Perforce has a new feature to shelve open changelists on the server side for review. See http://www.perforce.com/perforce/doc.current/manuals/cmdref/shelve.html
Unfortunately, RB v1.5.4 post-review does not seem able to pull diffs from such changelists until they're committed.
It'd be really useful if RB added support to diff shelved files in pending changelists, so reviews could be performed before the code is checked-in the shared repository.
Files that have been shelved can be accessed with the p4 diff, p4 diff2, p4 files, and p4 print commands, using the revision specifier @=change, where change is the pending changelist number, so this may be a fairly small enhancement?
Thank you for the great work on this project!