For Approval: Microsoft Permissive License
chris at metatrontech.com
Sun Aug 19 19:12:40 UTC 2007
Donovan Hawkins wrote:
> So the only thing standing between these "permissive" licenses and
> compatiblity with GPL v3 is the flawed advertising clause from BSDL,
> something that is widely regarded as an impractical mistake. Whether
> you call these "non-permissive" or "permissive but flawed" is a minor
> point...I would choose "non-permissive" myself.
Hmmm.... First GPL v3 section 7b may provide compatibility with BSD-like
licenses with advertising clauses depending on how obtrusive they are
(the FSF's comments to this effect seems to indicate that they are
concerned about proliferation of such advertising notices, not the
original notices themselves). Thus compatibility with these licenses may
be case-by-case. IANAL and YMMV....
Back to the Microsoft license. After re-reading the GPL v3 (nominate
that license for the most complicated and incomprehensible submission to
OSI for approval to date), I have concluded that there are major license
compatibility problems if a GPL v3 application *requires* components
under these licenses. While I can imagine there might be ways around
these problems, they are not any less onerous than dealing with any
other license compatibility. Like many other aspects of the GPL v3, it
is hard to say whether optional dependencies would be a problem, and it
is harder to evaluate the MS-PL which may be compatible.
The basic issue is that the GPL v3 defines the "Corresponding Source" as:
'The “Corresponding Source” for a work in object code form means all the
source code needed to generate, install, and (for an executable work)
run the object code and to modify the work, including scripts to control
those activities. However, it does not include the work's System
Libraries, or general-purpose tools or generally available free programs
which are used unmodified in performing those activities but which are
not part of the work. For example, Corresponding Source includes
interface definition files associated with source files for the work,
and the source code for shared libraries and dynamically linked
subprograms that the work is specifically designed to require, such as
by intimate data communication or control flow between those subprograms
and other parts of the work.
The Corresponding Source need not include anything that users can
regenerate automatically from other parts of the Corresponding Source.
The Corresponding Source for a work in source code form is that same work.'
Section 6 (Conveying non-source forms) states:
'You may convey a covered work in object code form under the terms of
sections 4 and 5, provided that you also convey the machine-readable
Corresponding Source under the terms of this License, in one of these
It seems clear to me that any component falling under the Corresponding
Source definition must be able to be distributed under terms of which
the GPL v3 must be either identical or a proper subset. Because the
MS-CL provides per-file restrictions, I don't see how this could be met.
The MS-PL is harder for me to evaluate. A lot of it depends on what 7b
additional terms allow under the GPL v3. The MS-PL could be read as
requiring the distribution of the license as a legal notice (seems
reasonable to me) and possibly noting which sections of code are
MS-PL-licensed. Again, this seems to be in line with the GPL v3 7b
options by my reading.
However, there is one further issue with the MS-PL which might or might
not preclude using them together:
The MS-PL ties the definition of derivative work to US law. I am not
sure if there could be cases where this could run you into trouble with
the GPL v3 which ties it to whatever court wants to hear the case but I
wouldn't think this would be a problem, but I do wonder if there might
be jurisdictions where there might be a conflict. For example, are there
places where things might be considered derivative works which might be
fair use by US standards? Would this use be precluded in such
jurisdictions under the MS-PL because it doesn't give you to prepare
such works? Might there be other conflicts?
Again, I don't think this is a problem, and as a developer probably
wouldn't worry about it. But I could see it being a question when people
look at trying to split hairs to their own substantial benefit.
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