Re: Apt pinning.
On Sat 27 Nov 2021 at 19:07:14 (+0000), Tim Woodall wrote:
> On Sat, 27 Nov 2021, Dan Ritter wrote:
> > Tim Woodall wrote:
> > > Can anyone tell me exactly what this Pin line I have actually does - or
> > > even better point me to a webpage that has more than "if you want to do
> > > this use this" type of example?
> > >
> > > (FTAOD I know that this isn't right and is inconsistent but before I
> > > start changing it I want to really understand what it's currently doing)
> > >
> > > I have a local repository:
> > >
> > > Codename: buster
> > > Components: main
> > > Date: Thu, 25 Nov 2021 19:42:12 +0000
> > > Description: Debs for local installing
> > > Label: local debs
> > > Origin: local debs
> > > Suite: oldstable
> > >
> > > And I have a pin (which I've failed to update since bullseye became
> > > stable hence the a=stable)
> > >
> > > Package: *
> > > Pin: release o=local debs,a=stable,n=buster,l=local debs,c=main,b=amd64
> > > Pin-Priority: 900
> >
> > man apt_preferences # go ahead and read it, it's well-organized
> >
>
> Many thanks. I think I've been lucky and stumbled into something that
> worked for me but isn't very robust.
>
> I've never set a default release, I've never added (except for sources)
> sources.list entries other than for things I've wanted installed. So the
> 900 worked.
>
> Need to think about whether I want to change that - I cannot immediately
> see how it improves things for me but it might make sense to change if
> that's what everybody else does. It will undoubtedly cause me
> head-scratching when I upgrade to Trixy and it doesn't work...
>
>
> > > I'm trying to solve a (minor) problem I'm having during upgrades from
> > > buster to bullseye where I've backported make from bullseye to buster.
> > > So on my buster systems I have:
> > > make/oldstable,now 4.3-4.1+tjw10r1 amd64 [installed]
> > >
> > > while once I've upgraded to bullseye I want to "downgrade" from my
> > > backported package to make 4.3-4.1 and then continue to track bullseye.
> >
> > You will need a priority over 1000.
> >
> > I don't recommend this, but you get to keep all the pieces.
> >
>
> Yes, I don't think I can do this with a generic pin. Maybe pinning
> origin "" to -100 might work - not sure if that will uninstall or
> downgrade (I'll experiment). I think adding explicit pins to my
> 'bullseye-local-sources' package for these packages I want to downgrade
> might be my only option. For the two packages I have that I want to
> downgrade during the update to bullseye it's easy enough to manually fix
> and I haven't yet had to backport anything to bullseye that won't keep a
> patched version during the upgrade to Trixy.
>
> Thanks for the pointers.
The obvious way to do this would seem to be using an epoch,
like 5:, to give your package priority over newer versions.
This is standard practice for self-compiled kernels, because
newer versions are being released all the time.
Should you chance upon https://wiki.debian.org/Teams/Dpkg/FAQ,
note that those exhortations apply to packages being placed
into shared repositories, not to personal usage like yours.
> > > When debian went from v2.2 potato to v3 woody, would this pin stop
> > > working? Because woody would be stable and potato oldstable at that
> > > point.
Epochs are unaffected by any such considerations: they override the
whole versioning system. BTW I can't recall seeing an official Debian
epoch as high as 2: though someone will probably correct me.
Cheers,
David.
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