6 files changed, 22 insertions, 42 deletions
diff --git a/activesupport/CHANGELOG b/activesupport/CHANGELOG
index 92767bafa3..3bd6a4adcf 100644
--- a/activesupport/CHANGELOG
+++ b/activesupport/CHANGELOG
@@ -1,5 +1,7 @@
 *SVN*
 
+* Refactor Time and Date#months_since and #months_ago to use #advance.  #9863 [Geoff Buesing]
+
 * Rebundle Builder 2.1.2 but prefer a newer RubyGem if available.  [Jeremy Kemper]
 
 * Add Range#overlaps?(range), Range#include?(range), and Range#step without a block. [brandon]
diff --git a/activesupport/lib/active_support/core_ext/date/calculations.rb b/activesupport/lib/active_support/core_ext/date/calculations.rb
index df35410b3e..c1f4eb21be 100644
--- a/activesupport/lib/active_support/core_ext/date/calculations.rb
+++ b/activesupport/lib/active_support/core_ext/date/calculations.rb
@@ -93,30 +93,12 @@ module ActiveSupport #:nodoc:
         
         # Returns a new Date/DateTime representing the time a number of specified months ago
         def months_ago(months)
-          months_since(-months)
+          advance(:months => -months)
         end
 
+        # Returns a new Date/DateTime representing the time a number of specified months in the future
         def months_since(months)
-          year, month, day = self.year, self.month, self.day
-
-          month += months
-
-          # in case months is negative
-          while month < 1
-           month += 12
-           year -= 1
-          end
-
-          # in case months is positive
-          while month > 12
-           month -= 12
-           year += 1
-          end
-
-          max = ::Time.days_in_month(month, year)
-          day = max if day > max
-
-          change(:year => year, :month => month, :day => day)
+          advance(:months => months)
         end
 
         # Returns a new Date/DateTime representing the time a number of specified years ago
@@ -124,6 +106,7 @@ module ActiveSupport #:nodoc:
           change(:year => self.year - years)
         end
 
+        # Returns a new Date/DateTime representing the time a number of specified years in the future
         def years_since(years)
           change(:year => self.year + years)
         end
diff --git a/activesupport/lib/active_support/core_ext/time/calculations.rb b/activesupport/lib/active_support/core_ext/time/calculations.rb
index 5754ca1bca..04da03110f 100644
--- a/activesupport/lib/active_support/core_ext/time/calculations.rb
+++ b/activesupport/lib/active_support/core_ext/time/calculations.rb
@@ -98,30 +98,12 @@ module ActiveSupport #:nodoc:
 
         # Returns a new Time representing the time a number of specified months ago
         def months_ago(months)
-          months_since(-months)
+          advance(:months => -months)
         end
 
+        # Returns a new Time representing the time a number of specified months in the future
         def months_since(months)
-          year, month, mday = self.year, self.month, self.mday
-
-          month += months
-
-          # in case months is negative
-          while month < 1
-            month += 12
-            year -= 1
-          end
-
-          # in case months is positive
-          while month > 12
-            month -= 12
-            year += 1
-          end
-
-          max = ::Time.days_in_month(month, year)
-          mday = max if mday > max
-
-          change(:year => year, :month => month, :day => mday)
+          advance(:months => months)
         end
 
         # Returns a new Time representing the time a number of specified years ago
@@ -129,6 +111,7 @@ module ActiveSupport #:nodoc:
           change(:year => self.year - years)
         end
 
+        # Returns a new Time representing the time a number of specified years in the future
         def years_since(years)
           change(:year => self.year + years)
         end
diff --git a/activesupport/test/core_ext/date_ext_test.rb b/activesupport/test/core_ext/date_ext_test.rb
index 7396c5c9a7..b86bb2dc6b 100644
--- a/activesupport/test/core_ext/date_ext_test.rb
+++ b/activesupport/test/core_ext/date_ext_test.rb
@@ -85,6 +85,10 @@ class DateExtCalculationsTest < Test::Unit::TestCase
     assert_equal Date.new(2006,1,5),  Date.new(2005,6,5).months_since(7)
     assert_equal Date.new(2006,6,5),  Date.new(2005,6,5).months_since(12)
     assert_equal Date.new(2007,6,5),  Date.new(2005,6,5).months_since(24)
+    assert_equal Date.new(2005,4,30),  Date.new(2005,3,31).months_since(1)
+    assert_equal Date.new(2005,2,28),  Date.new(2005,1,29).months_since(1)
+    assert_equal Date.new(2005,2,28),  Date.new(2005,1,30).months_since(1)
+    assert_equal Date.new(2005,2,28),  Date.new(2005,1,31).months_since(1)
   end
 
   def test_years_ago
diff --git a/activesupport/test/core_ext/date_time_ext_test.rb b/activesupport/test/core_ext/date_time_ext_test.rb
index 911bd7925e..27c2291442 100644
--- a/activesupport/test/core_ext/date_time_ext_test.rb
+++ b/activesupport/test/core_ext/date_time_ext_test.rb
@@ -103,6 +103,10 @@ class DateTimeExtCalculationsTest < Test::Unit::TestCase
     assert_equal DateTime.civil(2006,1,5,10),  DateTime.civil(2005,6,5,10,0,0).months_since(7)
     assert_equal DateTime.civil(2006,6,5,10),  DateTime.civil(2005,6,5,10,0,0).months_since(12)
     assert_equal DateTime.civil(2007,6,5,10),  DateTime.civil(2005,6,5,10,0,0).months_since(24)
+    assert_equal DateTime.civil(2005,4,30,10),  DateTime.civil(2005,3,31,10,0,0).months_since(1)
+    assert_equal DateTime.civil(2005,2,28,10),  DateTime.civil(2005,1,29,10,0,0).months_since(1)
+    assert_equal DateTime.civil(2005,2,28,10),  DateTime.civil(2005,1,30,10,0,0).months_since(1)
+    assert_equal DateTime.civil(2005,2,28,10),  DateTime.civil(2005,1,31,10,0,0).months_since(1)
   end
 
   def test_years_ago
diff --git a/activesupport/test/core_ext/time_ext_test.rb b/activesupport/test/core_ext/time_ext_test.rb
index 5f06a4efa7..da8cd6ec5b 100644
--- a/activesupport/test/core_ext/time_ext_test.rb
+++ b/activesupport/test/core_ext/time_ext_test.rb
@@ -110,6 +110,10 @@ class TimeExtCalculationsTest < Test::Unit::TestCase
     assert_equal Time.local(2006,1,5,10),  Time.local(2005,6,5,10,0,0).months_since(7)
     assert_equal Time.local(2006,6,5,10),  Time.local(2005,6,5,10,0,0).months_since(12)
     assert_equal Time.local(2007,6,5,10),  Time.local(2005,6,5,10,0,0).months_since(24)
+    assert_equal Time.local(2005,4,30,10),  Time.local(2005,3,31,10,0,0).months_since(1)
+    assert_equal Time.local(2005,2,28,10),  Time.local(2005,1,29,10,0,0).months_since(1)
+    assert_equal Time.local(2005,2,28,10),  Time.local(2005,1,30,10,0,0).months_since(1)
+    assert_equal Time.local(2005,2,28,10),  Time.local(2005,1,31,10,0,0).months_since(1)
   end
 
   def test_years_ago