Merge pull request #9330 from bdmac/time_zone_select_dup

Fix time_zone_options_for_select to not mutate TimeZones array

actionpack/CHANGELOG.md

@@ -1,5 +1,13 @@
 ## Rails 4.0.0 (unreleased) ##
 
+*   Fix `time_zone_options_for_select` to call `dup` on the returned TimeZone array.
+    
+    Previously if you supplied :priority_zones options to `time_zone_options_for_select`
+    the memoized ActiveSupport::TimeZone.all array would be mutated.  Calling
+    `dup` prevents mutation of the main TimeZones array.
+    
+    *Brian McManus*
+    
 *   Remove support for parsing YAML parameters from request.
 
     *Aaron Patterson*

actionpack/lib/action_view/helpers/form_options_helper.rb

@@ -560,7 +560,7 @@ module ActionView
       def time_zone_options_for_select(selected = nil, priority_zones = nil, model = ::ActiveSupport::TimeZone)
         zone_options = "".html_safe
 
-        zones = model.all
+        zones = model.all.dup
         convert_zones = lambda { |list| list.map { |z| [ z.to_s, z.name ] } }
 
         if priority_zones

actionpack/test/template/form_options_helper_test.rb

@@ -416,6 +416,13 @@ class FormOptionsHelperTest < ActionView::TestCase
                  "<option value=\"D\">D</option>",
                  opts
   end
+  
+  def test_time_zone_options_with_priority_zones_does_not_mutate_time_zones
+    original_zones = ActiveSupport::TimeZone.all.dup
+    zones = [ ActiveSupport::TimeZone.new( "B" ), ActiveSupport::TimeZone.new( "E" ) ]
+    opts = time_zone_options_for_select( nil, zones )
+    assert_equal original_zones, ActiveSupport::TimeZone.all
+  end
 
   def test_time_zone_options_returns_html_safe_string
     assert time_zone_options_for_select.html_safe?