alias_method_chain preserves method punctuation so foo, foo?, and foo! may be...

alias_method_chain preserves method punctuation so foo, foo?, and foo! may be chained with the same feature.

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@4482 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activerecord/lib/active_record/validations.rb

@@ -218,7 +218,7 @@ def self.included(base) # :nodoc:
       base.extend ClassMethods
       base.class_eval do
         alias_method_chain :save, :validation
-        alias_method_chain :save!, :validation!       
+        alias_method_chain :save!, :validation
         alias_method_chain :update_attribute, :validation_skipping
       end
     end

activesupport/CHANGELOG

 *SVN*
 
+* alias_method_chain preserves method punctuation so foo, foo?, and foo! may be chained with the same feature. [Jeremy Kemper]
+    Example:
+      alias_method_chain :save!, :validation
+    is equivalent to
+      alias_method :save_without_validation!, :save!
+      alias_method :save!, :save_with_validation!
+
 * Enhance Symbol#to_proc so it works with list objects, such as multi-dimensional arrays. Closes #5295 [nov@yo.rim.or.jp].  Example:
 
     {1 => "one", 2 => "two", 3 => "three"}.sort_by(&:first).map(&:last)

activesupport/lib/active_support/core_ext/module/aliasing.rb

@@ -9,11 +9,22 @@ class Module
   #   alias_method_chain :foo, :feature
   #
   # And both aliases are set up for you.
+  #
+  # Query and bang methods (foo?, foo!) keep the same punctuation:
+  #
+  #   alias_method_chain :foo?, :feature
+  #
+  # is equivalent to
+  #
+  #   alias_method :foo_without_feature?, :foo?
+  #   alias_method :foo?, :foo_without_feature?
+  #
+  # so you can safely chain foo, foo?, and foo! with the same feature.
   def alias_method_chain(target, feature)
     # Strip out punctuation on predicates or bang methods since
     # e.g. target?_without_feature is not a valid method name.
-    aliased_target = target.to_s.sub(/[?!]/, '')
-    alias_method "#{aliased_target}_without_#{feature}", target
-    alias_method target, "#{aliased_target}_with_#{feature}"
+    aliased_target, punctuation = target.to_s.sub(/([?!])$/, ''), $1
+    alias_method "#{aliased_target}_without_#{feature}#{punctuation}", target
+    alias_method target, "#{aliased_target}_with_#{feature}#{punctuation}"
   end
 end