This morning I've added the RequireRestart signal into PackageKit, and connected it up with the server and client. All code is in git master.
The restart types are system (reboot), session (logout and back in) and application (restart program).
Only the dummy backend supports this for now, although it's trivial to add to the others.
Request for yum help:
Do you know python? Are you familiar with rpm and yum internals? if so please email me – the yum backend needs some serious love. I've got a few people helping with PackageKit the moment; Tom Parker is rocking with the libapt-pkg backend and skvidal and Luke Macken are helping with the yum backend but I need more people to write new backend code.
Request for backend writers:
Want to join the fun? The core code and API are ready, any there is even a README for you to follow. I would like to see urpmi and conary backends added next week if possible. All it takes is someone very familiar with the packaging system and a few hours of time. If you supply me with scripts that adhere to the common helper standard then I'll even wire up PackageKit for you.