ActiveRecord adding to negative date year - ruby-on-rails

Question

I need to be able to save negative dates, but have been running into a problem: ActiveRecord is adding 1 to the year when retrieving the date from the database.
The migration uses t.date.
Here's a quick example:
I create and save a model with a date value of Date.new(-44, 3, 15).
When inserting into the database, and inside the database, the year is correct. A manual psql check confirmed this.
However, when retrieving the date from the DB using ActiveRecord, the year is -43.
I've googled and searched SO with no results. Any idea what is causing this?

Answer 1

http://ruby-doc.org/stdlib-1.9.3/libdoc/date/rdoc/Date.html#method-c-new
...BCE years are counted astronomically.
...the year before the year 1 is the year zero,
and the year preceding the year zero is the year -1.
Researching this I thought you had discovered a defect in Date#parse, then I thought it was working 'as designed', now I am not sure anymore :(
Date.parse('2015-06-15 CE') == Date.new(2015, 6, 15)
# => true
Date.parse('0000-01-01 CE') == Date.new(0, 1, 1)
# => true
Date.parse('0002-01-01 BCE') == Date.new(-1, 1, 1)
# => true
Date.parse('0000-01-01 CE') == Date.parse('0001-01-01 BCE')
# => true
Date.parse('0001-01-01 BCE') == Date.new(0, 1, 1)
# => true
https://en.wikipedia.org/wiki/Astronomical_year_numbering
The year 1 BC/BCE is numbered 0, the year 2 BC is numbered −1
So it appears to work 'as designed', but maybe not as expected
# The year 1 BC/BCE is numbered 0
Date.parse('0001-01-01 BCE') == Date.new(0, 1, 1)
# the year 2 BC is numbered −1
Date.parse('0002-01-01 BCE') == Date.new(-1, 1, 1)
What does this mean for you and your rails app?
User input is most likely submitted in the format '0044-03-15 BC' as a string (params), which is assigned to a model attribute.
x = Widget.create(date_column: '0044-03-15 BC')
x.date_column
=> Wed, 15 Mar -0043
x.attributes_before_type_cast['date_column']
=> "0044-03-15 BC"
x.attributes_before_type_cast['date_column'].to_date
=> Wed, 15 Mar -0043
guessing to_date is also using Date.parse
I'm really not sure how the correct value gets stored in postgres, but rails is going to use Date.parse on that value and be off by a year when displaying the users entered date (BCE only).
some possible hacky workarounds
1) Store the values as integers
class Whatever < ActiveRecord::Base
# 'date' column -> the_date stored as an integer
# override the columns 'getter' method
def the_date
the_time = Time.at(self[:the_date])
Date.new(the_time.year, the_time.month, the_time.day)
end
end
# Time#to_i - epoch time
x = Whatever.create(the_date: Time.new(-44, 3, 15, 0, 0, 0).to_i)
2) Store the year, month, day as separate database fields?
class Whatever < ActiveRecord::Base
# 'date' stored as 3 integer columns -> the_date_year, the_date_month, the_date_day
# use this in views, etc...
def the_date
Date.new(the_date_year, the_date_month, the_date_day)
end
end
hopefully somebody else has a better solution...