[Pkg-utopia-maintainers] Bug#923244: Bug#923244: libelogind ABI compatibility pending

[Mark Hindley]

On Tue, Mar 05, 2019 at 09:11:28PM +0100, Michael Biebl wrote:
> >> This has the potential for some interesting breakage, like the real
> >> systemd being installed and used together with libelogind0.
> >> We would need to make sure something like that can never happen (ideas
> >> how to solve that?)
> > 
> > Obviously that wouldn't work.
> > 
> > At the moment elogind conflicts with systemd and depends on libelogind0. So you
> > either end up with systemd + libsystemd0 or elogind + libelogind0. 
> 
> 
> If the versions of elogind and systemd match up, you could end up with
> systemd + libelogind0.
> 
> But to be
> > sure we could add libelogind0 conflicts systemd?
> 
> This would need some testing if apt would do the right thing when
> switching from sysvinit-core + elogind to systemd-sysv + systemd.
> I've seen too many weird apt errors that were caused by Conflicts...

I have just tested this: starting with sysvinit +  elogind

test at DebianUnstable:~$ sudo apt-get install default-logind
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Note, selecting 'libpam-systemd' instead of 'default-logind'
The following additional packages will be installed:
  libargon2-1 libcryptsetup12 libnss-systemd libsystemd0 systemd systemd-sysv
Suggested packages:
  systemd-container
The following packages will be REMOVED:
  elogind libelogind0 libpam-elogind libpam-elogind-compat sysvinit-core
The following NEW packages will be installed:
  libargon2-1 libcryptsetup12 libnss-systemd libpam-systemd libsystemd0 systemd systemd-sysv
0 upgraded, 7 newly installed, 5 to remove and 0 not upgraded.
Need to get 4,536 kB of archives.
After this operation, 12.6 MB of additional disk space will be used.
Do you want to continue? [Y/n] y

Looks right to me. The installation proceeds without problems.

Incidentally, apt appears to resolve this identically irresepctive of whether
libelogind0 conflicts systemd. But I am happy to include that as an extra protection.

> In general, I'm ok with your plan (and thanks for the work you put into
> it).
> The bit about libelogind0 replacing (and providing) libsystemd0 feels
> like it has the potential for subtle breakages.

I understand that and was initially concerned about that too. However, as
elogind upstream have committed to maintaining ABI compatibility and if we do a
versioned provides, I can't come up with a breakage scenario.

> So I'd like the input from other pkg-utopia/pkg-systemd maintainers,
> especially Martin and Felipe.

Yes, me too. Thanks.

Mark