[IronPython] Microsoft Permissive License's asymmetry of binary and source distribution

Sanghyeon Seo sanxiyn at gmail.com
Tue Aug 28 23:14:09 PDT 2007


I hope this post is on topic on this list, since IronPython 2.0 is
licensed under Microsoft Permissive License (Ms-PL), currently v1.1.

As you may have heard, Microsoft Permissive License was submitted to
Open Source Initiative for its license approval process.

During the process, many people pointed out an asymmetry in Ms-PL's
permission for binary and source distribution.

Namely the cluase "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". In other words,

Source distribution: only under Ms-PL
Binary distribution: under a license that compiles with Ms-PL

I haven't given my due attention to this clause in the past, but given
the extremely clear wording, this is obviously intentional.

Now, suppose a collective work composed of Ms-PL-licensed sources and
GPL-licensed sources. My understanding is that it is undistributable
in source code form since both licenses want it to be licensed "under
this license". I think GPL would "comply with Ms-PL", but GPL requires
distributing in binary form to be accompanied with the complete
machine-readable source code, so the source code needs to be
distributable too.

That would be rather unfortunate, since I like both Ms-PL and GPL. But
I guess that's what Microsoft intended after all.

I'm not a lawyer, this not legal advice, corrections welcome, etc.

Seo Sanghyeon

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