I have an existing, non-empty svn repository that currently is not hosted or even tracked by Phabricator. The server it's on is dying, and I figure that's a great reason to migrate it to Phabricator. Is it possible to turn it into a Phabricator-hosted repository? Sort of like Q123, except I don't want/need to keep the repository accessible from outside Phabricator at all.

I tried creating a new hosted repo in Diffusion, then going directly to the filesystem and replacing the Phabricator-created repo directory with my existing repo directory, and finally running bin/repository refs NEWLYCREATEDCALLSIGN, and all my existing commits are suddenly visible in Diffusion. So that appears to work; is it safe to do it that way? If not, is there any officially sanctioned approach?