Duplicating the options hash in Date#advance to prevent modification of the...

Duplicating the options hash in Date#advance to prevent modification of the original [#1133 state:resolved]
Signed-off-by: NJoshua Peek <josh@joshpeek.com>

activesupport/lib/active_support/core_ext/date/calculations.rb

@@ -82,6 +82,7 @@ def minus_with_duration(other) #:nodoc:
   # Provides precise Date calculations for years, months, and days.  The +options+ parameter takes a hash with
   # any of these keys: <tt>:years</tt>, <tt>:months</tt>, <tt>:weeks</tt>, <tt>:days</tt>.
   def advance(options)
+    options = options.dup
     d = self
     d = d >> options.delete(:years) * 12 if options[:years]
     d = d >> options.delete(:months)     if options[:months]

activesupport/test/core_ext/date_ext_test.rb

@@ -251,6 +251,12 @@ def test_current_returns_time_zone_today_when_zone_default_set
     Time.zone_default = nil
   end
 
+  def test_date_advance_should_not_change_passed_options_hash
+    options = { :years => 3, :months => 11, :days => 2 }
+    Date.new(2005,2,28).advance(options)
+    assert_equal({ :years => 3, :months => 11, :days => 2 }, options)
+  end
+
   protected
     def with_env_tz(new_tz = 'US/Eastern')
       old_tz, ENV['TZ'] = ENV['TZ'], new_tz