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Re: sunset clauses

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On Wed, May 15, 2002 at 03:57:36PM -0700, Mark Rafn wrote:
> What?  This seems an odd position - apt can go into main with a license 
> that would keep KDE out?  

As strange as it seems, yes; someone else's package can render your own
un-redistributable.  That is a property of the GNU GPL.

> > Apt got a sunset clause as a generous move to help somebodye ELSE out
> > with THEIR license problem.  Do you perceive that as illegitimate, or as
> > rendering apt non-DFSG-free?
> I'm afraid I haven't read the apt license.  Could you summarize the sunset 
> clause in it?

Do you read this mailing this?  I just posted it today.

Also, what is so difficult about typing "pager

> "rendering apt non-DFSG-free" is not what anyone is claiming.  "failing to
> make Debian's packaging of apt DFSG-free" is how I might phrase it.  I'd
> certainly not claim that a sunset clause makes something unfree.  I DO
> claim that such a clause makes it as free as the intersection of the
> licenses rather than the union of them.

Only one license applies to APT; the GNU GPL.

> > If not, then perhaps we have found a dividing line that distinguishes
> > acceptable uses of sunset clauses from unacceptable ones.
> I propose this line:  If our packaging (aka derived work including any
> linking we do) is DFSG-free both before and after the sunset, then we
> accept it into main.

That describes apt perfectly.  It does not describe KDE back before Qt
was GPL'ed, and it does not describe, e.g., nessus today.

> My concern is to prevent us creating a Debian release that is 
> non-distributable after some future date.  

I agree and share this goal, however you seem to be overlooking an
important distinction:

                        GPL'ed application A
                              /  \
                             /    \
                            /      \
            GPL'ed library B        GPL-incompatible library C

A license addition to B that grants permission for usage with C, even
with a sunset clause, does not impact the re-distributability of B.  It
does impact the distributability of A.

A license addition to A is necessary for it to be distributable at all,
because it is GPL'ed and links against C.  Any GPL'ed libraries like B
against which A links will also require additional grants of permission
for A to link with C.  Again, regardless of whether A links against B or
not, A is going to require a license addition to link against C, because
A is GPL'ed and C is not GPL-compatible.  The licensing of A under the
GPL is therefore not sufficient for A to be redistributable in binary
form, and so a license addition is necessary.  If there is a sunset
clause A's license addition, then it can render itself unredistributable
at some future date.  This is not true of B.

I therefore agree with your premise, but not your conclusion: if a
Debian package is DFSG-free regardless of whether certain time-limited
portions of its license are in force, then the package is DFSG-free.
However, apt's sunset clause was and is not illegitimate, because apt
was just as DFSG free on November 14, 2000, as it was on November 16,

G. Branden Robinson                |     No math genius, eh?  Then perhaps
Debian GNU/Linux                   |     you could explain to me where you
branden@debian.org                 |     got these...       PENROSE TILES!
http://people.debian.org/~branden/ |     -- Stephen R. Notley

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