Bug#864597: upgrade-reports: jessie -> stretch: gnome fails to upgrade: cycle found while processing triggers

[Andreas Beckmann]

On 2017-06-15 22:31, Niels Thykier wrote:
> Guillem and I have been talking about this over IRC and have a theory.
> 
> Basically, jessie's verison of desktop-file-utils and shared-mime-info
> have "-await" triggers (implicit) which will push other packages into a
> "TRIGGER_PENDING" state.
>   Once they are in that state, the "damage" is done and those other
> packages will no longer satisfy dependencies until the trigger has been
> processed.  Notably, dpkg is unable to /undo/ this state even if the
> trigger changes from -await to -noawait during the upgrade.

I think this theory is wrong. (Unless dpkg keeps packages in
trigger-pending state *after* a successful apt-get upgrade.)

I tested earlier this week the following upgrade path in piuparts:
Upgrade from jessie task-gnome-desktop with --install-recommends to
stretch (but with desktop-file-utils and shared-mime-info switched to
interest-noawait triggers in stretch).
The first (apt-get upgrade) phase upgraded both of these packages as
well as gnome-menues and finished with success. I assume there are no
pending triggers left at this point, and the 3 interesting packages have
noawait triggers.
The second phase (apt-get dist-upgrade) still runs into the trigger cycle.


Andreas