6 files changed, 41 insertions, 7 deletions
diff --git a/activesupport/lib/active_support/core_ext/date/freeze.rb b/activesupport/lib/active_support/core_ext/date/freeze.rb
index 4edd715ba2..a731f8345e 100644
--- a/activesupport/lib/active_support/core_ext/date/freeze.rb
+++ b/activesupport/lib/active_support/core_ext/date/freeze.rb
@@ -5,7 +5,7 @@
 # first call will result in a frozen object error since the memo
 # instance variable is uninitialized.
 #
-# Work around by eagerly memoizing before freezing.
+# Work around by eagerly memoizing before the first freeze.
 #
 # Ruby 1.9 uses a preinitialized instance variable so it's unaffected.
 # This hack is as close as we can get to feature detection:
@@ -17,9 +17,11 @@ if RUBY_VERSION < '1.9'
     if frozen_object_error.message =~ /frozen/
       class Date #:nodoc:
         def freeze
-          self.class.private_instance_methods(false).each do |m|
-            if m.to_s =~ /\A__\d+__\Z/
-              instance_variable_set(:"@#{m}", [send(m)])
+          unless frozen?
+            self.class.private_instance_methods(false).each do |m|
+              if m.to_s =~ /\A__\d+__\Z/
+                instance_variable_set(:"@#{m}", [send(m)])
+              end
             end
           end
 
diff --git a/activesupport/lib/active_support/core_ext/module/delegation.rb b/activesupport/lib/active_support/core_ext/module/delegation.rb
index 3a7652f5bf..1777a4b32d 100644
--- a/activesupport/lib/active_support/core_ext/module/delegation.rb
+++ b/activesupport/lib/active_support/core_ext/module/delegation.rb
@@ -113,7 +113,7 @@ class Module
       raise ArgumentError, "Can only automatically set the delegation prefix when delegating to a method."
     end
 
-    prefix = options[:prefix] && "#{options[:prefix] == true ? to : options[:prefix]}_" || ''
+    prefix = options[:prefix] ? "#{options[:prefix] == true ? to : options[:prefix]}_" : ''
 
     file, line = caller.first.split(':', 2)
     line = line.to_i
diff --git a/activesupport/lib/active_support/core_ext/string/output_safety.rb b/activesupport/lib/active_support/core_ext/string/output_safety.rb
index c27cbc37c5..20e40fe40f 100644
--- a/activesupport/lib/active_support/core_ext/string/output_safety.rb
+++ b/activesupport/lib/active_support/core_ext/string/output_safety.rb
@@ -51,7 +51,8 @@ class ERB
     #   <%=j @person.to_json %>
     #
     def json_escape(s)
-      s.to_s.gsub(/[&"><]/) { |special| JSON_ESCAPE[special] }
+      result = s.to_s.gsub(/[&"><]/) { |special| JSON_ESCAPE[special] }
+      s.html_safe? ? result.html_safe : result
     end
 
     alias j json_escape
@@ -74,6 +75,7 @@ end
 
 module ActiveSupport #:nodoc:
   class SafeBuffer < String
+    UNSAFE_STRING_METHODS = ["capitalize", "chomp", "chop", "delete", "downcase", "gsub", "lstrip", "next", "reverse", "rstrip", "slice", "squeeze", "strip", "sub", "succ", "swapcase", "tr", "tr_s", "upcase"].freeze
     alias safe_concat concat
 
     def concat(value)
@@ -110,6 +112,18 @@ module ActiveSupport #:nodoc:
 
       to_str.to_yaml(*args)
     end
+
+    UNSAFE_STRING_METHODS.each do |unsafe_method|
+      class_eval <<-EOT, __FILE__, __LINE__
+        def #{unsafe_method}(*args)
+          super.to_str
+        end
+
+        def #{unsafe_method}!(*args)
+          raise TypeError, "Cannot modify SafeBuffer in place"
+        end
+      EOT
+    end
   end
 end
 
diff --git a/activesupport/test/core_ext/date_ext_test.rb b/activesupport/test/core_ext/date_ext_test.rb
index d81693209f..b4f848cd44 100644
--- a/activesupport/test/core_ext/date_ext_test.rb
+++ b/activesupport/test/core_ext/date_ext_test.rb
@@ -454,4 +454,10 @@ class DateExtBehaviorTest < Test::Unit::TestCase
       Date.today.freeze.inspect
     end
   end
+
+  def test_can_freeze_twice
+    assert_nothing_raised do
+      Date.today.freeze.freeze
+    end
+  end
 end
diff --git a/activesupport/test/safe_buffer_test.rb b/activesupport/test/safe_buffer_test.rb
index a4e2acbb32..3a9854358c 100644
--- a/activesupport/test/safe_buffer_test.rb
+++ b/activesupport/test/safe_buffer_test.rb
@@ -60,4 +60,16 @@ class SafeBufferTest < ActiveSupport::TestCase
     yaml = YAML.dump data
     assert_equal({'str' => str}, YAML.load(yaml))
   end
+
+  test "Should not return safe buffer from gsub" do
+    altered_buffer = @buffer.gsub('', 'asdf')
+    assert_equal 'asdf', altered_buffer
+    assert !altered_buffer.html_safe?
+  end
+
+  test "Should not allow gsub! on safe buffers" do
+    assert_raise TypeError do
+      @buffer.gsub!('', 'asdf')
+    end
+  end
 end
diff --git a/activesupport/test/test_test.rb b/activesupport/test/test_test.rb
index ee5a20c789..5bd995aa32 100644
--- a/activesupport/test/test_test.rb
+++ b/activesupport/test/test_test.rb
@@ -50,7 +50,7 @@ class AssertDifferenceTest < ActiveSupport::TestCase
 
     def test_expression_is_evaluated_in_the_appropriate_scope
       silence_warnings do
-        local_scope = 'foo'
+        local_scope = local_scope = 'foo'
         assert_difference('local_scope; @object.num') { @object.increment }
       end
     end