[copyleft-next] transitive grace period

Richard Fontana fontana at sharpeleven.org
Thu Feb 21 17:50:31 UTC 2013


On Wed, Feb 20, 2013 at 08:04:58PM +0000, Zooko Wilcox-OHearn wrote:
> Folks:
> 
> I'm interested in the possibility of using (a future version of)
> copyleft-next for Tahoe-LAFS ¹. 

Awesome!

> 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
> people.

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
  derived works).

(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
> hypothetical:
> 
> 1. Copyright to the Tahoe-LAFS source code is held by The Tahoe-LAFS
> Software Foundation.
> 
> 2. LeastAuthority.com (that's my company) has written extensions to
> Tahoe-LAFS, which constitute a derived work of Tahoe-LAFS source code.
> LeastAuthority.com has no special permissions to use the Tahoe-LAFS
> source code other than the publicly available open source licensing
> cited above.
> 
> 3. LeastAuthority.com would like to keep our derived work proprietary
> for a limited time — 12 months from when we start redistributing or
> hosting it.
> 
> 4. LeastAuthority.com 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.
>
> 5. LeastAuthority.com 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?

Mostly 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.

LeastAuthority.com, 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?

Yes. 

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]).

- RF



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