Subject: Re: BSD and MIT license "compliance" with the MS-PL
From: Chuck Swiger <chuck@codefab.com>
Date: Fri, 17 Apr 2009 15:57:13 -0700

On Apr 17, 2009, at 3:09 PM, saulgoode@flashingtwelve.brickfilms.com  
wrote:
> How is Mr Rosenberg's assertion supported by the wording of the  
> license?  *Copyright law* decides whether "combining" code results  
> in a derivative or collective work, not a license (especially so if  
> the license does not address the issue).
>
> Unless there is language within the license addressing this issue,  
> the author of the license has no say in whether the combination of  
> code under disparate licenses should be considered to result in a  
> derived, or even collective, work. This a determination made only by  
> the holders of the code's copyrights (in that they may choose  
> whether or not to litigate infringement) and, ultimately, the courts.

Copyright law and (if necessary through litigation) a judge would make  
a determination whether a particular combination of code is a  
derivative or collective work, agreed.

MS-PL 3(d) says that "If you distribute any portion of the software in  
source code form, you may do so only under this license by including a  
complete copy of this license with your distribution. If you  
distribute any portion of the software in compiled or object code  
form, you may only do so under a license that complies with this  
license."  So long as the portion of code originally under the MS-PL  
remains licensed under the MS-PL, and the work as a whole is not  
distributed under terms which contradict those of the MS-PL, then  
you're fine IMHO.

That's the most straightforward reading of what "complies with this  
license" means.

>> I think this makes it clear that the MS-PL is fully compatible with  
>> (a
>> phrase that seems more sensible to use here than "compliant with")
>> other permissive licenses such as the BSD and MIT licenses, and that
>> this was intended, not accidental.
>
> I agree that the licensing would make more sense if "compatible  
> with" were used instead of "complies with". But changing the wording  
> also alters the meaning. Shouldn't we need analyze a license from  
> the standpoint of what it actually says? There would be a  
> significant distinction, as an example, between a license that is  
> "compatible with" the GPL and one which "complies with" the GPL.
>
> The wording of the MS-PL gives every indication that combined works  
> need to "comply with" the MS-PL. Since BSD and MIT licenses do not  
> provide patent indemnification, they do not "comply with" the MS-PL.  
> If it were not for the MS-PL license demand that combined works must  
> comply, they should be "compatible with" it -- but the fact of the  
> matter is the MS-PL license demands compliance.

*All* licenses demand compliance with the terms as far as the licensed  
materials are concerned, although the obligations for simple  
permissive licenses are generally no more onerous than keeping the  
copyright and license text intact.

You are right that one could not take some code under the MS-PL,  
combine with code under the BSD license, and release the combination  
under the BSD license alone, because that would not comply with the  
obligations mentioned in the MS-PL; however, there is nothing in  
either of the BSD or MIT licenses which forbids you from combining  
software under such terms with software under the MS-PL, and releasing  
that combination as a whole under the terms of the MS-PL instead.

Regards,
-- 
-Chuck