Comment 5 for bug 197916

>It's actually intended behavior. Otherwise you can't rename (change only the case) directory:
>
>bzr init
>bzr mkdir foo
>bzr mv foo Foo

Couldn't you handle both cases by checking the underlying file system and seeing if it support case sensitivity? If not, then the command does nothing. (You could return an error). Otherwise, the command continues as you intend. On the flip side:

>mkdir b
>bzr mv A/file B/file

a check for case-sensitivity of the file system in this case would allow the command to complete appropriately, but only if the file system was NOT case sensitive.