error converting a file-rename patch from git to darcs

[sharkcz]

transferred from Fedora's bugzilla, for all details (logs, config, test repo, ...) please see  https://bugzilla.redhat.com/show_bug.cgi?id=495423

I was attempting to do something very unusual (possibly completely unique). I had a darcs repository which did not have file renames recorded correctly (they were recorded as patch containing file deletes and file adds). I wanted to "fix" this problem by converting the repo from darcs to git, and git to darcs again, to make use of git's automatic file rename detection. It almost worked. However, tailor choked on the renamed files.