For Approval: Microsoft Permissive License

Chris Travers chris at
Sun Aug 19 06:40:28 UTC 2007

> How does approving these licenses benefit the Open Source community as a
> whole, especially given that these licenses seem deliberately crafted to
> dig a moat separating the authors and code of the projects in question
> from any other open source license or code cooties, rather than building
> a bridge?
Although I am not Bill nor do I work for Microsoft (nor are they even an 
active customer of mine at the moment), I figure I would mention that I 
have contributed some works under the MS-PL.  While these works are 
technical documentation instead of software, and so may be outside the 
bounds of this discussion, I do have some experience with this license 
(even if I still choose GPL v2 for *most* work today).

To my knowledge these patent defense clauses were started by IBM in the 
IBM Public License Version 1, and were actually initially extremely 
controversial.  The argument was that if you *use* the software, I can 
incorporate your patents into the software and if you sue me, you lose 
your rights to *use* the software because other patent licenses are 
revoked.  Some lawyers suggested that this amounted to a license to 
steal.  IANAL myself however.

I don't think the question of whether Microsoft incorporated these terms 
because they are incompatible with the GPL v2 (which requires that you 
*guarantee* patent licenses downstream possibly through an action 
separate from the license, and there is no procedure for revoking them 
if patent suits are filed) is the issue.  I think the discussion should 
be limited to the 4 corners of the license as much as possible aside 
possibly from concerns over proliferation of licenses and even there I 
think we are better to ask people to reconsider than to reject licenses 
otherwise.  The sole exception might be if two licenses were merely 
copies of eachother with names changed.  Otherwise, I don't think that 
we are qualified to evaluate whatever specific legal concerns may have 
lead to different licenses, and whether these are legitimate or not.

Whether Microsoft intended these to be incompatible with the GPL v2 and 
compatible with the Apache License 2.0 would not be an issue except in 
some peoples minds.  The fact is, I don't read anything in these 
licenses which preclude being included in GPL v3 "corresponding source" 
or work as a whole.  Certainly copying and pasting of code would be 
problematic, and there are other cases where one might run into 
problems, but incompatibility is not complete with either license and is 
far less with the GPL v3.
> This is a serious question, even if the OSD-compliance of the licenses
> does not hinge on it.
I think that upholding a consistent standard ultimately benefits OSI.  I 
think that we need to do so.  Thus far, I haven't heard any argument 
*against* approval which doesn't come down to questioning Microsoft's 
intentions.  As I have outlined elsewhere, including this is a dangerous 
mistake for any future license submissions because it opens up the 
possibility of questioning anyone else's intentions too, seriously 
undermines our ability to have a credible presence in the community, and 
otherwise undermines our work.

Best Wishes,
Chris Travers
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