Move ActiveModel::AttributeMethods#attribute_methods_generated? to ActiveRecord, so it's flexible now

[#6428 state:resolved]

Signed-off-by: José Valim <jose.valim@gmail.com>

4 files changed, 39 insertions, 28 deletions

diff --git a/activemodel/CHANGELOG b/activemodel/CHANGELOG
index 9dd5e03685..3082c7186a 100644
--- a/activemodel/CHANGELOG
+++ b/activemodel/CHANGELOG
@@ -2,6 +2,8 @@
 
 * Added ActiveModel::SecurePassword to encapsulate dead-simple password usage with BCrypt encryption and salting [DHH]
 
+* ActiveModel::AttributeMethods allows attributes to be defined on demand [Alexander Uvarov]
+
 
 *Rails 3.0.2 (unreleased)*
 
diff --git a/activemodel/lib/active_model/attribute_methods.rb b/activemodel/lib/active_model/attribute_methods.rb
index 8f3782eb48..2a99450a3d 100644
--- a/activemodel/lib/active_model/attribute_methods.rb
+++ b/activemodel/lib/active_model/attribute_methods.rb
@@ -260,30 +260,30 @@ module ActiveModel
       #     end
       #   end
       def define_attribute_methods(attr_names)
-        return if attribute_methods_generated?
-        attr_names.each do |attr_name|
-          attribute_method_matchers.each do |matcher|
-            unless instance_method_already_implemented?(matcher.method_name(attr_name))
-              generate_method = "define_method_#{matcher.prefix}attribute#{matcher.suffix}"
+        attr_names.each { |attr_name| define_attribute_method(attr_name) }
+      end
+
+      def define_attribute_method(attr_name)
+        attribute_method_matchers.each do |matcher|
+          unless instance_method_already_implemented?(matcher.method_name(attr_name))
+            generate_method = "define_method_#{matcher.prefix}attribute#{matcher.suffix}"
 
-              if respond_to?(generate_method)
-                send(generate_method, attr_name)
-              else
-                method_name = matcher.method_name(attr_name)
+            if respond_to?(generate_method)
+              send(generate_method, attr_name)
+            else
+              method_name = matcher.method_name(attr_name)
 
-                generated_attribute_methods.module_eval <<-STR, __FILE__, __LINE__ + 1
-                  if method_defined?('#{method_name}')
-                    undef :'#{method_name}'
-                  end
-                  define_method('#{method_name}') do |*args|
-                    send('#{matcher.method_missing_target}', '#{attr_name}', *args)
-                  end
-                STR
-              end
+              generated_attribute_methods.module_eval <<-STR, __FILE__, __LINE__ + 1
+                if method_defined?('#{method_name}')
+                  undef :'#{method_name}'
+                end
+                define_method('#{method_name}') do |*args|
+                  send('#{matcher.method_missing_target}', '#{attr_name}', *args)
+                end
+              STR
             end
           end
         end
-        @attribute_methods_generated = true
       end
 
       # Removes all the previously dynamically defined methods from the class
@@ -291,7 +291,6 @@ module ActiveModel
         generated_attribute_methods.module_eval do
           instance_methods.each { |m| undef_method(m) }
         end
-        @attribute_methods_generated = nil
       end
 
       # Returns true if the attribute methods defined have been generated.
@@ -303,11 +302,6 @@ module ActiveModel
         end
       end
 
-      # Returns true if the attribute methods defined have been generated.
-      def attribute_methods_generated?
-        @attribute_methods_generated ||= nil
-      end
-
       protected
         def instance_method_already_implemented?(method_name)
           method_defined?(method_name)
diff --git a/activemodel/test/cases/attribute_methods_test.rb b/activemodel/test/cases/attribute_methods_test.rb
index 422aa25668..b001adb35a 100644
--- a/activemodel/test/cases/attribute_methods_test.rb
+++ b/activemodel/test/cases/attribute_methods_test.rb
@@ -42,10 +42,16 @@ class AttributeMethodsTest < ActiveModel::TestCase
                      ModelWithAttributes2.send(:attribute_method_matchers)
   end
 
+  test '#define_attribute_method generates attribute method' do
+    ModelWithAttributes.define_attribute_method(:foo)
+
+    assert_respond_to ModelWithAttributes.new, :foo
+    assert_equal "value of foo", ModelWithAttributes.new.foo
+  end
+
   test '#define_attribute_methods generates attribute methods' do
     ModelWithAttributes.define_attribute_methods([:foo])
 
-    assert ModelWithAttributes.attribute_methods_generated?
     assert_respond_to ModelWithAttributes.new, :foo
     assert_equal "value of foo", ModelWithAttributes.new.foo
   end
@@ -53,7 +59,6 @@ class AttributeMethodsTest < ActiveModel::TestCase
   test '#define_attribute_methods generates attribute methods with spaces in their names' do
     ModelWithAttributesWithSpaces.define_attribute_methods([:'foo bar'])
   
-    assert ModelWithAttributesWithSpaces.attribute_methods_generated?
     assert_respond_to ModelWithAttributesWithSpaces.new, :'foo bar'
     assert_equal "value of foo bar", ModelWithAttributesWithSpaces.new.send(:'foo bar')
   end
@@ -69,7 +74,6 @@ class AttributeMethodsTest < ActiveModel::TestCase
     ModelWithAttributes.define_attribute_methods([:foo])
     ModelWithAttributes.undefine_attribute_methods
 
-    assert !ModelWithAttributes.attribute_methods_generated?
     assert !ModelWithAttributes.new.respond_to?(:foo)
     assert_raises(NoMethodError) { ModelWithAttributes.new.foo }
   end
diff --git a/activerecord/lib/active_record/attribute_methods.rb b/activerecord/lib/active_record/attribute_methods.rb
index 284ae2bebc..5833c65893 100644
--- a/activerecord/lib/active_record/attribute_methods.rb
+++ b/activerecord/lib/active_record/attribute_methods.rb
@@ -10,7 +10,18 @@ module ActiveRecord
       # Generates all the attribute related methods for columns in the database
       # accessors, mutators and query methods.
       def define_attribute_methods
+        return if attribute_methods_generated?
         super(column_names)
+        @attribute_methods_generated = true
+      end
+
+      def attribute_methods_generated?
+        @attribute_methods_generated ||= false
+      end
+
+      def undefine_attribute_methods(*args)
+        super
+        @attribute_methods_generated = false
       end
 
       # Checks whether the method is defined in the model or any of its subclasses