-L is supposed to print files without matches.
Only print the filenames of files that do NOT match. This is
equivalent to specifying −l and −v.
However, this is wrong. -l -v actually prints files that have at least one non-matching line, and not what we want -L to do, which is to print files that have only non-matching lines.
This needs a fix and a test, although chances are this will not get fixed in ack 1.x. I've added it as a ticket to the ack2 project. petdance/ack2#210
Originally reported by Seungbeom Kim email@example.com
This has been taken care of in ack2.