When displaying changes, use '-' if id of associated object is blank

app/helpers/application_helper.rb

@@ -397,6 +397,7 @@ module ApplicationHelper
   # Returns object in its current state if its alive
   # Otherwise Returns object state just before deletion
   def current_or_last_object_state(model_name, id)
+    return nil unless id.present? && model_name.present?
     begin
       object = model_name.constantize.find_by(id: id)
     rescue NameError

app/views/shared/_object_changes.html.haml

@@ -23,11 +23,11 @@
                 %td
                   - associated_object = current_or_last_object_state(model_name, values[0])
                   = associated_object.try(:title) || associated_object.try(:name)
-                  = "(ID: #{values[0].blank? ?  '-' : values[0]})"
+                  = values[0].blank? ? '-' : "(ID: #{values[0]})"
               %td
                 - associated_object = current_or_last_object_state(model_name, values[1])
                 = associated_object.try(:title) || associated_object.try(:name)
-                = "(ID: #{values[1].blank? ?  '-' : values[1]})"
+                = (values[1].blank? ? '-' : "(ID: #{values[1]})")
 
             - else
               - if version.event != 'create'
@@ -46,6 +46,6 @@
               %td
                 - associated_object = current_or_last_object_state(model_name, value)
                 = associated_object.try(:title) || associated_object.try(:name)
-                = "(ID: #{value.blank? ?  '-' : value})"
+                = value.blank? ? '-' : "(ID: #{value})"
             - else
               %td= value.blank? ?  '-' : value