A co-worker came to me today with a curious error message:

use DateTime;
my $date = DateTime->new( year => 2013, month => 4, day => 15 );
$date->set_time_zone("Australia/Sydney");
print $date->today;'

This code gives the error Can't locate object method "_normalize_nanoseconds" via package "2013-04-15T00:00:00" at /usr2/local/perlbrew/perls/perl-5.16.3/lib/site_perl/5.16.3/x86_64-linux-thread-multi/DateTime.pm line 252.

The package "2013-04-15T00:00:00" is the curious part: It looks like a stringified DateTime, but who could possibly be stringifying a DateTime object and then using that as a package name?

At the Bank we have a home-grown ETL framework that we've been using for quite some time. We recently completed a total rewrite, but unfortunately we left out a few changes. Had I gotten those changes in 5 months ago, I would have only had to break the API of about 10 modules. Today, in order to make those changes, I have to break the API of 122 modules.

What follows is an account of this ordeal, provided for entertainment value only. There will be a future post that explains some of the things I did to make this task surmountable.