Originally reported in Debian against ack 2.15_01, but I can also reproduce this with ack 2.14 as well as ack 2.15_03:
This program emits a perl warning when it is run from a directory that has been removed. To demonstrate:
$ mkdir /tmp/aaa
$ cd /tmp/aaa
$ rmdir /tmp/aaa
$ ack foo
Use of uninitialized value $cwd in pattern match (m//) at /usr/share/perl5/App/Ack/ConfigFinder.pm line 122.
Originally reported in Debian against ack 2.15_01, but I can also reproduce this with ack 2.14 as well as ack 2.15_03: