[Foundation-l] What's appropriate attribution?

[Gregory Maxwell]

On Tue, Oct 21, 2008 at 12:26 AM, Jussi-Ville Heiskanen
<cimonavaro at gmail.com> wrote:
[snip]
> As I understand it (correct me if I am wrong), one of the
> salient problems with "close but no cigar" license compatibility
> is that a license either *is* "viral", or it *is not*. And getting
> by that is near impossible in a way that is coherent.

Nope.

Basically you can't be compatible and not expose yourself to some
weaknesses in the other license:  You're exposed to the risk that the
other is two permissive if you follow a "allow any act permitted by
either" combination,  or too restrictive if you follow a "allow only
acts permitted by both", or some variant depending on how the
combination permission is constructed.   If both licenses are copyleft
(what you're calling viral) then you may end up in a case where
further downstream works must be under the combined licenses, unless
that situation is specifically avoided in *both* copyleft licenses.

...But if you consider compatibility to be important (and I think
everyone can agree that it's at least somewhat important some of the
time) then your only other alternatives are getting both works dual
licensed or both re-licensed under a single license.  Neither of which
should be better than the controlled exposure.


You don't have to take my word for it, There is an existence proof:
GPLv3 accomplishes license compatibility with other  licenses, not
merely license which allow covered works to be simply re-licensed as
GPLv3.

See:
http://www.gnu.org/licenses/gpl-faq.html#WhatDoesCompatMean

http://www.gnu.org/copyleft/gpl.html  Section 7

(actually, the AGPL compatibility in Section 13 is basically the type
of compatibility I prefer: Explicit bidirectional compatibility with
defined terms)