Fixed obscure reload bug where single collection inherited classes th…

…at didn't have associations defined in subclasses bombed when reloading.

lib/mongo_mapper/document.rb

@@ -427,7 +427,7 @@ def destroy
 
       def reload
         doc = self.class.find(_id)
-        self.class.associations.each { |name, assoc| send(name).reset }
+        self.class.associations.each { |name, assoc| send(name).reset if respond_to?(name) }
         self.attributes = doc.attributes
         self
       end

test/functional/test_document.rb

@@ -962,6 +962,8 @@ class ::DocParent
       class ::DocDaughter < ::DocParent; end
       class ::DocSon < ::DocParent; end
       class ::DocGrandSon < ::DocSon; end
+
+      DocSon.many :children, :class_name => 'DocGrandSon'
 
       @parent = DocParent.new({:name => "Daddy Warbucks"})
       @daughter = DocDaughter.new({:name => "Little Orphan Annie"})
@@ -1100,6 +1102,13 @@ class ::DocGrandSon < ::DocSon; end
         DocParent.delete_all
       }.should change { DocParent.count }.by(-2)
     end
+
+    should "be able to reload parent inherited class" do
+      brian = DocParent.create(:name => 'Brian')
+      brian.name = 'B-Dawg'
+      brian.reload
+      brian.name.should == 'Brian'
+    end
   end
 
   context "timestamping" do