Merge branch 'master' into nested_has_many_through

Conflicts:
	activerecord/CHANGELOG
	activerecord/lib/active_record/association_preload.rb
	activerecord/lib/active_record/associations.rb
	activerecord/lib/active_record/associations/class_methods/join_dependency.rb
	activerecord/lib/active_record/associations/class_methods/join_dependency/join_association.rb
	activerecord/lib/active_record/associations/has_many_association.rb
	activerecord/lib/active_record/associations/has_many_through_association.rb
	activerecord/lib/active_record/associations/has_one_association.rb
	activerecord/lib/active_record/associations/has_one_through_association.rb
	activerecord/lib/active_record/associations/through_association_scope.rb
	activerecord/lib/active_record/reflection.rb
	activerecord/test/cases/associations/has_many_through_associations_test.rb
	activerecord/test/cases/associations/has_one_through_associations_test.rb
	activerecord/test/cases/reflection_test.rb
	activerecord/test/cases/relations_test.rb
	activerecord/test/fixtures/memberships.yml
	activerecord/test/models/categorization.rb
	activerecord/test/models/category.rb
	activerecord/test/models/member.rb
	activerecord/test/models/reference.rb
	activerecord/test/models/tagging.rb

1 files changed, 24 insertions, 10 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