Bug#727708: systemd jessie -> jessie+1 upgrade problems

[Sam Hartman <hartmans@debian.org>]

>>>>> "Adrian" == Adrian Bunk <bunk@stusta.de> writes:


    Adrian> Yes, it is speculation that other new features (or even
    Adrian> bugfixes) might appear in the kernel and might become
    Adrian> mandatory in systemd between jessie and jessie+1.

    Adrian> But that is a risk, and it is a risk that is unique to the
    Adrian> systemd option since none of the alternatives is
    Adrian> Linux-only. [2]

    Adrian> My whole point is not about kdbus specifically (which might
    Adrian> even end up in the jessie kernel), but about that (IMHO
    Adrian> substantial) risk.

I'm confused, when I hear you say that this risk is unique to the
systemd option and not shared by other options.  I would understand that
statement if we thought we could avoid systemd entirely.  It sounds like
we may be able to avoid systemd as pid 1 but systemd is very likely to
play an important role in the Debian desktop storpy even if we adopt
another pid 1.

It seems like if systemd starts depending on a new kernel feature then
it might well need that feature even when not running as pid 1.

So, when evaluating the opportunity costs of this risk in the pid 1
debate it seems like there are two important mitigating circumstances:

* The extent to which upstream will provide stability, reducing the risk

* The extent to which we cannot avoid the risk even if we choose another
  pid 1, reducing the portion of the cost of this risk properly in-scope
  for this bug.

I understand some systems may not need systemd if we choose one of the
other options.  However saying "if you installed Gnome you cannot
upgrade," seems like a fairly unfortunate statement.

At some level, we also need to be community players.  Since upgrade
stability is important to us, we should advocate for it in open-source
projects that we depend on.  On the flip side, if enough of the rest of
the community after having carefully considered our arguments decides
that our desire for stability is too expensive, perhaps we need to
reconsider our position.  I hope we don't need to do that, but sometimes
when enough of the rest of the world disagrees with you, you need to
move on.