Fix inconsistent parsing of Durations with both months and years #27610

Merged
merged 1 commit into from Jan 12, 2017
@@ -130,7 +130,7 @@ def assert_hsts(expected, url: "https://example.org", hsts: { subdomains: true }
end
test ":expires supports AS::Duration arguments" do
- assert_hsts "max-age=31557600; includeSubDomains", hsts: { expires: 1.year }
+ assert_hsts "max-age=31556952; includeSubDomains", hsts: { expires: 1.year }
end
test "include subdomains" do
@@ -1,3 +1,28 @@
+* Fix inconsistent results when parsing large durations and constructing durations from code
+
+ ActiveSupport::Duration.parse('P3Y') == 3.years # It should be true
+
+ Duration parsing made independent from any moment of time:
+ Fixed length in seconds is assigned to each duration part during parsing.
+
+ Changed duration of months and years in seconds to more accurate and logical:
+
+ 1. The value of 365.2425 days in Gregorian year is more accurate
+ as it accounts for every 400th non-leap year.
+
+ 2. Month's length is bound to year's duration, which makes
+ sensible comparisons like `12.months == 1.year` to be `true`
+ and nonsensical ones like `30.days == 1.month` to be `false`.
+
+ Calculations on times and dates with durations shouldn't be affected as
+ duration's numeric value isn't used in calculations, only parts are used.
+
+ Methods on `Numeric` like `2.days` now use these predefined durations
+ to avoid duplicating of duration constants through the codebase and
+ eliminate creation of intermediate durations.
+
+ *Andrey Novikov, Andrew White*
+
* Change return value of `Rational#duplicable?`, `ComplexClass#duplicable?`
to false.
@@ -18,12 +18,12 @@ class Integer
# # equivalent to Time.now.advance(months: 4, years: 5)
# (4.months + 5.years).from_now
def months
- ActiveSupport::Duration.new(self * 30.days, [[:months, self]])
+ ActiveSupport::Duration.new(self * ActiveSupport::Duration::PARTS_IN_SECONDS[:months].to_i, [[:months, self]])
end
alias :month :months
def years
- ActiveSupport::Duration.new(self * 365.25.days.to_i, [[:years, self]])
+ ActiveSupport::Duration.new(self * ActiveSupport::Duration::PARTS_IN_SECONDS[:years].to_i, [[:years, self]])
end
alias :year :years
end
@@ -27,39 +27,39 @@ def seconds
#
# 2.minutes # => 2 minutes
def minutes
- ActiveSupport::Duration.new(self * 60, [[:minutes, self]])
+ ActiveSupport::Duration.new(self * ActiveSupport::Duration::PARTS_IN_SECONDS[:minutes], [[:minutes, self]])
end
alias :minute :minutes
# Returns a Duration instance matching the number of hours provided.
#
# 2.hours # => 2 hours
def hours
- ActiveSupport::Duration.new(self * 3600, [[:hours, self]])
+ ActiveSupport::Duration.new(self * ActiveSupport::Duration::PARTS_IN_SECONDS[:hours], [[:hours, self]])
end
alias :hour :hours
# Returns a Duration instance matching the number of days provided.
#
# 2.days # => 2 days
def days
- ActiveSupport::Duration.new(self * 24.hours, [[:days, self]])
+ ActiveSupport::Duration.new(self * ActiveSupport::Duration::PARTS_IN_SECONDS[:days], [[:days, self]])
end
alias :day :days
# Returns a Duration instance matching the number of weeks provided.
#
# 2.weeks # => 2 weeks
def weeks
- ActiveSupport::Duration.new(self * 7.days, [[:weeks, self]])
+ ActiveSupport::Duration.new(self * ActiveSupport::Duration::PARTS_IN_SECONDS[:weeks], [[:weeks, self]])
end
alias :week :weeks
# Returns a Duration instance matching the number of fortnights provided.
#
# 2.fortnights # => 4 weeks
def fortnights
- ActiveSupport::Duration.new(self * 2.weeks, [[:weeks, self * 2]])
+ ActiveSupport::Duration.new(self * 2 * ActiveSupport::Duration::PARTS_IN_SECONDS[:weeks], [[:weeks, self * 2]])
end
alias :fortnight :fortnights
@@ -7,7 +7,15 @@ module ActiveSupport
#
# 1.month.ago # equivalent to Time.now.advance(months: -1)
class Duration
- EPOCH = ::Time.utc(2000)
+ PARTS_IN_SECONDS = {
+ seconds: 1, # Used in parse method for ease of handling part hashes with seconds
+ minutes: 60,
+ hours: 60 * 60,
+ days: 24 * 60 * 60,
+ weeks: 7 * 24 * 60 * 60,
+ months: ((365.2425 / 12) * 24 * 60 * 60).ceil, # 1 year is always 12 months long, no sense to bind it to days
+ years: (365.2425 * 24 * 60 * 60).ceil, # Gregorian year length to account for the every 400 non-leap year
+ }.freeze
attr_accessor :value, :parts
@@ -78,14 +86,14 @@ def to_s
# 1.day.to_i # => 86400
#
# Note that this conversion makes some assumptions about the
- # duration of some periods, e.g. months are always 30 days
- # and years are 365.25 days:
+ # duration of some periods, e.g. months are always 1/12 of year
+ # and years are 365.2425 days:
#
- # # equivalent to 30.days.to_i
- # 1.month.to_i # => 2592000
+ # # equivalent to (1.year / 12).to_i
+ # 1.month.to_i # => 2629746
#
- # # equivalent to 365.25.days.to_i
- # 1.year.to_i # => 31557600
+ # # equivalent to 365.2425.days.to_i
+ # 1.year.to_i # => 31556952
#
# In such cases, Ruby's core
# Date[http://ruby-doc.org/stdlib/libdoc/date/rdoc/Date.html] and
@@ -148,7 +156,10 @@ def respond_to_missing?(method, include_private = false) #:nodoc:
# If invalid string is provided, it will raise +ActiveSupport::Duration::ISO8601Parser::ParsingError+.
def self.parse(iso8601duration)
parts = ISO8601Parser.new(iso8601duration).parse!
- new(EPOCH.advance(parts) - EPOCH, parts)
+ total_seconds = parts.inject(0) do |total, (part, value)|
+ total + value * PARTS_IN_SECONDS[part]
+ end
+ new(total_seconds, parts)
end
# Build ISO 8601 Duration string for this duration.
@@ -340,6 +340,7 @@ def test_iso8601_parsing_across_autumn_dst_boundary
travel_to Time.utc(2016, 11, 4) do
assert_equal 604800, ActiveSupport::Duration.parse("P7D").to_i
assert_equal 604800, ActiveSupport::Duration.parse("P1W").to_i
+ assert_equal ActiveSupport::Duration.parse(3.years.iso8601).to_i, 3.years.to_i
end
end
end
@@ -12,7 +12,7 @@ def setup
10.minutes => 600,
1.hour + 15.minutes => 4500,
2.days + 4.hours + 30.minutes => 189000,
- 5.years + 1.month + 1.fortnight => 161589600
+ 5.years + 1.month + 1.fortnight => 161624106
}
end
@@ -61,10 +61,10 @@ def test_chaining_duration_operations
end
def test_duration_after_conversion_is_no_longer_accurate
- assert_equal 30.days.to_i.seconds.since(@now), 1.month.to_i.seconds.since(@now)
- assert_equal 365.25.days.to_f.seconds.since(@now), 1.year.to_f.seconds.since(@now)
- assert_equal 30.days.to_i.seconds.since(@dtnow), 1.month.to_i.seconds.since(@dtnow)
- assert_equal 365.25.days.to_f.seconds.since(@dtnow), 1.year.to_f.seconds.since(@dtnow)
+ assert_equal (1.year / 12).to_i.seconds.since(@now), 1.month.to_i.seconds.since(@now)
+ assert_equal 365.2425.days.to_f.seconds.since(@now), 1.year.to_f.seconds.since(@now)
+ assert_equal (1.year / 12).to_i.seconds.since(@dtnow), 1.month.to_i.seconds.since(@dtnow)
+ assert_equal 365.2425.days.to_f.seconds.since(@dtnow), 1.year.to_f.seconds.since(@dtnow)
end
def test_add_one_year_to_leap_day
@@ -683,7 +683,7 @@ Ruby instruction to be executed -- in this case, Active Support's `week` method.
51: #
52: # 2.weeks # => 14 days
53: def weeks
-=> 54: ActiveSupport::Duration.new(self * 7.days, [[:days, self * 7]])
+=> 54: ActiveSupport::Duration.new(self * ActiveSupport::Duration::PARTS_IN_SECONDS[:weeks], [[:weeks, self]])
55: end
56: alias :week :weeks
57: