Bug#751589: sysvinit-core: /sbin/init missing after switching from systemd to sysvinit

[Sven Joachim]

On 2014-06-14 19:37 +0200, Michael Biebl wrote:

> [Hit the send button a bit too early]
>
> Am 14.06.2014 19:34, schrieb Michael Biebl:
>> As I'm not able to reproduce the issue, I'm unable to test if replacing
>> Breaks with Conflicts actually fixes this particular bug you are seeing.
>
> Michael, could you test if you can reliably reproduce the issue?

I could reproduce it by manually downgrading sysvinit to an older
version and then removing systemd (this is the situation Michael was
in).  In this case, apt-get decides to upgrade sysvinit and unpacks
sysvinit-core before removing systemd-sysv:

,----
| # apt-get remove systemd
| Reading package lists... Done
| Building dependency tree       
| Reading state information... Done
| The following extra packages will be installed:
|   sysvinit sysvinit-core
| The following packages will be REMOVED:
|   systemd systemd-sysv
| The following NEW packages will be installed:
|   sysvinit-core
| The following packages will be upgraded:
|   sysvinit
| 1 upgraded, 1 newly installed, 2 to remove and 0 not upgraded.
| Need to get 0 B/211 kB of archives.
| After this operation, 5042 kB disk space will be freed.
| Do you want to continue? [Y/n] 
| Preconfiguring packages ...
| Selecting previously unselected package sysvinit-core.
| (Reading database ... 13913 files and directories currently installed.)
| Preparing to unpack .../sysvinit-core_2.88dsf-53.2_i386.deb ...
| Unpacking sysvinit-core (2.88dsf-53.2) ...
| Replaced by files in installed package systemd-sysv (204-10) ...
| Processing triggers for man-db (2.6.7.1-1) ...
| dpkg: dependency problems prevent configuration of sysvinit-core:
|  systemd-sysv (204-10) breaks sysvinit-core and is installed.
| 
| dpkg: error processing package sysvinit-core (--configure):
|  dependency problems - leaving unconfigured
| Errors were encountered while processing:
|  sysvinit-core
| E: Sub-process /usr/bin/dpkg returned an error code (1)
`----

A subsequent "apt-get remove systemd systemd-sysv" then leaves the
system without /sbin/init.

Cheers,
       Sven