# HG changeset patch
# User Toshi MARUYAMA
# Parent 79ff96a8ae8096ab626d6944cecc4909c9391616
qnew

diff --git a/lib/redmine/helpers/gantt.rb b/lib/redmine/helpers/gantt.rb
--- a/lib/redmine/helpers/gantt.rb
+++ b/lib/redmine/helpers/gantt.rb
@@ -220,6 +220,7 @@ module Redmine
           return if abort?
         end
         versions = project_versions(project)
+        sort_versions!(versions)
         versions.each do |version|
           render_version(project, version, options)
         end
@@ -675,18 +676,26 @@ module Redmine
         start_date + (end_date - start_date + 1) * (progress / 100.0)
       end
 
-      # Sorts a collection of issues by start_date, due_date, id for gantt rendering
+      # Sorts a collection of issues by start_date for gantt rendering
       def sort_issues!(issues)
         issues.sort! { |a, b| gantt_issue_compare(a, b) }
       end
 
-      # TODO: top level issues should be sorted by start date
       def gantt_issue_compare(x, y)
-        if x.root_id == y.root_id
-          x.lft <=> y.lft
-        else
-          x.root_id <=> y.root_id
-        end
+        sort_dates_x = [(x.root.start_date or x.start_date or Date.new()), x.root_id, (x.start_date or Date.new()), x.lft]
+        sort_dates_y = [(y.root.start_date or y.start_date or Date.new()), y.root_id, (y.start_date or Date.new()), y.lft]
+        sort_dates_x <=> sort_dates_y
+      end
+
+      # Sorts a collection of versions by due_date for gantt rendering
+      def sort_versions!(versions)
+        versions.sort! { |a, b| gantt_version_compare(a, b) }
+      end
+
+      def gantt_version_compare(x, y)
+        sort_dates_x = [(x.due_date or Date.new()), x.id]
+        sort_dates_y = [(y.due_date or Date.new()), y.id]
+        sort_dates_x <=> sort_dates_y
       end
 
       def current_limit