From: Greg Go <ruby-forum@...>
Date: 2008-01-11T11:58:15+09:00
Subject: Re: DateTime new_offset unexpected results

Todd Benson wrote:
> On Jan 10, 2008 9:33 AM, Greg Go <ruby-forum@incognitology.com> wrote:
>> Todd Benson wrote:
>> > On Jan 9, 2008 10:11 PM, Greg Go <ruby-forum@incognitology.com> wrote:
>> >> >
>> >> > puts @jd ###
>> >> you're going with this -- am I missing something with the way that ruby
>> >> handles class variables?
>> >
>> > Simple.  Just wanted to see if your dstStart and dstEnd vars were
>> > correct, and if, in fact, you were actually entering the if condition.
> 
> By this last statement, I meant if you were entering the if condition
> during rise event with -6.
> 
>> > It's probably the bug that was mentioned, but I can't reproduce your
>> > error.
>> >
>> > Todd
> 
>> Ah, I see. What I was doing to confirm that I had entered the test
>> condition was changing the value of offset to, for example
>> Rational(-8,24), and Rational(-5,24).
>>
>> I'll see if I can work up a test case and post it, just to be complete.
> 
> You don't have to get super crazy :-).  Do whatever you think will
> help.  Like I said, I don't see the same error on my system, but I
> also don't have your data (your code might have changed the class
> variables before the if statement during the "rise" event is what I
> was thinking).
> 
> Todd

Todd, et al:

This demonstrates the bug:


@ut = DateTime.new!(2454535.05902777)

# According to http://aa.usno.navy.mil/data/docs/JulianDate.php:
# JD 2454535.05902 is CE 2008 March 09 13:24:59.3 UT

puts @ut.to_s  #=> 2008-03-09T13:24:59+00:00

(4..8).each do |i|
   puts @ut.new_offset(Rational(-i,24))
end

# 2008-03-09T09:24:59-04:00
# 2008-03-09T08:24:59-05:00
# 2008-03-09T06:24:59-06:00 <- Should be 2008-03-09T07:24:59-06:00
# 2008-03-09T06:24:59-07:00
# 2008-03-09T05:24:59-08:00


Thanks,
Greg





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