GPLv3, LGPLv3 Review (WAS: License Committee Report for July 2007)

John Cowan cowan at
Tue Jul 31 22:42:22 UTC 2007

Wilson, Andrew scripsit:

> Ah, now we're getting to the nub of the problem.


> This is wrong.

I disagree.

> In this scenario, you are in fact relicensing the BSD components under
> GPLv2, as you have rights to do providing you leave the original BSD
> copyright notices and disclaimer of warranty intact.

How on earth can I change the license (which is what "relicense" means)
on a copy of a copyrighted work that belongs to someone else?  A license
is an act of sovereign power by the copyright owner that grants rights
to the licensees.  Absent a grant of the power to relicense (a word,
as well as a right, not present in the BSD license), I cannot possibly
do such a thing.

This is the core of my argument.  There is, and in most cases, can be no
relicensing of components, yet "make use of the library" compatibility
exists between the LGPL (v2 or v3) and essentially all other licenses.
(As I said to start with, "modified version of the library" compatibility
does not.)

> When you link GPLv2 with LGPLv2 components, you are implicitly
> exercising the conversion to GPLv2 option that is inherent in LGPLv2.
> Absent said conversion you would be in violation of the GPLv2 copyleft.
> Ditto for the case where you link GPLv3 code with LGPLv3 code.
> You are implicitly stripping the extra section 7 permissions to yield
> bare GPLv3.

Well, you could do that, yes.  But you could also avail yourself of the
LGPL-granted rights in section 6 (v2) or 4 (v3), just as when you link
an LGPLed library with an MPLed work to form a Larger Work (MPL jargon)
or a Combined Work (LGPLv3 jargon).  Under the combined terms of the MPL
and the LGPL, provided you keep the components in separate files, you
can license the resulting work under any license at all (usual proviso):
a proprietary one, GPLv2, or anything you want.

> You have no such option under the terms of the license to relicense
> LGPLv3-only code to GPLv2.

I agree with *that*, I just see no necessity to do so.  Your arguments
are not addressing the powers granted by section 6 (or 4).

> Once you understand this, you see the compatibility problem.

I *understand* your argument fine.  I just think it's wrong, is all.

John Cowan    cowan at
Nobody expects the RESTifarian Inquisition!  Our chief weapon is
surprise ... surprise and tedium  ... tedium and surprise ....
Our two weapons are tedium and surprise ... and ruthless disregard
for unpleasant facts....  Our three weapons are tedium, surprise, and
ruthless disregard ... and an almost fanatical devotion to Roy Fielding....

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