Off-by-one error in yearly reminder

[Aaron Moman]

I woke up this morning to this reminder:

Hi there,

I just want to remind you that [redacted] is turning 63 in 42 days (Friday May 13).

Have a good day!

However, the birthday is actually on May 14. Here is the relevant portion of the .email-reminders file:
    <event type="birthday">
      <name>[redacted]</name>
      <reminders>
        <reminder type="days before">42</reminder>
      </reminders>
      <day>14</day>
      <month>05</month>
      <year>1948</year>
    </event>

My best guess is that the error lies in this code from will_occur in YearlyEvent.pm:
    if ($modifier) {
        $modified_date = DateCalc($modified_date, " - $modifier days");
    }

Which would mean the error is probably in Date::Manip, but I didn't debug the code to find out.

Something I've checked (to make sure I'm not wasting your time):
There wasn't another entry in the file with a date of May 13th.

Summary: A reminder for 42 days before May 14th should fire on April 2nd, not April 1st. Also, it should remind me for May 14th not May 13th.

[Aaron Moman (admoman)]

In case it matters:
I have version 6.22 of Date::Manip installed for perl v5.10.1 (Ubuntu 10.10 package).
Email-reminders was installed via apt-get. Version 0.7.6.

[François Marier (fmarier)]

Interesting.

It could also be some sort of rounding error... I'll have a look, thanks for reporting this!