Bug#975554: udev and systemd version should always be in sync

[Ansgar]

Package: udev
Version: 247~rc2-2
Severity: important

I had installed systemd/247~rc2-2 from experimental, but kept udev at
246.6-2 (version currently in unstable) as it wasn't automatically
upgraded.

This combination made various things very unhappy (possibly due to the
"bind" uevents mentioned in systemd's NEWS for 247?), in particular
dracut no longer booted.

After upgrading udev to 247~rc2-2 and regenerating the initramfs the
system works fine again.

udev and systemd should probably be kept in sync, but I'm not sure how
best to achieve this given we don't want a versioned dependency from
systemd on udev, nor from udev on systemd.  Maybe udev should have
"Breaks: systemd (!= ${binary:Version})"?  But I'm not sure if that
might result in apt suggesting to remove udev instead.

Ansgar

-- Package-specific info:

-- System Information:
Debian Release: bullseye/sid
  APT prefers unstable-debug
  APT policy: (500, 'unstable-debug'), (500, 'testing-debug'), (500, 'testing'), (300, 'buildd-unstable'), (300, 'unstable'), (1, 'buildd-experimental'), (1, 'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 5.9.0-3-amd64 (SMP w/8 CPU threads)
Locale: LANG=C.UTF-8, LC_CTYPE=C.UTF-8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages udev depends on:
ii  adduser       3.118
ii  dpkg          1.20.5
ii  libacl1       2.2.53-8
ii  libblkid1     2.36.1-1
ii  libc6         2.31-4
ii  libkmod2      27+20200310-2
ii  libselinux1   3.1-2+b1
ii  libudev1      247~rc2-2
ii  systemd-sysv  246.6-2
ii  util-linux    2.36.1-1

udev recommends no packages.

udev suggests no packages.

Versions of packages udev is related to:
ii  systemd  247~rc2-2

-- debconf information excluded