Bug#746578: libpam-systemd: for upgrade safety, swap or-dependency to systemd-shim|systemd-sysv

[Zack Weinberg]

Package: libpam-systemd
Version: 204-10
Severity: important

For safety of upgrades from wheezy to jessie, the process of upgrading
packages and installing new ones *must not* change either the currently-
running init or the init that will manage the system on the next boot.
The sysadmin needs an opportunity to check over any local customizations
and then explicitly make the switch.  Currently, libpam-systemd tries to
pull in systemd-sysv, which conflicts with sysvinit-core, which violates
this principle.

The desired state for jessie is that systemd-sysv and sysvinit-core should
be coinstallable, with an alternatives-like mechanism for deciding
which package actually provides init (if this can be done with actual
alternatives for /sbin/init, that would be ideal, but I suspect it cannot
be that simple).

I will be filing another bug against systemd-sysv and sysvinit-core to
that effect, but as an immediate stopgap measure to prevent breakage,
libpam-systemd should swap its or-dependency on systemd-sysv|systemd-shim
so that systemd-shim is first.  That will prevent upgrades of *unrelated*
packages from changing the running init system.

severity:important to block testing propagation; systems running testing
with unattended upgrades enabled are one of the situations that need
the extra safety net of a guarantee that a transition to systemd will
not occur without deliberate sysadmin action.

-- System Information:
Debian Release: jessie/sid
  APT prefers unstable
  APT policy: (501, 'unstable'), (500, 'testing'), (101, 'experimental')
Architecture: amd64 (x86_64)

Kernel: Linux 3.14-1-amd64 (SMP w/8 CPU cores)
Locale: LANG=en_US.utf8, LC_CTYPE=en_US.utf8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash

Versions of packages libpam-systemd depends on:
ii  libc6              2.18-5
ii  libcap2            1:2.22-1.2
ii  libdbus-1-3        1.8.2-1
ii  libpam-runtime     1.1.8-3
ii  libpam0g           1.1.8-3
ii  multiarch-support  2.18-5
ii  systemd            204-10
ii  systemd-shim       6-3

libpam-systemd recommends no packages.

libpam-systemd suggests no packages.

-- no debconf information