Issue list improvements for subtasking (#5196):

* makes the parent task column available
* display the issue hierarchy when list is sorted by parent

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@3618 e93f8b46-1217-0410-a6f0-8f06a7374b81

app/models/query.rb

@@ -27,10 +27,11 @@ class QueryColumn
       self.groupable = name.to_s
     end
     self.default_order = options[:default_order]
+    @caption_key = options[:caption] || "field_#{name}"
   end
   
   def caption
-    l("field_#{name}")
+    l(@caption_key)
   end
   
   # Returns true if the column is sortable, otherwise false
@@ -120,6 +121,7 @@ class Query < ActiveRecord::Base
   @@available_columns = [
     QueryColumn.new(:project, :sortable => "#{Project.table_name}.name", :groupable => true),
     QueryColumn.new(:tracker, :sortable => "#{Tracker.table_name}.position", :groupable => true),
+    QueryColumn.new(:parent, :sortable => ["#{Issue.table_name}.root_id", "#{Issue.table_name}.lft ASC"], :default_order => 'desc', :caption => :field_parent_issue),
     QueryColumn.new(:status, :sortable => "#{IssueStatus.table_name}.position", :groupable => true),
     QueryColumn.new(:priority, :sortable => "#{IssuePriority.table_name}.position", :default_order => 'desc', :groupable => true),
     QueryColumn.new(:subject, :sortable => "#{Issue.table_name}.subject"),