License compatibility of MS-PL and MS-CL (Was: (RE: Groklaw's OSI item (was: When will CPAL actually be _used_?))

[Matthew Flaschen]

Chris Travers wrote:
> However, suppose we extend the BSDL slightly to
> conform to the language of the GPL3 but place an equivalent restriction as
> the MS-PL:
> 
> * Any portion of this code which has not been substantively altered

What does "substantially" mean?

> must bear a notice stating that it is still original, is authored by <author>,
> and has been publically licensed by the author under the terms of this
> modified BSD license.  One may use additional comments to indicate ends of
> such sections.
> 
> Would such a BSDL now be incompatible with the GPL3?

I don't see why.  It says the code is still "under the terms of this
modified BSD license", but it doesn't say it can't be under another
compatible license as well.

> Would this be allowed under the 7b legal/attribution notices?
> 
> Now, what affect does this have in practice?  In my view, it identifies
> which sections of the code can safely be extracted without infringing on the
> GPL work's copyrights (since they don't extend to the excerpt).

Maybe.  It depends what substantially means.  If "insubstantial"
modifications still can have copyright protection, then they may be
under GPLv3 only.  This effectively means the BSD notice is lying in
saying all the code in the section is "still original" and under BSD.

> Now, how does this *functionally* differ from the MS-PL?

Only the MS-PL says "only under this license".  Even this modified BSD
(that seems to run counter to the purposes of BSD) has nothing similar.

> Therefore is the MS-PL really any less compatible with the GPL3 than
the BSDL?

Yes, because of the use of the word "only".

Matt Flaschen