On Thu, Oct 26, 2000 at 02:21:06PM -0600, Jason Gunthorpe wrote:
> On Fri, 27 Oct 2000, Anthony Towns wrote:
> > > > This means future debs can't be installed with the current dpkg. It
> > > > means future dpkg's can never output anything. It means all debs that do
> > > > anything important in their postinst need an --assert-somethingorother
> > > > in their preinst. Seems like needless complexity to me.
> > With emphasis on the "needless".
> I think it is important, hardly needless.
Perhaps you could provide some examples where it'd be particularly useful,
then.
I find it hard to believe that this thread can reasonably go from
"there's no need for output at all for any reason" to "there's a need
for so much output that we must be able to categorise it and filter it,
and to hell with backwards compatability".
> > > Why don't we make one, and solve these problems too?
> > We already have a migration plan for incompatible changes to dpkg: use
> > --assert-somethingorother in the preinst. This seems to have worked
> We haven't had to use something like that in a long time. I don't think
> it will be as effective these days.
You'll be unable to install the .deb until your dpkg correctly supports
versioned provides (the preinst would fail), and apt won't have any idea
how to do the upgrade. This seems about exactly the same as previously.
> > like a fairly similar addition that will be able to be handled in much
> > the same way. Was there something else you were referring to?
> The upgrade problems with versioned provides can't be handled by a
> --assert thingy, dpkg and apt will have to be upgraded to versions that
> understand them before they can be safely used at all.
dpkg already correctly fails on unimplemented --asserts. Apt simply has
no way of automatically coping when it's existing algorithm fails. [0]
Cheers,
aj
[0] One possibility might be having Apt try to just ignore all the stanzas
it can't understand and try to upgrade itself if it finds the Packages
file too complicated to cope with. This means that apt, and things it
depends on can't use complicated things that apt can't cope with,
just as dpkg can't really rely on pre-depends.
--
Anthony Towns <aj@humbug.org.au> <http://azure.humbug.org.au/~aj/>
I don't speak for anyone save myself. GPG signed mail preferred.
``We reject: kings, presidents, and voting.
We believe in: rough consensus and working code.''
-- Dave Clark
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