On Wed, Feb 20, 2013 at 08:04:58PM +0000, Zooko Wilcox-OHearn wrote:
I'm interested in the possibility of using (a future version of)
copyleft-next for Tahoe-LAFS ¹.
One possible way to do that would be
to define "version 2 of the Transitive Grace Period Public Licence" to
be some future version of copyleft-next, or a derivative of
copyleft-next. Since Tahoe-LAFS is licensed ³ under "Transitive Grace
Period Public Licence, version 1 or, at your option, any later
version", then I think this would allow everyone to start using
Tahoe-LAFS under the terms of copyleft-next.
There is certainly precedent for that (e.g., the little-known AGPLv2,
or the naming of EPL 1.0 as the successor to CPL 1.0).
Now, I'm writing to ask: what would it take for me to offer a
*transitive* grace period for proprietary derived works? If I
understand correctly, §2 prevents a copyright holder from granting
only copyleft (not permissive) rights to some people under
copyleft-next while granting time-unlimited permissive works to other
I wouldn't describe it that way, though I am not sure if I understand
your reading of it, so I'll explain what this section is intended to
do (in the 0.2.0 version):
* If I (copyright holder) offer My Work (the work I inject with my
copyright interest) under copyleft-next, and later (after a 1-year
grace period has elapsed) offer the same work or [approximately] a
derivative work under a *proprietary* license (defined negatively as
something that doesn't meet the OSI OSD), then I additionally
license my copyright in My Work under the Apache License 2.0 (thus
giving everyone in the world an equal right to make proprietary
(In the expected case, this would only apply to the original
copyleft-next upstream copyright holder, though it currently isn't
written with such a limitation.)
However, consider this scenario, which is actually real life and not
1. Copyright to the Tahoe-LAFS source code is held by The Tahoe-LAFS
(that's my company) has written extensions to
Tahoe-LAFS, which constitute a derived work of Tahoe-LAFS source code.
has no special permissions to use the Tahoe-LAFS
source code other than the publicly available open source licensing
would like to keep our derived work proprietary
for a limited time — 12 months from when we start redistributing or
would like to *not have the option* of changing
our minds and keeping the derived work proprietary for longer than
that. This may be surprising to you, but it is a form of safety for
our customers. We're hoping to get more customers because they know
that we *don't have that option*, even if we were to get bought out by
a larger company with very different plans than ours.
would like, at that future time when we grant
open source rights to use our derived work, if other people are able
to make derived works of our derived work, and if they are able to
keep their derived work proprietary for a limited time, but it is
important to us that they are *not* able to keep their derived work
proprietary for longer than that.
All of the above is actually true, except of course that the parts
about what we desire and intend may change with the weather.
Now if I understand correctly, if the Tahoe-LAFS Software Foundation
were to license the Tahoe-LAFS source code under copyleft-next v0.2,
then the Tahoe-LAFS Software Foundation would be able to make
proprietary derived works, or to license others to do so, in a
time-limited way, but LeastAuthority.com
would not. Is that correct?
The Tahoe-LAFS Software Foundation can do proprietary licensing of
derived works (or license others to do so) forever. However, under
copyleft-next 0.2.0 secton 2, the longest it can simultaneously
license a given work under copyleft-next and 'offer to license'
proprietary derivative works of that given work, without *also*
licensing the given work under the Apache License 2.0, is one year.
, however, must license its derivative work of that
given work under copyleft-next 0.2.0 (or the GPL, or possibly a later
version of copyleft-next).
Do you see why that doesn't satisfy our (current) desires?
It's easy to imagine revising a couple of sections of the license to
add such a grace period in. My assumption is that many potential users
of this kind of license would not wish to have such a grace period, so
I'd think it should be an optional feature that is switched on by the
original licensor rather than a default.
I assume you'd prefer something different from a GPL-style permissive
exception or 'additional permission', or a supplementary condition
tacked on (even if the main license explicitly said that such
categories of conditions did not lead to a license violation or
inconsistency [cf. GPLv3 section 7]).