autopkgtest incus-lxc currently failing on debusine.d.n (for bullseye and bookworm)

Describe the bug

Testing the incus-lxc autopkgtest backend currently fails on debusine.d.n. This was triggered using a test openssh packages:

https://debusine.debian.net/debian/developers-santiagotest/artifact/1638016/file/cmd-output.log

autopkgtest [17:25:04]: testbed dpkg architecture: amd64
autopkgtest [17:25:04]: testbed apt version: 2.2.4
autopkgtest [17:25:05]: @@@@@@@@@@@@@@@@@@@@ test bed setup
autopkgtest: WARNING: Failed to get the testbed release: Could not guess the default release from the APT sources.
autopkgtest [17:25:05]: updating testbed package index (apt update)
Err:1 http://deb.debian.org/debian bullseye InRelease
  Temporary failure resolving 'deb.debian.org'
Reading package lists...
W: Failed to fetch http://deb.debian.org/debian/dists/bullseye/InRelease  Temporary failure resolving 'deb.debian.org'
W: Some index files failed to download. They have been ignored, or old ones used instead.
autopkgtest [17:25:05]: upgrading testbed (apt dist-upgrade and autopurge)
Reading package lists...
Building dependency tree...
Reading state information...
Calculating upgrade...Starting pkgProblemResolver with broken count: 0
Starting 2 pkgProblemResolver with broken count: 0
Done

0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
Reading package lists...
Building dependency tree...
Reading state information...
Starting pkgProblemResolver with broken count: 0
Starting 2 pkgProblemResolver with broken count: 0
Done
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
autopkgtest [17:25:07]: testbed running kernel: Linux 6.1.0-33-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.1.133-1 (2025-04-10)
autopkgtest [17:25:07]: @@@@@@@@@@@@@@@@@@@@ source /tmp/debusine-fetch-exec-upload-ytkav6zv/openssh_8.4p1-5+deb11u4~1.gbpecdef6.dsc
dpkg-source: warning: extracting unsigned source package (/tmp/autopkgtest.tVHSt0/openssh_8.4p1-5+deb11u4~1.gbpecdef6.dsc)
dpkg-source: info: extracting openssh in src
dpkg-source: info: unpacking openssh_8.4p1.orig.tar.gz
dpkg-source: info: unpacking openssh_8.4p1-5+deb11u4~1.gbpecdef6.debian.tar.xz
dpkg-source: info: using patch list from debian/patches/series
dpkg-source: info: applying gssapi.patch
dpkg-source: info: applying restore-tcp-wrappers.patch
dpkg-source: info: applying selinux-role.patch
dpkg-source: info: applying ssh-vulnkey-compat.patch
dpkg-source: info: applying keepalive-extensions.patch
dpkg-source: info: applying syslog-level-silent.patch
dpkg-source: info: applying user-group-modes.patch
dpkg-source: info: applying scp-quoting.patch
dpkg-source: info: applying shell-path.patch
dpkg-source: info: applying dnssec-sshfp.patch
dpkg-source: info: applying mention-ssh-keygen-on-keychange.patch
dpkg-source: info: applying package-versioning.patch
dpkg-source: info: applying debian-banner.patch
dpkg-source: info: applying authorized-keys-man-symlink.patch
dpkg-source: info: applying openbsd-docs.patch
dpkg-source: info: applying ssh-argv0.patch
dpkg-source: info: applying doc-hash-tab-completion.patch
dpkg-source: info: applying ssh-agent-setgid.patch
dpkg-source: info: applying no-openssl-version-status.patch
dpkg-source: info: applying gnome-ssh-askpass2-icon.patch
dpkg-source: info: applying systemd-readiness.patch
dpkg-source: info: applying debian-config.patch
dpkg-source: info: applying restore-authorized_keys2.patch
dpkg-source: info: applying conch-old-privkey-format.patch
dpkg-source: info: applying revert-ipqos-defaults.patch
dpkg-source: info: applying revert-x32-sandbox-breakage.patch
dpkg-source: info: applying ssh-copy-id-heredoc-syntax.patch
dpkg-source: info: applying ssh-agent-double-free.patch
dpkg-source: info: applying sandbox-pselect6_time64.patch
dpkg-source: info: applying CVE-2023-38408-1.patch
dpkg-source: info: applying CVE-2023-38408-2.patch
dpkg-source: info: applying CVE-2021-41617-1.patch
dpkg-source: info: applying CVE-2021-41617-2.patch
dpkg-source: info: applying CVE-2023-48795.patch
dpkg-source: info: applying CVE-2023-51385.patch
autopkgtest [17:25:09]: testing package openssh version 1:8.4p1-5+deb11u4~1.gbpecdef6
autopkgtest [17:25:09]: build not needed
autopkgtest [17:25:09]: test regress: preparing testbed
Err:1 http://deb.debian.org/debian bullseye InRelease
  Temporary failure resolving 'deb.debian.org'
Reading package lists...
W: Failed to fetch http://deb.debian.org/debian/dists/bullseye/InRelease  Temporary failure resolving 'deb.debian.org'
W: Some index files failed to download. They have been ignored, or old ones used instead.
Reading package lists...
Building dependency tree...
Reading state information...
Package apt-utils is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source
However the following packages replace it:
  apt

E: Package 'apt-utils' has no installation candidate
autopkgtest [17:25:11]: ERROR: "sh -ec 
  if ! type apt-ftparchive >/dev/null 2>&1; then
    # if there is nothing in the cache, we have to update first before we can
    # install anything
    [ -n "$(apt-get indextargets 2>/dev/null)" ] || apt-get update 2>&1
    DEBIAN_FRONTEND=noninteractive apt-get install -y apt-utils 2>&1
  fi
  (cd /tmp/autopkgtest.tVHSt0/binaries; apt-ftparchive packages . > Packages; apt-ftparchive release . > Release)
  printf 'Package: *\nPin: origin ""\nPin-Priority: 1002\n' > /etc/apt/preferences.d/90autopkgtest
  echo "deb [ trusted=yes ] file:///tmp/autopkgtest.tVHSt0/binaries /" >/etc/apt/sources.list.d/autopkgtest.list
  if [ "x`ls /var/lib/dpkg/updates`" != x ]; then
    echo >&2 "/var/lib/dpkg/updates contains some files, aargh"; exit 1
  fi
  apt-get --quiet --no-list-cleanup -o Dir::Etc::sourcelist=/etc/apt/sources.list.d/autopkgtest.list -o Dir::Etc::sourceparts=/dev/null update 2>&1
  cp /var/lib/dpkg/status /tmp/autopkgtest.tVHSt0/1-apt-update.out
  " failed with status 100

aborted: False
returncode: 20

How to reproduce the bug

There is a (temporal) santiago-bullseye-1 workflow under developers-santiagotest workspace, with this metadata:

architectures:
- amd64
- i386
- arm64
- armhf
autopkgtest_backend: incus-lxc
codename: bullseye
enable_upload: false
lintian_backend: unshare
piuparts_backend: unshare
reverse_dependencies_autopkgtest_suite: bullseye@debian:suite
sbuild_backend: unshare
upload_include_binaries: false
upload_merge_uploads: false
vendor: debian

Runtime environment

Operating system

Versions of debusine and its dependencies

0.11.1.dev11+g8cd5e6bb (debusine.d.n)