method transplanting between modules isn't supported on 1.9

activerecord/lib/active_record/attribute_methods/read.rb

+require 'active_support/core_ext/module/method_transplanting'
+
 module ActiveRecord
   module AttributeMethods
     module Read
@@ -62,9 +64,30 @@ def cache_attribute?(attr_name)
 
         protected
 
-        def define_method_attribute(name)
-          method = ReaderMethodCache[name]
-          generated_attribute_methods.module_eval { define_method name, method }
+        if Module.methods_transplantable?
+          def define_method_attribute(name)
+            method = ReaderMethodCache[name]
+            generated_attribute_methods.module_eval { define_method name, method }
+          end
+        else
+          def define_method_attribute(name)
+            safe_name = name.unpack('h*').first
+            temp_method = "__temp__#{safe_name}"
+
+            ActiveRecord::AttributeMethods::AttrNames.set_name_cache safe_name, name
+
+            generated_attribute_methods.module_eval <<-STR, __FILE__, __LINE__ + 1
+              def #{temp_method}
+                name = ::ActiveRecord::AttributeMethods::AttrNames::ATTR_#{safe_name}
+                read_attribute(name) { |n| missing_attribute(n, caller) }
+              end
+            STR
+
+            generated_attribute_methods.module_eval do
+              alias_method name, temp_method
+              undef_method temp_method
+            end
+          end
         end
 
         private

activerecord/lib/active_record/attribute_methods/write.rb

+require 'active_support/core_ext/module/method_transplanting'
+
 module ActiveRecord
   module AttributeMethods
     module Write
@@ -23,13 +25,29 @@ def #{method_name}(value)
       module ClassMethods
         protected
 
-        # See define_method_attribute in read.rb for an explanation of
-        # this code.
-        def define_method_attribute=(name)
-          method = WriterMethodCache[name]
-          generated_attribute_methods.module_eval {
-            define_method "#{name}=", method
-          }
+        if Module.methods_transplantable?
+          # See define_method_attribute in read.rb for an explanation of
+          # this code.
+          def define_method_attribute=(name)
+            method = WriterMethodCache[name]
+            generated_attribute_methods.module_eval {
+              define_method "#{name}=", method
+            }
+          end
+        else
+          def define_method_attribute=(name)
+            safe_name = name.unpack('h*').first
+            ActiveRecord::AttributeMethods::AttrNames.set_name_cache safe_name, name
+
+            generated_attribute_methods.module_eval <<-STR, __FILE__, __LINE__ + 1
+              def __temp__#{safe_name}=(value)
+                name = ::ActiveRecord::AttributeMethods::AttrNames::ATTR_#{safe_name}
+                write_attribute(name, value)
+              end
+              alias_method #{(name + '=').inspect}, :__temp__#{safe_name}=
+              undef_method :__temp__#{safe_name}=
+            STR
+          end
         end
       end
 

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

+class Module
+  ###
+  # TODO: remove this after 1.9 support is dropped
+  def methods_transplantable? # :nodoc:
+    x = Module.new { def foo; end }
+    Module.new { define_method :bar, x.instance_method(:foo) }
+    true
+  rescue TypeError
+    false
+  end
+end