From 705b09e781af7461dba4667152524ecbb5b4e23b Mon Sep 17 00:00:00 2001
From: Tammo Freese <tammofreese@tammo-freeses-macbook.local>
Date: Sat, 31 May 2008 11:54:25 +0200
Subject: [PATCH] I made alias_method_chain more extensible, it now calls aliased methods from superclass and replacements of the ..._with_... methods

---
 .../lib/active_support/core_ext/module/aliasing.rb |   19 ++++++++-
 activesupport/lib/active_support/deprecation.rb    |    9 +++-
 activesupport/test/core_ext/module_test.rb         |   43 ++++++++++++++++++++
 3 files changed, 68 insertions(+), 3 deletions(-)

diff --git a/activesupport/lib/active_support/core_ext/module/aliasing.rb b/activesupport/lib/active_support/core_ext/module/aliasing.rb
index 1894e3b..98e4881 100644
--- a/activesupport/lib/active_support/core_ext/module/aliasing.rb
+++ b/activesupport/lib/active_support/core_ext/module/aliasing.rb
@@ -28,9 +28,26 @@ class Module
     
     with_method, without_method = "#{aliased_target}_with_#{feature}#{punctuation}", "#{aliased_target}_without_#{feature}#{punctuation}"
     
+    method_defined_here = (instance_methods(false) + private_instance_methods(false)).include?(RUBY_VERSION < '1.9' ? target.to_s : target)
+    unless method_defined_here
+      module_eval <<-EOS
+        def #{target}(*args, &block)
+          super
+        end
+      EOS
+    end  
+    
     alias_method without_method, target
-    alias_method target, with_method
     
+    target_method_exists = (instance_methods + private_instance_methods).include?(RUBY_VERSION < '1.9' ? with_method : with_method.to_sym) 
+    raise NameError unless target_method_exists
+    
+    module_eval <<-EOS
+      def #{target}(*args, &block)
+        self.__send__(:'#{with_method}', *args, &block)
+      end
+    EOS
+
     case
       when public_method_defined?(without_method)
         public target
diff --git a/activesupport/lib/active_support/deprecation.rb b/activesupport/lib/active_support/deprecation.rb
index 758aef5..ed68d4e 100644
--- a/activesupport/lib/active_support/deprecation.rb
+++ b/activesupport/lib/active_support/deprecation.rb
@@ -67,10 +67,15 @@ module ActiveSupport
         end
 
         def extract_callstack(callstack)
-          if md = callstack.first.match(/^(.+?):(\d+)(?::in `(.*?)')?/)
+          # Depending on ruby version, the caller of the deprecated method 
+          # is the second or third element of the callstack:
+          # In 1.8, the first is __send__, the second is the deprecated method. 
+          # In 1.9, the first is the deprecated method.
+          call = callstack[RUBY_VERSION < '1.9' ? 2 : 1]
+          if md = call.match(/^(.+?):(\d+)(?::in `(.*?)')?/)
             md.captures
           else
-            callstack.first
+            call
           end
         end
     end
diff --git a/activesupport/test/core_ext/module_test.rb b/activesupport/test/core_ext/module_test.rb
index ecdea38..5671aa5 100644
--- a/activesupport/test/core_ext/module_test.rb
+++ b/activesupport/test/core_ext/module_test.rb
@@ -290,4 +290,47 @@ class MethodAliasingTest < Test::Unit::TestCase
     assert_equal 'duck_with_orange', @instance.duck
     assert FooClassWithBarMethod.public_method_defined?(:duck)
   end
+  
+  def test_alias_method_chain_allows_redefinition_of_aliased_public_method_in_superclass
+    Object.const_set :FooClassSubClass, Class.new(FooClassWithBarMethod)
+    FooClassSubClass.class_eval do
+      include BarMethodAliaser
+    end
+    FooClassWithBarMethod.class_eval do
+      def bar_with_new; 'new_bar' end
+      alias_method_chain :bar, :new
+    end
+    assert_equal 'new_bar_with_baz', FooClassSubClass.new.bar
+  ensure
+    Object.instance_eval { remove_const :FooClassSubClass }
+  end
+  
+  def test_alias_method_chain_allows_redefinition_of_aliased_private_method_in_superclass
+    Object.const_set :FooClassSubClass, Class.new(FooClassWithBarMethod)
+    FooClassWithBarMethod.class_eval do
+      private :bar
+    end  
+    FooClassSubClass.class_eval do
+      include BarMethodAliaser
+    end
+    FooClassWithBarMethod.class_eval do
+      private
+      def bar_with_new; 'new_bar' end
+      alias_method_chain :bar, :new
+    end
+    assert_equal 'new_bar_with_baz', FooClassSubClass.new.__send__(:bar)
+  ensure
+    Object.instance_eval { remove_const :FooClassSubClass }
+  end
+  
+  def test_alias_method_chain_allows_redefinition_of_with_method
+    FooClassWithBarMethod.class_eval do
+      include BarMethodAliaser
+      def bar_with_baz_with_buzz
+        bar_with_baz_without_buzz << '_with_buzz'
+      end
+      alias_method_chain :bar_with_baz, :buzz
+    end  
+    assert_equal 'bar_with_baz_with_buzz', FooClassWithBarMethod.new.bar
+  end  
 end
-- 
1.5.4.5