Time.days_in_month defaults to current year if no year is supplied as argument, uses Date.gregorian_leap? to determine leap year, and uses constant lookup to determine days in month. Closes #10799 [Radar]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@8715 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

3 files changed, 22 insertions, 13 deletions

diff --git a/activesupport/CHANGELOG b/activesupport/CHANGELOG
index f8d25d130c..8514db47fe 100644
--- a/activesupport/CHANGELOG
+++ b/activesupport/CHANGELOG
@@ -1,5 +1,7 @@
 *SVN*
 
+* Time.days_in_month defaults to current year if no year is supplied as argument #10799 [Radar], uses Date.gregorian_leap? to determine leap year, and uses constant lookup to determine days in month [Geoff Buesing]  
+
 * Adding Time and DateTime #compare_with_coercion, which layers behavior on #<=> so that any combination of Time, DateTime and ActiveSupport::TimeWithZone instances can be chronologically compared [Geoff Buesing]
 
 * TimeZone#now returns an ActiveSupport::TimeWithZone [Geoff Buesing]
diff --git a/activesupport/lib/active_support/core_ext/time/calculations.rb b/activesupport/lib/active_support/core_ext/time/calculations.rb
index 534571fe61..eb342084a8 100644
--- a/activesupport/lib/active_support/core_ext/time/calculations.rb
+++ b/activesupport/lib/active_support/core_ext/time/calculations.rb
@@ -18,19 +18,14 @@ module ActiveSupport #:nodoc:
           end
         end
 
+        COMMON_YEAR_DAYS_IN_MONTH = [nil, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]
+
         module ClassMethods
-          # Return the number of days in the given month. If a year is given,
-          # February will return the correct number of days for leap years.
-          # Otherwise, this method will always report February as having 28
-          # days.
-          def days_in_month(month, year=nil)
-            if month == 2
-              !year.nil? && (year % 4 == 0) && ((year % 100 != 0) || (year % 400 == 0)) ?  29 : 28
-            elsif month <= 7
-              month % 2 == 0 ? 30 : 31
-            else
-              month % 2 == 0 ? 31 : 30
-            end
+          # Return the number of days in the given month. 
+          # If no year is specified, it will use the current year. 
+          def days_in_month(month, year = now.year)
+            return 29 if month == 2 && ::Date.gregorian_leap?(year)
+            COMMON_YEAR_DAYS_IN_MONTH[month]
           end
 
           # Returns a new Time if requested year can be accommodated by Ruby's Time class
diff --git a/activesupport/test/core_ext/time_ext_test.rb b/activesupport/test/core_ext/time_ext_test.rb
index 170caf3e09..a7faf4808b 100644
--- a/activesupport/test/core_ext/time_ext_test.rb
+++ b/activesupport/test/core_ext/time_ext_test.rb
@@ -348,7 +348,7 @@ class TimeExtCalculationsTest < Test::Unit::TestCase
     assert_equal midnight.midnight, (midnight + 1.hour + 0.000001).midnight
   end
 
-  def test_days_in_month
+  def test_days_in_month_with_year
     assert_equal 31, Time.days_in_month(1, 2005)
 
     assert_equal 28, Time.days_in_month(2, 2005)
@@ -367,6 +367,18 @@ class TimeExtCalculationsTest < Test::Unit::TestCase
     assert_equal 30, Time.days_in_month(11, 2005)
     assert_equal 31, Time.days_in_month(12, 2005)
   end
+  
+  uses_mocha 'TestTimeDaysInMonthWithoutYearArg' do
+    def test_days_in_month_feb_in_common_year_without_year_arg
+      Time.stubs(:now).returns(Time.utc(2007))
+      assert_equal 28, Time.days_in_month(2)
+    end
+  
+    def test_days_in_month_feb_in_leap_year_without_year_arg
+      Time.stubs(:now).returns(Time.utc(2008))
+      assert_equal 29, Time.days_in_month(2)
+    end
+  end
 
   def test_time_with_datetime_fallback
     assert_equal Time.time_with_datetime_fallback(:utc, 2005, 2, 21, 17, 44, 30), Time.utc(2005, 2, 21, 17, 44, 30)