Viral permissiveness

Steve Thomas steve.thomas.private at
Thu Jan 22 15:49:14 UTC 2009


> I have seen multiple mentions on this thread about "relicensing" a BSD
> licensed code as GPL.

"relicensing" as meant in this thread is a restricted kind of
sublicensing as described in thread [1]. Please read thread [1].

> Nobody except the copyright owner can change the license.

This is strictly true, but read on.

> If a different license is added it is only for the new code. It doesn't
> change the license for the original existing code.

It depends on precisely what you mean by "only for the new code". The
FSF in your reference [2] says:

"The GPL is a copyleft license; it formally requires that modified
versions of GPL'd programs be distributed under the terms of the GPL.
Although the issue of the breadth of the GPL copyleft on modified
versions is beyond the scope of this document, it is significant that
most GPL licensors have refused to adopt a narrow view of what causes
added code to fall under the copyleft requirement. Developers
incorporating permissive-licensed code into a GPL'd project can
generally assume, then, that the totality of the modified project is
covered by the GPL."

So "the totality of the modified project", including maybe even a
_verbatim copy_ of code taken under a BSD-license, "is covered by the
GPL". Also, again in [2]:

"3.2 Requirements of the permissive license

The other half of the question is whether the non-GPL license presents
any obstacle to incorporation of the code it covers into a larger work
that is covered as a whole by the GPL's copyleft. For most who are
familiar with such licenses, the answer might appear to be obvious,
but it deserves some attention. The terms of permissive licenses allow
unlimited modification and redistribution in source or binary form, so
long as the stated minimal notice preservation requirements are met.
An isolated reading of these simple licenses, in ignorance of
historical community practice, can in some cases support more than one
interpretation, depending on whether certain permissions are implicit
or explicit and on the treatment of that difference under local law.

>From the beginnings of their use, however, the permissive licenses
have been understood by their licensors and licensees alike to permit
the code they cover to be incorporated within larger works covered as
a whole by more restrictive terms, including more restrictive FOSS
licenses like the GPL as well as, indeed, by proprietary licenses.
This understanding represents the uninterrupted, longstanding practice
and expectation of the global information technology industry,
including both its free and proprietary divisions, with vast
commercial reliance on the result. As such, disruption of the
established interpretation of the permissive licenses is neither
likely nor desirable."

For what it's worth, I am also a legal naif who made an "isolated
reading of these simple licenses, in ignorance of historical community
practice" and formed a similar half-correct understanding to yours -
held until quite recently. The fact that BSD-licenses can be, and
often are, straightforwardly relicensed (in the sense of [1]) is
crucial in the context of this thread.

Matthew > I fail to see how you could draft a license that is both
copyleft and permissive.

I meant permissive relatively, as in the opposite of restrictive:
"contract A is more permissive than contract B". Unfortunately, the
convention is to use the term "permissive" - without a capital P - for
non-copyleft, highly (relatively) permissive, easily relicensable
contracts, like BSD. I should have adhered to this silent didacticism
- apologies.

The contract I am interested in would, pivotally IMO, be more
permissive/less restrictive than the GPL in respect of binary
distributions but also will probably have to be less permissive/more
restrictive than the GPL in regard of the ability of creators of
derived works to not "reciprocate" := license modifications of
contributions back to the contributors on the same terms as the
contributors' original license. Probably. Otherwise I'll be ...

Remco > [..] just as arrogant and altruist-abusing (not my words).

Not your words, but you did choose to use them.

My GnuPG key ID is 0x82314996
Preferred keyserver: hkp://


More information about the License-discuss mailing list