#3178: using a transaction and two save to create an impediment with the appropriate "blocks"-relationship

app/models/impediment.rb

@@ -15,9 +15,13 @@ class Impediment < Task
     task.safe_attributes = params
     task.remaining_hours = 0 if IssueStatus.find(params[:status_id]).is_closed?
 
-    task.blocks_ids = params[:blocks]
-
-    if task.save
+    #an issue relation can not be established between new nodes because their relationship can not be
+    #evaluated and issue relations between parent and descendant are prohibited. Therefore we need to
+    #save two times in a transaction
+    task.transaction do
+      task.save
+      task.blocks_ids = params[:blocks]
+      task.save
       task.move_after params[:prev]
     end