Comment 18 for bug 53340

I hit a variation of this - and here is what I think makes a complete list:

directory, no .bzr
empty .bzr
.bzr with branch-format etc, no /repository, /branch
.bzr with empty repository dir, no /branch
.bzr with repository with format marker, no /branch
.bzr with repository, empty /branch
.bzr with repository, branch with format marker

We probably have more conditions that a re slight variations. I like aarons proposal to do rename-into-place for each thing to remove drop-link error cases.