Issue parsing filenames without extension

When reading the files from backup.d, if there is a file without an extension, the filename is not parsed correctly:

Error: Can't process file '/etc/backup.d/21-local-filelist': no handler script for suffix 'd/21-local-filelist'

So, it parsed the extension as starting with the '.' in 'backup.d'. What I expected would happen was it see no extension ("${base:0:1}" == "0") and just report that it was skipping the file. In my case, I have a file that is used by an action but is not an action itself; I want it to be ignored.