Don't delegate to private methods of the targer

And make sure that it doesn't even try to call the method in the target.

2 files changed, 19 insertions, 1 deletions

diff --git a/activesupport/lib/active_support/core_ext/module/delegation.rb b/activesupport/lib/active_support/core_ext/module/delegation.rb
index fe680c87b8..7f968d10b5 100644
--- a/activesupport/lib/active_support/core_ext/module/delegation.rb
+++ b/activesupport/lib/active_support/core_ext/module/delegation.rb
@@ -267,7 +267,11 @@ class Module
       end
 
       def method_missing(method, *args, &block)
-        #{target}.send(method, *args, &block)
+        if #{target}.respond_to?(method)
+          #{target}.public_send(method, *args, &block)
+        else
+          super
+        end
       end
     RUBY
   end
diff --git a/activesupport/test/core_ext/module_test.rb b/activesupport/test/core_ext/module_test.rb
index 0120aae492..75490bf4c9 100644
--- a/activesupport/test/core_ext/module_test.rb
+++ b/activesupport/test/core_ext/module_test.rb
@@ -40,6 +40,12 @@ class Someone < Struct.new(:name, :place)
 
   FAILED_DELEGATE_LINE_2 = __LINE__ + 1
   delegate :bar, :to => :place, :allow_nil => true
+
+  private
+
+  def private_name
+    "Private"
+  end
 end
 
 Invoice   = Struct.new(:client) do
@@ -338,6 +344,14 @@ class ModuleTest < ActiveSupport::TestCase
     assert_equal "David", DecoratedReserved.new(@david).name
   end
 
+  def test_delegate_to_missing_does_not_delegate_to_private_methods
+    e = assert_raises(NoMethodError) do
+      DecoratedReserved.new(@david).private_name
+    end
+
+    assert_match(/undefined method `private_name' for/, e.message)
+  end
+
   def test_parent
     assert_equal Yz::Zy, Yz::Zy::Cd.parent
     assert_equal Yz, Yz::Zy.parent