Bug#1120555: debootstrap: debootstrap fails for ubuntu/focal

[Dima Kogan <dima@secretsauce.net>]

Package: debootstrap
Version: 1.0.141
Severity: normal

Hi. Today this happens:

  $ sudo debootstrap focal tst/

  I: Target architecture can be executed
  I: Keyring file not available at /usr/share/keyrings/ubuntu-archive-removed-keys.gpg; switching to https mirror https://old-releases.ubuntu.com/ubuntu
  I: Retrieving InRelease 
  I: Retrieving Release 
  E: Failed getting release file https://old-releases.ubuntu.com/ubuntu/dists/focal/Release

This is due to ubuntu doing something weird, but still it would be nice
if it worked. The problem is that focal is Ubuntu 20.04, which is very
old. debootstrap checks to see if this distro is "supported"; it decides
that it isn't supported, and thus it uses the old-releases.u.c url. This
is apparently wrong.

The logic is in /usr/share/debootstrap/scripts/focal, which is a symlink
to /usr/share/debootstrap/scripts/gutsy. The relevant logic in that file
is:

  if command -v ubuntu-distro-info >/dev/null 2>&1; then
          if ubuntu-distro-info --supported | grep -q "$SUITE" >/dev/null 2>&1; then
                  supported=true
          else
                  supported=false
          fi
  elif command -v curl >/dev/null 2>&1 && command -v jq >/dev/null 2>&1; then
          supported="$(curl -s https://endoflife.date/api/ubuntu.json | jq --arg suite $SUITE '[.[] | select((.extendedSupport // .support) > (now | strftime("%Y-%m-%d")) and (.codename | test($suite; "i")))] | isempty(.[]) | not')"
  elif command -v wget >/dev/null 2>&1 && command -v jq >/dev/null 2>&1; then
          supported="$(wget -qO- https://endoflife.date/api/ubuntu.json | jq --arg suite $SUITE '[.[] | select((.extendedSupport // .support) > (now | strftime("%Y-%m-%d")) and (.codename | test($suite; "i")))] | isempty(.[]) | not')"
  else
          supported=true
  fi

  if [ "$supported" = true ]; then
          case "$ARCH" in
                  amd64|i386)
                          default_mirror http://archive.ubuntu.com/ubuntu
                  ;;
                  *)
                          default_mirror http://ports.ubuntu.com/ubuntu-ports
                  ;;
          esac
          keyring /usr/share/keyrings/ubuntu-archive-keyring.gpg
  else
          default_mirror http://old-releases.ubuntu.com/ubuntu
          keyring /usr/share/keyrings/ubuntu-archive-removed-keys.gpg
  fi

So there are several "supported" checks. The very first one is triggered
on my box. I get:

  $ ubuntu-distro-info --supported

  jammy
  noble

Note that "focal" is not on the "supported" list.

OK. So since ultimately we want to figure out which server we should
use, how about we ask the server what exists and what doesn't. I
replaced that whole block above with:

  if curl -sf http://archive.ubuntu.com/ubuntu/dists/$SUITE/main/binary-$ARCH > /dev/null; then
    default_mirror http://archive.ubuntu.com/ubuntu/
    keyring /usr/share/keyrings/ubuntu-archive-keyring.gpg
  elif curl -sf http://ports.ubuntu.com/ubuntu-ports/dists/$SUITE/main/binary-$ARCH > /dev/null; then
    default_mirror http://ports.ubuntu.com/ubuntu-ports/
    keyring /usr/share/keyrings/ubuntu-archive-keyring.gpg
  elif curl -sf http://old-releases.ubuntu.com/ubuntu/dists/$SUITE/main/binary-$ARCH > /dev/null; then
    default_mirror http://old-releases.ubuntu.com/ubuntu/
    keyring /usr/share/keyrings/ubuntu-archive-removed-keys.gpg
  else
    error 1 SOMETHING "No ubuntu mirror for suite $SUITE, arch $ARCH"
  fi

And it works for focal for both amd64 and arm64. Probably worrks for
more than just focal too. Should we make this change?

Note that I don't know how to report the error, so "SOMETHING" above
should be replaced.

Thanks!