Fewer object allocations

activemodel/lib/active_model/attribute_methods.rb

@@ -317,7 +317,7 @@ def instance_method_already_implemented?(method_name)
 
       private
         class AttributeMethodMatcher
-          attr_reader :prefix, :suffix
+          attr_reader :prefix, :suffix, :method_missing_target
 
           AttributeMethodMatch = Struct.new(:target, :attr_name)
 
@@ -325,22 +325,20 @@ def initialize(options = {})
             options.symbolize_keys!
             @prefix, @suffix = options[:prefix] || '', options[:suffix] || ''
             @regex = /^(#{Regexp.escape(@prefix)})(.+?)(#{Regexp.escape(@suffix)})$/
+            @method_missing_target = :"#{@prefix}attribute#{@suffix}"
+            @method_name = "#{prefix}%s#{suffix}"
           end
 
           def match(method_name)
-            if matchdata = @regex.match(method_name)
-              AttributeMethodMatch.new(method_missing_target, matchdata[2])
+            if @regex =~ method_name
+              AttributeMethodMatch.new(method_missing_target, $2)
             else
               nil
             end
           end
 
           def method_name(attr_name)
-            "#{prefix}#{attr_name}#{suffix}"
-          end
-
-          def method_missing_target
-            :"#{prefix}attribute#{suffix}"
+            @method_name % attr_name
           end
         end
     end

activerecord/test/cases/attribute_methods_test.rb

@@ -541,7 +541,7 @@ def test_read_attributes_respect_access_control
     topic = @target.new(:title => "The pros and cons of programming naked.")
     assert !topic.respond_to?(:title)
     exception = assert_raise(NoMethodError) { topic.title }
-    assert_equal "Attempt to call private method", exception.message
+    assert_match %r(^Attempt to call private method), exception.message
     assert_equal "I'm private", topic.send(:title)
   end
 
@@ -551,7 +551,7 @@ def test_write_attributes_respect_access_control
     topic = @target.new
     assert !topic.respond_to?(:title=)
     exception = assert_raise(NoMethodError) { topic.title = "Pants"}
-    assert_equal "Attempt to call private method", exception.message
+    assert_match %r(^Attempt to call private method), exception.message
     topic.send(:title=, "Very large pants")
   end
 
@@ -561,7 +561,7 @@ def test_question_attributes_respect_access_control
     topic = @target.new(:title => "Isaac Newton's pants")
     assert !topic.respond_to?(:title?)
     exception = assert_raise(NoMethodError) { topic.title? }
-    assert_equal "Attempt to call private method", exception.message
+    assert_match %r(^Attempt to call private method), exception.message
     assert topic.send(:title?)
   end