what updates currently fall into the category of 'requires logout, but not restart' ?

seems to me that most core updates should be 'requires restart' and most app updates should just ask the user for restarting the app afterwards.

Agree. That entire category of things assumes that there aren't other user sessions on the system too. And this includes gdm / login screen sessions.

For apps, restarting the app afterwards is a bad idea too because the app may fail during exit due to missing stuff. This was historically a big problem with Firefox.

I suppose ideally for apps we'd have a way to keep the app files around until the last instance exits. Perhaps this is like unlinking and leaving a file descriptor open.

But agree for the core - just restart and make it snappy.

There's no good way for PackageKit to distinguish between applications and the system, because everything is just a package.

I think probably the best fix here is to:

s/logout/restart/
s/reboot/restart/

And just optimize "restart" to be "log out" if we don't need to actually reboot.

Isn't this fixed now? I'm pretty sure it's not g-s-d's updates plugin that triggers that dialogue.

We're discussing the offline updates stuff for F20 which will fix this, i.e. make all the updates offline.