain. For now the packaging is stalled, but I hope to hear word from you about this so that we can release the package. Thanks again!

Tue May 12 12:29:22 2009 frequency [...] cpan.org - Correspondence added

Subject:

Module Licensing

On closer analysis of Matsumoto's reference implementation posted at http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/MT2002/CODES/mt19937ar.c It would appear the new code is in fact under the MIT-X11 License, or possibly modified BSD. On Tue May 12 12:27:29 2009, FREQUENCY wrote: Show quoted text

> Hi there: > > Thanks for Perl-izing such a great algorithm and maintaining this > module. I've been in the process of getting a Debian package ready, and > an important part of this is exploring licensing arrangements. > > The licensing information for a couple files is pretty dubious. > > Your module is distributed under the Artistic License, but the files > _mt.c and mt.h were (to my knowledge) licensed under the GPL. > Matsumoto's web site says: "Until 2001/4/6, MT had been distributed > under GNU Public License, but after 2001/4/6, we decided to let MT be > used for any purpose, including commercial use. 2002-versions > mt19937ar.c, mt19937ar-cok.c are considered to be usable freely." (See: > http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/MT2002/elicense.html) > > Now, as far as I know, GPL doesn't allow explicit relicensing of its > code like that. It looks as if the new one is entirely public domain, in > which case you can include the new version in your module without > modifying your license. However I'm not entirely sure about the > intentions of the author, and while he says that it can be used freely, > that doesn't exactly mean that it's public domain, and doesn't say what > to do for jurisdictions that do not permit authors to release their work > to the public domain. > > For now the packaging is stalled, but I hope to hear word from you about > this so that we can release the package. > > Thanks again!

Tue May 12 12:29:23 2009 frequency [...] cpan.org - Status changed from 'new' to 'open'

Tue May 12 18:05:42 2009 frequency [...] cpan.org - Cc pkg-perl-maintainers@lists.alioth.debian.org added

Mon May 18 00:34:56 2009 ams [...] toroid.org - Correspondence added

Subject:	Re: [rt.cpan.org #45998]
Date:	Mon, 18 May 2009 10:04:35 +0530
To:	Jonathan Yu via RT <bug-Math-Random-MT [...] rt.cpan.org>
From:	Abhijit Menon-Sen <ams [...] toroid.org>

At 2009-05-12 12:27:30 -0400, bug-Math-Random-MT@rt.cpan.org wrote: Show quoted text

> > It looks as if the new one is entirely public domain, in which case > you can include the new version in your module without modifying your > license.

The version of mt19937ar.c included in Math::Random::MT dates from 2002. I see no licensing problem. Show quoted text

> However I'm not entirely sure about the intentions of the author

I wrote to the authors when I first wrote the module, and they are aware of the license and the mode of distribution; and they had no objections. -- ams

Mon May 18 19:20:18 2009 frequency [...] cpan.org - Correspondence added

From:

frequency [...] cpan.org

Hi ams: For the Mersenne Twister module, I marked it as BSD-Licensed in Debian. If you have explicit permission from the authors to relicense it under your license and copyright, then please paste that e-mail here for future reference. As far as I can tell though, the code you used is the same as: http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/MT2002/CODES/mt19937ar.c At the top, you can see there is a copy of the New BSD License (a.k.a. 3-clause BSD License). For Debian modules, we require (per Debian policy) both a License and Copyright for each file in a distribution. Generally we just assume that all files are under the same license as mentioned in a LICENSE file (if present) or README. However your distribution lacks both of those. Debian also likes to maintain separate copyright statements from code that is distributed as a single package. So while your main package is licensed under the Artistic License, the code you have included (the Mersenne Twister reference implementation) is licensed under the BSD License (as far as we can tell). As an aside, I'm not sure how compatible the BSD and Artistic licenses are, and Perl modules are generally dual-licensed as Artistic and GNU General Public License (ie, the same terms as Perl itself). Hope this helps, and thanks again for a great package :-) Cheers, Jonathan On Mon May 18 00:34:56 2009, ams@toroid.org wrote: Show quoted text

> At 2009-05-12 12:27:30 -0400, bug-Math-Random-MT@rt.cpan.org wrote:

> > > > It looks as if the new one is entirely public domain, in which case > > you can include the new version in your module without modifying your > > license.

> > The version of mt19937ar.c included in Math::Random::MT dates from 2002. > I see no licensing problem. >

> > However I'm not entirely sure about the intentions of the author

> > I wrote to the authors when I first wrote the module, and they are aware > of the license and the mode of distribution; and they had no objections. > > -- ams

Thu Aug 06 00:04:26 2009 ams [...] toroid.org - Correspondence added

Subject:	Re: [rt.cpan.org #45998]
Date:	Thu, 6 Aug 2009 09:34:06 +0530
To:	Jonathan Yu via RT <bug-Math-Random-MT [...] rt.cpan.org>
From:	Abhijit Menon-Sen <ams [...] toroid.org>

At 2009-05-18 19:20:18 -0400, bug-Math-Random-MT@rt.cpan.org wrote: Show quoted text

> > If you have explicit permission from the authors to relicense it under > your license and copyright, then please paste that e-mail here for > future reference.

I don't know what you would accept as "explicit permission". To me, the conversation I had with the authors asking "Is it ok if I do this?" and their reply "Fine" qualifies, especially since it predated this new BSD licensed code. But I don't want to think about the licensing any more, and I'd rather that there be no uncertainty about it, so I've released 1.08 explicitly under the three-clause BSD license. -- ams

Thu Aug 06 00:43:32 2009 frequency [...] cpan.org - Correspondence added

From:

frequency [...] cpan.org

Hi ams: On Thu Aug 06 00:04:26 2009, ams@toroid.org wrote: Show quoted text

> At 2009-05-18 19:20:18 -0400, bug-Math-Random-MT@rt.cpan.org wrote:

> > > > If you have explicit permission from the authors to relicense it under > > your license and copyright, then please paste that e-mail here for > > future reference.

> > I don't know what you would accept as "explicit permission". To me, the > conversation I had with the authors asking "Is it ok if I do this?" and > their reply "Fine" qualifies, especially since it predated this new BSD > licensed code. But I don't want to think about the licensing any more, > and I'd rather that there be no uncertainty about it, so I've released > 1.08 explicitly under the three-clause BSD license.

I'm not a lawyer, and I haven't consulted one. As a software developer, I totally understand your stance. Thanks very much for all of your help here :-) I'm really just interested in ensuring that the (very useful) package can be disseminated as easily as possible, and copyright/licensing is just one of those things in open source that makes it easy to do so. Again, many, many, many thanks for all of your help. I apologize for having to be so pedantic about things, but I believe your changes are satisfactory (in terms of Debian). Indeed we've already begun distributing the package and it's starting to gain some traction on Debian machines -- its popcon score is currently at 7 installs, which isn't bad for such a new package. As someone interested in PRNG stuff myself, I am very appreciative of the work you've done here. Cheers, Jonathan

Thu Aug 06 00:44:03 2009 frequency [...] cpan.org - Subject changed from (no value) to 'License/Copyright Information'

Thu Aug 06 00:44:03 2009 frequency [...] cpan.org - Status changed from 'open' to 'resolved'