Bug#994042: libc6: debconf text fallback failed to accept input, had to be killed leading to broken dist-upgrade

[Aurelien Jarno <aurelien@aurel32.net>]

Hi,

On 2021-09-15 21:54, Colin Watson wrote:
> On Fri, Sep 10, 2021 at 09:59:44PM +0200, Aurelien Jarno wrote:
> > On 2021-09-10 20:39, Colin Watson wrote:
> > > On Fri, Sep 10, 2021 at 09:03:32PM +0200, Aurelien Jarno wrote:
> > > > I gave a try with debconf-show instead. I have attached a totally
> > > > untested patch to check that we agree on the way to do it.
> > > 
> > > I think you forgot to attach the patch?
> > 
> > Dooh. Please find a new version attached.
> 
> The general idea of this looks good to me.  I've left some detailed
> review comments below, and IMO we should test it against my reproducer
> (especially since this preinst patch needs to end up in bullseye).

Thanks for the fixes.

> > > I managed to reproduce the reported bug by taking Neil's full package
> > > list, mangling it to roughly make sense on buster, installing all of
> > > that, and then doing "apt upgrade && apt full-upgrade" (my own habit is
> > > just to do "apt full-upgrade", but in this case the initial "apt
> > > upgrade" is crucial).  I'm now trying to more or less bisect the package
> > > list to find something rather more minimal; this is a slow process, but
> > > no roadblocks so far, and I'll let you know when I have something.
> > 
> > Thanks a lot for your help.
> 
> OK, it took much longer than I expected because I wasn't able to do it
> by just bisecting the package list, but here's a reproducer.  I ran this
> in a fresh container produced by "lxc launch images:debian/buster"; I
> expect other container tools can be made to exhibit this too, though it
> may be sensitive to exactly which packages are in the base image.
> 
>   # apt update && apt -y install gimp libc6-dev postgresql whiptail
>   # cat >/etc/apt/sources.list <<EOF
>   deb http://deb.debian.org/debian bullseye main
>   deb http://security.debian.org/debian-security bullseye-security main
>   # apt update && apt -y upgrade && apt -y dist-upgrade

Thanks for the reproducer. I have been able to use it to test the fixes,
both with upgrade + dist-upgrade to check that the problem is fixed, and
with dist-upgrade only to check that things still work when debconf is
usable.

Regards,
Aurelien

-- 
Aurelien Jarno                          GPG: 4096R/1DDD8C9B
aurelien@aurel32.net                 http://www.aurel32.net