Comment 18 for bug 373726

It is a dangerous thing to be doing, because we don't have a way to propagate that sort of change. I don't have a great answer, but it is something that I think needs real discussion about what should happen...

Certainly bzr-svn is the only tool that can generate (file_id, revision_id) pairs when we don't know anything about the revision_id... (conversions from arch don't do it, general ghosts can't)
The small issues we've had in bzr are about a (file_id, revision_id) when Inventory[revision_id] doesn't claim the same text to be modified. We haven't encountered texts from ghosts before so that we know what to do in this case.