(bug) unable apply a coupon if this coupon has used by an user removed

CHANGELOG.md

@@ -1,5 +1,7 @@
 # Changelog Fab-manager
 
+- Fix a bug: unable apply a coupon if this coupon has used by an user removed
+
 ## v5.4.24 2022 October 14
 
 - Fix a bug: unable debit hours of prepaid pack after a reservation of machine

app/models/coupon.rb

@@ -82,7 +82,8 @@ class Coupon < ApplicationRecord
   end
 
   def users
-    invoices.map(&:user)
+    # compact to user removed
+    invoices.map(&:user).compact
   end
 
   def users_ids
@@ -104,5 +105,4 @@ class Coupon < ApplicationRecord
   def delete_gateway_coupon
     PaymentGatewayService.new.delete_coupon(id)
   end
-
 end