Bug#727708: Please clarify L options with regard to interfaces

[Colin Watson <cjwatson@debian.org>]

On Fri, Feb 07, 2014 at 01:44:42PM +0000, Ian Jackson wrote:
> Sam Hartman writes ("Bug#727708: Please clarify L options with regard to interfaces"):
> > * Colin said that it would be OK to depend on a stable interface such as
> >   logind-208 provided that multiple implementations could exist.
> 
> Colin, I think you need to clarify this.  I think it matters very much
> whether multiple implementations _do_ exist.

There are three cases here:

 1) direct dependency on init system, no attempt to make allowances
 2) dependency on reasonably-understood/specified interface that happens
    to have only one implementation right now
 3) dependency on interface with multiple implementations

I think Ian and I are agreed that L excludes 1), and permits 3).  On
reflection I think I agree that L has to exclude 2) as well.

However, the specific question Ansgar asked me was about logind
(presumably >> 204).  Serge Hallyn's cgmanager work appears to me to be
far enough along that this is likely to progress to 3) soon enough, and
well before jessie.

In the event that nobody gets logind working with cgmanager in the next
few months, I appreciate that I may have to eat my words.  As a
practical matter, I certainly don't think it's appropriate to hold back
logind integration forever.  I just don't think that's a likely outcome
given the work in progress.

-- 
Colin Watson                                       [cjwatson@debian.org]