Optimize Issue#recalculate_attributes_for to avoid unnecessary saves and cascading callbacks (#43607).

Patch by Go MAEDA (user:maeda).


git-svn-id: https://svn.redmine.org/redmine/trunk@24223 e93f8b46-1217-0410-a6f0-8f06a7374b81

app/models/issue.rb

@@ -1904,7 +1904,7 @@ class Issue < ApplicationRecord
       end
 
       # ancestors will be recursively updated
-      p.save(:validate => false)
+      p.save(:validate => false) if p.has_changes_to_save?
     end
   end