[Debconf-devel] Bug#1108312: debconf-apt-progress fails in d-i when libtext-iconv-perl is not installed

[Jarl Gullberg]

Package: debconf
Version: 1.5.91
Severity: normal
Tags: d-i
X-Debbugs-Cc: jarl.gullberg at algiz.nu, debian-boot at lists.debian.org

Dear Maintainer,

I recently ran into an issue with installing a Debian 13 system using the "minbase"
variant of debootstrap, which only includes the absolute core packages necessary.

During the "Installing base system" step of d-i, installation eventually fails when
busybox is installed. I checked the logs, and it appears that the issue lies with 
an inability to load the libtext-iconv-perl package.

https://gist.github.com/Nihlus/37a53d8d62d1c0a8884b72cd84cde477

I dug into the code behind this and narrowed it down to a call from d-i to
debconf-apt-progress in /bin/apt-install, which executes

    ERRCODE=0
    in-target sh -c "debconf-apt-progress --no-progress --logstderr -- \
            apt-get $apt_opts install $packages" || ERRCODE=$?

This returns an error code of 255, which promptly fails the whole installation.

Normally, Debian installations do not use minbase, which means that debconf-i18n 
will be installed (as it is Priority: important). This brings in libtext-iconv-perl
as a transitive dependency.

However, if a minbase installation is attempted, only Priority: essential packages and
apt are installed. None of these carry a dependency on libtext-iconv-perl, and we
hit whatever is causing this error to bubble up to d-i.

The easiest way to reproduce this is by preseeding the Debian installer with the
following value:

    d-i base-installer/debootstrap_variant string minbase

This will force d-i to use the minbase variant, and installation will fail during 
the initial system bootstrapping.

The issue can be worked around by including libtext-iconv-perl as an explicit 
additional package (also with preseeding).

    d-i base-installer/includes string libtext-iconv-perl

-- System Information:
Debian Release: 13.0
  APT prefers testing-security
  APT policy: (500, 'testing-security'), (500, 'testing')
Architecture: amd64 (x86_64)

Kernel: Linux 6.12.27-amd64 (SMP w/4 CPU threads; PREEMPT)
Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8), LANGUAGE=en_GB:en
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

debconf depends on no packages.

Versions of packages debconf recommends:
ii  apt           3.0.2
ii  apt-utils     3.0.2
ii  debconf-i18n  1.5.91

Versions of packages debconf suggests:
pn  debconf-doc                <none>
pn  debconf-kde-helper         <none>
pn  debconf-utils              <none>
pn  libgtk3-perl               <none>
pn  libnet-ldap-perl           <none>
pn  libterm-readline-gnu-perl  <none>
ii  perl                       5.40.1-3
ii  whiptail                   0.52.25-1

-- debconf information:
  debconf/frontend: Dialog
  debconf/priority: high
  debconf-apt-progress/preparing:
  debconf-apt-progress/title:
  debconf-apt-progress/media-change:
  debconf-apt-progress/info: