[gentoo-dev] [RFC] Adding 'GPL-2-only', 'GPL-3-only' etc. license variants for better auditing

[Michał Górny]

Hi,

TL;DR: I'd like to replace 'GPL-2' with 'GPL-2-only' etc., having
the former trigger QA warning asking the dev to double-check if it's
'GPL-2-only' or 'GPL-2+'.


GNU Licenses currently don't carry an upgrade clause -- instead, authors
are expected to decide whether they permit upgrade to newer versions of
the license in question, or require users to stick with their version of
choice.

Their decision is normally indicated in copyright notices on top
of source files.  Those that permit upgrade usually state 'either
version N of the License, or (at your option) any later version.', while
others remove the 'or...' or even replace with 'only' (sometimes
removing 'either', sometimes leaving it ;-)).

The truth is, many developers don't go that far to verify it.  Instead,
they usually look at 'COPYING' or 'LICENSE', read the version there
and put 'GPL-2', 'GPL-3' etc. in the ebuild.  It doesn't help that
GitHub does the same and shows the result as easy-to-read note on top of
repo.


For some time I've been reviewing packages I'm (co-)maintaining, as well
as proxy-maint submissions for this particular problem.  However,
surprisingly many projects actually go the 'version N only' route, even
in middle of environments that are 'N+' like Xfce.  As a result, I've
ended up rechecking the same packages over and over again to the point
of starting to add comments saying 'yes, this is GPL-2 only'.

I'd like to propose to employ a more systematic method of resolving this
problem.  I would like to add additional explicit 'GPL-n-only' licenses,
and discourage using short 'GPL-n' in favor of them.  The end result
would be three licenses per every version/variant, e.g.:

  GPL-2-only -- version 2 only
  GPL-2+     -- version 2 or newer
  GPL-2      -- might be either, audit necessary

The main idea is that we'd be able to easily find 'non-audited' packages
with GPL-2 entries, and replace them with either GPL-2+ or GPL-2-only
after auditing.  While technically it would still be possible for people
to wrongly set LICENSE to GPL-2-only, I think this explicit distinction
will help people notice that there actually is a deeper difference,
and it will still catch people who just type 'GPL-n' without looking
into the license directory.

For a start, I'd only go for adding the '-only' variants to the most
common licenses, i.e. GPL-2, -3, LGPL-2, -2.1, -3, AGPL-3, maybe some
FDL versions.  I don't think we need this for the long 'exception'
variants -- I suspect that if someone did research enough to notice
the exception, then most likely he would also notice the 'or newer'.


WDYT?

-- 
Best regards,
Michał Górny