The GPLv3 draft does not impose any use restrictions -- it imposes *modification* restrictions.
Posted Sep 27, 2006 9:01 UTC (Wed) by
xoddam (subscriber, #2322)
In reply to:
No restrictions on use. by JoeF
Parent article:
Some GPLv3 clarifications from the FSF
I reread the draft more closely, and it turns out that my conclusion
above (that the Affero licence restriction is ineffectual) is completely
wrong. I'm sorry if I've misled anyone :-)
The reason is that copyright extends to the right to prepare derivative
works. The GPL grants you permission to modify a program, *with
restrictions* (this is nothing new to version 3). In some countries the
principle of fair use applies; if the restrictions in question are
somehow 'unfair' they may be unenforceable.
> I provide the output of the program, which is probably not
> under the GPL. Otherwise, the output of gcc, regardless of
> if it is used to compile a proprietary program or another
> GPL-ed program, would be under the GPL as well.
I was talking (beside the point, as it turns out) about some theoretical
way someone might try to use their exclusive right over distribution to
force you to use their work in a particular way. They can't. They
*particularly* couldn't do so using the GPL, because the GPL (all
versions, text taken from the current GPLv3 draft) contains the
assurance:
"The output from running it is covered by this License only if the
output, given its content, constitutes a covered work."
> So, if [the licence of] an application like a Web service
> ... requires me to put up a link to the source, it is a
> use restriction.
Copyright can impose no restriction on your use of a work once you have a
copy, and the GPL explicitly acknowledges this -- the chief difference
between version 2 and version 3 is that the GPLv2 doesn't qualify it
with "unmodified". This may be the ultimate source of our confusion.
What copyright *can* impose is a restriction on your right to modify the
work, so if the code you received implements a certain feature, the
licence may prohibit you from removing it. The GPL does contain such a
restriction (clause 2c of version 2, or 5c of the draft of version 3):
You must include prominent copyright and licence information in an
interactive program, unless the original work was interactive and does
not do so. (By the by in this day and age of source control I believe
GPLv2 clause 2a, requiring prominent notice of modifications within the
modified files, is honoured mostly in the breach) The Affero General
Public Licence is a licence derived from GPLv2 by adding a clause 2d,
which disallows removal of their "download the source" feature:
http://www.affero.org/oagpl.html
"If the Program as you received it is intended to interact with users
through a computer network and if, in the version you received, any user
interacting with the Program was given the opportunity to request
transmission to that user of the Program's complete source code, you must
not remove that facility from your modified version of the Program or
work based on the Program, and must offer an equivalent opportunity for
all users interacting with your Program through a computer network to
request immediate transmission by HTTP of the complete source code of
your modified version or other derivative work."
If you think that's unfair, travel to a country with extra-strong Fair
Use rights before violating the licence :-)
The draft GPLv3 alone does not contain any such requirement. What it
*does* do is allow people who are redistributing things under the terms
of the licence to use a (slightly) different licence. One of the
permitted additional restrictions is an "Affero clause".
> So, then, a) why is this clause in the draft,
This clause exists so that code under GPLv3 may be combined with code
under another licence which already has restrictions that *aren't* in
GPLv3. The result may be developed and distributed under the
intersection of the permissions in the two licences. The GPLv2 does not
permit this, as *no* extra restrictions may be imposed. In general terms
this is about expanding the GPL ecosystem, and a specific short-term goal
is to allow the efforts of the Apache Foundation and the Free Software
Foundation to develop free Java class libraries to be combined and
distributed together under a "GPLv3 + Apache patent clauses" licence.
If anything, the bit about Web applications was added as an afterthought,
because one company has already produced software under a licence which
is GPLv2 plus the restriction under discussion. This means that Affero
can move to "GPLv3 + Affero clause" when the GPLv3 is ready, and that
third parties may combine GPLv3 code with such Affero code without
worrying about licence incompatibility -- once again, this isn't possible
with the GPLv2.
All the restrictions under discussion are restrictions on modification
and redistribution, not use.
> b) why do some people feel the need to argue for it with their
> personal ethics?
I wasn't aware they were. It's a pretty esoteric clause, IMO. In any
case, if they were arguing for the actual text, they weren't arguing for
use restrictions. For what it's worth, the FSF argues for its licence
changes not from 'personal' ethics but from the ethics of the 'Four
Freedoms', which I'm sure I don't need to repeat.
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