MS-PL/GPL compatibility, was Re: For Approval: Microsoft Permissive License

[Tobia Conforto]

Sorry for the double post, but let me rephrase my reply using the term
"permissions" instead of "restrictions".  As you correctly pointed out,
a license is but a grant of permissions not already granted by law,
plus a disclaimer.


Chris Travers wrote:
> Jon Rosenberg wrote:
> > Can MS-PL code be redistributed under a different license?:
> >
> > No.  The license states that "If you distribute any portion of the
> > software in source code form, you may do so only under this
> > license…"
>
> the above condition does not by itself pose a GPL compatibility issue
> unless the license fails to grant some permissions granted by the GPL

It poses a GPL compatibility issue because the license forbids you to
redistribute the code (which is not yours) with a different set of
permissions than those you received it with: not with more permissions
(which even you don't have), not with less permissions (doing so would
take away from the code some rights that they want preserved.)

If I take a MS-PL file (not mine) and a GPL file, combine them into a
derived work and release it as GPL, the GPL requires the whole work
(including the MS-PL part) to be released with permissions exactly equal
to the GPL; and the MS-PL requires the MS-PL part to be released with
permissions exactly equal to the MS-PL, which are different from the GPL.

The only solution I can see is not to distribute a work derived from (or
including) both GPL and MS-PL code.


Tobia