Allow to read and write AR attributes with non valid identifiers

activerecord/lib/active_record/attribute_methods/read.rb

@@ -70,7 +70,10 @@ def define_read_method(symbol, attr_name, column)
             if cache_attribute?(attr_name)
               access_code = "@attributes_cache['#{attr_name}'] ||= (#{access_code})"
             end
-            generated_attribute_methods.module_eval("def _#{symbol}; #{access_code}; end; alias #{symbol} _#{symbol}", __FILE__, __LINE__)
+            generated_attribute_methods.module_eval do
+              define_method("_#{symbol}") { eval(access_code) }
+              alias_method(symbol, "_#{symbol}")
+            end
           end
       end
 

activerecord/lib/active_record/attribute_methods/write.rb

@@ -10,7 +10,9 @@ module Write
       module ClassMethods
         protected
           def define_method_attribute=(attr_name)
-            generated_attribute_methods.module_eval("def #{attr_name}=(new_value); write_attribute('#{attr_name}', new_value); end", __FILE__, __LINE__)
+            generated_attribute_methods.send(:define_method, "#{attr_name}=") do |new_value|
+              write_attribute(attr_name, new_value)
+            end
           end
       end
 

activerecord/test/cases/base_test.rb

@@ -45,6 +45,8 @@ class ReadonlyTitlePost < Post
   attr_readonly :title
 end
 
+class Weird < ActiveRecord::Base; end
+
 class Boolean < ActiveRecord::Base; end
 
 class BasicsTest < ActiveRecord::TestCase
@@ -477,6 +479,16 @@ def test_readonly_attributes
     assert_equal "changed", post.body
   end
 
+  def test_non_valid_identifier_column_name
+    weird = Weird.create('a$b' => 'value')
+    weird.reload
+    assert_equal 'value', weird.send('a$b')
+
+    weird.update_attribute('a$b', 'value2')
+    weird.reload
+    assert_equal 'value2', weird.send('a$b')
+  end
+
   def test_multiparameter_attributes_on_date
     attributes = { "last_read(1i)" => "2004", "last_read(2i)" => "6", "last_read(3i)" => "24" }
     topic = Topic.find(1)

activerecord/test/schema/schema.rb

@@ -690,6 +690,9 @@ def create_table(*args, &block)
     t.integer :molecule_id
     t.string :name
   end
+  create_table :weirds, :force => true do |t|
+    t.string 'a$b'
+  end
 
   except 'SQLite' do
     # fk_test_has_fk should be before fk_test_has_pk