Merge remote branch 'rails/master' into identity_map

Conflicts:
	activerecord/examples/performance.rb
	activerecord/lib/active_record/association_preload.rb
	activerecord/lib/active_record/associations.rb
	activerecord/lib/active_record/associations/association_proxy.rb
	activerecord/lib/active_record/autosave_association.rb
	activerecord/lib/active_record/base.rb
	activerecord/lib/active_record/nested_attributes.rb
	activerecord/test/cases/relations_test.rb

3 files changed, 37 insertions, 26 deletions

diff --git a/activerecord/lib/active_record/attribute_methods/primary_key.rb b/activerecord/lib/active_record/attribute_methods/primary_key.rb
index 75ae06f5e9..fcdd31ddea 100644
--- a/activerecord/lib/active_record/attribute_methods/primary_key.rb
+++ b/activerecord/lib/active_record/attribute_methods/primary_key.rb
@@ -14,26 +14,37 @@ module ActiveRecord
         # Defines the primary key field -- can be overridden in subclasses. Overwriting will negate any effect of the
         # primary_key_prefix_type setting, though.
         def primary_key
-          reset_primary_key
+          @primary_key ||= reset_primary_key
         end
 
         def reset_primary_key #:nodoc:
-          key = get_primary_key(base_class.name)
+          key = self == base_class ? get_primary_key(base_class.name) :
+            base_class.primary_key
+
           set_primary_key(key)
           key
         end
 
         def get_primary_key(base_name) #:nodoc:
-          key = 'id'
+          return 'id' unless base_name && !base_name.blank?
+
           case primary_key_prefix_type
-            when :table_name
-              key = base_name.to_s.foreign_key(false)
-            when :table_name_with_underscore
-              key = base_name.to_s.foreign_key
+          when :table_name
+            base_name.foreign_key(false)
+          when :table_name_with_underscore
+            base_name.foreign_key
+          else
+            if ActiveRecord::Base != self && connection.table_exists?(table_name)
+              connection.primary_key(table_name)
+            else
+              'id'
+            end
           end
-          key
         end
 
+        attr_accessor :original_primary_key
+        attr_writer :primary_key
+
         # Sets the name of the primary key column to use to the given value,
         # or (if the value is nil or false) to the value returned by the given
         # block.
@@ -42,9 +53,12 @@ module ActiveRecord
         #     set_primary_key "sysid"
         #   end
         def set_primary_key(value = nil, &block)
-          define_attr_method :primary_key, value, &block
+          @primary_key ||= ''
+          self.original_primary_key = @primary_key
+          value &&= value.to_s
+          connection_pool.primary_keys[table_name] = value
+          self.primary_key = block_given? ? instance_eval(&block) : value
         end
-        alias :primary_key= :set_primary_key
       end
     end
   end
diff --git a/activerecord/lib/active_record/attribute_methods/read.rb b/activerecord/lib/active_record/attribute_methods/read.rb
index 506f6e878f..ab86d8bad1 100644
--- a/activerecord/lib/active_record/attribute_methods/read.rb
+++ b/activerecord/lib/active_record/attribute_methods/read.rb
@@ -20,7 +20,7 @@ module ActiveRecord
         # be cached. Usually caching only pays off for attributes with expensive conversion
         # methods, like time related columns (e.g. +created_at+, +updated_at+).
         def cache_attributes(*attribute_names)
-          attribute_names.each {|attr| cached_attributes << attr.to_s}
+          cached_attributes.merge attribute_names.map { |attr| attr.to_s }
         end
 
         # Returns the attributes which are cached. By default time related columns
@@ -39,7 +39,7 @@ module ActiveRecord
             if serialized_attributes.include?(attr_name)
               define_read_method_for_serialized_attribute(attr_name)
             else
-              define_read_method(attr_name.to_sym, attr_name, columns_hash[attr_name])
+              define_read_method(attr_name, attr_name, columns_hash[attr_name])
             end
 
             if attr_name == primary_key && attr_name != "id"
@@ -54,17 +54,17 @@ module ActiveRecord
 
           # Define read method for serialized attribute.
           def define_read_method_for_serialized_attribute(attr_name)
-            access_code = "@attributes_cache['#{attr_name}'] ||= unserialize_attribute('#{attr_name}')"
-            generated_attribute_methods.module_eval("def #{attr_name}; #{access_code}; end", __FILE__, __LINE__)
+            access_code = "@attributes_cache['#{attr_name}'] ||= @attributes['#{attr_name}']"
+            generated_attribute_methods.module_eval("def _#{attr_name}; #{access_code}; end; alias #{attr_name} _#{attr_name}", __FILE__, __LINE__)
           end
 
           # Define an attribute reader method.  Cope with nil column.
           def define_read_method(symbol, attr_name, column)
-            cast_code = column.type_cast_code('v') if column
-            access_code = cast_code ? "(v=@attributes['#{attr_name}']) && #{cast_code}" : "@attributes['#{attr_name}']"
+            cast_code = column.type_cast_code('v')
+            access_code = "(v=@attributes['#{attr_name}']) && #{cast_code}"
 
             unless attr_name.to_s == self.primary_key.to_s
-              access_code = access_code.insert(0, "missing_attribute('#{attr_name}', caller) unless @attributes.has_key?('#{attr_name}'); ")
+              access_code.insert(0, "missing_attribute('#{attr_name}', caller) unless @attributes.has_key?('#{attr_name}'); ")
             end
 
             if cache_attribute?(attr_name)
@@ -106,14 +106,10 @@ module ActiveRecord
 
       # Returns the unserialized object of the attribute.
       def unserialize_attribute(attr_name)
-        unserialized_object = object_from_yaml(@attributes[attr_name])
+        coder = self.class.serialized_attributes[attr_name]
+        unserialized_object = coder.load(@attributes[attr_name])
 
-        if unserialized_object.is_a?(self.class.serialized_attributes[attr_name]) || unserialized_object.nil?
-          @attributes.frozen? ? unserialized_object : @attributes[attr_name] = unserialized_object
-        else
-          raise SerializationTypeMismatch,
-            "#{attr_name} was supposed to be a #{self.class.serialized_attributes[attr_name]}, but was a #{unserialized_object.class.to_s}"
-        end
+        @attributes.frozen? ? unserialized_object : @attributes[attr_name] = unserialized_object
       end
 
       private
diff --git a/activerecord/lib/active_record/attribute_methods/time_zone_conversion.rb b/activerecord/lib/active_record/attribute_methods/time_zone_conversion.rb
index dc2785b6bf..76218d2a73 100644
--- a/activerecord/lib/active_record/attribute_methods/time_zone_conversion.rb
+++ b/activerecord/lib/active_record/attribute_methods/time_zone_conversion.rb
@@ -40,12 +40,13 @@ module ActiveRecord
           def define_method_attribute=(attr_name)
             if create_time_zone_conversion_attribute?(attr_name, columns_hash[attr_name])
               method_body, line = <<-EOV, __LINE__ + 1
-                def #{attr_name}=(time)
+                def #{attr_name}=(original_time)
+                  time = original_time.dup unless original_time.nil?
                   unless time.acts_like?(:time)
                     time = time.is_a?(String) ? Time.zone.parse(time) : time.to_time rescue time
                   end
                   time = time.in_time_zone rescue nil if time
-                  write_attribute(:#{attr_name}, time)
+                  write_attribute(:#{attr_name}, (time || original_time))
                 end
               EOV
               generated_attribute_methods.module_eval(method_body, __FILE__, line)