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

[Michael Biebl]

Am 05.03.19 um 18:17 schrieb Mark Hindley:
> On Tue, Mar 05, 2019 at 05:58:30PM +0100, Michael Biebl wrote:
>> Am 05.03.19 um 15:34 schrieb Mark Hindley:
>>>
>>> reassign -1 elogind
>>> retitle -1 Make libelogind0 ABI compatible with libsystemd0
>>> tags -1 + pending
>>> thanks
>>>
>>> On Wed, Feb 27, 2019 at 05:12:50PM +0000, Mark Hindley wrote:
>>>> We are currently liasing with elogind upstream who are making libelogind ABI
>>>> compatible with libsystemd. See https://github.com/elogind/elogind/issues/97
>>>
>>> ABI compatibility between libelogind.so and libsystemd.so is complete upstream.
>>> Initial testing with the necessary symlinks now produces full function with
>>> stock policykit-1.
>>
>> Can you eloborate on that a bit?
>> Why exactly is libelogind0 needed at all in Debian, where we have
>> libsystemd0?
> 
> Because the elogind implementation of sd-login is necessarily different. For
> example, elogind doesn't support the concept of slices or scopes.
> 
>> I would very much prefer if we could simply drop libelogind0 and make
>> sure elogind + libsystemd0 works. Has this route been tried?
> 
> Yes. It can't work. See https://github.com/elogind/elogind/issues/95#issuecomment-438335747

It's not immediately obvious to me, why elogind couldn't provide (or
fake) the on-disk data structures to be compatible with what
libsystemd0's logind implementation expects. Would this have any
undesired side-effects?


>> It sounds like you want to make libelogind0 Conflicts/Replaces/Provides:
>> libsystemd0.
> 
> Yes, versioned provides.
> 
>> 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...

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


Regards,
Michael



-- 
Why is it that all of the instruments seeking intelligent life in the
universe are pointed away from Earth?

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