[This bug is probably misfiled, I have no idea which GNOME component is
responsible for the actual behaviour so this is a guess based on the
fact that I interact with the UI to trigger it.]

When I select "Power off" from the power menu at the top right of the
screen if there any pending package updates then instead of shutting
down GNOME will reboot into a single user mode, apply the pending
package updates and then shut down.  I have never noticed any visible
indication that this will happen rather than an immediate shutdown.

On my system when there is a kernel package update this renders the
system unbootable, my /boot partition does not have enough space to
store two copies of the initramfs so installation of the new kernel
package is left half finished with no modules available.  This in turn
causes boot failures since the display driver is the nVidia module and
the nouveau driver which gets loaded instead simply does not work on
this hardware.

I can imagine this may also be an issue in cases where the user needs to
power the system off urgently, for example due to running out of
battery, and since I use an encrypted rootfs I am also routinely
suprised to find that the system I thought I had turned off has been
sitting at the decrypt filesystem prompt for an extended period.

I would expect some indication that upgrades are to happen, and for
there to be some way to skip the update and just do a normal shutdown
instead.  Windows has a model where when updates are pending some
additional shutdown and reboot options are provided called "Update and
X".

When shutting down using "Power Off" you should see a checkbox in the
shutdown dialog.

There is something there, but that's too late - the dialog often takes a
little while to appear (I think having updates actually slows it down)
and is a long way away visually from the shutdown menu option (center of
the screen as opposed to top right).  Since the dialog appears as a
matter of routine you're likely to be used to doing something like walk
away from the computer while the timer expires, quickly dismissing the
dialog with the keyboard or just clicking the button without reading
anything.  A warning about there being updates and option to control
things really needs to be visible *before* initiating shutdown, not
popped up after the user has initiated the shutdown process.

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