My company uses arcanist and differential along with subversion. arc diff gives us a very useful mechanism to share, review, and amend code before deploying. We treat each Differential as a sort of code branch. Unfortunately, when preparing to update a Differential, there seems to be no way to see what the new changes will be when compared to those already present in the Differential.

When using arc diff --update with svn, it would be really helpful to have a means to see the local changes that differ from those in the differential. Effectively this would allow svn users to do something like git diff when used on a branch, showing changes since the last update to that differential.