Merge pull request #5 from mavenlink/fix_ancestry_depth_for_multi_level_stories

Update root_ancestor_id of descendants when parent is made a root

Author: Shirish Pampoorickal

lib/arboreal/instance_methods.rb

@@ -115,7 +115,7 @@ def apply_ancestry_change_to_descendants
 
     def descendant_attributes_to_update(old_path_string)
       if root_relation_enabled?
-        ["root_ancestor_id = ?, materialized_path = REPLACE(materialized_path, ?, ?)", root_ancestor_id, old_path_string, path_string]
+        ["root_ancestor_id = ?, materialized_path = REPLACE(materialized_path, ?, ?)", root_ancestor_id || id, old_path_string, path_string]
       else
         ["materialized_path = REPLACE(materialized_path, ?, ?)", old_path_string, path_string]
       end

spec/hierarchy_spec.rb

@@ -240,6 +240,7 @@
 
   describe "when a node becomes a root" do
     before do
+      Node.create!(:name => "Southbank", :parent => @melbourne)
       @victoria.update_attribute(:parent_id, nil)
     end
 
@@ -254,6 +255,10 @@
     it "persists changes to the ancestors" do
       @victoria.reload.ancestors.should be_empty
     end
+
+    it 'updates the root of its descendants' do
+      @victoria.descendants.map(&:root_ancestor).uniq.should == [@victoria]
+    end
   end
 
   describe "node created using find_or_create_by" do