Bug#634607: Add Affero GPL license to /usr/share/common-licenses
Jonathan Yu <jawnsy@cpan.org> writes:
> To be fair, I don't think that inclusion in common-licenses is what you
> think it is. Russ can correct me if I'm mistaken here, but my impression
> is that common-licenses is around for a technical purpose: to conserve
> on disk space where many packages share a common license (rather than
> installing thousands of copies of a given file) as well as save some
> disk space on mirrors (as individual packages using those common
> licenses do not need to include the license text, and may simply refer
> to the file in common licenses).
Jonathan's pretty much hit it on the nose here.
The default, for any package in Debian, is to include the license with the
package. This is clearly and obviously correct, it's the default
expectation set by most of the licenses, and it requires no special
thought or consideration.
However, were Debian to do that, we would end up with over 10,000 copies
of the GPL v2 in the archive because more than half of the software in
Debian is covered by the GPL, at least in part. This just seems sort of
silly. Hence common-licenses; it's there so that we don't install
thousands of copies of the GPL on a typical system, basically. At least,
that's how I look at it.
common-licenses started, IIRC, with the licenses that are specifically
called out in the DFSG as example free software licenses, which muddles
matters somewhat, but all of those licenses are also extremely popular
ones used by thousands of packages in Debian. (Except for the BSD
license, which shouldn't have been there for a variety of reasons and
which we're trying to get people to move away from referencing.) Here are
the licenses that were part of common-licenses when I first started
working on Policy, and the number of references:
Artistic 2776
GPL (any) 21496
GPL (symlink) 8326
GPL 2 10821
LGPL (any) 7977
LGPL (symlink) 2134
LGPL 2 5689
LGPL 2.1 4084
As you can see, those are all into the "it would be rather silly to
include a copy of this license in each of those packages" territory.
Over time, we've added more licenses in those "groups":
GPL 1 2159
GPL 3 3785
LGPL 3 947
The GPL v1 was added so that Perl could refer to its actual license rather
than to the symlink that was then pointing to GPL v3, not because Debian
thinks anyone should release new software (other than software licensed
under the same terms as Perl for compatibility purposes) under the GPL v1.
Notice that the LGPL is used quite a bit less than everything else on that
list, but the assumption is that, over time, some of the 9600 other LGPL
packages will probably move, so it will likely grow over time. Plus, it's
strange to have one version of a license but not the others.
We've also added some other licenses that seemed to reach the same
threshold of "it's silly to ship this many separate copies of this
license":
Apache 2.0 1474
GFDL (any) 939
GFDL (symlink) 395
GFDL 1.2 550
GFDL 1.3 79
In retrospect, I think adding the GFDL was a mistake. Not only was it not
used anywhere near as widely as it seemed like it would be when it was
first released, but because we added it we got into a "trap" of adding
newer versions, and the GFDL 1.3 by its usage count does not belong in
common-licenses at all. But hindsight is always easier than foresight.
The Apache 2.0 license is a fair bit below the other "core" licenses, but
was added after the GFDL and is more widely used than it.
The strongest candidate for inclusion that isn't currently in
common-licenses is verison 1.1 of the MPL:
MPL 1.1 740
Whether that's at the threshold where it's silly to include that many
copies in the archive is something that's been debated back and forth
without a clear consensus.
--
Russ Allbery (rra@debian.org) <http://www.eyrie.org/~eagle/>
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