bug#47576: [security] ibus-daemon launches ungrafted subprocesses

[Mark H Weaver]

I wrote:
> I still have no clue where the reference to that mysterious old version
> (/gnu/store/a4r6q1fbfqapy5hrrxap1yg96rjgln6q-ibus-1.5.22) is coming
> from.

I found them:

  ~/.cache/ibus/bus/registry
  /var/lib/gdm/.cache/ibus/bus/registry

On my system, those files include absolute pathnames to programs in
/gnu/store/a4r6q1fbfqapy5hrrxap1yg96rjgln6q-ibus-1.5.22, which I
compiled last December.

That old store item has been kept safe from GC for only one reason:
because 'ibus-daemon', along with its subprocesses, tend to be running
whenever I run "guix gc", and "guix gc" protects store items that are
currently in use by active processes.

      Mark