Enable frozen string literals.

Make all string literals immutable by default.

app/helpers/application_helper.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ApplicationHelper
   def listing_type(*fields, member_check: true, types: [:revert, :standard])
     (fields.reduce(false) { |acc, field| acc || params.dig(:search, field).present? } && (!member_check || CurrentUser.is_member?) ? types[0] : types[1])

app/helpers/artist_commentaries_helper.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ArtistCommentariesHelper
   def format_commentary_title(title, classes: "")
     tag.h3 do

app/helpers/artist_commentary_versions_helper.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ArtistCommentaryVersionsHelper
   def commentary_version_field_diff(commentary_version, type, field)
     other = commentary_version.send(params[:type])

app/helpers/artist_versions_helper.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ArtistVersionsHelper
   def artist_version_other_names_diff(artist_version, type)
     other = artist_version.send(type)

app/helpers/components_helper.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ComponentsHelper
   def post_preview(post, fit: :fixed, **options)
     render PostPreviewComponent.new(post: post, fit: fit, **options)

app/helpers/delayed_jobs_helper.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DelayedJobsHelper
   def print_name(job)
     case job.name

app/helpers/forum_topics_helper.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ForumTopicsHelper
   def forum_topic_category_select(object, field)
     select(object, field, ForumTopic.reverse_category_mapping.to_a)

app/helpers/icon_helper.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module IconHelper
   def icon_tag(icon_class, class: nil, **options)
     klass = binding.local_variable_get(:class)

app/helpers/ip_addresses_helper.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module IpAddressesHelper
   # https://www.bing.com/maps/embed-a-map
   # https://docs.microsoft.com/en-us/bingmaps/articles/create-a-custom-map-url

app/helpers/note_versions_helper.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module NoteVersionsHelper
   def note_version_position_diff(note_version, type)
     other = note_version.send(type)

app/helpers/pool_versions_helper.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module PoolVersionsHelper
   def pool_version_show_diff(pool_version, type)
     other = pool_version.send(type)

app/helpers/popular_posts_helper.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module PopularPostsHelper
   def next_date_for_scale(date, scale)
     case scale

app/helpers/post_versions_helper.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module PostVersionsHelper
   def post_version_diff(post_version, type)
     return "" if type == "previous" && post_version.version == 1
@@ -22,7 +24,7 @@ module PostVersionsHelper
       obsolete_added_tags = added_tags - other_tags
       obsolete_removed_tags = removed_tags & other_tags
     end
-    html = '<span class="diff-list">'
+    html = '<span class="diff-list">'.dup
 
     added_tags.each do |tag|
       obsolete_class = (obsolete_added_tags.include?(tag) ? "diff-obsolete" : "")

app/helpers/posts_helper.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module PostsHelper
   def reportbooru_enabled?
     Danbooru.config.reportbooru_server.present? && Danbooru.config.reportbooru_key.present?

app/helpers/seo_helper.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # https://yoast.com/structured-data-schema-ultimate-guide/
 # https://technicalseo.com/tools/schema-markup-generator/
 # https://developers.google.com/search/docs/data-types/sitelinks-searchbox

app/helpers/tags_helper.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module TagsHelper
   def tag_class(tag)
     return nil if tag.blank?

app/helpers/uploads_helper.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module UploadsHelper
   def render_status(upload)
     case upload.status

app/helpers/user_upgrades_helper.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module UserUpgradesHelper
   def cents_to_usd(cents)
     number_to_currency(cents / 100, precision: 0)

app/helpers/users_helper.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module UsersHelper
   def unread_dmail_indicator(user)
     "(#{user.unread_dmail_count})" if user.unread_dmail_count > 0

app/helpers/wiki_page_versions_helper.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module WikiPageVersionsHelper
   def wiki_version_show_diff(wiki_page_version, type)
     other = wiki_page_version.send(type)

app/helpers/wiki_pages_helper.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module WikiPagesHelper
   def wiki_page_other_names_list(wiki_page)
     names_html = wiki_page.other_names.map do |name|