[Harmony-Review] Providing a copyleft-compatible option?

Dan Scott dan at coffeecode.net
Sun Apr 17 15:24:06 UTC 2011

Over on identi.ca, a lengthy thread has brought up a number of issues
(some more substantial than others, IMO). One of those issues is that
the current CLA drafts don't include an outbound-licensing option that
ensures that a contribution submitted under a copyleft license will
remain copyleft.

We added 2.1(d) option 4 ("any licenses which are recommended by
the Free Software Foundation for use in GNU projects") thinking that
that would satisfy the desire for a copyleft-only set of outbound
licenses, but:

  * Is a clear list of licenses which satisfies this condition published
    anywhere? From the FSF side, I found a list of GNU licenses at
    http://www.fsf.org/licensing/education - but those aren't explicitly
    identified as "recommended for use in GNU projects". On the GNU
    side, http://www.gnu.org/licenses/licenses.html states "we normally
    use the GNU General Public License (GNU GPL), but occasionally we
    use other free software licenses". "Normally" may or may not be
    interpreted in this case as the only "recommended" license.

  * If the argument is made that the GNU project's use of other free
    software licenses includes the (linked-to) "GPL-compatible Free
    Software Licenses"
    then that list includes many non-copyleft permissive licenses; so
    the desire to limit to a copyleft-only set of outbound licenses is

If we can't provide a definitive list of copyleft-only licenses that
meets the intention of 2.1(d) option 4, then we can fall back to 2.1(d)
option 1: "We agree to license the Contribution only under the terms of
the license or licenses which We are using". "We" is defined as the
"fill in the blank" value at the start of the CLA, so presumably the
project, organization, or company. Many projects that publish
their code under a copyleft license include components of code from
permissively-license projects, which leaves open a huge loophole for
relicensing code under a permissive license.

For example: original code for the primary project I contribute to is
licensed under GPL v2, but we distribute tarballs that include a custom
build of Dojo Toolkit which is itself licensed under the Modified BSD.
One could therefore argue that our project is "using" both GPL v2 and
the Modified BSD license, and by the current terms of 2.1(d) option 1 a
contributor would have no assurance that their code would not be able to
be relicensed by the project under the Modified BSD license.

This problem with 2.1(d) option 1 is, of course, greatly magnified once
you move beyond a single software project as "We/Us" to umbrella
organizations and companies which almost certainly "use" permissive
licensed code in one way or another.

One way to satisfy the intent to provide a copyleft-only list of
outbound licenses would be to replace 2.1(d) option 4 with an explicit list of
strong copyleft licenses - which, from scanning the GNU list of
licenses, would leave the GPL and AGPL as the only choices.

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