gantt: sort versions by start date (#7335)

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@11898 e93f8b46-1217-0410-a6f0-8f06a7374b81

lib/redmine/helpers/gantt.rb

@@ -220,6 +220,7 @@ module Redmine
           return if abort?
         end
         versions = project_versions(project)
+        self.class.sort_versions!(versions)
         versions.each do |version|
           render_version(project, version, options)
         end
@@ -690,6 +691,14 @@ module Redmine
         ancesters_start_date
       end
 
+      def self.sort_versions!(versions)
+        versions.sort! {|a, b| sort_version_logic(a) <=> sort_version_logic(b)}
+      end
+
+      def self.sort_version_logic(version)
+        [(version.start_date || Date.new()), version.id]
+      end
+
       def current_limit
         if @max_rows
           @max_rows - @number_of_rows