Bug#1060700: Requesting advice regarding the impact of problems caused by aliasing on declared Conflicts
Hi Sam,
On Wed, Jan 17, 2024 at 09:33:25AM -0700, Sam Hartman wrote:
> I'd really like to understand why this is desired dpkg behavior.
I fear I have to defer to Guillem on this one. My rough understanding is
that we can minimize the window of time during which the files are
missing. Though given that apt only exercises this feature on mutual
conflicts and otherwise removes the conflicted package early, the
practical consequences of that reasoning may be questionable.
> I appreciate that even if it is not desired behavior, we might not be
> able to get it fixed in ways that matter for this discussion.
This is the main reason for me having skipped the question of whether
that behaviour is desirable.
> However my intuition is that it will help me at least think about the
> situation.
That is a very sensible approach.
> As an example if the reason that behavior is needed has to do with some
> situation involving essential packages and conflicts, I'd like to
> understand that situation and how common it is.
Practically speaking, it cannot be very common. In the essential set, we
very much avoid Conflicts where possible and the DEP17 work will not
introduce Conflicts in the Priority: required set for mitigating P1
(file loss due to move between packages and from aliased to physical)
problems. All of those problems will use protective diversions that do
not run into the risk at hand. The one Conflicts that I plan to
introduce in essential is gzip -> zutils. Outside, apt prefers resolving
these by removing packages before there is a concurrent unpack
situation.
> It would not be the first time in this discussion that we have
> discovered a new complexity.
Sure thing. Late discovery of new complexities is the biggest risk of
the DEP17 transition.
Helmut
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