From fd2d379d03ed926c995324fd6fefb89f2f19be9d Mon Sep 17 00:00:00 2001
From: Kirill Shnurov <k@zx0.ru>
Date: Fri, 10 Aug 2018 16:58:12 +0300
Subject: [PATCH] Scoped: generate new slug if scope changed

---
 lib/friendly_id/scoped.rb |  4 ++++
 test/scoped_test.rb       | 13 +++++++++++++
 2 files changed, 17 insertions(+)

diff --git a/lib/friendly_id/scoped.rb b/lib/friendly_id/scoped.rb
index 22ea05a2a..d974db5c4 100644
--- a/lib/friendly_id/scoped.rb
+++ b/lib/friendly_id/scoped.rb
@@ -139,6 +139,10 @@ def slug_generator
     end
     private :slug_generator
 
+    def should_generate_new_friendly_id?
+      (changed & friendly_id_config.scope_columns).any? || super
+    end
+
     # This module adds the `:scope` configuration option to
     # {FriendlyId::Configuration FriendlyId::Configuration}.
     module Configuration
diff --git a/test/scoped_test.rb b/test/scoped_test.rb
index 182b5ed53..8415e9682 100644
--- a/test/scoped_test.rb
+++ b/test/scoped_test.rb
@@ -81,4 +81,17 @@ def model_class
     end
   end
 
+  test "should generate new slug when scope changes" do
+    transaction do
+      novelist = Novelist.create! :name => "a"
+      publisher = Publisher.create! :name => "b"
+      novel1 = Novel.create! :name => "c", :novelist => novelist, :publisher => publisher
+      novel2 = Novel.create! :name => "c", :novelist => novelist, :publisher => Publisher.create(:name => "d")
+      assert_equal novel1.friendly_id, novel2.friendly_id
+      novel2.publisher = publisher
+      novel2.save!
+      assert novel2.friendly_id != novel1.friendly_id
+    end
+  end
+
 end