Merge pull request #8656 from alphagov/ensure-a-documents-slug-is-not…

…-set-to-nil-for-special-characters

Ensure document retains slug when edition title has special chars

app/models/document.rb

@@ -86,6 +86,11 @@ def update_slug_if_possible(new_title)
     candidate_slug = normalize_friendly_id(new_title)
     unless candidate_slug == slug
       update!(sluggable_string: new_title)
+      # when special characters or scipts are used from the non-latin alphabets
+      # friendly_id sets the documents slug to nil. This ensures that it
+      # retains the default behaviour id of the document as the slug rather than being nil
+      # as implemented in the #ensure_document_has_a_slug after_create callback
+      ensure_document_has_a_slug
     end
   end
 

db/data_migration/20231219193828_backfill_documents_with_blank_slugs.rb

@@ -0,0 +1,3 @@
+Document.where(slug: nil).each do |document|
+  document.update_column(:slug, document.id.to_s)
+end

test/unit/app/models/document_test.rb

@@ -350,4 +350,28 @@ class DocumentTest < ActiveSupport::TestCase
     assert_nil unpublished.document.live_edition
     assert_nil draft.document.live_edition
   end
+
+  test "#update_slug_if_possible updates the slug to the title passed maps to a diffrent slug" do
+    document = build(:document)
+    new_slug = "new_slug"
+    document.expects(:update!).with(sluggable_string: new_slug).once
+
+    document.update_slug_if_possible(new_slug)
+  end
+
+  test "#update_slug_if_possible does nothing to the slug if the title passed in maps to the current slug" do
+    document = build_stubbed(:document)
+    document.expects(:update!).never
+
+    document.update_slug_if_possible(document.slug)
+  end
+
+  test "#update_slug_if_possible ensures that the slug is set to the documents id if the new title contains special characters" do
+    document = create(:document, slug: nil)
+    slug_with_special_characters = "首次中英高级别安全"
+
+    document.update_slug_if_possible(slug_with_special_characters)
+
+    assert_equal document.id.to_s, document.reload.slug
+  end
 end