As described in issue #2842:
The editor vtable's delete_entry() function is path-kind ignorant,
which means that client-side editors trying to compensate for
over-informative server-side editor drivers don't have enough information
to correctly distinguish whether a deletion of an immediate child should
be allowed to pass thru when using svn_depth_files.
If I, as a depth-filtering editor, am told to delete to delete a file in
svn_depth_files mode, I know it's cool to do so. If I'm told to delete a
directory, it's not so cool. But to make that call, I need to know what path
kind I'm dealing with. But the positioning of the depth filtering editor makes
path kind determination ... difficult.