#419

backend/app/controllers/application_controller.rb

@@ -92,6 +92,4 @@ class ApplicationController < ActionController::API
 
     value
   end
-
-  def resolve_locale! = Locale.find_by(code: params[:locale]) || Locale.nipponese
 end

backend/app/controllers/deerjikists_controller.rb

@@ -1,7 +1,5 @@
 class DeerjikistsController < ApplicationController
   def show
-    locale = resolve_locale!
-
     platform = params[:platform].to_s.strip
     code = params[:code].to_s.strip
     return render_bad_request('platform は必須です．') if platform.blank?
@@ -9,10 +7,10 @@ class DeerjikistsController < ApplicationController
 
     deerjikist = Deerjikist
                  .joins(:tag)
-                 .includes(tag: :tag_names)
+                 .includes(tag: :tag_name)
                  .find_by(platform:, code:)
     if deerjikist
-      render json: DeerjikistRepr.base(deerjikist, language_code: locale.language_code)
+      render json: DeerjikistRepr.base(deerjikist)
     else
       head :not_found
     end
@@ -22,7 +20,6 @@ class DeerjikistsController < ApplicationController
     return head :unauthorized unless current_user
     return head :forbidden unless current_user.gte_member?
 
-    locale = resolve_locale!
     platform = params[:platform].to_s.strip
     code = params[:code].to_s.strip
     tag_id = params[:tag_id].to_i
@@ -35,7 +32,7 @@ class DeerjikistsController < ApplicationController
       d.save!
     end
 
-    render json: DeerjikistRepr.base(deerjikist, language_code: locale.language_code)
+    render json: DeerjikistRepr.base(deerjikist)
   end
 
   def destroy

backend/app/controllers/gekanator_posts_controller.rb

@@ -2,7 +2,7 @@ class GekanatorPostsController < ApplicationController
   def index
     posts =
         Post
-        .preload(:post_similarities, tags: :tag_names)
+        .preload(:post_similarities, tags: :tag_name)
         .with_attached_thumbnail
         .order(Arel.sql(
             'COALESCE(posts.original_created_before - INTERVAL 1 MINUTE, ' \
@@ -56,7 +56,7 @@ class GekanatorPostsController < ApplicationController
   def tag_json tag
     {
       id: tag.id,
-      name: tag.name('ja'),
+      name: tag.name,
       category: tag.category
     }
   end

backend/app/controllers/gekanator_questions_controller.rb

@@ -126,9 +126,9 @@ class GekanatorQuestionsController < ApplicationController
     end
 
     Tag
-        .joins(:tag_names)
+        .joins(:tag_name)
         .where(category: categories.uniq)
-        .where(tag_names: { language_code: 'ja', primary_flg: true, name: names.uniq })
+        .where(tag_names: { name: names.uniq })
         .where.not(deprecated_at: nil)
         .pluck('tags.category', 'tag_names.name')
         .each_with_object({ }) do |(category, name), h|

backend/app/controllers/materials_controller.rb

@@ -7,8 +7,6 @@ class MaterialsController < ApplicationController
   rescue_from MaterialZipExporter::MissingFileError, with: :render_zip_missing_file
 
   def index
-    locale = resolve_locale!
-
     page = (params[:page].presence || 1).to_i
     limit = (params[:limit].presence || 20).to_i
 
@@ -22,7 +20,7 @@ class MaterialsController < ApplicationController
     q = Material.includes(:material_export_items,
                           thumbnail_attachment: :blob,
                           file_attachment: :blob,
-                          tag: :tag_names)
+                          tag: :tag_name)
     q = q.where(tag_id: nil) if filters[:tag_state] == 'untagged'
     q = q.where.not(tag_id: nil) if filters[:tag_state] == 'tagged'
     q = apply_material_tag_filter(q, filters, tag_graph)
@@ -44,10 +42,7 @@ class MaterialsController < ApplicationController
         .offset(offset)
         .to_a
 
-    response = { materials: MaterialRepr.list_many(
-                   materials,
-                   host: request.base_url,
-                   language_code: locale.language_code),
+    response = { materials: MaterialRepr.list_many(materials, host: request.base_url),
                  count: }
     if filters[:tag_id]
       response[:tag_scope] = material_index_tag_scope(filters, tag_graph)
@@ -60,8 +55,6 @@ class MaterialsController < ApplicationController
   end
 
   def show
-    locale = resolve_locale!
-
     material =
         Material
         .includes(:tag, :material_export_items)
@@ -70,17 +63,15 @@ class MaterialsController < ApplicationController
         .find_by(id: params[:id])
     return head :not_found unless material
 
-    wiki_page_body = material.tag&.tag_name('ja')&.wiki_page&.current_revision&.body
+    wiki_page_body = material.tag&.tag_name&.wiki_page&.current_revision&.body
 
-    render json: MaterialRepr.base(material, host: request.base_url,
-                                   language_code: locale.language_code).merge(wiki_page_body:)
+    render json: MaterialRepr.base(material, host: request.base_url).merge(wiki_page_body:)
   end
 
   def create
     return head :unauthorized unless current_user
     return head :forbidden unless current_user.gte_member?
 
-    locale = resolve_locale!
     tag_name_raw = params[:tag].to_s.strip
     file = params[:file]
     file_sha256 = MaterialFileSha256.from_upload(file)
@@ -98,14 +89,13 @@ class MaterialsController < ApplicationController
 
     begin
       Material.transaction do
-        tag = resolve_material_tag!(locale, tag_name_raw)
+        tag = resolve_material_tag!(tag_name_raw)
         material = Material.new(tag:, url:,
                                 created_by_user: current_user,
                                 updated_by_user: current_user)
         material.file.attach(uploaded_blob) if uploaded_blob
         material.save!
-        TagVersioning.record_tag_snapshot!(tag, created_by_user: current_user,
-                                           language_code: locale.language_code)
+        TagVersioning.record_tag_snapshot!(tag, created_by_user: current_user)
         upsert_export_paths!(material)
         MaterialVersionRecorder.record!(material:, event_type: :create,
                                         created_by_user: current_user)
@@ -117,8 +107,7 @@ class MaterialsController < ApplicationController
 
     if material
       log_thumbnail_generation(material, MaterialThumbnailGenerator.generate!(material))
-      render json: MaterialRepr.base(material, host: request.base_url,
-                                     language_code: locale.language_code), status: :created
+      render json: MaterialRepr.base(material, host: request.base_url), status: :created
     else
       render_validation_error material
     end
@@ -143,14 +132,12 @@ class MaterialsController < ApplicationController
     block = MaterialImportBlockMatcher.match_for_sha256(file_sha256)
     return render_material_import_block(block) if block
 
-    locale = resolve_locale!
-
     uploaded_blob = build_uploaded_material_blob!(file, file_sha256)
 
     begin
       Material.transaction do
         MaterialVersionRecorder.ensure_snapshot!(material, created_by_user: current_user)
-        tag = resolve_material_tag!(locale, tag_name_raw)
+        tag = resolve_material_tag!(tag_name_raw)
         material.assign_attributes(tag:, url:, updated_by_user: current_user)
         if uploaded_blob
           material.file.attach(uploaded_blob)
@@ -158,8 +145,7 @@ class MaterialsController < ApplicationController
           material.file.detach
         end
         material.save!
-        TagVersioning.record_tag_snapshot!(tag, created_by_user: current_user,
-                                           language_code: locale.language_code)
+        TagVersioning.record_tag_snapshot!(tag, created_by_user: current_user)
         upsert_export_paths!(material)
         MaterialVersionRecorder.record!(material:, event_type: :update,
                                         created_by_user: current_user)
@@ -171,8 +157,7 @@ class MaterialsController < ApplicationController
 
     log_thumbnail_generation(material, MaterialThumbnailGenerator.generate!(material))
 
-    render json: MaterialRepr.base(material, host: request.base_url,
-                                   language_code: locale.language_code)
+    render json: MaterialRepr.base(material, host: request.base_url)
   end
 
   def destroy
@@ -251,8 +236,10 @@ class MaterialsController < ApplicationController
     nil
   end
 
-  def resolve_material_tag! locale, tag_name_raw
-    Tag.find_or_create_by_tag_name!(locale, tag_name_raw, category: :material)
+  def resolve_material_tag! tag_name_raw
+    tag_name = TagName.find_or_create_by!(name: tag_name_raw)
+    tag = tag_name.tag
+    tag || Tag.create!(tag_name:, category: :material)
   end
 
   def material_index_needs_tag_name? filters
@@ -266,12 +253,7 @@ class MaterialsController < ApplicationController
   end
 
   def material_index_join_tag_name q
-    q.left_joins(:tag).joins(<<~SQL.squish)
-      LEFT JOIN tag_names
-        ON tag_names.tag_id = tags.id
-       AND tag_names.language_code = 'ja'
-       AND tag_names.primary_flg = TRUE
-    SQL
+    q.left_joins(tag: :tag_name)
   end
 
   def material_index_join_file_blob q
@@ -287,11 +269,9 @@ class MaterialsController < ApplicationController
 
   def apply_material_query q, term
     like = "%#{ ActiveRecord::Base.sanitize_sql_like(term) }%"
-    q.where(<<~SQL.squish, q: like)
-      tag_names.name LIKE :q
-      OR materials.url LIKE :q
-      OR material_file_blobs.filename LIKE :q
-    SQL
+    q.where('tag_names.name LIKE :q OR materials.url LIKE :q OR ' \
+            'material_file_blobs.filename LIKE :q',
+            q: like)
   end
 
   def apply_material_media_kind q, media_kind
@@ -343,9 +323,8 @@ class MaterialsController < ApplicationController
         end
     tags_by_id =
         Tag
-        .joins(:tag_names)
-        .where(id: scope_tag_ids,
-               tag_names: { language_code: 'ja', primary_flg: true })
+        .joins(:tag_name)
+        .where(id: scope_tag_ids)
         .pluck('tags.id', 'tag_names.name', 'tags.category', 'tags.deprecated_at')
         .each_with_object({ }) do |(id, name, category, deprecated_at), hash|
           hash[id] = { id:, name:, category:, deprecated: deprecated_at.present? }

backend/app/controllers/nico_tags_controller.rb

@@ -1,7 +1,5 @@
 class NicoTagsController < ApplicationController
   def index
-    locale = resolve_locale!
-
     name = params[:name].presence
     linked_tag = params[:linked_tag].presence
     link_status = params[:link_status].presence
@@ -26,7 +24,7 @@ class NicoTagsController < ApplicationController
         ExternalTag
         .joins("LEFT JOIN (#{ post_tag_max_sql }) post_tag_max " \
                'ON post_tag_max.external_tag_id = external_tags.id')
-        .includes(linked_tags: { tag_names: :wiki_page })
+        .includes(linked_tags: { tag_name: :wiki_page })
     if name
       q = q.where(('external_tags.name LIKE ? ' +
                    "OR CONCAT(external_tags.platform, ':', external_tags.name) LIKE ?"),
@@ -36,8 +34,7 @@ class NicoTagsController < ApplicationController
     if linked_tag
       linked_tag_ids =
           Tag
-          .joins(:tag_names)
-          .where(tag_names: { language_code: 'ja', primary_flg: true })
+          .joins(:tag_name)
           .where('tag_names.name LIKE ?', "%#{ linked_tag }%")
           .pluck(:id)
       linked_nico_tag_ids = NicoTagRelation.where(tag_id: linked_tag_ids).pluck(:nico_tag_id)
@@ -70,9 +67,7 @@ class NicoTagsController < ApplicationController
     render json: { tags: tags.map { |tag|
       external_tag_json(tag).merge(
           recent_post_tag_created_at: tag.recent_post_tag_created_at,
-          linked_tags: tag.linked_tags.map { |lt|
-            TagRepr.base(lt, language_code: locale.language_code)
-          })
+          linked_tags: tag.linked_tags.map { |lt| TagRepr.base(lt) })
     }, count: }
   end
 
@@ -86,8 +81,6 @@ class NicoTagsController < ApplicationController
     return head :unauthorized unless current_user
     return head :forbidden unless current_user.gte_member?
 
-    locale = resolve_locale!
-
     id = params[:id].to_i
 
     tag = ExternalTag.find(id)
@@ -96,14 +89,10 @@ class NicoTagsController < ApplicationController
     linked_tags = nil
 
     ApplicationRecord.transaction do
-      linked_tags = Tag.normalise_tags!(locale, linked_tag_names,
-                                        with_tagme: false,
+      linked_tags = Tag.normalise_tags!(linked_tag_names, with_tagme: false,
                                                           with_no_deerjikist: false)
 
-      TagVersioning.record_tag_snapshots!(
-          linked_tags,
-          created_by_user: current_user,
-          language_code: locale.language_code)
+      TagVersioning.record_tag_snapshots!(linked_tags, created_by_user: current_user)
 
       tag.linked_tags = linked_tags
       tag.save!
@@ -113,9 +102,7 @@ class NicoTagsController < ApplicationController
                                      created_by_user: current_user)
     end
 
-    render json: tag.linked_tags.map { |t|
-      TagRepr.base(t, language_code: locale.language_code)
-    }, status: :ok
+    render json: tag.linked_tags.map { |t| TagRepr.base(t) }, status: :ok
   rescue Tag::NicoTagNormalisationError
     render_validation_error fields: { tags: ['ニコニコ・タグ同士は連携できません．'] }
   rescue ActiveRecord::RecordInvalid => e

backend/app/controllers/posts_controller.rb

@@ -7,8 +7,6 @@ class PostsController < ApplicationController
   end
 
   def index
-    locale = resolve_locale!
-
     url = params[:url].presence
     title = params[:title].presence
     original_created_from = params[:original_created_from].presence
@@ -48,12 +46,12 @@ class PostsController < ApplicationController
         'COALESCE(pt_max.max_updated_at, posts.updated_at))'
 
     q =
-        filtered_posts(locale)
+        filtered_posts
         .joins("LEFT JOIN (#{ pt_max_sql }) pt_max ON pt_max.post_id = posts.id")
         .reselect('posts.*', Arel.sql("#{ updated_at_all_sql } AS updated_at_all"))
         .preload(:external_tags, :uploaded_user, :parents, :children,
                  post_tags: [:sections, { tag: [:deerjikists, :materials,
-                                                { tag_names: :wiki_page }] }])
+                                                { tag_name: :wiki_page }] }])
         .with_attached_thumbnail
 
     q = q.where('posts.url LIKE ?', "%#{ url }%") if url
@@ -92,8 +90,7 @@ class PostsController < ApplicationController
     q = q.except(:select, :order)
 
     render json: { posts: posts.map { |post|
-      PostRepr.base(post, language_code: locale.language_code)
-              .merge(updated_at: post.updated_at_all).tap do |json|
+      PostRepr.base(post).merge(updated_at: post.updated_at_all).tap do |json|
         json['thumbnail'] =
             if post.thumbnail.attached?
               rails_storage_proxy_url(post.thumbnail, only_path: false)
@@ -105,19 +102,17 @@ class PostsController < ApplicationController
   end
 
   def random
-    locale = resolve_locale!
-
     post =
-        filtered_posts(locale)
+        filtered_posts
         .preload(:uploaded_user, :parents, :children,
                  post_tags: [:sections, { tag: [:deerjikists, :materials,
-                                                { tag_names: :wiki_page }] }])
+                                                { tag_name: :wiki_page }] }])
         .with_attached_thumbnail
         .order('RAND()')
         .first
     return head :not_found unless post
 
-    render json: PostRepr.base(post, current_user, language_code: locale.language_code)
+    render json: PostRepr.base(post, current_user)
   end
 
   def metadata
@@ -192,13 +187,11 @@ class PostsController < ApplicationController
   end
 
   def show
-    locale = resolve_locale!
-
     post =
         Post
         .includes(:uploaded_user, :parents, :children,
                   post_tags: [:sections, { tag: [:deerjikists, :materials,
-                                                 { tag_names: :wiki_page }] }])
+                                                 { tag_name: :wiki_page }] }])
         .with_attached_thumbnail
         .find_by(id: params[:id])
     return head :not_found unless post
@@ -212,21 +205,18 @@ class PostsController < ApplicationController
                                  parent_posts:,
                                  child_posts:,
                                  sibling_posts:,
-                                 related:,
-                                 language_code: locale.language_code)
-                         .merge(tags: build_tag_tree_for(post, locale.language_code))
+                                 related:)
+                         .merge(tags: build_tag_tree_for(post))
   end
 
   def create
     return head :unauthorized unless current_user
     return head :forbidden unless current_user.gte_member?
 
-    locale = resolve_locale!
-
     preflight = PostCreatePreflight.new(
         attributes: post_create_attributes,
         thumbnail: params[:thumbnail],
-        host: request.base_url).run(locale)
+        host: request.base_url).run
     return render json: dry_run_json(preflight) if bool?(:dry)
     if preflight[:existing_post_id].present?
       post = Post.new(url: preflight[:url])
@@ -252,10 +242,10 @@ class PostsController < ApplicationController
                                    :post_tag_specs,
                                    :tag_sections,
                                    :normalised_parent_post_ids).symbolize_keys).merge(
-                               thumbnail: params[:thumbnail])).create!(locale)
+                               thumbnail: params[:thumbnail])).create!
 
     post.reload
-    render json: PostRepr.base(post, language_code: locale.language_code), status: :created
+    render json: PostRepr.base(post), status: :created
   rescue PostCreatePreflight::ValidationFailed => e
     render_validation_error fields: e.fields, base: e.base_errors
   rescue Tag::NicoTagNormalisationError
@@ -281,18 +271,13 @@ class PostsController < ApplicationController
     return head :forbidden unless current_user.gte_member?
     return head :unsupported_media_type unless request.content_mime_type == Mime[:multipart_form]
     return head :payload_too_large if request.content_length.to_i > MAX_BULK_REQUEST_BYTES
-
-    locale = resolve_locale!
-
     posts = parse_bulk_posts_manifest
     thumbnails = parse_bulk_thumbnails(posts.length)
-
     result = PostBulkCreator.new(
         actor: current_user,
         posts:,
         thumbnails:,
-        host: request.base_url).run(locale)
-
+        host: request.base_url).run
     render json: result
   rescue JSON::ParserError
     render_bad_request 'posts manifest の JSON が不正です．'
@@ -325,7 +310,6 @@ class PostsController < ApplicationController
     base_version_no = parse_base_version_no
     return render_bad_request('base_version_no は必須です．') if !(force) && !(base_version_no)
 
-    locale = Locale.find_by(code: params[:locale].presence) || Locale.nipponese
     title = params[:title].presence
     tag_names = params[:tags].to_s.split
     original_created_from = params[:original_created_from]
@@ -345,10 +329,9 @@ class PostsController < ApplicationController
         base_version = post.post_versions.find_by!(version_no: base_version_no)
 
         base_snapshot = post_snapshot_from_version(base_version)
-        current_snapshot = post_snapshot_from_record(post, locale)
+        current_snapshot = post_snapshot_from_record(post)
       end
-      incoming_snapshot = post_incoming_snapshot(locale:,
-                                                 title:,
+      incoming_snapshot = post_incoming_snapshot(title:,
                                                  original_created_from:,
                                                  original_created_before:,
                                                  tag_names:,
@@ -377,14 +360,14 @@ class PostsController < ApplicationController
             end
           end
 
-      apply_post_snapshot!(locale, post, snapshot_to_apply)
+      apply_post_snapshot!(post, snapshot_to_apply)
     end
 
     return render json: conflict_json, status: :conflict if conflict_json
 
     post.reload
-    json = PostRepr.base(post, current_user, language_code: locale.language_code)
-    json['tags'] = build_tag_tree_for(post, locale.language_code)
+    json = PostRepr.base(post, current_user)
+    json['tags'] = build_tag_tree_for(post)
     render json:, status: :ok
   rescue Tag::NicoTagNormalisationError
     render_validation_error fields: { tags: ['ニコニコ・タグは直接指定できません．'] }
@@ -402,19 +385,19 @@ class PostsController < ApplicationController
 
   private
 
-  def filtered_posts locale
+  def filtered_posts
     tag_names = params[:tags].to_s.split
     match_type = params[:match]
     if tag_names.present?
-      filter_posts_by_tags(locale, tag_names, match_type)
+      filter_posts_by_tags(tag_names, match_type)
     else
       Post.all
     end
   end
 
-  def filter_posts_by_tags locale, tag_names, match_type
+  def filter_posts_by_tags tag_names, match_type
     literals = tag_names.map do |raw_name|
-      { name: TagName.canonicalise(locale, raw_name.sub(/\Anot:/i, '')).first,
+      { name: TagName.canonicalise(raw_name.sub(/\Anot:/i, '')).first,
         negative: raw_name.downcase.start_with?('not:') }
     end
 
@@ -422,11 +405,11 @@ class PostsController < ApplicationController
 
     if match_type == 'any'
       literals.reduce(Post.none) do |posts, literal|
-        posts.or(tag_literal_relation(locale, literal[:name], negative: literal[:negative]))
+        posts.or(tag_literal_relation(literal[:name], negative: literal[:negative]))
       end
     else
       literals.reduce(Post.all) do |posts, literal|
-        ids = tagged_post_ids_for(locale, literal[:name])
+        ids = tagged_post_ids_for(literal[:name])
         if literal[:negative]
           posts.where.not(id: ids)
         else
@@ -436,8 +419,8 @@ class PostsController < ApplicationController
     end
   end
 
-  def tag_literal_relation locale, name, negative:
-    ids = tagged_post_ids_for(locale, name)
+  def tag_literal_relation name, negative:
+    ids = tagged_post_ids_for(name)
     if negative
       Post.where.not(id: ids)
     else
@@ -445,11 +428,11 @@ class PostsController < ApplicationController
     end
   end
 
-  def tagged_post_ids_for locale, name
+  def tagged_post_ids_for(name)
     posts_by_internal_tags =
         Post
-        .joins(tags: :tag_names)
-        .where(tag_names: { language_code: locale.language_code, name: })
+        .joins(tags: :tag_name)
+        .where(tag_names: { name: })
         .select(:id)
 
     posts_by_external_tags =
@@ -491,7 +474,7 @@ class PostsController < ApplicationController
     end
   end
 
-  def build_tag_tree_for post, language_code = 'ja'
+  def build_tag_tree_for post
     post_tags = post.post_tags.reject { |post_tag| post_tag.tag.deprecated? }
     tags = post_tags.map(&:tag)
     tag_ids = tags.map(&:id)
@@ -521,7 +504,7 @@ class PostsController < ApplicationController
       sections = sections_by_tag_id.fetch(tag_id, [])
 
       if path.include?(tag_id)
-        return TagRepr.inline(tag, language_code:).merge(children: [], sections:)
+        return TagRepr.inline(tag).merge(children: [], sections:)
       end
 
       if memo.key?(tag_id)
@@ -533,7 +516,7 @@ class PostsController < ApplicationController
 
       children = child_ids.filter_map { |cid| build_node.(cid, new_path) }
 
-      memo[tag_id] = TagRepr.inline(tag, language_code:).merge(children:, sections:)
+      memo[tag_id] = TagRepr.inline(tag).merge(children:, sections:)
     end
 
     internal_tags = root_ids.filter_map { |id| build_node.call(id, []) }
@@ -689,45 +672,39 @@ class PostsController < ApplicationController
     version.tags_json
         .select { _1.key?('tag_id') }
         .map { Post.tag_snapshot_literal(_1) }
-        .compact
         .sort
   end
 
-  def post_snapshot_from_record post, locale
+  def post_snapshot_from_record post
     { title: post.title,
       video_ms: post.video_ms,
       original_created_from: snapshot_time(post.original_created_from),
       original_created_before: snapshot_time(post.original_created_before),
-      tag_names: editable_tag_names_from_post(post, locale.language_code),
+      tag_names: editable_tag_names_from_post(post),
       parent_post_ids: post.parent_posts.order(:id).pluck(:id) }
   end
 
-  def editable_tag_names_from_post post, language_code
+  def editable_tag_names_from_post post
     post
         .post_tags
-        .joins(tag: :tag_names)
+        .joins(tag: :tag_name)
         .merge(Tag.where(deprecated_at: nil))
-        .where(tag_names: { language_code:, primary_flg: true })
-        .includes(:sections, tag: :tag_names)
+        .includes(:sections, tag: :tag_name)
         .order('tag_names.name')
         .map do |post_tag|
-      name = post_tag.tag.name(language_code)
+      name = post_tag.tag.tag_name.name
       sections = post_tag.sections.sort_by(&:begin_ms)
 
       next name if sections.empty?
 
       "#{ name }#{ sections.map { Post.section_literal(_1) }.join }"
-    end.compact.sort
+    end
   end
 
-  def post_incoming_snapshot locale:, title:, original_created_from:, original_created_before:,
+  def post_incoming_snapshot title:, original_created_from:, original_created_before:,
                              tag_names:, video_ms_param:, duration_param:, parent_post_ids:
     validate_original_created_values!(original_created_from, original_created_before)
-
-    Tag.normalise_tags!(locale, tag_names,
-                        with_tagme: false,
-                        with_no_deerjikist: false,
-                        deny_deprecated: true,
+    Tag.normalise_tags!(tag_names, with_tagme: false, deny_deprecated: true,
                                    with_sections: true) => { tags:, sections: }
 
     tags = Tag.expand_parent_tags(tags).reject(&:deprecated?)
@@ -739,7 +716,7 @@ class PostsController < ApplicationController
       original_created_from: snapshot_time(original_created_from),
       original_created_before: snapshot_time(original_created_before),
       tag_names: tags.uniq(&:id).map { |tag|
-        "#{ tag.name(locale.language_code) }#{ sections[tag.id].to_a.map { section_literal(_1) }.join }"
+        "#{ tag.name }#{ sections[tag.id].to_a.map { section_literal(_1) }.join }"
       }.sort,
       parent_post_ids: parent_post_ids.sort }
   end
@@ -863,7 +840,7 @@ class PostsController < ApplicationController
     (added_by_current & removed_by_me).present? || (removed_by_current & added_by_me).present?
   end
 
-  def apply_post_snapshot! locale, post, snapshot
+  def apply_post_snapshot! post, snapshot
     PostVersionRecorder.ensure_snapshot!(post, created_by_user: current_user)
 
     post.update!(title: snapshot[:title],
@@ -871,12 +848,11 @@ class PostsController < ApplicationController
                  original_created_from: snapshot[:original_created_from],
                  original_created_before: snapshot[:original_created_before])
 
-    Tag.normalise_tags!(locale, snapshot[:tag_names],
+    Tag.normalise_tags!(snapshot[:tag_names],
                         with_tagme: false,
                         deny_deprecated: true,
                         with_sections: true) => { tags:, sections: }
-    TagVersioning.record_tag_snapshots!(tags, created_by_user: current_user,
-                                        language_code: locale.language_code)
+    TagVersioning.record_tag_snapshots!(tags, created_by_user: current_user)
 
     tags = Tag.expand_parent_tags(tags).reject(&:deprecated?)
 

backend/app/controllers/tag_versions_controller.rb

@@ -1,6 +1,5 @@
 class TagVersionsController < ApplicationController
   def index
-    locale = resolve_locale!
     tag_id = params[:id].presence
     page = (params[:page].presence || 1).to_i
     limit = (params[:limit].presence || 20).to_i
@@ -19,8 +18,7 @@ class TagVersionsController < ApplicationController
         SQL
       .select('tag_versions.*', 'prev.name AS prev_name', 'prev.category AS prev_category',
               'prev.deprecated_at AS prev_deprecated_at',
-              'prev.aliases AS prev_aliases', 'prev.names AS prev_names',
-              'prev.parent_tag_ids AS prev_parent_tag_ids')
+              'prev.aliases AS prev_aliases', 'prev.parent_tag_ids AS prev_parent_tag_ids')
     q = q.where('tag_versions.tag_id = ?', tag_id) if tag_id
 
     count = q.except(:select, :order, :limit, :offset).count
@@ -29,20 +27,18 @@ class TagVersionsController < ApplicationController
                 .limit(limit)
                 .offset(offset)
 
-    render json: { versions: serialise_versions(versions, locale.language_code), count: }
+    render json: { versions: serialise_versions(versions), count: }
   end
 
   private
 
-  def serialise_versions rows, language_code
+  def serialise_versions rows
     user_ids = rows.map(&:created_by_user_id).compact.uniq
     users_by_id = User.where(id: user_ids).pluck(:id, :name).to_h
 
     rows.map do |row|
-      current_names = names_for_locale(row.names, language_code)
-      previous_names = names_for_locale(row.attributes['prev_names'], language_code)
-      cur_aliases = current_names.reject { _1['primary_flg'] }.map { _1['name'] }
-      prev_aliases = previous_names.reject { _1['primary_flg'] }.map { _1['name'] }
+      cur_aliases = split_values(row.aliases)
+      prev_aliases = split_values(row.attributes['prev_aliases'])
 
       cur_parent_tag_ids = split_parent_tag_ids(row.parent_tag_ids)
       prev_parent_tag_ids = split_parent_tag_ids(row.attributes['prev_parent_tag_ids'])
@@ -51,23 +47,21 @@ class TagVersionsController < ApplicationController
 
       tags_by_id =
           Tag
-          .includes(:tag_names, :materials, tag_names: :wiki_page)
+          .includes(:tag_name, :materials, { tag_name: :wiki_page })
           .where(id: all_parent_tag_ids)
           .index_by(&:id)
 
       parent_tags =
           build_version_values(cur_parent_tag_ids, prev_parent_tag_ids, key: :tag_id)
           .map do |h|
-            { tag: TagRepr.base(tags_by_id[h[:tag_id]], language_code:),
+            { tag: TagRepr.base(tags_by_id[h[:tag_id]]),
               type: h[:type] }
           end
 
       { tag_id: row.tag_id,
         version_no: row.version_no,
         event_type: row.event_type,
-        names: row.names,
-        name: { current: current_names.find { _1['primary_flg'] }&.fetch('name'),
-                prev: previous_names.find { _1['primary_flg'] }&.fetch('name') },
+        name: { current: row.name, prev: row.attributes['prev_name'] },
         category: { current: row.category, prev: row.attributes['prev_category'] },
         deprecated_at: { current: row.deprecated_at&.iso8601,
                          prev: row.attributes['prev_deprecated_at']&.iso8601 },
@@ -97,12 +91,5 @@ class TagVersionsController < ApplicationController
 
   def split_values(values) = values.to_s.split(/\s+/).reject(&:blank?)
 
-  def names_for_locale names, language_code
-    values = names.is_a?(String) ? JSON.parse(names) : Array(names)
-    values.select { _1['language_code'] == language_code }
-  rescue JSON::ParserError
-    []
-  end
-
   def split_parent_tag_ids(values) = split_values(values).map(&:to_i)
 end

backend/app/controllers/tags_controller.rb

@@ -5,8 +5,6 @@ require 'set'
 
 class TagsController < ApplicationController
   def index
-    locale = resolve_locale!
-
     post_id = params[:post]
 
     name = params[:name].presence
@@ -38,14 +36,9 @@ class TagsController < ApplicationController
 
     tags =
         if post_id.present?
-          Tag
-              .joins(:posts, :tag_names)
-              .where(tag_names: { language_code: locale.language_code, primary_flg: true },
-                     posts: { id: post_id })
+          Tag.joins(:posts, :tag_name).where(posts: { id: post_id })
         else
-          Tag
-              .joins(:tag_names)
-              .where(tag_names: { language_code: locale.language_code, primary_flg: true })
+          Tag.joins(:tag_name)
         end
 
     external_tags =
@@ -174,10 +167,9 @@ class TagsController < ApplicationController
 
     tags_by_id =
         Tag
-        .joins(:tag_names)
-        .includes(:tag_names, :materials, tag_names: :wiki_page)
-        .where(tag_names: { language_code: locale.language_code, primary_flg: true },
-               id: tag_ids)
+        .joins(:tag_name)
+        .includes(:tag_name, :materials, tag_name: :wiki_page)
+        .where(id: tag_ids)
         .index_by(&:id)
     external_tags_by_id =
         ExternalTag
@@ -186,7 +178,7 @@ class TagsController < ApplicationController
 
     render json: { tags: rows.map { |row|
       if row['source'] == 'tag'
-        TagRepr.base(tags_by_id.fetch(row['id']), language_code: locale.language_code)
+        TagRepr.base(tags_by_id.fetch(row['id']))
       else
         external_tag_json(external_tags_by_id.fetch(row['id']))
       end
@@ -198,8 +190,7 @@ class TagsController < ApplicationController
     parent_tag_id = nil if parent_tag_id <= 0
     material_filter = material_filter_param(default: 'any')
 
-    locale = resolve_locale!
-    graph = build_with_depth_graph(material_filter, locale.language_code)
+    graph = build_with_depth_graph(material_filter)
 
     tag_ids =
         if parent_tag_id
@@ -214,8 +205,6 @@ class TagsController < ApplicationController
   end
 
   def autocomplete
-    locale = resolve_locale!
-
     q = params[:q].to_s.strip.sub(/\Anot:/i, '')
     prefix = "#{ ActiveRecord::Base.sanitize_sql_like(q) }%"
 
@@ -224,36 +213,35 @@ class TagsController < ApplicationController
 
     alias_rows =
         TagName
-        .where(language_code: locale.language_code, primary_flg: false)
         .where('name LIKE ?', prefix)
-        .pluck(:tag_id, :name)
+        .where.not(canonical_id: nil)
+        .pluck(:canonical_id, :name)
 
-    matched_alias_by_tag_id = { }
-    tag_ids = []
-    alias_rows.each do |tag_id, alias_name|
-      tag_ids << tag_id
-      matched_alias_by_tag_id[tag_id] ||= alias_name
+    matched_alias_by_tag_name_id = { }
+    canonical_ids = []
+
+    alias_rows.each do |canonical_id, alias_name|
+      canonical_ids << canonical_id
+      matched_alias_by_tag_name_id[canonical_id] ||= alias_name
     end
 
     base =
         Tag
-        .joins(:tag_names)
-        .includes(:tag_names, :materials, tag_names: :wiki_page)
-        .where(tag_names: { language_code: locale.language_code, primary_flg: true },
-               deprecated_at: nil)
+        .joins(:tag_name)
+        .includes(:tag_name, :materials, tag_name: :wiki_page)
+        .where(deprecated_at: nil)
     base = base.where('tags.post_count > 0') if present_only
 
     canonical_hit = base.where('tag_names.name LIKE ?', prefix)
 
-    internal_tags = canonical_hit.or(base.where(id: tag_ids.uniq))
+    internal_tags = canonical_hit.or(base.where(tag_name_id: canonical_ids.uniq))
 
     internal_rows =
         internal_tags
         .order(Arel.sql('tags.post_count DESC, tag_names.name'))
         .limit(20)
         .map { |tag|
-          TagRepr.base(tag, language_code: locale.language_code)
-                 .merge(matched_alias: matched_alias_by_tag_id[tag.id])
+          TagRepr.base(tag).merge(matched_alias: matched_alias_by_tag_name_id[tag.tag_name_id])
         }
 
     return render json: internal_rows unless with_nico
@@ -270,22 +258,19 @@ class TagsController < ApplicationController
 
     rows =
         (internal_rows + external_rows)
-        .sort_by { |row| [-row['post_count'], row['name'] || row[:name]] }
+        .sort_by { |row| [-row['post_count'], row['name']] }
         .first(20)
 
     render json: rows
   end
 
   def show
-    locale = resolve_locale!
-
     tag =
         Tag
-        .joins(:tag_names)
-        .includes(:tag_names, :materials, tag_names: :wiki_page)
-        .find_by(id: params[:id],
-                 tag_names: { language_code: locale.language_code, primary_flg: true })
-    return render json: TagRepr.base(tag, language_code: locale.language_code) if tag
+        .joins(:tag_name)
+        .includes(:tag_name, :materials, tag_name: :wiki_page)
+        .find_by(id: params[:id])
+    return render json: TagRepr.base(tag) if tag
 
     external_tag = ExternalTag.find_by(id: params[:id])
     return render json: ExternalTagRepr.base(external_tag) if external_tag
@@ -297,14 +282,12 @@ class TagsController < ApplicationController
     name = params[:name].to_s.strip
     return render_bad_request('name は必須です．') if name.blank?
 
-    locale = resolve_locale!
-
     tag =
         Tag
-        .joins(:tag_names)
-        .includes(:tag_names, :materials, tag_names: :wiki_page)
-        .find_by(tag_names: { name:, language_code: locale.language_code, primary_flg: true })
-    return render json: TagRepr.base(tag, language_code: locale.language_code) if tag
+        .joins(:tag_name)
+        .includes(:tag_name, :materials, tag_name: :wiki_page)
+        .find_by(tag_names: { name: })
+    return render json: TagRepr.base(tag) if tag
 
     platform, external_name = name.split(':', 2)
     return head :not_found unless external_name
@@ -316,52 +299,35 @@ class TagsController < ApplicationController
   end
 
   def deerjikists
-    locale = resolve_locale!
-
-    tag = 
-        Tag.joins(:tag_names)
-        .includes(:tag_names, tag_names: :wiki_page)
-        .find_by(id: params[:id],
-                 tag_names: { language_code: locale.language_code, primary_flg: true })
+    tag = Tag.joins(:tag_name)
+             .includes(:tag_name, tag_name: :wiki_page)
+             .find_by(id: params[:id])
     return head :not_found unless tag
 
-    render json: { tag: TagRepr.base(tag, language_code: locale.language_code),
-                   deerjikists: DeerjikistRepr.many(
-                       tag.deerjikists,
-                       language_code: locale.language_code) }
+    render json: { tag: TagRepr.base(tag),
+                   deerjikists: DeerjikistRepr.many(tag.deerjikists) }
   end
 
   def deerjikists_by_name
     name = params[:name].to_s.strip
     return render_bad_request('name は必須です．') if name.blank?
 
-    locale = resolve_locale!
-
-    tag =
-        Tag
-        .joins(:tag_names)
-        .includes(:tag_names, tag_names: :wiki_page)
-        .find_by(tag_names: { name:, language_code: locale.language_code, primary_flg: true })
+    tag = Tag.joins(:tag_name)
+             .includes(:tag_name, tag_name: :wiki_page)
+             .find_by(tag_names: { name: })
     return head :not_found unless tag
 
-    render json: { tag: TagRepr.base(tag, language_code: locale.language_code),
-                   deerjikists: DeerjikistRepr.many(
-                       tag.deerjikists,
-                       language_code: locale.language_code) }
+    render json: { tag: TagRepr.base(tag),
+                   deerjikists: DeerjikistRepr.many(tag.deerjikists) }
   end
 
   def update_deerjikists
     return head :unauthorized unless current_user
     return head :forbidden unless current_user.gte_member?
 
-    locale = resolve_locale!
-
-    tag =
-        Tag
-        .joins(:tag_names)
-        .includes(:tag_names, tag_names: :wiki_page)
-        .find_by(id: params[:id],
-                 tag_names: { language_code: locale.language_code, primary_flg: true })
+    tag = Tag.joins(:tag_name)
+             .includes(:tag_name, tag_name: :wiki_page)
+             .find_by(id: params[:id])
     return head :not_found unless tag
 
     rows = normalise_deerjikist_rows(tag)
@@ -380,7 +346,7 @@ class TagsController < ApplicationController
         row_indexes_by_key.key?([deerjikist.platform, deerjikist.code])
       }
 
-      render_deerjikist_conflicts(locale, requested_deerjikists, row_indexes_by_key, tag)
+      render_deerjikist_conflicts(requested_deerjikists, row_indexes_by_key, tag)
       raise ActiveRecord::Rollback if performed?
 
       requested_keys_set = requested_keys.to_set
@@ -401,7 +367,7 @@ class TagsController < ApplicationController
           render_deerjikist_form_record_invalid(deerjikist, row_index) unless deerjikist.save
         rescue ActiveRecord::RecordNotUnique
           conflicts = lock_deerjikists_for_tag_update(tag.id, [[platform, code]])
-          render_deerjikist_conflicts(locale, conflicts, row_indexes_by_key, tag)
+          render_deerjikist_conflicts(conflicts, row_indexes_by_key, tag)
         end
         raise ActiveRecord::Rollback if performed?
       end
@@ -409,28 +375,22 @@ class TagsController < ApplicationController
 
     return if performed?
 
-    render json: DeerjikistRepr.many(tag.reload.deerjikists,
-                                     language_code: locale.language_code)
+    render json: DeerjikistRepr.many(tag.reload.deerjikists)
   end
 
   def materials_by_name
     name = params[:name].to_s.strip
     return render_bad_request('name は必須です．') if name.blank?
-
-    locale = resolve_locale!
-
     material_filter = material_filter_param(default: 'any')
 
-    tag =
-        Tag
-        .joins(:tag_names)
-        .includes(:tag_names, :materials, tag_names: :wiki_page)
-        .find_by(tag_names: { name:, language_code: locale.language_code, primary_flg: true })
+    tag = Tag.joins(:tag_name)
+             .includes(:tag_name, :materials, tag_name: :wiki_page)
+             .find_by(tag_names: { name: })
     return head :not_found unless tag
 
-    graph = build_with_depth_graph(material_filter, locale.language_code)
+    graph = build_with_depth_graph(material_filter)
 
-    render json: build_tag_children(tag, graph:, language_code: locale.language_code)
+    render json: build_tag_children(tag, graph:)
   end
 
   def update_all
@@ -446,9 +406,7 @@ class TagsController < ApplicationController
     return render_unprocessable_entity('カテゴリは必須です．', field: :category) if category.blank?
     return render_unprocessable_entity '廃止状態は必須です．', field: :deprecated unless params.key?(:deprecated)
 
-    locale = resolve_locale!
-
-    return unless validate_tag_rename(locale, tag, name)
+    return unless validate_tag_rename(tag, name)
 
     alias_names = params[:aliases].to_s.split.uniq
     parent_names = params[:parent_tags].to_s.split.uniq
@@ -459,25 +417,24 @@ class TagsController < ApplicationController
     end
 
     ApplicationRecord.transaction do
-      TagVersioning.ensure_snapshot!(tag, created_by_user: current_user,
-                                     language_code: locale.language_code)
+      TagVersioning.ensure_snapshot!(tag, created_by_user: current_user)
 
-      old_name = tag.name(locale.language_code)
+      old_name = tag.name
       name_changed = name != old_name
-      wiki_page = tag.tag_name(locale.language_code)&.wiki_page if name_changed
+      wiki_page = tag.tag_name.wiki_page if name_changed
 
       if tag.deprecated? == deprecated
         tag.update!(category:)
       else
         tag.update!(category:, deprecated_at: deprecated ? Time.current : nil)
       end
-      rename_tag_name!(locale, tag, name) if name_changed
+      rename_tag_name!(tag, name) if name_changed
 
-      alias_names << old_name if name_changed && old_name.present?
+      alias_names << old_name if name_changed
       alias_names.delete(name)
 
-      update_aliases!(locale, tag, alias_names)
-      update_parent_tags!(locale, tag, parent_names)
+      update_aliases!(tag, alias_names)
+      update_parent_tags!(tag, parent_names)
 
       tag.reload
 
@@ -485,20 +442,17 @@ class TagsController < ApplicationController
           tag,
           event_type: :update,
           created_by_user: current_user,
-          language_code: locale.language_code,
           name_changed:,
           wiki_page:)
     end
 
-    render json: TagRepr.base(tag.reload, language_code: locale.language_code)
+    render json: TagRepr.base(tag.reload)
   end
 
   def update
     return head :unauthorized unless current_user
     return head :forbidden unless current_user.gte_member?
 
-    locale = resolve_locale!
-
     name = params[:name].presence
     category = params[:category].presence
     deprecated_given = params.key?(:deprecated)
@@ -506,21 +460,20 @@ class TagsController < ApplicationController
 
     tag = Tag.find(params[:id])
 
-    return unless validate_tag_rename(locale, tag, name)
+    return unless validate_tag_rename(tag, name)
 
     if category.present? && category == 'nico'
       return render_unprocessable_entity 'ニコタグは変更できません．', field: :category
     end
 
     ApplicationRecord.transaction do
-      TagVersioning.ensure_snapshot!(tag, created_by_user: current_user,
-                                     language_code: locale.language_code)
+      TagVersioning.ensure_snapshot!(tag, created_by_user: current_user)
 
-      old_name = tag.name(locale.language_code)
+      old_name = tag.name
       name_changed = name.present? && name != old_name
-      wiki_page = tag.tag_name(locale.language_code)&.wiki_page if name_changed
+      wiki_page = tag.tag_name.wiki_page if name_changed
 
-      rename_tag_name!(locale, tag, name) if name_changed
+      rename_tag_name!(tag, name) if name_changed
       tag.update!(category:) if category.present?
       if deprecated_given && tag.deprecated? != deprecated
         tag.update!(deprecated_at: deprecated ? Time.current : nil)
@@ -532,12 +485,11 @@ class TagsController < ApplicationController
           tag,
           event_type: :update,
           created_by_user: current_user,
-          language_code: locale.language_code,
           name_changed:,
           wiki_page:)
     end
 
-    render json: TagRepr.base(tag.reload, language_code: locale.language_code)
+    render json: TagRepr.base(tag.reload)
   end
 
   private
@@ -549,7 +501,7 @@ class TagsController < ApplicationController
     value
   end
 
-  def build_with_depth_graph material_filter, language_code
+  def build_with_depth_graph material_filter
     children_by_parent_id = Hash.new { |h, k| h[k] = [] }
     parent_ids_by_child_id = Hash.new { |h, k| h[k] = [] }
 
@@ -564,11 +516,8 @@ class TagsController < ApplicationController
 
     material_tag_ids = Material.unscoped.kept.where.not(tag_id: nil).distinct.pluck(:tag_id).to_set
 
-    tags_by_id =
-        Tag
-        .joins(:tag_names)
-        .where(id: tag_ids,
-               tag_names: { language_code:, primary_flg: true })
+    tags_by_id = Tag.joins(:tag_name)
+                    .where(id: tag_ids)
                     .pluck('tags.id', 'tag_names.name', 'tags.category', 'tags.deprecated_at')
                     .each_with_object({ }) do |(id, name, category, deprecated_at), h|
       h[id] = { name:, category:, deprecated: deprecated_at.present?,
@@ -702,33 +651,29 @@ class TagsController < ApplicationController
       children: [] }
   end
 
-  def build_tag_children tag, graph: nil, language_code: 'ja'
+  def build_tag_children tag, graph: nil
     material = tag.materials.first
     tag_graph = graph && graph[:tags_by_id][tag.id]
     material =
         nil if tag_graph && !with_depth_visible_tag?(tag_graph, graph[:material_filter])
 
-    children = tag.children.sort_by { _1.name(language_code) }
+    children = tag.children.sort_by(&:name)
     if graph
       children = children.filter { |child_tag| visible_subtree?(child_tag.id, graph) }
     end
 
-    TagRepr.base(tag, language_code:).merge(
-        children: children.map { build_tag_children(_1, graph:, language_code:) },
+    TagRepr.base(tag).merge(
+        children: children.map { build_tag_children(_1, graph:) },
         has_material: tag_graph ? tag_graph[:has_material] : material.present?,
-        material: material && MaterialRepr.base(
-            material,
-            host: request.base_url,
-            language_code:))
+        material: material && MaterialRepr.base(material, host: request.base_url))
   end
 
-  def record_tag_version! tag, event_type:, created_by_user:, language_code: 'ja',
-                          name_changed: false, wiki_page: nil
-    TagVersionRecorder.record!(tag:, event_type:, created_by_user:, language_code:)
+  def record_tag_version! tag, event_type:, created_by_user:, name_changed: false, wiki_page: nil
+    TagVersionRecorder.record!(tag:, event_type:, created_by_user:)
 
     return unless name_changed
 
-    wiki_page ||= tag.tag_name('ja')&.wiki_page
+    wiki_page ||= tag.tag_name.wiki_page
     return unless wiki_page&.wiki_versions&.exists?
 
     WikiVersionRecorder.record!(
@@ -737,43 +682,30 @@ class TagsController < ApplicationController
         created_by_user:)
   end
 
-  def validate_tag_rename locale, tag, name
-    return true if name.blank? || name == tag.name(locale.language_code)
+  def validate_tag_rename tag, name
+    return true if name.blank? || name == tag.name
 
-    system_tag_names = ['タグ希望', 'bot操作', 'ニジラー情報不詳', '動画', 'ニコニコ']
-    if TagName.exists?(tag_id: tag.id,
-                       language_code: 'ja',
-                       primary_flg: true,
-                       name: system_tag_names)
+    if tag.in?([Tag.tagme, Tag.bot, Tag.no_deerjikist, Tag.video, Tag.niconico])
       render_unprocessable_entity 'システム・タグの名称は変更できません．', field: :name
       return false
     end
 
-    target_tag_name = TagName.find_by(language_code: locale.language_code, name:)
-    return true unless target_tag_name&.primary_flg
+    target_tag_name = TagName.find_by(name:)
+    return true if target_tag_name.nil?
+    return true if target_tag_name.canonical_id?
 
     render_unprocessable_entity 'その名前は既に使はれてゐます．', field: :name
     false
   end
 
-  def rename_tag_name! locale, tag, name
-    return if name == tag.name(locale.language_code)
+  def rename_tag_name! tag, name
+    return if name == tag.name
 
-    current_tag_name = tag.tag_name(locale.language_code)
-    target_tag_name = TagName.find_by(language_code: locale.language_code, name:)
+    current_tag_name = tag.tag_name
+    target_tag_name = TagName.find_by(name:)
 
-    unless target_tag_name
-      if current_tag_name
+    if target_tag_name.nil?
       current_tag_name.update!(name:)
-      else
-        current_tag_name = TagName.create!(
-            tag:,
-            language_code: locale.language_code,
-            script_code: locale.script_code,
-            name:,
-            primary_flg: true)
-        tag.association(:tag_names).reset
-      end
       return
     end
 
@@ -781,89 +713,71 @@ class TagsController < ApplicationController
   end
 
   def promote_tag_alias! tag, current_tag_name:, promoted_tag_name:
-    old_owner_tag = promoted_tag_name.tag
+    old_owner_tag = promoted_tag_name.canonical&.tag
 
     if old_owner_tag && old_owner_tag != tag
       TagVersioning.ensure_snapshot!(old_owner_tag, created_by_user: current_user)
     end
 
-    current_tag_name.wiki_page&.update!(tag_name_id: promoted_tag_name.id)
-    current_tag_name.association(:wiki_page).reset
+    promoted_tag_name.update!(canonical: nil)
 
-    current_tag_name.update!(canonical_id: promoted_tag_name.id, primary_flg: false)
-    promoted_tag_name.update!(tag:, canonical_id: nil, primary_flg: true)
-
-    TagName.where(tag:,
-                  language_code: current_tag_name.language_code,
-                  primary_flg: false)
+    TagName.where(canonical_id: current_tag_name.id)
            .where.not(id: promoted_tag_name.id)
            .find_each do |alias_tag_name|
-      alias_tag_name.update!(canonical_id: promoted_tag_name.id, primary_flg: false)
+      alias_tag_name.update!(canonical: promoted_tag_name)
     end
 
-    tag.update!(tag_name_id: promoted_tag_name.id)
+    current_tag_name.wiki_page&.update!(tag_name: promoted_tag_name)
+    tag.update!(tag_name: promoted_tag_name)
     current_tag_name.association(:wiki_page).reset
     current_tag_name.association(:tag).reset
-    current_tag_name.reload.update!(canonical_id: promoted_tag_name.id, primary_flg: false)
+    current_tag_name.reload.update!(canonical: promoted_tag_name)
 
     return unless old_owner_tag && old_owner_tag != tag
 
-    record_tag_version!(old_owner_tag.reload, event_type: :update,
-                        created_by_user: current_user,
-                        language_code: current_tag_name.language_code)
+    record_tag_version!(old_owner_tag.reload, event_type: :update, created_by_user: current_user)
   end
 
-  def update_aliases! locale, tag, alias_names
+  def update_aliases! tag, alias_names
     alias_names = alias_names.uniq
 
     affected_tags = [tag]
 
-    primary_tag_name = TagName.find_by!(tag:,
-                                        language_code: locale.language_code,
-                                        primary_flg: true)
-    current_aliases = tag.tag_names.where(language_code: locale.language_code,
-                                          primary_flg: false).to_a
+    current_aliases = tag.tag_name.aliases.to_a
 
     current_aliases.each do |alias_tag_name|
       next if alias_names.include?(alias_tag_name.name)
 
-      affected_tags << alias_tag_name.tag
+      affected_tags << alias_tag_name.canonical&.tag
     end
 
     alias_names.each do |alias_name|
-      alias_tag_name = TagName.find_by(language_code: locale.language_code, name: alias_name)
-      affected_tags << alias_tag_name&.tag
+      alias_tag_name = TagName.find_or_create_by!(name: alias_name)
+      affected_tags << alias_tag_name.canonical&.tag
     end
 
     affected_tags.compact.uniq.each do |affected_tag|
-      TagVersioning.ensure_snapshot!(affected_tag, created_by_user: current_user,
-                                     language_code: locale.language_code)
+      TagVersioning.ensure_snapshot!(affected_tag, created_by_user: current_user)
     end
 
     current_aliases.each do |alias_tag_name|
       next if alias_names.include?(alias_tag_name.name)
 
-      alias_tag_name.update!(canonical_id: nil, tag_id: nil)
+      alias_tag_name.update!(canonical: nil)
     end
 
     alias_names.each do |alias_name|
-      alias_tag_name = TagName.find_or_initialize_by(
-          language_code: locale.language_code,
-          name: alias_name)
-      alias_tag_name.script_code = locale.script_code
-      alias_tag_name.update!(tag:, primary_flg: false, canonical_id: primary_tag_name.id)
+      alias_tag_name = TagName.find_or_create_by!(name: alias_name)
+      alias_tag_name.update!(canonical: tag.tag_name)
     end
 
     affected_tags.compact.uniq.each do |affected_tag|
-      record_tag_version!(affected_tag, event_type: :update,
-                          created_by_user: current_user,
-                          language_code: locale.language_code)
+      record_tag_version!(affected_tag, event_type: :update, created_by_user: current_user)
     end
   end
 
-  def update_parent_tags! locale, tag, parent_names
-    parent_tags = Tag.normalise_tags!(locale, parent_names,
-                                      with_tagme: false,
+  def update_parent_tags! tag, parent_names
+    parent_tags = Tag.normalise_tags!(parent_names, with_tagme: false,
                                                     with_no_deerjikist: false)
 
     old_parent_tags = tag.parents.to_a
@@ -937,15 +851,13 @@ class TagsController < ApplicationController
       .to_a
   end
 
-  def render_deerjikist_conflicts locale, deerjikists, row_indexes_by_key, tag
+  def render_deerjikist_conflicts deerjikists, row_indexes_by_key, tag
     conflicts = deerjikists.filter { |deerjikist| deerjikist.tag_id != tag.id }
     return if conflicts.empty?
 
-    tag_names_by_id =
-        Tag
-        .joins(:tag_names)
-        .where(tag_names: { language_code: locale.language_code, primary_flg: true },
-               id: conflicts.map(&:tag_id).uniq)
+    tag_names_by_id = Tag
+                      .joins(:tag_name)
+                      .where(id: conflicts.map(&:tag_id).uniq)
                       .pluck('tags.id', 'tag_names.name')
                       .to_h
     fields = { }

backend/app/controllers/theatre_skip_events_controller.rb

@@ -6,7 +6,7 @@ class TheatreSkipEventsController < ApplicationController
     events =
         TheatreSkipEvent
         .where(theatre_id: params[:theatre_id])
-        .includes(:post, tags: :tag_names)
+        .includes(:post, tags: :tag_name)
         .order(created_at: :desc)
         .limit(limit)
 
@@ -14,7 +14,7 @@ class TheatreSkipEventsController < ApplicationController
       { id: event.id,
         theatre_id: event.theatre_id,
         post: { id: event.post.id, title: event.post.title, url: event.post.url },
-        tags: event.tags.map { |tag| { id: tag.id, name: tag.name('ja') } },
+        tags: event.tags.map { |tag| { id: tag.id, name: tag.name } },
         programme_position: event.programme_position,
         created_at: event.created_at }
     }

backend/app/controllers/wiki_pages_controller.rb

@@ -94,11 +94,7 @@ class WikiPagesController < ApplicationController
     return render_unprocessable_entity('タイトルは必須です．', field: :title) if title.blank?
     return render_unprocessable_entity('本文は必須です．', field: :body) if body.blank?
 
-    tag_name = TagName.find_or_create_by!(language_code: 'ja', name: title) do |name|
-      name.script_code = 'Jpan'
-      name.primary_flg = true
-      name.auto_generated = false
-    end
+    tag_name = TagName.find_or_create_by!(name: title)
 
     page =
         Wiki::Commit.create_content!(

backend/app/models/external_tag.rb

@@ -14,11 +14,7 @@ class ExternalTag < ApplicationRecord
 
   has_many :linked_tags, through: :nico_tag_relations, source: :tag
 
-  def snapshot_linked_tag_names language_code = 'ja'
-    linked_tags
-        .joins(:tag_names)
-        .where(tag_names: { language_code:, primary_flg: true })
-        .order('tag_names.name')
-        .pluck('tag_names.name')
+  def snapshot_linked_tag_names
+    linked_tags.joins(:tag_name).order('tag_names.name').pluck('tag_names.name')
   end
 end

backend/app/models/language.rb

@@ -1,3 +0,0 @@
-class Language < ApplicationRecord
-  has_many :locales, foreign_key: :language_code, primary_key: :code
-end

backend/app/models/locale.rb

@@ -1,24 +0,0 @@
-class Locale < ApplicationRecord
-  after_create_commit :generate_tag_names!
-
-  belongs_to :language, foreign_key: :language_code, primary_key: :code
-  belongs_to :script, foreign_key: :script_code, primary_key: :code
-
-  def self.nipponese = Locale.find('ja')
-
-  private
-
-  def generate_tag_names!
-    tag_ids = TagName.where(language_code:, primary_flg: true).pluck(:tag_id)
-    Tag.where.not(id: tag_ids).find_each do
-      TagName.create!(tag_id: _1.id,
-                      language_code:,
-                      name: TagName.generate_name(self, _1, _1.name('ja')),
-                      script_code:,
-                      primary_flg: true,
-                      # TODO: 公証実装したら書く．
-                      # auto_generated: true,
-                      canonical_id: nil)
-    end
-  end
-end

backend/app/models/post.rb

@@ -126,14 +126,13 @@ class Post < ApplicationRecord
     super(options).merge(thumbnail: nil)
   end
 
-  def snapshot_tag_names language_code = 'ja'
+  def snapshot_tag_names
     post_tags
-        .joins(tag: :tag_names)
-        .where(tag_names: { language_code:, primary_flg: true })
-        .includes(:sections, tag: :tag_names)
+        .joins(tag: :tag_name)
+        .includes(:sections, tag: :tag_name)
         .order('tag_names.name')
         .map do |post_tag|
-      name = post_tag.tag.name(language_code)
+      name = post_tag.tag.tag_name.name
       sections = post_tag.sections.sort_by(&:begin_ms)
 
       next name if sections.empty?
@@ -153,17 +152,16 @@ class Post < ApplicationRecord
     "#{ tag.fetch('name') }#{ sections.join }"
   end
 
-  def snapshot_tags_json language_code = 'ja'
+  def snapshot_tags_json
     tag_snapshots =
         post_tags
-            .joins(tag: :tag_names)
-            .where(tag_names: { language_code:, primary_flg: true })
-            .includes(:sections, tag: :tag_names)
+            .joins(tag: :tag_name)
+            .includes(:sections, tag: :tag_name)
             .order('tags.id')
             .map { |pt|
           { 'tag_id' => pt.tag.id,
             'version_no' => pt.tag.version_no,
-            'name' => pt.tag.name(language_code),
+            'name' => pt.tag.name,
             'category' => pt.tag.category,
             'sections' => pt.sections.sort_by(&:begin_ms).map {
                             { 'begin_ms' => _1.begin_ms, 'end_ms' => _1.end_ms }

backend/app/models/script.rb

@@ -1,3 +0,0 @@
-class Script < ApplicationRecord
-  ;
-end

backend/app/models/tag.rb

@@ -50,10 +50,14 @@ class Tag < ApplicationRecord
 
   has_many :tag_versions
 
-  has_many :tag_names
+  belongs_to :tag_name
+  delegate :wiki_page, to: :tag_name
 
   attribute :version_no, :integer, default: 1
 
+  delegate :name, to: :tag_name, allow_nil: true
+  validates :tag_name, presence: true
+
   enum :category, deerjikist:  'deerjikist',
                   meme:        'meme',
                   character:   'character',
@@ -63,8 +67,9 @@ class Tag < ApplicationRecord
 
   validates :category, presence: true, inclusion: { in: Tag.categories.keys }
 
+  validate :tag_name_mustnt_start_with_nico
+  validate :tag_name_must_be_canonical
   validate :category_must_be_deerjikist_with_deerjikists
-  validate :tag_names_must_be_valid
 
   CATEGORY_PREFIXES = {
       'general:'    => :general,
@@ -78,20 +83,8 @@ class Tag < ApplicationRecord
       'mtr:'        => :material,
       'meta:'       => :meta }.freeze
 
-  SYSTEM_TAG_NAMES = ['タグ希望', 'bot操作', 'ニジラー情報不詳', '動画', 'ニコニコ', 'YouTube'].freeze
-
-  def tag_name language_code
-    if tag_names.loaded?
-      tag_names.find { _1.language_code == language_code && _1.primary_flg }
-    else
-      tag_names.find_by(language_code:, primary_flg: true)
-    end
-  end
-  def name(language_code) = tag_name(language_code)&.name
-  def wiki_page = tag_name('ja')&.wiki_page
-
-  def system?
-    tag_name('ja')&.name.in?(SYSTEM_TAG_NAMES)
+  def name= val
+    (self.tag_name ||= build_tag_name).name = val
   end
 
   def deprecated? = deprecated_at?
@@ -102,16 +95,14 @@ class Tag < ApplicationRecord
 
   def has_deerjikists = deerjikists.loaded? ? deerjikists.any? : deerjikists.exists?
 
-  def self.tagme = find_or_create_by_tag_name!(Locale.nipponese, 'タグ希望', category: :meta)
-  def self.bot = find_or_create_by_tag_name!(Locale.nipponese, 'bot操作', category: :meta)
-  def self.no_deerjikist =
-      find_or_create_by_tag_name!(Locale.nipponese, 'ニジラー情報不詳', category: :meta)
-  def self.video = find_or_create_by_tag_name!(Locale.nipponese, '動画', category: :meta)
-  def self.niconico = find_or_create_by_tag_name!(Locale.nipponese, 'ニコニコ', category: :meta)
-  def self.youtube = find_or_create_by_tag_name!(Locale.nipponese, 'YouTube', category: :meta)
+  def self.tagme = find_or_create_by_tag_name!('タグ希望', category: :meta)
+  def self.bot = find_or_create_by_tag_name!('bot操作', category: :meta)
+  def self.no_deerjikist = find_or_create_by_tag_name!('ニジラー情報不詳', category: :meta)
+  def self.video = find_or_create_by_tag_name!('動画', category: :meta)
+  def self.niconico = find_or_create_by_tag_name!('ニコニコ', category: :meta)
+  def self.youtube = find_or_create_by_tag_name!('YouTube', category: :meta)
 
-  def self.normalise_tags! locale, tag_names,
-                           with_tagme: true,
+  def self.normalise_tags! tag_names, with_tagme: true,
                                       with_no_deerjikist: true,
                                       deny_deprecated: false,
                                       with_sections: false
@@ -141,11 +132,11 @@ class Tag < ApplicationRecord
         raise SectionLiteralParseError.new(raw_name, raw_name)
       end
 
-      name = TagName.canonicalise(locale, name).first
+      name = TagName.canonicalise(name).first
 
-      find_or_create_by_tag_name!(locale, name, category: (cat || :general)).tap do |tag|
+      find_or_create_by_tag_name!(name, category: (cat || :general)).tap do |tag|
         if deny_deprecated && tag.deprecated?
-          raise DeprecatedTagNormalisationError, [tag.name(locale.language_code)]
+          raise DeprecatedTagNormalisationError, [tag.name]
         end
 
         tag.update!(category: cat) if cat && tag.category != cat
@@ -231,23 +222,13 @@ class Tag < ApplicationRecord
     [left_end_ms, right_end_ms].max
   end
 
-  def self.find_or_create_by_tag_name! locale, name, category:
-    language_code = locale.language_code
-    name = name.to_s.strip
+  def self.find_or_create_by_tag_name! name, category:
+    tn = TagName.find_or_create_by!(name: name.to_s.strip)
+    tn = tn.canonical if tn.canonical_id?
 
-    tn = TagName.find_or_create_by!(language_code:, name:) do
-      _1.script_code = locale.script_code
-      _1.primary_flg = true
+    Tag.find_or_create_by!(tag_name_id: tn.id) do |t|
+      t.category = category
     end
-
-    tag = tn.tag
-    return tag if tag
-
-    tag = Tag.create!(tag_name_id: tn.id, category:)
-    tn.update!(tag:)
-    tag.association(:tag_names).reset
-
-    tag
   rescue ActiveRecord::RecordNotUnique
     retry
   end
@@ -276,15 +257,13 @@ class Tag < ApplicationRecord
           end
         end
 
-        source_tag_name = source_tag.tag_name('ja')
+        source_tag_name = source_tag.tag_name
 
         if source_tag_name.wiki_page.present?
           raise ActiveRecord::RecordInvalid.new(source_tag_name)
         end
 
         TagVersioning.record!(source_tag, event_type: :discard, created_by_user:)
-        source_tag.tag_names.update_all(tag_id: target_tag.id, primary_flg: false,
-                                        updated_at: Time.current)
         source_tag.destroy!
 
         source_tag_name.update_columns(canonical_id: target_tag.tag_name_id,
@@ -305,27 +284,25 @@ class Tag < ApplicationRecord
     target_tag.reload
   end
 
-  def snapshot_aliases(language_code)
-    tag_names.where(language_code:, primary_flg: false).order(:name).pluck(:name)
-  end
+  def snapshot_aliases = tag_name.aliases.order(:name).pluck(:name)
 
   def snapshot_parent_tag_ids = parents.order(:id).pluck(:id)
 
-  def snapshot_linked_tag_names language_code
-    linked_tags
-        .joins(:tag_names)
-        .where(tag_names: { language_code:, primary_flg: true })
-        .order('tag_names.name')
-        .pluck('tag_names.name')
+  def snapshot_linked_tag_names
+    linked_tags.joins(:tag_name).order('tag_names.name').pluck('tag_names.name')
   end
 
   private
 
-  def tag_names_must_be_valid
-    tag_names.each do |tag_name|
-      next if tag_name.valid?
+  def tag_name_mustnt_start_with_nico
+    if name.to_s.downcase.start_with?('nico:')
+      errors.add :name, 'タグの命名規則に反してゐます．'
+    end
+  end
 
-      tag_name.errors[:name].each { errors.add :name, _1 }
+  def tag_name_must_be_canonical
+    if tag_name&.canonical_id?
+      errors.add :tag_name, 'tag_names へは実体を示す必要があります．'
     end
   end
 

backend/app/models/tag_name.rb

@@ -1,54 +1,43 @@
 class TagName < ApplicationRecord
-  belongs_to :language, foreign_key: :language_code, primary_key: :code
-  belongs_to :tag, optional: true
+  has_one :tag
   has_one :wiki_page
 
-  validates :name, presence: true,
-                   length: { maximum: 255 },
-                   uniqueness: { scope: :language_code }
+  belongs_to :canonical, class_name: 'TagName', optional: true
+  has_many :aliases, class_name: 'TagName', foreign_key: :canonical_id
 
+  validates :name, presence: true, length: { maximum: 255 }, uniqueness: true
+
+  validate :canonical_must_be_canonical
   validate :alias_name_must_not_have_prefix
-  validate :alias_must_not_have_wiki_page
+  validate :canonical_must_not_be_present_with_tag_or_wiki_page
   validate :name_must_be_sanitised
-  validate :name_mustnt_start_with_nico
 
-  def primary? = primary_flg
-
-  def self.canonicalise locale, names
+  def self.canonicalise names
     names = Array(names).map { |n| n.to_s.strip }.reject(&:blank?)
     return [] if names.blank?
 
-    tns = TagName.where(language_code: locale.language_code, name: names).index_by(&:name)
+    tns = TagName.includes(:canonical).where(name: names).index_by(&:name)
 
-    names.map { |name|
-      tag_name = tns[name]
-      if !tag_name || tag_name.primary?
-        name
-      else
-        TagName.find_by(language_code: locale.language_code,
-                        tag_id: tag_name.tag_id,
-                        primary_flg: true)&.name || name
-      end
-    }.uniq
-  end
-
-  def self.generate_name locale, tag, name
-    # TODO: 言語ごとの自動命名ロジック完成したら書く．
-
-    "Tag_##{ tag.id }"
+    names.map { |name| tns[name]&.canonical&.name || name }.uniq
   end
 
   private
 
+  def canonical_must_be_canonical
+    if canonical&.canonical_id?
+      errors.add :canonical, 'canonical は実体を示す必要があります．'
+    end
+  end
+
   def alias_name_must_not_have_prefix
-    if !(primary?) && name.to_s.include?(':')
+    if canonical_id? && name.to_s.include?(':')
       errors.add :name, 'エーリアス名にプレフィクスを含むことはできません．'
     end
   end
 
-  def alias_must_not_have_wiki_page
-    if !(primary?) && wiki_page
-      errors.add :primary_flg, 'Wiki 参照がある名前はエーリアスになれません．'
+  def canonical_must_not_be_present_with_tag_or_wiki_page
+    if canonical_id? && (tag || wiki_page)
+      errors.add :canonical, 'タグもしくは Wiki の参照がある名前はエーリアスになれません．'
     end
   end
 
@@ -57,10 +46,4 @@ class TagName < ApplicationRecord
       errors.add :name, '名前に使用できない文字が含まれてゐます．'
     end
   end
-
-  def name_mustnt_start_with_nico
-    if name.to_s.downcase.start_with?('nico:')
-      errors.add :name, 'タグの命名規則に反してゐます．'
-    end
-  end
 end

backend/app/models/tag_name_sanitisation_rule.rb

@@ -15,30 +15,23 @@ class TagNameSanitisationRule < ApplicationRecord
     end
 
     def apply!
-      Language.find_each do |language|
-        TagName.where(language:).find_each do |tn|
+      TagName.find_each do |tn|
         name = sanitise(tn.name)
         next if name == tn.name
 
         TagName.transaction do
-            existing_tn = TagName.find_by(language:, name:)
+          existing_tn = TagName.find_by(name:)
           if existing_tn
-              unless existing_tn.primary_flg
-                existing_tn = TagName.find_by!(language:,
-                                               tag_id: existing_tn.tag_id,
-                                               primary_flg: true)
-              end
+            existing_tn = existing_tn.canonical || existing_tn
             next if existing_tn.id == tn.id
 
-              existing_tag = existing_tn.tag
-              source_tag = tn.tag
+            existing_tag = Tag.find_by(tag_name_id: existing_tn.id)
+            source_tag = Tag.find_by(tag_name_id: tn.id)
 
             if existing_tag
               Tag.merge_tags!(existing_tag, source_tag) if tn.tag
             elsif source_tag
-                tn.update_columns(tag_id: nil, updated_at: Time.current)
               source_tag.update_columns(tag_name_id: existing_tn.id, updated_at: Time.current)
-                existing_tn.update_columns(tag_id: source_tag.id, updated_at: Time.current)
             end
             tn.destroy!
 
@@ -50,7 +43,6 @@ class TagNameSanitisationRule < ApplicationRecord
         end
       end
     end
-    end
 
     private
 

backend/app/models/tag_version.rb

@@ -11,6 +11,5 @@ class TagVersion < ApplicationRecord
                     meta: 'meta' }, validate: true
 
   validates :name, presence: true
-  validates :names, presence: true
   validates :category, presence: true
 end

backend/app/representations/deerjikist_repr.rb

@@ -6,12 +6,11 @@ module DeerjikistRepr
 
   module_function
 
-  def base deerjikist, language_code: 'ja'
-    deerjikist.as_json(BASE).merge(
-        tag: deerjikist.tag && TagRepr.base(deerjikist.tag, language_code:))
+  def base deerjikist
+    deerjikist.as_json(BASE)
   end
 
-  def many deerjikists, language_code: 'ja'
-    deerjikists.map { |d| base(d, language_code:) }
+  def many deerjikists
+    deerjikists.map { |d| base(d) }
   end
 end

backend/app/representations/material_repr.rb

@@ -12,15 +12,14 @@ module MaterialRepr
 
   module_function
 
-  def base material, host:, language_code: 'ja'
+  def base material, host:
     material.as_json(BASE).merge(
-        tag: material.tag && TagRepr.base(material.tag, language_code:),
         file: if material.file.attached?
                 Rails.application.routes.url_helpers.rails_storage_proxy_url(
                     material.file, host:)
               end,
         thumbnail: thumbnail_url(material, host:),
-        thumbnail_fallback_text: thumbnail_fallback_text(material, language_code:),
+        thumbnail_fallback_text: thumbnail_fallback_text(material),
         thumbnail_fallback_kind: thumbnail_fallback_kind(material),
         media_kind: media_kind(material),
         file_byte_size: material.file_byte_size,
@@ -28,11 +27,11 @@ module MaterialRepr
         export_items: export_items(material))
   end
 
-  def many materials, host:, language_code: 'ja'
-    materials.map { |m| base(m, host:, language_code:) }
+  def many materials, host:
+    materials.map { |m| base(m, host:) }
   end
 
-  def list material, host:, language_code: 'ja'
+  def list material, host:
     { id: material.id,
       version_no: material.version_no,
       url: material.url,
@@ -41,9 +40,9 @@ module MaterialRepr
       source_path: material.source_path,
       source_file_id: material.source_file_id,
       normalized_source_key: material.normalized_source_key,
-      tag: compact_tag(material.tag, language_code:),
+      tag: compact_tag(material.tag),
       thumbnail: thumbnail_url(material, host:),
-      thumbnail_fallback_text: thumbnail_fallback_text(material, language_code:),
+      thumbnail_fallback_text: thumbnail_fallback_text(material),
       thumbnail_fallback_kind: thumbnail_fallback_kind(material),
       media_kind: media_kind(material),
       content_type: material.content_type,
@@ -54,8 +53,8 @@ module MaterialRepr
       export_items: export_items(material) }
   end
 
-  def list_many materials, host:, language_code: 'ja'
-    materials.map { |m| list(m, host:, language_code:) }
+  def list_many materials, host:
+    materials.map { |m| list(m, host:) }
   end
 
   def export_paths material
@@ -80,8 +79,8 @@ module MaterialRepr
         material.thumbnail, host:)
   end
 
-  def thumbnail_fallback_text material, language_code:
-    material.tag&.name(language_code) || material.created_at&.strftime('%Y-%m-%d')
+  def thumbnail_fallback_text material
+    material.tag&.name || material.created_at&.strftime('%Y-%m-%d')
   end
 
   def thumbnail_fallback_kind material
@@ -99,11 +98,11 @@ module MaterialRepr
     'file_other'
   end
 
-  def compact_tag tag, language_code:
+  def compact_tag tag
     return nil unless tag
 
     { id: tag.id,
-      name: tag.name(language_code),
+      name: tag.name,
       category: tag.category,
       deprecated_at: tag.deprecated_at }
   end

backend/app/representations/post_repr.rb

@@ -17,23 +17,23 @@ module PostRepr
 
   module_function
 
-  def base post, current_user = nil, host: nil, language_code: 'ja'
+  def base post, current_user = nil, host: nil
     json =
         if host.present?
           common(post, host:)
         else
           common(post)
         end
-    json['tags'] = tag_json(post, language_code:)
+    json['tags'] = tag_json(post)
     json['uploaded_user'] = post.uploaded_user && UserRepr.base(post.uploaded_user)
     json['viewed'] = current_user ? current_user.viewed?(post) : false
     json
   end
 
   def detail post, current_user = nil, parent_posts: [], child_posts: [],
-             sibling_posts: { }, related: [], host: nil, language_code: 'ja'
+             sibling_posts: { }, related: [], host: nil
     if host.present?
-      base(post, current_user, host:, language_code:).merge(
+      base(post, current_user, host:).merge(
           'parent_posts' => cards(parent_posts, host:),
           'child_posts' => cards(child_posts, host:),
           'sibling_posts' => sibling_posts.transform_keys(&:to_s).transform_values { |posts|
@@ -41,7 +41,7 @@ module PostRepr
           },
           'related' => cards(related, host:))
     else
-      base(post, current_user, language_code:).merge(
+      base(post, current_user).merge(
           'parent_posts' => cards(parent_posts),
           'child_posts' => cards(child_posts),
           'sibling_posts' => sibling_posts.transform_keys(&:to_s).transform_values { |posts|
@@ -86,14 +86,14 @@ module PostRepr
                        end)
   end
 
-  def tag_json post, language_code:
+  def tag_json post
     internal_tags =
         post
         .post_tags
         .reject { _1.tag.deprecated? }
-        .sort_by { TagRepr.name_for(_1.tag, language_code) }
+        .sort_by { _1.tag.name }
         .map { |post_tag|
-          TagRepr.inline(post_tag.tag, language_code:).merge(
+          TagRepr.inline(post_tag.tag).merge(
               'children' => [],
               'sections' => post_tag.sections.as_json(only: [:begin_ms, :end_ms]))
         }

backend/app/representations/tag_repr.rb

@@ -3,23 +3,18 @@
 
 module TagRepr
   BASE = { only: [:id, :category, :post_count, :created_at, :updated_at, :deprecated_at],
-           methods: [:has_wiki, :material_id, :has_deerjikists] }.freeze
+           methods: [:name, :has_wiki, :material_id, :has_deerjikists] }.freeze
 
   module_function
 
-  def base tag, language_code: 'ja'
-    tag.as_json(BASE).merge(name: name_for(tag, language_code),
-                            aliases: tag.snapshot_aliases(language_code),
-                            parents: tag.parents.map { inline(_1, language_code:) })
+  def base tag
+    tag.as_json(BASE).merge(aliases: tag.snapshot_aliases,
+                            parents: tag.parents.map { _1.as_json(BASE) })
   end
 
-  def inline tag, language_code: 'ja'
-    tag.as_json(BASE).merge(name: name_for(tag, language_code), aliases: [], parents: [])
+  def inline tag
+    tag.as_json(BASE).merge(aliases: [], parents: [])
   end
 
-  def many(tags, language_code: 'ja') = tags.map { |tag| base(tag, language_code:) }
-
-  def name_for tag, language_code
-    tag.name(language_code) || (tag.system? ? tag.name('ja') : nil)
-  end
+  def many(tags) = tags.map { |t| base(t) }
 end

backend/app/services/material_version_recorder.rb

@@ -31,7 +31,7 @@ class MaterialVersionRecorder < VersionRecorder
     { url: @record.url,
       parent: @record.parent,
       tag: @record.tag,
-      tag_name: @record.tag&.name('ja'),
+      tag_name: @record.tag&.name,
       tag_category: @record.tag&.category,
       source_kind: @record.source_kind,
       source_uri: @record.source_uri,

backend/app/services/post_bulk_creator.rb

@@ -6,7 +6,7 @@ class PostBulkCreator
     @host = host
   end
 
-  def run locale
+  def run
     results = Array.new(@posts.length)
     mutex = Mutex.new
     next_index = 0
@@ -27,7 +27,7 @@ class PostBulkCreator
                 break if index >= @posts.length
 
                 attributes = @posts[index]
-                results[index] = create_row(locale, actor, attributes, index)
+                results[index] = create_row(actor, attributes, index)
               rescue StandardError => e
                 Rails.logger.error(
                     "post_bulk_creator_worker_failure #{ { error: e.class.name,
@@ -61,12 +61,12 @@ class PostBulkCreator
 
   private
 
-  def create_row locale, actor, attributes, index
+  def create_row actor, attributes, index
     preflight =
         PostCreatePreflight.new(
             attributes: attributes,
             thumbnail: thumbnail_for(index, attributes),
-            host: @host).run(locale)
+            host: @host).run
     if preflight[:existing_post_id].present?
       return {
           status: 'skipped',
@@ -76,7 +76,7 @@ class PostBulkCreator
 
     post = PostCreator.new(
         actor: actor,
-        attributes: normalised_attributes(attributes, preflight, index)).create!(locale)
+        attributes: normalised_attributes(attributes, preflight, index)).create!
     result = {
         status: 'created',
         post: { id: post.id } }

backend/app/services/post_create_plan.rb

@@ -8,13 +8,13 @@ class PostCreatePlan
     @existing_tags_by_name = nil
   end
 
-  def build! locale
-    direct_tag_specs, tag_sections = parse_direct_tag_specs(locale)
-    default_tag_specs = build_default_tag_specs(locale, direct_tag_specs)
+  def build!
+    direct_tag_specs, tag_sections = parse_direct_tag_specs
+    default_tag_specs = build_default_tag_specs(direct_tag_specs)
     snapshot_tag_specs = merge_tag_specs(direct_tag_specs + default_tag_specs)
-    preload_existing_tags_by_name!(locale, snapshot_tag_specs.map { _1[:name] })
-    validate_new_tag_specs!(locale, snapshot_tag_specs)
-    post_tag_specs = expand_parent_tag_specs(locale, snapshot_tag_specs)
+    preload_existing_tags_by_name!(snapshot_tag_specs.map { _1[:name] })
+    validate_new_tag_specs!(snapshot_tag_specs)
+    post_tag_specs = expand_parent_tag_specs(snapshot_tag_specs)
     video_ms = normalise_video_ms(snapshot_tag_specs)
     validate_video_sections!(video_ms, tag_sections)
     parent_post_ids = normalise_parent_post_ids
@@ -42,16 +42,14 @@ class PostCreatePlan
 
   def tag_names = @attributes[:tags].to_s.split
 
-  def parse_direct_tag_specs locale
+  def parse_direct_tag_specs
     tag_sections = { }
     direct_tag_specs = []
 
     tag_names.each do |raw_name|
-      tag_name, category, sections = parse_raw_tag_name(locale, raw_name)
-      existing_tag = existing_tags_by_name(locale)[tag_name]
-      if existing_tag&.deprecated?
-        raise Tag::DeprecatedTagNormalisationError, [existing_tag.name(locale.language_code)]
-      end
+      tag_name, category, sections = parse_raw_tag_name(raw_name)
+      existing_tag = existing_tags_by_name[tag_name]
+      raise Tag::DeprecatedTagNormalisationError, [existing_tag.name] if existing_tag&.deprecated?
 
       direct_tag_specs << {
           name: tag_name,
@@ -67,7 +65,7 @@ class PostCreatePlan
     [merge_tag_specs(direct_tag_specs), tag_sections]
   end
 
-  def parse_raw_tag_name locale, raw_name
+  def parse_raw_tag_name raw_name
     name = raw_name.to_s
     prefix, category =
         Tag::CATEGORY_PREFIXES.find {
@@ -76,7 +74,7 @@ class PostCreatePlan
     name = name.sub(/\A#{ prefix }/i, '')
 
     sections = []
-    while match = name.match(/\A(\S*?)\[([^\[\]\s]*)-([^\[\]\s]*)\](\S*)\z/)
+    while (match = name.match(/\A(\S*?)\[([^\[\]\s]*)-([^\[\]\s]*)\](\S*)\z/))
       name = "#{ match[1] }#{ match[4] }"
       next if match[2].empty? && match[3].empty?
 
@@ -89,17 +87,17 @@ class PostCreatePlan
       raise Tag::SectionLiteralParseError.new(raw_name, raw_name)
     end
 
-    [resolved_tag_name(locale, name), category&.to_sym, sections]
+    [resolved_tag_name(name), category&.to_sym, sections]
   end
 
-  def build_default_tag_specs locale, direct_tag_specs
+  def build_default_tag_specs direct_tag_specs
     default_tag_specs = []
     if direct_tag_specs.length < 10 && direct_tag_specs.none? { _1[:name] == TAGME_TAG_NAME }
       default_tag_specs << {
           name: TAGME_TAG_NAME,
           category: :meta }
     end
-    if direct_tag_specs.none? { deerjikist_tag_spec?(locale, _1) }
+    if direct_tag_specs.none? { deerjikist_tag_spec?(_1) }
       default_tag_specs << {
           name: NO_DEERJIKIST_TAG_NAME,
           category: :meta }
@@ -108,18 +106,17 @@ class PostCreatePlan
     default_tag_specs
   end
 
-  def validate_new_tag_specs! locale, specs
+  def validate_new_tag_specs! specs
     Array(specs).each do |spec|
-      next if existing_tags_by_name(locale).key?(spec[:name])
+      next if existing_tags_by_name.key?(spec[:name])
 
-      validate_new_tag_spec!(locale, spec)
+      validate_new_tag_spec!(spec)
     end
   end
 
-  def validate_new_tag_spec! locale, spec
-    tag_name = TagName.new(name: spec[:name], language_code: locale.language_code,
-                           script_code: locale.script_code, primary_flg: true)
-    tag = Tag.new(category: spec[:category])
+  def validate_new_tag_spec! spec
+    tag_name = TagName.new(name: spec[:name])
+    tag = Tag.new(category: spec[:category], tag_name:)
     return if tag_name.valid? && tag.valid?
 
     post = Post.new
@@ -134,15 +131,13 @@ class PostCreatePlan
     raise ActiveRecord::RecordInvalid, post
   end
 
-  def expand_parent_tag_specs locale, snapshot_tag_specs
-    existing_snapshot_tags = snapshot_tag_specs.filter_map do
-      existing_tags_by_name(locale)[_1[:name]]
-    end
+  def expand_parent_tag_specs snapshot_tag_specs
+    existing_snapshot_tags = snapshot_tag_specs.filter_map { existing_tags_by_name[_1[:name]] }
     expanded_parent_specs =
         Tag.expand_parent_tags(existing_snapshot_tags)
            .reject(&:deprecated?)
            .map { |tag|
-             { name: tag.name(locale.language_code),
+             { name: tag.name,
                category: tag.category.to_sym }
         }
     merge_tag_specs(snapshot_tag_specs + expanded_parent_specs)
@@ -161,37 +156,33 @@ class PostCreatePlan
     }.values.sort_by { _1[:name] }
   end
 
-  def existing_tags_by_name locale
+  def existing_tags_by_name
     @existing_tags_by_name ||= begin
-      names = tag_names.map { canonical_tag_name_without_sections(locale, _1) }.uniq
-      TagName.where(language_code: locale.language_code, primary_flg: true, name: names)
-             .includes(:tag)
-             .each_with_object({ }) { |tag_name, tags| tags[tag_name.name] = tag_name.tag }
+      names = tag_names.map { canonical_tag_name_without_sections(_1) }.uniq
+      Tag.joins(:tag_name).where(tag_names: { name: names }).index_by(&:name)
     end
   end
 
-  def preload_existing_tags_by_name! locale, names
+  def preload_existing_tags_by_name! names
     wanted_names = Array(names).map { _1.to_s }.reject(&:blank?).uniq
-    missing_names = wanted_names - existing_tags_by_name(locale).keys
+    missing_names = wanted_names - existing_tags_by_name.keys
     return if missing_names.empty?
 
-    existing_tags_by_name(locale).merge!(
-        TagName.where(language_code: locale.language_code,
-                      primary_flg: true,
-                      name: missing_names)
-               .includes(:tag)
-               .each_with_object({ }) { |tag_name, tags| tags[tag_name.name] = tag_name.tag })
+    existing_tags_by_name.merge!(
+        Tag.joins(:tag_name)
+           .where(tag_names: { name: missing_names })
+           .index_by(&:name))
   end
 
-  def canonical_tag_name_without_sections locale, raw_name
-    name, = parse_raw_tag_name(locale, raw_name)
+  def canonical_tag_name_without_sections raw_name
+    name, = parse_raw_tag_name(raw_name)
     name
   end
 
-  def deerjikist_tag_spec? locale, spec
+  def deerjikist_tag_spec? spec
     return true if spec[:category] == :deerjikist
 
-    existing_tags_by_name(locale)[spec[:name]]&.deerjikist?
+    existing_tags_by_name[spec[:name]]&.deerjikist?
   end
 
   def normalise_parent_post_ids
@@ -269,12 +260,10 @@ class PostCreatePlan
     end
   end
 
-  def resolved_tag_name locale, name
-    tag_name = TagName.find_by(language_code: locale.language_code, name:)
-    return name if !(tag_name) || tag_name.primary?
+  def resolved_tag_name name
+    tag_name = TagName.includes(:canonical).find_by(name:)
+    return name if tag_name.nil?
 
-    TagName.find_by(language_code: locale.language_code,
-                    tag_id: tag_name.tag_id,
-                    primary_flg: true)&.name || name
+    (tag_name.canonical || tag_name).name
   end
 end

backend/app/services/post_create_preflight.rb

@@ -15,10 +15,9 @@ class PostCreatePreflight
     @host = host
   end
 
-  def run locale
+  def run
     preview = PostImportPreviewer.new.preview_rows(
         rows: [preview_row],
-        locale:,
         fetch_metadata: false).first
     if preview[:existing_post_id].present?
       return {
@@ -54,7 +53,7 @@ class PostCreatePreflight
             original_created_from: preview[:attributes]['original_created_from'],
             original_created_before: preview[:attributes]['original_created_before'],
             duration: preview[:attributes]['duration'],
-            video_ms: preview[:attributes]['video_ms'] }).build!(locale)
+            video_ms: preview[:attributes]['video_ms'] }).build!
 
     {
         url: plan[:url],

backend/app/services/post_creator.rb

@@ -9,7 +9,7 @@ class PostCreator
     @field_warnings = { }
   end
 
-  def create! locale
+  def create!
     thumbnail_attachment = prepare_thumbnail_attachment
     post = Post.new(title: @attributes[:title].presence,
                     url: @attributes[:url],
@@ -21,17 +21,14 @@ class PostCreator
     ApplicationRecord.transaction do
       post.save!
       post.thumbnail.attach(thumbnail_attachment) if thumbnail_attachment.present?
-      snapshot_tags = planned_snapshot_tags(locale)
-      post_tags = planned_post_tags(locale)
-      sections = planned_sections(locale)
-      TagVersioning.record_tag_snapshots!(
-          snapshot_tags,
-          created_by_user: @actor,
-          language_code: locale.language_code)
-      post.video_ms = planned_video_ms(locale)
+      snapshot_tags = planned_snapshot_tags
+      post_tags = planned_post_tags
+      sections = planned_sections
+      TagVersioning.record_tag_snapshots!(snapshot_tags, created_by_user: @actor)
+      post.video_ms = planned_video_ms
       post.save!
       sync_post_tags!(post, post_tags, sections)
-      sync_parent_posts!(post, planned_parent_post_ids(locale))
+      sync_parent_posts!(post, planned_parent_post_ids)
       PostVersionRecorder.record!(post:, event_type: :create, created_by_user: @actor)
     end
     post
@@ -48,73 +45,69 @@ class PostCreator
         thumbnail_base: @attributes[:thumbnail_base].presence)
   end
 
-  def planned_snapshot_tags(locale) = planned_create_attributes(locale)[:snapshot_tags]
+  def planned_snapshot_tags = planned_create_attributes[:snapshot_tags]
 
-  def planned_post_tags(locale) = planned_create_attributes(locale)[:post_tags]
+  def planned_post_tags = planned_create_attributes[:post_tags]
 
-  def planned_sections(locale) = planned_create_attributes(locale)[:tag_sections]
+  def planned_sections = planned_create_attributes[:tag_sections]
 
-  def planned_parent_post_ids locale
-    planned_create_attributes(locale)[:normalised_parent_post_ids]
+  def planned_parent_post_ids = planned_create_attributes[:normalised_parent_post_ids]
+
+  def planned_video_ms
+    planned_create_attributes[:video_ms]
   end
 
-  def planned_video_ms locale
-    planned_create_attributes(locale)[:video_ms]
-  end
-
-  def planned_create_attributes locale
+  def planned_create_attributes
     @planned_create_attributes ||= begin
       if @attributes.key?(:snapshot_tag_specs)
-        snapshot_tags = materialise_tags(locale, @attributes[:snapshot_tag_specs] || [])
-        post_tags = materialise_tags(locale, @attributes[:post_tag_specs] || [])
+        snapshot_tags = materialise_tags(@attributes[:snapshot_tag_specs] || [])
+        post_tags = materialise_tags(@attributes[:post_tag_specs] || [])
         {
             snapshot_tags: snapshot_tags,
             post_tags: post_tags,
             tag_sections: materialise_sections(
                 @attributes[:tag_sections] || { },
                 snapshot_tags,
-                post_tags,
-                locale),
+                post_tags),
             normalised_parent_post_ids: @attributes[:normalised_parent_post_ids] || [],
             video_ms: @attributes[:video_ms] }
       else
-        build_materialised_plan(locale)
+        build_materialised_plan
       end
     end
   end
 
-  def build_materialised_plan locale
-    plan = PostCreatePlan.new(attributes: @attributes).build!(locale)
-    snapshot_tags = materialise_tags(locale, plan[:snapshot_tag_specs] || [])
-    post_tags = materialise_tags(locale, plan[:post_tag_specs] || [])
+  def build_materialised_plan
+    plan = PostCreatePlan.new(attributes: @attributes).build!
+    snapshot_tags = materialise_tags(plan[:snapshot_tag_specs] || [])
+    post_tags = materialise_tags(plan[:post_tag_specs] || [])
     {
         snapshot_tags: snapshot_tags,
         post_tags: post_tags,
         tag_sections: materialise_sections(
             plan[:tag_sections] || { },
             snapshot_tags,
-            post_tags,
-            locale),
+            post_tags),
         normalised_parent_post_ids: plan[:normalised_parent_post_ids] || [],
         video_ms: plan[:video_ms] }
   end
 
-  def materialise_tags locale, specs
+  def materialise_tags specs
     Array(specs).each_with_object({ }) do |spec, tags|
       name = spec[:name] || spec['name']
       category = spec[:category] || spec['category']
       next if name.blank? || category.blank?
 
-      tag = Tag.find_or_create_by_tag_name!(locale, name, category:)
+      tag = Tag.find_or_create_by_tag_name!(name, category:)
       tag.update!(category:) if tag.category.to_sym != category.to_sym
       tags[name] ||= tag
     end.values
   end
 
-  def materialise_sections sections_by_name, snapshot_tags, post_tags, locale = Locale.nipponese
-    tags_by_name = post_tags.index_by { _1.name(locale.language_code) }
+  def materialise_sections sections_by_name, snapshot_tags, post_tags
+    tags_by_name = post_tags.index_by(&:name)
     snapshot_tags.each do |tag|
-      tags_by_name[tag.name(locale.language_code)] ||= tag
+      tags_by_name[tag.name] ||= tag
     end
 
     sections_by_name.each_with_object({ }) do |(tag_name, ranges), sections|

backend/app/services/post_import_previewer.rb

@@ -16,7 +16,7 @@ class PostImportPreviewer
   THUMBNAIL_FETCH_WARNING = 'サムネールを取得できませんでした．'.freeze
   METADATA_FETCH_WARNING = '自動取得に失敗しました．'.freeze
 
-  def preview_rows rows:, locale: Locale.nipponese, fetch_metadata: true, metadata_cache: { }
+  def preview_rows rows:, fetch_metadata: true, metadata_cache: { }
     prepared_rows = rows.map { prepare_row(_1) }
     url_counts = prepared_rows.filter_map { _1[:normal_url] }.tally
     existing_posts =
@@ -30,14 +30,13 @@ class PostImportPreviewer
         url_counts)
     known_tags =
         preload_known_tags(
-            locale,
             prepared_rows,
             fetch_metadata,
             metadata_cache,
             existing_posts,
             url_counts)
     prepared_rows.map { |row|
-      preview_row(locale, row,
+      preview_row(row,
                   fetch_metadata:,
                   metadata_cache:,
                   existing_posts:,
@@ -60,7 +59,7 @@ class PostImportPreviewer
     source.merge(url_text: url, normal_url:, url_error: validate_url_safety(normal_url))
   end
 
-  def preview_row locale, row,
+  def preview_row row,
                   fetch_metadata:,
                   metadata_cache:,
                   existing_posts:,
@@ -125,8 +124,7 @@ class PostImportPreviewer
 
     attributes['url'] = url
     validate_basic_data(attributes, validation_errors)
-    validate_preview_tags(locale,
-                          merged_tags(tag_sources, provenance['tags']),
+    validate_preview_tags(merged_tags(tag_sources, provenance['tags']),
                           validation_errors,
                           known_tags)
     validate_parents(attributes['parent_post_ids'], validation_errors, existing_parent_ids)
@@ -348,7 +346,7 @@ class PostImportPreviewer
     { data: { }, warnings: { 'url' => [METADATA_FETCH_WARNING] }, validation_errors: { } }
   end
 
-  def preload_known_tags locale, prepared_rows, fetch_metadata, metadata_cache, existing_posts, url_counts
+  def preload_known_tags prepared_rows, fetch_metadata, metadata_cache, existing_posts, url_counts
     names = prepared_rows.flat_map { |row|
       attributes = initial_attributes(row)
       provenance = initial_provenance(row)
@@ -360,13 +358,15 @@ class PostImportPreviewer
         metadata = metadata_for(row[:normal_url], metadata_cache)
         apply_metadata!(attributes, provenance, tag_sources, metadata[:data])
       end
-      preview_tag_names(locale, merged_tags(tag_sources, provenance['tags']))
+      preview_tag_names(merged_tags(tag_sources, provenance['tags']))
     }.compact.uniq
     return { } if names.empty?
 
-    TagName.where(language_code: locale.language_code, primary_flg: true, name: names)
-           .includes(:tag)
-           .each_with_object({ }) { |tag_name, tags| tags[tag_name.name] = tag_name.tag }
+    Tag.joins(:tag_name)
+      .where(tag_names: { name: names })
+      .includes(:tag_name)
+      .to_a
+      .index_by(&:name)
   end
 
   def preload_parent_ids prepared_rows
@@ -437,21 +437,19 @@ class PostImportPreviewer
     sources['automatic'].to_s
   end
 
-  def preview_tag_names locale, raw
+  def preview_tag_names raw
     names = raw.to_s.split
     return [] if names.empty?
     if names.any? { _1.downcase.start_with?('nico:') }
       return []
     end
 
-    names.map { |name|
-      TagName.canonicalise(locale, name.sub(/\[.*\]\z/, '')).first
-    }
+    names.map { |name| TagName.canonicalise(name.sub(/\[.*\]\z/, '')).first }
   rescue Tag::SectionLiteralParseError
     []
   end
 
-  def validate_preview_tags locale, raw, errors, known_tags
+  def validate_preview_tags raw, errors, known_tags
     names = raw.to_s.split
     return if names.empty?
     if names.any? { _1.downcase.start_with?('nico:') }
@@ -459,11 +457,9 @@ class PostImportPreviewer
       return
     end
 
-    parsed = names.map { |name|
-      TagName.canonicalise(locale, name.sub(/\[.*\]\z/, '')).first
-    }
+    parsed = names.map { |name| TagName.canonicalise(name.sub(/\[.*\]\z/, '')).first }
     existing = parsed.filter_map { known_tags[_1] }
-    deprecated = existing.select(&:deprecated?).map { _1.name(locale.language_code) }
+    deprecated = existing.select(&:deprecated?).map(&:name)
     errors[:tags] = ["廃止済みタグがあります: #{ deprecated.join(' ') }"] if deprecated.present?
   rescue Tag::SectionLiteralParseError
     errors[:tags] = ['タグ区間の記法が不正です．']

backend/app/services/post_metadata_fetcher.rb

@@ -47,9 +47,9 @@ class PostMetadataFetcher
 
     existing_tags =
         Tag
-        .joins(:tag_names)
-        .where(tag_names: { language_code: 'ja', primary_flg: true, name: names })
-        .index_by { _1.name('ja') }
+        .joins(:tag_name)
+        .where(tag_names: { name: names })
+        .index_by(&:name)
 
     names.map { |name|
       tag = existing_tags[name]

backend/app/services/tag_version_recorder.rb

@@ -1,5 +1,5 @@
 class TagVersionRecorder < VersionRecorder
-  def self.record! tag:, event_type:, created_by_user:, **_options
+  def self.record! tag:, event_type:, created_by_user:
     new(tag:, event_type:, created_by_user:).record!
   end
 
@@ -14,25 +14,10 @@ class TagVersionRecorder < VersionRecorder
   def record_key = :tag
 
   def snapshot_attributes
-    names = snapshot_names
-    japanese_names = names.select { _1['language_code'] == 'ja' }
-    compatibility_names = japanese_names.presence || names
-
-    { name: compatibility_names.find { _1['primary_flg'] }['name'],
+    { name: @record.name,
       category: @record.category,
       deprecated_at: @record.deprecated_at,
-      aliases: compatibility_names.reject { _1['primary_flg'] }.map { _1['name'] }.join(' '),
-      names:,
+      aliases: @record.snapshot_aliases.join(' '),
       parent_tag_ids: @record.snapshot_parent_tag_ids.join(' ') }
   end
-
-  def snapshot_names
-    @record.tag_names.order(:language_code, primary_flg: :desc).order(:name).map { |tag_name|
-      { 'language_code' => tag_name.language_code,
-        'name' => tag_name.name,
-        'script_code' => tag_name.script_code,
-        'primary_flg' => tag_name.primary_flg,
-        'auto_generated' => tag_name.auto_generated }
-    }
-  end
 end

backend/app/services/tag_versioning.rb

@@ -1,22 +1,22 @@
 class TagVersioning
-  def self.record! tag, event_type:, created_by_user:, language_code: 'ja'
-    TagVersionRecorder.record!(tag:, event_type:, created_by_user:, language_code:)
+  def self.record! tag, event_type:, created_by_user:
+    TagVersionRecorder.record!(tag:, event_type:, created_by_user:)
   end
 
-  def self.ensure_snapshot! tag, created_by_user:, language_code: 'ja'
+  def self.ensure_snapshot! tag, created_by_user:
     return if tag.tag_versions.exists?
 
-    TagVersionRecorder.record!(tag:, event_type: :create, created_by_user:, language_code:)
+    TagVersionRecorder.record!(tag:, event_type: :create, created_by_user:)
   end
 
-  def self.record_tag_snapshot! tag, created_by_user:, language_code: 'ja'
+  def self.record_tag_snapshot! tag, created_by_user:
     event_type = tag.tag_versions.exists? ? :update : :create
-    record!(tag, event_type:, created_by_user:, language_code:)
+    record!(tag, event_type:, created_by_user:)
   end
 
-  def self.record_tag_snapshots! tags, created_by_user:, language_code: 'ja'
+  def self.record_tag_snapshots! tags, created_by_user:
     tags.each do |tag|
-      record_tag_snapshot!(tag, created_by_user:, language_code:)
+      record_tag_snapshot!(tag, created_by_user:)
     end
   end
 end

backend/app/services/theatre_post_selector.rb

@@ -41,7 +41,7 @@ class TheatrePostSelector
   def weighted_candidates
     @weighted_candidates ||= begin
       penalties = tag_penalties
-      posts = eligible_posts.includes(tags: :tag_names).to_a
+      posts = eligible_posts.includes(tags: :tag_name).to_a
 
       posts.map do |post|
         post_tags = post.tags.to_a
@@ -82,7 +82,7 @@ class TheatrePostSelector
   def tag_penalty_json
     return [] if tag_penalties.empty?
 
-    tags = Tag.where(id: tag_penalties.keys).includes(:tag_names).index_by(&:id)
+    tags = Tag.where(id: tag_penalties.keys).includes(:tag_name).index_by(&:id)
 
     tag_penalties
       .map { |tag_id, penalty|
@@ -113,7 +113,7 @@ class TheatrePostSelector
 
   def light_tag_json tag
     { id: tag.id,
-      name: tag.name('ja'),
+      name: tag.name,
       category: tag.category }
   end
 end

backend/db/migrate/20260922000000_create_languages.rb

@@ -1,20 +0,0 @@
-class CreateLanguages < ActiveRecord::Migration[8.0]
-  def up
-    create_table :languages, id: { type: :string, limit: 16 }, primary_key: :code do |t|
-      t.string :name, null: false
-      t.datetime :deprecated_at, index: true
-      t.datetime :created_at, null: false
-    end
-
-    execute <<~SQL
-      INSERT INTO
-        languages(code, name, created_at)
-      VALUES
-        ('ja', '日本語', #{ connection.quote Time.current })
-    SQL
-  end
-
-  def down
-    drop_table :languages
-  end
-end

backend/db/migrate/20260922010000_create_scripts.rb

@@ -1,20 +0,0 @@
-class CreateScripts < ActiveRecord::Migration[8.0]
-  def up
-    create_table :scripts, id: { type: 'CHAR(4)' }, primary_key: :code do |t|
-      t.string :name, null: false
-      t.datetime :deprecated_at, index: true
-      t.datetime :created_at, null: false
-    end
-
-    execute <<~SQL
-      INSERT INTO
-        scripts(code, name, created_at)
-      VALUES
-        ('Jpan', '漢字および仮名文字', #{ connection.quote Time.current })
-    SQL
-  end
-
-  def down
-    drop_table :scripts
-  end
-end

backend/db/migrate/20260922020000_create_locales.rb

@@ -1,25 +0,0 @@
-class CreateLocales < ActiveRecord::Migration[8.0]
-  def up
-    create_table :locales, id: { type: :string, limit: 32 }, primary_key: :code do |t|
-      t.string :language_code, limit: 16, null: false, index: true
-      t.column :script_code, 'CHAR(4)', null: false
-      t.string :name, null: false
-      t.datetime :deprecated_at, index: true
-      t.datetime :created_at, null: false
-
-      t.foreign_key :languages, column: :language_code, primary_key: :code
-      t.foreign_key :scripts, column: :script_code, primary_key: :code
-    end
-
-    execute <<~SQL
-      INSERT INTO
-        locales(code, language_code, script_code, name, created_at)
-      VALUES
-        ('ja', 'ja', 'Jpan', '日本語', #{ connection.quote Time.current })
-    SQL
-  end
-
-  def down
-    drop_table :locales
-  end
-end

backend/db/migrate/20260922030000_add_columns_to_tag_names.rb

@@ -1,59 +0,0 @@
-class AddColumnsToTagNames < ActiveRecord::Migration[8.0]
-  def up
-    add_reference :tag_names, :tag, after: :id, foreign_key: true
-    add_column :tag_names, :language_code, :string,
-               limit: 16, null: false, after: :tag_id, default: 'ja'
-    add_column :tag_names, :script_code, 'CHAR(4)',
-               null: false, after: :name, default: 'Jpan'
-    add_column :tag_names, :primary_flg, :boolean,
-               null: false, after: :script_code, default: true
-
-    add_foreign_key :tag_names, :languages, column: :language_code, primary_key: :code
-    add_foreign_key :tag_names, :scripts, column: :script_code, primary_key: :code
-
-    remove_index :tag_names, :name
-    add_index :tag_names, [:language_code, :name], unique: true
-
-    change_column_default :tag_names, :language_code, from: 'ja', to: nil
-    change_column_default :tag_names, :script_code, from: 'Jpan', to: nil
-
-    execute <<~SQL
-      UPDATE
-        tag_names tn
-        LEFT JOIN
-          tags AS t
-          ON
-            t.tag_name_id = COALESCE(tn.canonical_id, tn.id)
-      SET
-        tn.tag_id = t.id
-      , tn.primary_flg = CASE
-                         WHEN tn.canonical_id IS NULL THEN
-                           1
-                         ELSE
-                           0
-                         END
-    SQL
-
-    change_column_default :tag_names, :primary_flg, from: true, to: nil
-
-    add_column :tag_names, :primary_tag_id, :bigint,
-               as: 'CASE WHEN primary_flg THEN tag_id ELSE NULL END'
-    add_index :tag_names, [:primary_tag_id, :language_code], unique: true
-  end
-
-  def down
-    remove_index :tag_names, [:primary_tag_id, :language_code]
-    remove_column :tag_names, :primary_tag_id
-
-    remove_foreign_key :tag_names, column: :language_code
-    remove_foreign_key :tag_names, column: :script_code
-
-    remove_index :tag_names, [:language_code, :name]
-    add_index :tag_names, :name, unique: true
-
-    remove_column :tag_names, :primary_flg
-    remove_column :tag_names, :script_code
-    remove_column :tag_names, :language_code
-    remove_reference :tag_names, :tag, foreign_key: true
-  end
-end

backend/db/migrate/20260922040000_add_names_to_tag_versions.rb

@@ -1,38 +0,0 @@
-class AddNamesToTagVersions < ActiveRecord::Migration[8.0]
-  class TagVersion < ActiveRecord::Base
-    self.table_name = 'tag_versions'
-  end
-
-  def up
-    add_column :tag_versions, :names, :json
-    TagVersion.reset_column_information
-
-    say_with_time 'Backfilling multilingual tag version names' do
-      TagVersion.find_each do |version|
-        names = [{
-          language_code: 'ja',
-          name: version.name,
-          script_code: 'Jpan',
-          primary_flg: true,
-          auto_generated: false }]
-        names.concat(version.aliases.to_s.split.filter_map { |name|
-          next if name.blank?
-
-          {
-            language_code: 'ja',
-            name:,
-            script_code: 'Jpan',
-            primary_flg: false,
-            auto_generated: false }
-        })
-        version.update_columns(names: names)
-      end
-    end
-
-    change_column_null :tag_versions, :names, false
-  end
-
-  def down
-    remove_column :tag_versions, :names
-  end
-end

backend/db/migrate/20260922050000_add_auto_generated_to_tag_names.rb

@@ -1,19 +0,0 @@
-class AddAutoGeneratedToTagNames < ActiveRecord::Migration[8.0]
-  class TagVersion < ActiveRecord::Base
-    self.table_name = 'tag_versions'
-  end
-
-  def up
-    add_column :tag_names, :auto_generated, :boolean, null: false, default: false
-    TagVersion.reset_column_information
-
-    TagVersion.find_each do |version|
-      names = Array(version.names).map { |name| name.merge('auto_generated' => false) }
-      version.update_columns(names: names)
-    end
-  end
-
-  def down
-    remove_column :tag_names, :auto_generated
-  end
-end

backend/db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[8.0].define(version: 2026_09_22_050000) do
+ActiveRecord::Schema[8.0].define(version: 2026_09_21_230000) do
   create_table "active_storage_attachments", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.string "name", null: false
     t.string "record_type", null: false
@@ -138,24 +138,6 @@ ActiveRecord::Schema[8.0].define(version: 2026_09_22_050000) do
     t.index ["ip_address"], name: "index_ip_addresses_on_ip_address", unique: true
   end
 
-  create_table "languages", primary_key: "code", id: { type: :string, limit: 16 }, charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
-    t.string "name", null: false
-    t.datetime "deprecated_at"
-    t.datetime "created_at", null: false
-    t.index ["deprecated_at"], name: "index_languages_on_deprecated_at"
-  end
-
-  create_table "locales", primary_key: "code", id: { type: :string, limit: 32 }, charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
-    t.string "language_code", limit: 16, null: false
-    t.string "script_code", limit: 4, null: false
-    t.string "name", null: false
-    t.datetime "deprecated_at"
-    t.datetime "created_at", null: false
-    t.index ["deprecated_at"], name: "index_locales_on_deprecated_at"
-    t.index ["language_code"], name: "index_locales_on_language_code"
-    t.index ["script_code"], name: "fk_rails_0b74ce96a8"
-  end
-
   create_table "material_export_items", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.bigint "material_id", null: false
     t.string "profile", default: "legacy_drive", null: false
@@ -406,13 +388,6 @@ ActiveRecord::Schema[8.0].define(version: 2026_09_22_050000) do
     t.check_constraint "`version_no` > 0", name: "chk_posts_version_no_positive"
   end
 
-  create_table "scripts", primary_key: "code", id: { type: :string, limit: 4 }, charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
-    t.string "name", null: false
-    t.datetime "deprecated_at"
-    t.datetime "created_at", null: false
-    t.index ["deprecated_at"], name: "index_scripts_on_deprecated_at"
-  end
-
   create_table "settings", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.bigint "user_id", null: false
     t.datetime "created_at", null: false
@@ -445,21 +420,12 @@ ActiveRecord::Schema[8.0].define(version: 2026_09_22_050000) do
   end
 
   create_table "tag_names", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
-    t.bigint "tag_id"
-    t.string "language_code", limit: 16, null: false
     t.string "name", null: false
-    t.string "script_code", limit: 4, null: false
-    t.boolean "primary_flg", null: false
     t.bigint "canonical_id"
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
-    t.virtual "primary_tag_id", type: :bigint, as: "(case when `primary_flg` then `tag_id` else NULL end)"
-    t.boolean "auto_generated", default: false, null: false
     t.index ["canonical_id"], name: "index_tag_names_on_canonical_id"
-    t.index ["language_code", "name"], name: "index_tag_names_on_language_code_and_name", unique: true
-    t.index ["primary_tag_id", "language_code"], name: "index_tag_names_on_primary_tag_id_and_language_code", unique: true
-    t.index ["script_code"], name: "fk_rails_dd783b3d1c"
-    t.index ["tag_id"], name: "index_tag_names_on_tag_id"
+    t.index ["name"], name: "index_tag_names_on_name", unique: true
   end
 
   create_table "tag_similarities", primary_key: ["tag_id", "target_tag_id"], charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
@@ -481,7 +447,6 @@ ActiveRecord::Schema[8.0].define(version: 2026_09_22_050000) do
     t.datetime "deprecated_at"
     t.datetime "created_at", null: false
     t.bigint "created_by_user_id"
-    t.json "names", null: false
     t.index ["created_at"], name: "index_tag_versions_on_created_at"
     t.index ["created_by_user_id", "created_at"], name: "index_tag_versions_on_created_by_user_id_and_created_at", order: { created_at: :desc }
     t.index ["tag_id", "created_at"], name: "index_tag_versions_on_tag_id_and_created_at", order: { created_at: :desc }
@@ -736,8 +701,6 @@ ActiveRecord::Schema[8.0].define(version: 2026_09_22_050000) do
   add_foreign_key "gekanator_question_suggestions", "users"
   add_foreign_key "gekanator_questions", "gekanator_question_suggestions"
   add_foreign_key "gekanator_questions", "users", column: "created_by_id"
-  add_foreign_key "locales", "languages", column: "language_code", primary_key: "code"
-  add_foreign_key "locales", "scripts", column: "script_code", primary_key: "code"
   add_foreign_key "material_export_items", "materials"
   add_foreign_key "material_export_items", "users", column: "created_by_user_id"
   add_foreign_key "material_import_blocks", "users", column: "created_by_user_id"
@@ -771,10 +734,7 @@ ActiveRecord::Schema[8.0].define(version: 2026_09_22_050000) do
   add_foreign_key "settings", "users"
   add_foreign_key "tag_implications", "tags"
   add_foreign_key "tag_implications", "tags", column: "parent_tag_id"
-  add_foreign_key "tag_names", "languages", column: "language_code", primary_key: "code"
-  add_foreign_key "tag_names", "scripts", column: "script_code", primary_key: "code"
   add_foreign_key "tag_names", "tag_names", column: "canonical_id"
-  add_foreign_key "tag_names", "tags"
   add_foreign_key "tag_similarities", "tags"
   add_foreign_key "tag_similarities", "tags", column: "target_tag_id"
   add_foreign_key "tag_versions", "users", column: "created_by_user_id"

backend/spec/db/delete_discarded_tags_spec.rb

@@ -11,7 +11,6 @@ RSpec.describe 'discarded tag cleanup migrations' do
   end
 
   context 'with legacy records' do
-    # Reproduce the historical schema required by these pre-multilingual migrations.
     self.use_transactional_tests = false
 
     before do

backend/spec/factories/tag_names.rb

@@ -1,13 +1,5 @@
 FactoryBot.define do
   factory :tag_name do
-    language_code { 'ja' }
-    script_code { 'Jpan' }
-    primary_flg { true }
-    auto_generated { false }
-    sequence(:name) { |number| "tag-#{ SecureRandom.hex(4) }-#{ number }" }
-
-    trait :alias do
-      primary_flg { false }
-    end
+    name { "tag-#{SecureRandom.hex(4)}" }
   end
 end

backend/spec/factories/tags.rb

@@ -1,29 +1,15 @@
 FactoryBot.define do
   factory :tag do
     transient do
-      primary_name { nil }
-      primary_tag_name do
-        attributes = primary_name.nil? ? { } : { name: primary_name }
-        build(:tag_name, **attributes)
-      end
+      name { nil }
     end
 
     category { :general }
     post_count { 0 }
+    association :tag_name
 
     after(:build) do |tag, evaluator|
-      evaluator.primary_tag_name.primary_flg = true
-      tag.tag_names.target << evaluator.primary_tag_name
-    end
-
-    before(:create) do |tag, evaluator|
-      evaluator.primary_tag_name.save!
-      # Compatibility write only; ownership is established through tag_id below.
-      tag.tag_name_id = evaluator.primary_tag_name.id
-    end
-
-    after(:create) do |tag, evaluator|
-      evaluator.primary_tag_name.update!(tag:, primary_flg: true)
+      tag.name = evaluator.name if evaluator.name.present?
     end
   end
 end

backend/spec/models/locale_spec.rb

@@ -1,71 +0,0 @@
-require 'rails_helper'
-
-RSpec.describe Locale, type: :model do
-  def prepare_french_reference!
-    Language.find_or_create_by!(code: 'fr') { _1.name = 'French' }
-    Script.find_or_create_by!(code: 'Latn') { _1.name = 'Latin' }
-  end
-
-  def create_french_locale!
-    prepare_french_reference!
-    described_class.create!(code: 'fr', language_code: 'fr',
-                            script_code: 'Latn', name: 'French')
-  end
-
-  it 'generates a primary name for every existing tag using the name generator' do
-    first = create(:tag, primary_name: 'first_existing_tag')
-    second = create(:tag, primary_name: 'second_existing_tag')
-    allow(TagName).to receive(:generate_name).and_call_original
-    allow(TagName).to receive(:generate_name)
-        .with(kind_of(described_class), first, primary_tag_name_for(first, 'ja').name)
-        .and_return('name_from_generator')
-
-    locale = create_french_locale!
-
-    expect(TagName).to have_received(:generate_name)
-        .with(locale, first, primary_tag_name_for(first, 'ja').name)
-    expect(TagName).to have_received(:generate_name)
-        .with(locale, second, primary_tag_name_for(second, 'ja').name)
-    expect(first.tag_names.find_by!(language_code: 'fr', primary_flg: true))
-        .to have_attributes(name: 'name_from_generator', tag_id: first.id,
-                            language_code: 'fr', script_code: 'Latn',
-                            primary_flg: true)
-    expect(second.tag_names.find_by!(language_code: 'fr', primary_flg: true))
-        .to have_attributes(tag_id: second.id, language_code: 'fr',
-                            script_code: 'Latn', primary_flg: true)
-    expect(TagName.where(language_code: 'fr', primary_flg: true,
-                         tag_id: [first.id, second.id]).count).to eq(2)
-  end
-
-  it 'does not duplicate an existing primary name in the new language' do
-    prepare_french_reference!
-    tag = create(:tag, primary_name: 'already_named')
-    existing = create(:tag_name, name: 'nom_existant', tag:,
-                                 language_code: 'fr', script_code: 'Latn')
-
-    create_french_locale!
-
-    expect(TagName.where(tag_id: tag.id, language_code: 'fr', primary_flg: true))
-        .to contain_exactly(existing)
-    expect(existing.reload).to have_attributes(
-        tag_id: tag.id, language_code: 'fr', script_code: 'Latn', primary_flg: true)
-  end
-
-  it 'creates a primary name when the language has only an alias' do
-    prepare_french_reference!
-    tag = create(:tag, primary_name: 'alias_only_tag')
-    alias_name = create(:tag_name, :alias, name: 'alias_fr',
-                                          tag:,
-                                          language_code: 'fr', script_code: 'Latn')
-
-    create_french_locale!
-
-    expect(alias_name.reload).to have_attributes(
-        tag_id: tag.id,
-        language_code: 'fr', script_code: 'Latn', primary_flg: false)
-    generated = TagName.find_by!(tag_id: tag.id, language_code: 'fr', primary_flg: true)
-    expect(generated).to have_attributes(tag_id: tag.id, language_code: 'fr',
-                                         script_code: 'Latn', primary_flg: true)
-    expect(TagName.where(tag_id: tag.id, language_code: 'fr', primary_flg: true).count).to eq(1)
-  end
-end

backend/spec/models/material_export_item_spec.rb

@@ -2,7 +2,7 @@ require 'rails_helper'
 
 RSpec.describe MaterialExportItem, type: :model do
   let(:user) { create(:user, :member) }
-  let(:tag) { create(:tag, primary_name: 'export_item', category: :material) }
+  let(:tag) { Tag.create!(tag_name: TagName.create!(name: 'export_item'), category: :material) }
   let(:material) do
     Material.create!(tag:, url: 'https://example.com/material',
                      created_by_user: user, updated_by_user: user)

backend/spec/models/post_spec.rb

@@ -18,7 +18,7 @@ RSpec.describe Post, type: :model do
       expect(post.snapshot_tags_json).to eq([
           { 'tag_id' => tag.id,
             'version_no' => tag.version_no,
-            'name' => primary_tag_name_for(tag, 'ja').name,
+            'name' => tag.name,
             'category' => tag.category,
             'sections' => [{ 'begin_ms' => 2000, 'end_ms' => nil }] },
           { 'external_tag_id' => external.id }])

backend/spec/models/post_version_spec.rb

@@ -1,8 +1,8 @@
 require 'rails_helper'
 
 RSpec.describe PostVersion, type: :model do
-  let!(:tag_name) { create(:tag_name, name: 'post_version_spec_tag') }
-  let!(:tag) { create(:tag, primary_tag_name: tag_name, category: :general) }
+  let!(:tag_name) { TagName.create!(name: 'post_version_spec_tag') }
+  let!(:tag) { Tag.create!(tag_name: tag_name, category: :general) }
 
   let!(:post_record) do
     Post.create!(title: 'spec post', url: 'https://example.com/post-version-spec').tap do |post|

backend/spec/models/tag_implication_spec.rb

@@ -2,8 +2,8 @@ require 'rails_helper'
 
 RSpec.describe TagImplication, type: :model do
   it 'rejects a parent tag that would create a cycle' do
-    child = create(:tag, primary_name: 'tag_implication_cycle_child')
-    parent = create(:tag, primary_name: 'tag_implication_cycle_parent')
+    child = create(:tag, name: 'tag_implication_cycle_child')
+    parent = create(:tag, name: 'tag_implication_cycle_parent')
 
     described_class.create!(tag: child, parent_tag: parent)
 
@@ -17,9 +17,9 @@ RSpec.describe TagImplication, type: :model do
   end
 
   it 'terminates even when existing data already contains a cycle' do
-    child = create(:tag, primary_name: 'tag_implication_existing_cycle_child')
-    parent = create(:tag, primary_name: 'tag_implication_existing_cycle_parent')
-    ancestor = create(:tag, primary_name: 'tag_implication_existing_cycle_ancestor')
+    child = create(:tag, name: 'tag_implication_existing_cycle_child')
+    parent = create(:tag, name: 'tag_implication_existing_cycle_parent')
+    ancestor = create(:tag, name: 'tag_implication_existing_cycle_ancestor')
 
     described_class.create!(tag: parent, parent_tag: ancestor)
     described_class.insert_all!(

backend/spec/models/tag_name_sanitisation_rule_spec.rb

@@ -34,41 +34,9 @@ RSpec.describe TagNameSanitisationRule, type: :model do
       described_class.create!(priority: 10, source_pattern: '_', replacement: '')
     end
 
-    context 'when only another language has the sanitised name' do
-      include_context 'English locale'
-
-      it 'keeps both names when sanitisation produces a cross-language match' do
-        japanese = create(:tag_name, name: 'foobar')
-        english = create(:tag_name, name: 'temporary',
-                                   language_code: 'en', script_code: 'Latn')
-        english.update_columns(name: 'foo_bar')
-
-        expect { described_class.apply! }.not_to change(TagName, :count)
-
-        expect(english.reload).to have_attributes(name: 'foobar', language_code: 'en')
-        expect(japanese.reload).to have_attributes(name: 'foobar', language_code: 'ja')
-      end
-
-      it 'renames without merging tags or deleting either language identity' do
-        japanese = create(:tag, primary_name: 'foobar')
-        english_name = create(:tag_name, name: 'temporary',
-                                        language_code: 'en', script_code: 'Latn')
-        english = create(:tag, primary_tag_name: english_name)
-        english_name.update_columns(name: 'foo_bar')
-
-        described_class.apply!
-
-        expect(english_name.reload).to have_attributes(
-            name: 'foobar', language_code: 'en', tag_id: english.id)
-        expect(primary_tag_name_for(japanese.reload, 'ja')).to have_attributes(
-            name: 'foobar', language_code: 'ja', tag_id: japanese.id)
-        expect(primary_tag_name_for(english.reload, 'en')).to eq(english_name)
-      end
-    end
-
     context 'when no conflicting tag_name exists' do
       let!(:tag_name) do
-        create(:tag_name, name: 'tmp').tap do |tn|
+        TagName.create!(name: 'tmp').tap do |tn|
           tn.update_columns(name: 'foo_bar', updated_at: Time.current)
         end
       end
@@ -79,10 +47,10 @@ RSpec.describe TagNameSanitisationRule, type: :model do
       end
     end
 
-    context 'when a conflicting primary tag name exists' do
-      let!(:existing) { create(:tag_name, name: 'foobar') }
+    context 'when a conflicting canonical tag_name exists' do
+      let!(:existing) { TagName.create!(name: 'foobar') }
       let!(:source) do
-        create(:tag_name, name: 'tmp').tap do |tn|
+        TagName.create!(name: 'tmp').tap do |tn|
           tn.update_columns(name: 'foo_bar', updated_at: Time.current)
         end
       end
@@ -95,56 +63,48 @@ RSpec.describe TagNameSanitisationRule, type: :model do
     end
 
     context 'when the source tag_name has a tag and the existing one has no tag' do
-      let!(:existing) { create(:tag_name, name: 'foobar') }
-      let!(:source_tag) { create(:tag, primary_name: 'tmp', category: :general) }
-      let!(:source_tag_name_id) { primary_tag_name_for(source_tag, 'ja').id }
+      let!(:existing) { TagName.create!(name: 'foobar') }
+      let!(:source_tag) { create(:tag, name: 'tmp', category: :general) }
+      let!(:source_tag_name_id) { source_tag.tag_name_id }
 
       before do
-        primary_tag_name_for(source_tag, 'ja').update_columns(
-            name: 'foo_bar', updated_at: Time.current)
+        source_tag.tag_name.update_columns(name: 'foo_bar', updated_at: Time.current)
       end
 
       it 'moves the tag to the existing tag_name' do
         described_class.apply!
-        expect(existing.reload).to have_attributes(
-            tag_id: source_tag.id, language_code: 'ja', primary_flg: true)
-        expect(primary_tag_name_for(source_tag, 'ja')).to eq(existing)
-        expect(primary_tag_name_for(source_tag.reload, 'ja')).to eq(existing)
+        expected_tag_name_id = existing.canonical_id || existing.id
+        expect(source_tag.reload.tag_name_id).to eq(expected_tag_name_id)
         expect(TagName.unscoped.exists?(source_tag_name_id)).to be(false)
       end
     end
 
     context 'when the sanitised name is an alias of an existing tag' do
       let!(:existing_tag) { create(:tag) }
-      let!(:existing_primary) { primary_tag_name_for(existing_tag, 'ja') }
       let!(:alias_name) do
-        create(:tag_name, :alias, name: 'foobar', tag: existing_tag)
+        TagName.create!(name: 'foobar', canonical: existing_tag.tag_name)
       end
       let!(:source) do
-        create(:tag_name, name: 'tmp').tap do |tn|
+        TagName.create!(name: 'tmp').tap do |tn|
           tn.update_columns(name: 'foo_bar', updated_at: Time.current)
         end
       end
 
-      it 'deletes only the source and preserves the alias and its owning tag' do
+      it 'deletes only the source and preserves the alias and its canonical tag' do
         described_class.apply!
 
         expect(TagName.unscoped.exists?(source.id)).to be(false)
-        expect(alias_name.reload).to have_attributes(
-            tag_id: existing_tag.id, language_code: 'ja', primary_flg: false)
-        expect(TagName.find_by!(tag_id: existing_tag.id,
-                                language_code: 'ja', primary_flg: true))
-            .to eq(existing_primary)
+        expect(alias_name.reload.canonical).to eq(existing_tag.tag_name)
         expect(Tag.find(existing_tag.id)).to eq(existing_tag)
       end
     end
 
     context 'when both source and existing tag_names have tags' do
-      let!(:existing_tn) { create(:tag_name, name: 'foobar') }
-      let!(:existing_tag) { create(:tag, primary_tag_name: existing_tn, category: :general) }
+      let!(:existing_tn) { TagName.create!(name: 'foobar') }
+      let!(:existing_tag) { Tag.create!(tag_name: existing_tn, category: :general) }
 
-      let!(:source_tn) { create(:tag_name, name: 'tmp') }
-      let!(:source_tag) { create(:tag, primary_tag_name: source_tn, category: :general) }
+      let!(:source_tn) { TagName.create!(name: 'tmp') }
+      let!(:source_tag) { Tag.create!(tag_name: source_tn, category: :general) }
       let!(:source_tag_name_id) { source_tn.id }
 
       before do
@@ -160,7 +120,7 @@ RSpec.describe TagNameSanitisationRule, type: :model do
         expect(Tag.unscoped.exists?(source_tag.id)).to be(false)
         expect(TagName.unscoped.exists?(source_tag_name_id)).to be(false)
         expect(post.reload.tags).to contain_exactly(existing_tag)
-        expect(primary_tag_name_for(existing_tag.reload, 'ja').name).to eq('foobar')
+        expect(existing_tag.reload.name).to eq('foobar')
       end
     end
   end

backend/spec/models/tag_name_spec.rb

@@ -1,127 +0,0 @@
-require 'rails_helper'
-
-RSpec.describe TagName, type: :model do
-  include_context 'English locale'
-
-  it 'allows the same name in different languages' do
-    create(:tag_name, name: 'shared_name')
-    english = build(:tag_name, name: 'shared_name',
-                              language_code: 'en', script_code: 'Latn')
-
-    expect(english).to be_valid
-    expect { english.save! }.to change(described_class, :count).by(1)
-  end
-
-  it 'rejects a duplicate name within the same language' do
-    create(:tag_name, name: 'shared_name')
-    duplicate = build(:tag_name, name: 'shared_name')
-
-    expect(duplicate).to be_invalid
-    expect(duplicate.errors.of_kind?(:name, :taken)).to be(true)
-  end
-
-  it 'creates Japanese factory names without requiring a tag' do
-    name = create(:tag_name)
-
-    expect(name.reload).to have_attributes(
-        language_code: 'ja', script_code: 'Jpan', primary_flg: true, tag_id: nil)
-  end
-
-  it 'persists both sides of the representative tag factory association' do
-    name = create(:tag_name)
-    tag = create(:tag, primary_tag_name: name)
-
-    expect(name.reload).to have_attributes(
-        tag_id: tag.id, language_code: 'ja', script_code: 'Jpan', primary_flg: true)
-    expect(name.tag).to eq(tag)
-    expect(described_class.find_by!(tag_id: tag.id, language_code: 'ja', primary_flg: true))
-        .to eq(name)
-    expect(tag.reload.tag_name_id).to eq(name.id)
-  end
-
-  it 'builds a primary name without persisting the tag or its name' do
-    tag = nil
-
-    expect {
-      tag = build(:tag, primary_name: 'built_primary')
-    }.to change(Tag, :count).by(0).and change(described_class, :count).by(0)
-
-    expect(tag).to be_new_record
-    expect(tag.tag_names.target).to contain_exactly(have_attributes(
-        name: 'built_primary', language_code: 'ja', script_code: 'Jpan',
-        primary_flg: true))
-  end
-
-  it 'persists an alias owned by the same tag as its primary name' do
-    primary_name = create(:tag_name)
-    tag = create(:tag, primary_tag_name: primary_name)
-    alias_name = create(:tag_name, :alias, name: 'valid_alias', tag:)
-
-    expect(alias_name.reload).to have_attributes(
-        tag_id: tag.id,
-        primary_flg: false, language_code: 'ja')
-    primary = described_class.find_by!(tag_id: alias_name.tag_id,
-                                       language_code: alias_name.language_code,
-                                       primary_flg: true)
-    expect(primary).to eq(primary_name)
-  end
-
-  describe '.canonicalise' do
-    it 'leaves detached aliases unchanged' do
-      create(:tag_name, :alias, name: 'detached_alias')
-
-      expect(described_class.canonicalise(Locale.nipponese, ['detached_alias']))
-          .to eq(['detached_alias'])
-    end
-
-    it 'leaves an alias unchanged when its language has no primary' do
-      tag = create(:tag, primary_name: '日本語のみ')
-      create(:tag_name, :alias, tag:, name: 'orphan_english_alias',
-                                language_code: 'en', script_code: 'Latn')
-
-      expect(described_class.canonicalise(locale, ['orphan_english_alias']))
-          .to eq(['orphan_english_alias'])
-    end
-
-    it 'resolves the primary name of the alias language on the same tag' do
-      tag = create(:tag, primary_name: '日本語正本')
-      english_primary = create(:tag_name, tag:, name: 'english_primary',
-                                          language_code: 'en', script_code: 'Latn')
-      english_alias = create(:tag_name, :alias, tag:, name: 'english_alias',
-                                                 language_code: 'en', script_code: 'Latn')
-      representative_id = tag.tag_name_id
-
-      primary = described_class.find_by!(tag_id: english_alias.tag_id,
-                                         language_code: english_alias.language_code,
-                                         primary_flg: true)
-
-      expect(primary).to eq(english_primary)
-      expect(described_class.canonicalise(locale, [english_alias.name]))
-          .to eq([english_primary.name])
-      expect(tag.reload.tag_name_id).to eq(representative_id)
-    end
-
-    it 'resolves only aliases in the requested language' do
-      japanese = create(:tag, primary_name: 'japanese_canonical')
-      english_name = create(:tag_name, name: 'english_canonical',
-                                      language_code: 'en', script_code: 'Latn')
-      english = create(:tag, primary_tag_name: english_name)
-      japanese_alias = create(:tag_name, :alias, name: 'shared_alias',
-                                                 tag: japanese)
-      english_alias = create(:tag_name, :alias, name: 'shared_alias',
-                                                tag: english,
-                                                language_code: 'en', script_code: 'Latn')
-
-      expect(japanese_alias.reload).to have_attributes(
-          tag_id: japanese.id,
-          primary_flg: false, language_code: 'ja')
-      expect(english_alias.reload).to have_attributes(
-          tag_id: english.id,
-          primary_flg: false, language_code: 'en')
-      expect(described_class.canonicalise(locale, ['shared_alias']))
-          .to eq(['english_canonical'])
-      expect(described_class.canonicalise(Locale.nipponese, ['shared_alias']))
-          .to eq(['japanese_canonical'])
-    end
-  end
-end

backend/spec/models/tag_spec.rb

@@ -4,12 +4,12 @@ RSpec.describe Tag, type: :model do
   describe 'external tag separation' do
     ['nico:reserved', 'NiCo:reserved'].each do |name|
       it "rejects the reserved prefix #{ name } for internal tags" do
-        tag = build(:tag, primary_name: name)
+        tag = build(:tag, name:)
 
         expect(tag).to be_invalid
         expect(tag.errors[:name]).to be_present
         expect {
-          described_class.normalise_tags!(Locale.nipponese, [name])
+          described_class.normalise_tags!([name])
         }.to raise_error(Tag::NicoTagNormalisationError)
       end
     end
@@ -25,160 +25,128 @@ RSpec.describe Tag, type: :model do
   end
 
   describe '.normalise_tags!' do
-    it 'canonicalises aliases in the supplied language only' do
-      Language.find_or_create_by!(code: 'en') { _1.name = 'English' }
-      Script.find_or_create_by!(code: 'Latn') { _1.name = 'Latin' }
-      Locale.insert_all!([
-          { code: 'en', language_code: 'en', script_code: 'Latn',
-            name: 'English', created_at: Time.current }]) unless Locale.exists?(code: 'en')
-      english_locale = Locale.find('en')
-      japanese = create(:tag, primary_name: 'japanese_canonical')
-      english_name = create(:tag_name, name: 'english_canonical',
-                                      language_code: 'en', script_code: 'Latn')
-      english = create(:tag, primary_tag_name: english_name)
-      japanese_alias = create(:tag_name, :alias, name: 'shared_alias',
-                                                 tag: japanese)
-      english_alias = create(:tag_name, :alias, name: 'shared_alias',
-                                                tag: english,
-                                                language_code: 'en', script_code: 'Latn')
-
-      expect(japanese_alias.reload).to have_attributes(
-          tag_id: japanese.id,
-          primary_flg: false, language_code: 'ja')
-      expect(english_alias.reload).to have_attributes(
-          tag_id: english.id,
-          primary_flg: false, language_code: 'en')
-      expect(described_class.normalise_tags!(
-          english_locale, ['shared_alias'],
-          with_tagme: false, with_no_deerjikist: false)).to eq([english])
-      expect(described_class.normalise_tags!(
-          Locale.nipponese, ['shared_alias'],
-          with_tagme: false, with_no_deerjikist: false)).to eq([japanese])
-    end
-
     it 'rejects deprecated tags when deny_deprecated is enabled' do
-      tag_name = create(:tag_name, name: 'normalise deprecated tag')
-      deprecated_tag = create(:tag,
-          primary_tag_name: tag_name,
+      tag_name = TagName.create!(name: 'normalise deprecated tag')
+      deprecated_tag = Tag.create!(
+        tag_name:,
         category: :general,
-          deprecated_at: 1.day.from_now)
+        deprecated_at: 1.day.from_now
+      )
 
       expect {
-        described_class.normalise_tags!(Locale.nipponese,
-            [primary_tag_name_for(deprecated_tag, 'ja').name],
-            deny_deprecated: true)
+        described_class.normalise_tags!(
+          [deprecated_tag.name],
+          deny_deprecated: true
+        )
       }.to raise_error(Tag::DeprecatedTagNormalisationError) { |error|
-        expect(error.tag_names).to eq([primary_tag_name_for(deprecated_tag, 'ja').name])
+        expect(error.tag_names).to eq([deprecated_tag.name])
       }
     end
 
     it 'rejects invalid section literals instead of treating them as zero' do
       expect {
-        described_class.normalise_tags!(Locale.nipponese,
+        described_class.normalise_tags!(
           ['normalise_invalid_section[1:aa-2:00]'],
-            with_sections: true)
+          with_sections: true
+        )
       }.to raise_error(Tag::SectionLiteralParseError)
     end
 
     it 'parses open-ended section literals' do
-      result = described_class.normalise_tags!(Locale.nipponese,
+      result = described_class.normalise_tags!(
         ['伊地知ニジカ[1:00-]'],
-          with_sections: true)
+        with_sections: true
+      )
 
-      tag = result.fetch(:tags).find do |candidate|
-        primary_tag_name_for(candidate, 'ja').name == '伊地知ニジカ'
-      end
+      tag = result.fetch(:tags).find { _1.name == '伊地知ニジカ' }
       expect(result.fetch(:sections).fetch(tag.id)).to eq([[60_000, nil]])
     end
 
     it 'parses omitted begin as zero' do
-      result = described_class.normalise_tags!(Locale.nipponese,
+      result = described_class.normalise_tags!(
         ['伊地知ニジカ[-1:00]'],
-          with_sections: true)
+        with_sections: true
+      )
 
-      tag = result.fetch(:tags).find do |candidate|
-        primary_tag_name_for(candidate, 'ja').name == '伊地知ニジカ'
-      end
+      tag = result.fetch(:tags).find { _1.name == '伊地知ニジカ' }
       expect(result.fetch(:sections).fetch(tag.id)).to eq([[0, 60_000]])
     end
 
     it 'treats fully open section literals as plain tags' do
-      result = described_class.normalise_tags!(Locale.nipponese,
+      result = described_class.normalise_tags!(
         ['伊地知ニジカ[-]'],
-          with_sections: true)
+        with_sections: true
+      )
 
-      tag = result.fetch(:tags).find do |candidate|
-        primary_tag_name_for(candidate, 'ja').name == '伊地知ニジカ'
-      end
+      tag = result.fetch(:tags).find { _1.name == '伊地知ニジカ' }
       expect(result.fetch(:sections)[tag.id]).to be_nil
     end
 
     it 'treats [0:00-] as a plain tag' do
-      result = described_class.normalise_tags!(Locale.nipponese,
+      result = described_class.normalise_tags!(
         ['伊地知ニジカ[0:00-]'],
-          with_sections: true)
+        with_sections: true
+      )
 
-      tag = result.fetch(:tags).find do |candidate|
-        primary_tag_name_for(candidate, 'ja').name == '伊地知ニジカ'
-      end
+      tag = result.fetch(:tags).find { _1.name == '伊地知ニジカ' }
       expect(result.fetch(:sections)[tag.id]).to be_nil
     end
 
     it 'expands zero-width sections to one millisecond' do
-      result = described_class.normalise_tags!(Locale.nipponese,
+      result = described_class.normalise_tags!(
         ['伊地知ニジカ[1:00-1:00]'],
-          with_sections: true)
+        with_sections: true
+      )
 
-      tag = result.fetch(:tags).find do |candidate|
-        primary_tag_name_for(candidate, 'ja').name == '伊地知ニジカ'
-      end
+      tag = result.fetch(:tags).find { _1.name == '伊地知ニジカ' }
       expect(result.fetch(:sections).fetch(tag.id)).to eq([[60_000, 60_001]])
     end
 
     it 'swaps reversed section boundaries' do
-      result = described_class.normalise_tags!(Locale.nipponese,
+      result = described_class.normalise_tags!(
         ['伊地知ニジカ[2:00-1:00]'],
-          with_sections: true)
+        with_sections: true
+      )
 
-      tag = result.fetch(:tags).find do |candidate|
-        primary_tag_name_for(candidate, 'ja').name == '伊地知ニジカ'
-      end
+      tag = result.fetch(:tags).find { _1.name == '伊地知ニジカ' }
       expect(result.fetch(:sections).fetch(tag.id)).to eq([[60_000, 120_000]])
     end
 
     it 'merges open-ended sections over later bounded sections' do
-      result = described_class.normalise_tags!(Locale.nipponese,
+      result = described_class.normalise_tags!(
         ['伊地知ニジカ[1:00-][2:00-3:00]'],
-          with_sections: true)
+        with_sections: true
+      )
 
-      tag = result.fetch(:tags).find do |candidate|
-        primary_tag_name_for(candidate, 'ja').name == '伊地知ニジカ'
-      end
+      tag = result.fetch(:tags).find { _1.name == '伊地知ニジカ' }
       expect(result.fetch(:sections).fetch(tag.id)).to eq([[60_000, nil]])
     end
 
     it 'merges adjacent bounded and open-ended sections' do
-      result = described_class.normalise_tags!(Locale.nipponese,
+      result = described_class.normalise_tags!(
         ['伊地知ニジカ[1:00-3:00][3:00-]'],
-          with_sections: true)
+        with_sections: true
+      )
 
-      tag = result.fetch(:tags).find do |candidate|
-        primary_tag_name_for(candidate, 'ja').name == '伊地知ニジカ'
-      end
+      tag = result.fetch(:tags).find { _1.name == '伊地知ニジカ' }
       expect(result.fetch(:sections).fetch(tag.id)).to eq([[60_000, nil]])
     end
   end
 
   describe '.expand_parent_tags' do
     it 'expands through multiple deprecated parents to an active ancestor' do
-      child = create(:tag, primary_name: 'expand_child')
-      deprecated_parent = create(:tag,
-          primary_name: 'expand_deprecated_parent',
-          deprecated_at: Time.current)
-      deprecated_grandparent = create(:tag,
-          primary_name: 'expand_deprecated_grandparent',
-          deprecated_at: Time.current)
-      active_ancestor = create(:tag, primary_name: 'expand_active_ancestor')
+      child = create(:tag, name: 'expand_child')
+      deprecated_parent = create(
+        :tag,
+        name: 'expand_deprecated_parent',
+        deprecated_at: Time.current
+      )
+      deprecated_grandparent = create(
+        :tag,
+        name: 'expand_deprecated_grandparent',
+        deprecated_at: Time.current
+      )
+      active_ancestor = create(:tag, name: 'expand_active_ancestor')
       TagImplication.create!(tag: child, parent_tag: deprecated_parent)
       TagImplication.create!(tag: deprecated_parent, parent_tag: deprecated_grandparent)
       TagImplication.create!(tag: deprecated_grandparent, parent_tag: active_ancestor)
@@ -195,8 +163,8 @@ RSpec.describe Tag, type: :model do
     end
 
     it 'terminates when implications contain a cycle' do
-      first = create(:tag, primary_name: 'expand_cycle_first')
-      second = create(:tag, primary_name: 'expand_cycle_second')
+      first = create(:tag, name: 'expand_cycle_first')
+      second = create(:tag, name: 'expand_cycle_second')
       TagImplication.create!(tag: first, parent_tag: second)
       now = Time.current
       TagImplication.insert_all!(
@@ -215,156 +183,55 @@ RSpec.describe Tag, type: :model do
   end
 
   describe '.find_or_create_by_tag_name!' do
-    context 'with an explicit locale' do
-      include_context 'English locale'
-
-      it 'creates the representative name with locale attributes and ownership' do
-        tag = described_class.find_or_create_by_tag_name!(
-            locale, 'english_name', category: :character)
-
-        expect(primary_tag_name_for(tag, 'en')).to have_attributes(
-            language_code: 'en', script_code: 'Latn',
-            primary_flg: true, tag_id: tag.id)
-        expect(tag.category).to eq('character')
-      end
-
-      it 'creates separate tag identities for the same name in different languages' do
-        japanese = described_class.find_or_create_by_tag_name!(
-            Locale.nipponese, 'same_name', category: :general)
-        english = described_class.find_or_create_by_tag_name!(
-            locale, 'same_name', category: :character)
-
-        expect(english).not_to eq(japanese)
-        expect(primary_tag_name_for(english, 'en')).to have_attributes(
-            name: 'same_name', tag_id: english.id, language_code: 'en', primary_flg: true)
-        expect(primary_tag_name_for(japanese, 'ja')).to have_attributes(
-            name: 'same_name', tag_id: japanese.id, language_code: 'ja', primary_flg: true)
-        expect(described_class.find_or_create_by_tag_name!(
-            locale, 'same_name', category: :general)).to eq(english)
-        expect(described_class.find_or_create_by_tag_name!(
-            Locale.nipponese, 'same_name', category: :general)).to eq(japanese)
-      end
-
-      it 'preserves the V1 representative when looking up another primary language' do
-        tag = create(:tag, primary_name: '日本語代表名')
-        representative_id = tag.tag_name_id
-        english = create(:tag_name, name: 'english_primary', tag:,
-            language_code: 'en', script_code: 'Latn')
-
-        found = described_class.find_or_create_by_tag_name!(
-            locale, english.name, category: :general)
-
-        expect(found).to eq(tag)
-        expect(tag.reload.tag_name_id).to eq(representative_id)
-        expect(english.reload.tag_id).to eq(tag.id)
-      end
-
-      it 'normalises names using the supplied locale' do
-        tags = described_class.normalise_tags!(
-            locale, ['character:normalised_english'],
-            with_tagme: false, with_no_deerjikist: false)
-
-        expect(tags.length).to eq(1)
-        expect(primary_tag_name_for(tags.first, 'en')).to have_attributes(
-            name: 'normalised_english', language_code: 'en', script_code: 'Latn',
-            primary_flg: true, tag_id: tags.first.id)
-      end
-    end
-
     it 'creates a tag and name with the requested category after stripping whitespace' do
       tag = nil
 
       expect {
-        tag = described_class.find_or_create_by_tag_name!(Locale.nipponese,
+        tag = described_class.find_or_create_by_tag_name!(
             '  lookup_new  ', category: :character)
       }.to change(Tag, :count).by(1).and change(TagName, :count).by(1)
 
-      expect(primary_tag_name_for(tag, 'ja').name).to eq('lookup_new')
+      expect(tag.name).to eq('lookup_new')
       expect(tag.category).to eq('character')
     end
 
-    it 'reuses the owning tag for an alias without changing its category' do
+    it 'reuses the canonical tag for an alias without changing its category' do
       tag = create(:tag, category: :character)
-      representative_id = tag.tag_name_id
-      alias_name = create(:tag_name, :alias, name: 'lookup_alias', tag:)
-      expect(alias_name.reload).to have_attributes(
-          tag_id: tag.id,
-          primary_flg: false, language_code: 'ja')
+      alias_name = TagName.create!(name: 'lookup_alias', canonical: tag.tag_name)
       found = nil
 
       expect {
-        found = described_class.find_or_create_by_tag_name!(Locale.nipponese,
+        found = described_class.find_or_create_by_tag_name!(
             alias_name.name, category: :general)
       }.to change(Tag, :count).by(0).and change(TagName, :count).by(0)
 
       expect(found).to eq(tag)
       expect(found.category).to eq('character')
-      expect(tag.reload.tag_name_id).to eq(representative_id)
     end
 
-    it 'reuses the owning tag through another alias' do
-      tag = create(:tag)
-      primary = primary_tag_name_for(tag, 'ja')
-      alias_name = create(:tag_name, :alias, name: 'lookup_alias', tag:)
-      other_alias = create(:tag_name, :alias, name: 'lookup_other_alias', tag:)
-
-      expect([alias_name.reload, other_alias.reload]).to all(have_attributes(
-          tag_id: tag.id,
-          primary_flg: false, language_code: 'ja'))
+    it 'creates a tag for an existing canonical name reached through an alias' do
+      canonical = create(:tag_name)
+      alias_name = TagName.create!(name: 'lookup_alias', canonical:)
+      tag = nil
 
       expect {
-        found = described_class.find_or_create_by_tag_name!(Locale.nipponese,
+        tag = described_class.find_or_create_by_tag_name!(
             alias_name.name, category: :general)
-        expect(found).to eq(tag)
-      }.to change(Tag, :count).by(0).and change(TagName, :count).by(0)
+      }.to change(Tag, :count).by(1).and change(TagName, :count).by(0)
 
-      expect(primary_tag_name_for(tag.reload, 'ja')).to eq(primary)
+      expect(tag.tag_name).to eq(canonical)
     end
   end
 
   describe '.merge_tags!' do
     let!(:target_tag) { create(:tag, category: :general) }
     let!(:source_tag) { create(:tag, category: :general) }
-    let!(:source_tag_name) { primary_tag_name_for(source_tag, 'ja') }
+    let!(:source_tag_name) { source_tag.tag_name }
 
     let!(:post_record) do
       Post.create!(url: 'https://example.com/posts/1', title: 'test post')
     end
 
-    context 'with names in multiple languages' do
-      include_context 'English locale'
-
-      it 'keeps the target primary and moves source names as aliases' do
-        english_primary = create(:tag_name, tag: target_tag,
-            name: 'target_english', language_code: 'en', script_code: 'Latn')
-        source_primary = create(:tag_name, tag: source_tag,
-            name: 'source_english', language_code: 'en', script_code: 'Latn')
-        source_alias = create(:tag_name, :alias, tag: source_tag,
-            name: 'source_english_alias', language_code: 'en', script_code: 'Latn')
-
-        described_class.merge_tags!(target_tag, [source_tag])
-
-        expect(primary_tag_name_for(target_tag.reload, 'en')).to eq(english_primary)
-        expect([source_primary.reload, source_alias.reload]).to all(have_attributes(
-            tag_id: target_tag.id, language_code: 'en', primary_flg: false))
-      end
-
-      it 'inherits a source primary when the target has no name in that language' do
-        source_primary = create(:tag_name, tag: source_tag,
-            name: 'inherited_english', language_code: 'en', script_code: 'Latn')
-        source_alias = create(:tag_name, :alias, tag: source_tag,
-            name: 'inherited_alias', language_code: 'en', script_code: 'Latn')
-
-        described_class.merge_tags!(target_tag, [source_tag])
-
-        expect(primary_tag_name_for(target_tag.reload, 'en')).to eq(source_primary)
-        expect(source_primary.reload).to have_attributes(
-            tag_id: target_tag.id, language_code: 'en', primary_flg: true)
-        expect(source_alias.reload).to have_attributes(
-            tag_id: target_tag.id, language_code: 'en', primary_flg: false)
-      end
-    end
-
     context 'when merging a simple source tag' do
       let!(:source_post_tag) { PostTag.create!(post: post_record, tag: source_tag) }
 
@@ -376,8 +243,7 @@ RSpec.describe Tag, type: :model do
         expect(PostTag.exists?(post: post_record, tag: source_tag)).to be(false)
         expect(target_link).to be_present
         expect(Tag.unscoped.exists?(source_tag.id)).to be(false)
-        expect(source_tag_name.reload).to have_attributes(
-            tag_id: target_tag.id, language_code: 'ja', primary_flg: false)
+        expect(source_tag_name.reload.canonical_id).to eq(target_tag.tag_name_id)
         expect(target_tag.reload.post_count).to eq(1)
       end
     end
@@ -403,16 +269,15 @@ RSpec.describe Tag, type: :model do
         expect(target_post_tag.reload.sections).to contain_exactly(target_section)
 
         expect(Tag.unscoped.exists?(source_tag.id)).to be(false)
-        expect(source_tag_name.reload).to have_attributes(
-            tag_id: target_tag.id, language_code: 'ja', primary_flg: false)
+        expect(source_tag_name.reload.canonical_id).to eq(target_tag.tag_name_id)
         expect(target_tag.reload.post_count).to eq(1)
       end
     end
 
     it 'keeps source history and records the new target alias after deleting the source' do
       user = create_member_user!
-      source_name = primary_tag_name_for(source_tag, 'ja').name
-      source_alias = create(:tag_name, :alias, name: 'merge_alias', tag: source_tag)
+      source_name = source_tag.name
+      source_alias = TagName.create!(name: 'merge_alias', canonical: source_tag_name)
       TagVersioning.ensure_snapshot!(source_tag, created_by_user: user)
       original_version = source_tag.tag_versions.first
 
@@ -422,20 +287,13 @@ RSpec.describe Tag, type: :model do
       expect(versions.pluck(:version_no, :event_type))
           .to eq([[1, 'create'], [2, 'discard']])
       expect(versions.first).to eq(original_version)
-      expect(versions.last.created_by_user).to eq(user)
-      expect(versions.last.names).to include(
-          hash_including('language_code' => 'ja', 'name' => source_name,
-                         'primary_flg' => true, 'auto_generated' => false),
-          hash_including('language_code' => 'ja', 'name' => source_alias.name,
-                         'primary_flg' => false, 'auto_generated' => false))
+      expect(versions.last).to have_attributes(
+          name: source_name, aliases: source_alias.name, created_by_user: user)
       expect(Tag.unscoped.exists?(source_tag.id)).to be(false)
 
       target_versions = target_tag.tag_versions.order(:version_no)
       expect(target_versions.pluck(:event_type)).to eq(['create', 'update'])
-      target_aliases = target_versions.last.names.filter_map { |name|
-        name['name'] if name['language_code'] == 'ja' && !name['primary_flg']
-      }
-      expect(target_aliases).to contain_exactly('merge_alias', source_name)
+      expect(target_versions.last.aliases.split).to eq([source_name])
     end
 
     it 'deletes source relationships while preserving unrelated relationships' do
@@ -489,8 +347,7 @@ RSpec.describe Tag, type: :model do
         expect(Tag.unscoped.exists?(source_tag.id)).to be(false)
         expect(PostTag.exists?(post: post_record, tag: source_tag)).to be(false)
         expect(target_link).to be_present
-        expect(source_tag_name.reload).to have_attributes(
-            tag_id: target_tag.id, language_code: 'ja', primary_flg: false)
+        expect(source_tag_name.reload.canonical_id).to eq(target_tag.tag_name_id)
         expect(target_tag.reload.post_count).to eq(1)
       end
     end
@@ -521,8 +378,7 @@ RSpec.describe Tag, type: :model do
         expect(target_link).to be_present
 
         expect(Tag.unscoped.exists?(source_tag.id)).to be(false)
-        expect(source_tag_name.reload).to have_attributes(
-            tag_id: target_tag.id, language_code: 'ja', primary_flg: false)
+        expect(source_tag_name.reload.canonical_id).to eq(target_tag.tag_name_id)
         expect(target_tag.reload.post_count).to eq(1)
       end
     end
@@ -541,7 +397,7 @@ RSpec.describe Tag, type: :model do
 
       it 'rolls back earlier deletions, links, and history when a later source has a wiki' do
         earlier_source = create(:tag)
-        earlier_name = primary_tag_name_for(earlier_source, 'ja')
+        earlier_name = earlier_source.tag_name
         source_section = create(:post_tag_section, post: post_record,
                                                    tag: source_tag,
                                                    begin_ms: 1000, end_ms: 2000)
@@ -551,8 +407,7 @@ RSpec.describe Tag, type: :model do
         }.to raise_error(ActiveRecord::RecordInvalid)
 
         expect(Tag.unscoped.exists?(earlier_source.id)).to be(true)
-        expect(earlier_name.reload).to have_attributes(
-            tag_id: earlier_source.id, language_code: 'ja', primary_flg: true)
+        expect(earlier_name.reload.canonical_id).to be_nil
         expect(TagVersion.where(tag_id: [earlier_source.id, source_tag.id, target_tag.id]))
             .to be_empty
         expect(Tag.unscoped.exists?(source_tag.id)).to be(true)
@@ -561,8 +416,7 @@ RSpec.describe Tag, type: :model do
         expect(source_post_tag.sections).to contain_exactly(source_section)
         expect(PostTag.find_by(post: post_record, tag: target_tag)).to be_nil
         expect(source_tag.reload.post_count).to eq(1)
-        expect(source_tag_name.reload).to have_attributes(
-            tag_id: source_tag.id, language_code: 'ja', primary_flg: true)
+        expect(source_tag_name.reload.canonical_id).to be_nil
         expect(target_tag.reload.post_count).to eq(0)
       end
     end

backend/spec/models/version_record_spec.rb

@@ -1,7 +1,7 @@
 require 'rails_helper'
 
 RSpec.describe VersionRecord, type: :model do
-  let!(:tag) { create(:tag, primary_name: 'version_record_tag') }
+  let!(:tag) { create(:tag, name: 'version_record_tag') }
   let!(:nico_tag) { create(:external_tag, name: 'version_record_tag') }
 
   it 'makes TagVersion read only after create' do
@@ -9,11 +9,9 @@ RSpec.describe VersionRecord, type: :model do
       tag: tag,
       version_no: 1,
       event_type: 'create',
-      name: primary_tag_name_for(tag, 'ja').name,
+      name: tag.name,
       category: tag.category,
       aliases: '',
-      names: [{ language_code: 'ja', name: primary_tag_name_for(tag, 'ja').name,
-                script_code: 'Jpan', primary_flg: true }],
       parent_tag_ids: '',
       created_at: Time.current,
       created_by_user: nil
@@ -29,11 +27,9 @@ RSpec.describe VersionRecord, type: :model do
       tag: tag,
       version_no: 1,
       event_type: 'create',
-      name: primary_tag_name_for(tag, 'ja').name,
+      name: tag.name,
       category: tag.category,
       aliases: '',
-      names: [{ language_code: 'ja', name: primary_tag_name_for(tag, 'ja').name,
-                script_code: 'Jpan', primary_flg: true }],
       parent_tag_ids: '',
       created_at: Time.current,
       created_by_user: nil

backend/spec/requests/deerjikists_spec.rb

@@ -30,7 +30,7 @@ RSpec.describe 'Deerjikists API', type: :request do
 
         expect(json['tag']).to be_a(Hash)
         expect(json['tag']['id']).to eq(tag1.id)
-        expect(json['tag']['name']).to eq(primary_tag_name_for(tag1, 'ja').name)
+        expect(json['tag']['name']).to eq(tag1.name)
       end
     end
 

backend/spec/requests/error_responses_spec.rb

@@ -15,7 +15,7 @@ RSpec.describe 'error responses', type: :request do
 
     it 'returns a stable field-error payload for unprocessable requests' do
       member = create(:user, :member)
-      tag = create(:tag, category: :general, primary_name: 'error_response_tag')
+      tag = create(:tag, :general, name: 'error_response_tag')
       sign_in_as(member)
 
       patch "/tags/#{ tag.id }", params: { category: 'nico' }

backend/spec/requests/gekanator_learning_spec.rb

@@ -898,22 +898,23 @@ RSpec.describe 'Gekanator learning API', type: :request do
 
   describe 'GET /gekanator/questions' do
     it 'omits questions for deprecated tags' do
-      active_tag = create(:tag, primary_name: 'active_question_tag', category: :general)
-      deprecated_tag = create(:tag,
-          primary_name: 'deprecated_question_tag',
+      active_tag = Tag.create!(name: 'active_question_tag', category: :general)
+      deprecated_tag = Tag.create!(
+        name: 'deprecated_question_tag',
         category: :general,
-          deprecated_at: Time.current)
+        deprecated_at: Time.current
+      )
 
       [active_tag, deprecated_tag].each do |question_tag|
         GekanatorQuestion.create!(
-          text: "#{ primary_tag_name_for(question_tag, 'ja').name }?",
+          text: "#{ question_tag.name }?",
           kind: 'tag',
           source: 'admin_curated',
           status: 'accepted',
           priority_weight: 1.0,
           condition: {
             type: 'tag',
-            key: "#{ question_tag.category }:#{ primary_tag_name_for(question_tag, 'ja').name }"
+            key: "#{ question_tag.category }:#{ question_tag.name }"
           },
           created_by: admin
         )

backend/spec/requests/gekanator_posts_spec.rb

@@ -4,11 +4,12 @@ require 'rails_helper'
 RSpec.describe 'Gekanator posts API', type: :request do
   describe 'GET /gekanator/posts' do
     it 'omits deprecated tags and returns the stored similarity cosine' do
-      active_tag = create(:tag, primary_name: 'active tag', category: :general)
-      deprecated_tag = create(:tag,
-          primary_name: 'deprecated tag',
+      active_tag = Tag.create!(name: 'active tag', category: :general)
+      deprecated_tag = Tag.create!(
+        name: 'deprecated tag',
         category: :general,
-          deprecated_at: Time.current)
+        deprecated_at: Time.current
+      )
       post_record = Post.create!(title: 'source', url: 'https://example.com/source')
       target_post = Post.create!(title: 'target', url: 'https://example.com/target')
 

backend/spec/requests/locale_write_paths_spec.rb

@@ -1,237 +0,0 @@
-require 'rails_helper'
-
-RSpec.describe 'Locale propagation on write paths', type: :request do
-  include_context 'English locale'
-
-  let(:member) { create(:user, :member) }
-
-  before do
-    sign_in_as(member)
-  end
-
-  def expect_localised_tag(name, expected_locale)
-    tag_name = TagName.find_by!(name:, language_code: expected_locale.language_code)
-    expect(tag_name).to have_attributes(
-        script_code: expected_locale.script_code, primary_flg: true)
-    expect(tag_name.tag_id).to be_present
-    tag_name.tag
-  end
-
-  ['en', nil].each do |requested_locale|
-    context "with locale #{ requested_locale.inspect }" do
-      let(:locale_params) { requested_locale ? { locale: requested_locale } : { } }
-      let(:expected_locale) { requested_locale ? locale : Locale.nipponese }
-
-      it 'creates post tags in the requested language or Japanese fallback' do
-        post '/posts', params: locale_params.merge(
-            title: 'Locale post', url: 'https://example.com/locale-post',
-            tags: 'locale_post_tag', parent_post_ids: '')
-
-        expect(response).to have_http_status(:created), response.body
-        tag = expect_localised_tag('locale_post_tag', expected_locale)
-        expect(Post.find(json.fetch('id')).tags).to include(tag)
-      end
-
-      it 'updates post tags in the requested language or Japanese fallback' do
-        record = create(:post)
-        PostVersionRecorder.record!(post: record, event_type: :create, created_by_user: member)
-
-        put "/posts/#{ record.id }", params: locale_params.merge(
-            title: record.title, tags: 'locale_updated_tag', parent_post_ids: '',
-            base_version_no: record.reload.version_no)
-
-        expect(response).to have_http_status(:ok), response.body
-        tag = expect_localised_tag('locale_updated_tag', expected_locale)
-        expect(record.reload.tags).to include(tag)
-      end
-
-      it 'passes the resolved locale to bulk creation' do
-        # Worker propagation is exercised in post_bulk_creator_spec.
-        expect_any_instance_of(PostBulkCreator).to receive(:run)
-            .with(expected_locale).and_return(results: [])
-        manifest = [{ title: 'Bulk locale', url: 'https://example.com/bulk-locale',
-                      tags: 'bulk_locale_tag', parent_post_ids: '' }]
-
-        post '/posts/bulk', params: locale_params.merge(posts: JSON.generate(manifest)),
-                            headers: { 'CONTENT_TYPE' => 'multipart/form-data' }
-
-        expect(response).to have_http_status(:ok), response.body
-      end
-
-      it 'creates materials with tags in the resolved locale' do
-        post '/materials', params: locale_params.merge(
-            tag: 'locale_material', url: 'https://example.com/material')
-
-        expect(response).to have_http_status(:created), response.body
-        tag = expect_localised_tag('locale_material', expected_locale)
-        expect(Material.find(json.fetch('id')).tag).to eq(tag)
-      end
-
-      it 'updates materials with tags in the resolved locale' do
-        tag = create(:tag, category: :material)
-        material = Material.create!(tag:, url: 'https://example.com/material')
-
-        put "/materials/#{ material.id }", params: locale_params.merge(
-            tag: 'locale_material_updated', url: material.url)
-
-        expect(response).to have_http_status(:ok), response.body
-        resolved_tag = expect_localised_tag('locale_material_updated', expected_locale)
-        expect(material.reload.tag).to eq(resolved_tag)
-      end
-
-      it 'links Nico external tags to internal tags in the resolved locale' do
-        external = create(:external_tag)
-        NicoTagVersionRecorder.record!(
-            external_tag: external, event_type: :create, created_by_user: member)
-
-        put "/tags/nico/#{ external.id }", params: locale_params.merge(tags: 'locale_link')
-
-        expect(response).to have_http_status(:ok), response.body
-        tag = expect_localised_tag('locale_link', expected_locale)
-        expect(external.reload.linked_tags).to contain_exactly(tag)
-      end
-
-      it 'creates parent tags in the resolved locale' do
-        tag = create(:tag)
-
-        put "/tags/#{ tag.id }", params: locale_params.merge(
-            name: primary_tag_name_for(tag, 'ja').name, category: tag.category, deprecated: false,
-            aliases: '', parent_tags: 'locale_parent')
-
-        expect(response).to have_http_status(:ok), response.body
-        parent = expect_localised_tag('locale_parent', expected_locale)
-        expect(TagImplication.where(tag:).pluck(:parent_tag_id)).to eq([parent.id])
-      end
-    end
-  end
-
-  context 'with existing names in both languages' do
-    let!(:english_name) do
-      create(:tag_name, name: 'shared_name', language_code: 'en', script_code: 'Latn')
-    end
-    let!(:english_tag) { create(:tag, primary_tag_name: english_name, category: :material) }
-    let!(:japanese_tag) do
-      create(:tag, primary_name: 'temporary_japanese', category: :general).tap do |tag|
-        # Isolate lookup from the separately tested uniqueness validation.
-        primary_tag_name_for(tag, 'ja').update_columns(name: 'shared_name')
-      end
-    end
-
-    it 'plans and creates the post using the English identity and category' do
-      post '/posts', params: {
-          locale: 'en', title: 'English identity',
-          url: 'https://example.com/english-identity', tags: 'shared_name', parent_post_ids: '' }
-
-      expect(response).to have_http_status(:created), response.body
-      record = Post.find(json.fetch('id'))
-      expect(record.tags).to include(english_tag)
-      expect(record.tags).not_to include(japanese_tag)
-      expect(english_tag.reload.category).to eq('material')
-      expect(japanese_tag.reload.category).to eq('general')
-    end
-
-    it 'updates the post using the English identity' do
-      record = create(:post)
-      PostVersionRecorder.record!(post: record, event_type: :create, created_by_user: member)
-
-      put "/posts/#{ record.id }", params: {
-          locale: 'en', title: record.title, tags: 'shared_name', parent_post_ids: '',
-          base_version_no: record.reload.version_no }
-
-      expect(response).to have_http_status(:ok), response.body
-      expect(record.reload.tags).to include(english_tag)
-      expect(record.tags).not_to include(japanese_tag)
-    end
-
-    it 'resolves the English material tag' do
-      post '/materials', params: {
-          locale: 'en', tag: 'shared_name', url: 'https://example.com/english-material' }
-
-      expect(response).to have_http_status(:created), response.body
-      expect(Material.find(json.fetch('id')).tag).to eq(english_tag)
-      expect(Material.where(tag: japanese_tag)).to be_empty
-    end
-
-    it 'resolves the English parent tag' do
-      child = create(:tag)
-
-      put "/tags/#{ child.id }", params: {
-          locale: 'en', name: primary_tag_name_for(child, 'ja').name,
-          category: child.category, deprecated: false,
-          aliases: '', parent_tags: 'shared_name' }
-
-      expect(response).to have_http_status(:ok), response.body
-      expect(TagImplication.where(tag: child).pluck(:parent_tag_id)).to eq([english_tag.id])
-    end
-
-    it 'resolves the English internal tag for a Nico link' do
-      external = create(:external_tag)
-      NicoTagVersionRecorder.record!(
-          external_tag: external, event_type: :create, created_by_user: member)
-
-      put "/tags/nico/#{ external.id }", params: { locale: 'en', tags: 'shared_name' }
-
-      expect(response).to have_http_status(:ok), response.body
-      expect(external.reload.linked_tags).to contain_exactly(english_tag)
-    end
-  end
-
-  context 'when renaming or updating aliases in English' do
-    let!(:english_name) do
-      create(:tag_name, name: 'english_original', language_code: 'en', script_code: 'Latn')
-    end
-    let!(:tag) { create(:tag, primary_tag_name: english_name) }
-
-    it 'allows a rename to a name already used in Japanese' do
-      japanese = create(:tag, primary_name: 'rename_target')
-
-      patch "/tags/#{ tag.id }", params: { locale: 'en', name: 'rename_target' }
-
-      expect(response).to have_http_status(:ok), response.body
-      expect(primary_tag_name_for(tag.reload, 'en')).to have_attributes(
-          name: 'rename_target', language_code: 'en', tag_id: tag.id)
-      expect(primary_tag_name_for(japanese.reload, 'ja')).to have_attributes(
-          name: 'rename_target', language_code: 'ja', tag_id: japanese.id)
-    end
-
-    it 'creates aliases in the requested language' do
-      put "/tags/#{ tag.id }", params: {
-          locale: 'en', name: english_name.name,
-          category: tag.category, deprecated: false,
-          aliases: 'english_alias', parent_tags: '' }
-
-      expect(response).to have_http_status(:ok), response.body
-      expect(TagName.find_by!(language_code: 'en', name: 'english_alias'))
-          .to have_attributes(
-              script_code: 'Latn',
-              tag_id: tag.id, primary_flg: false, language_code: 'en')
-      primary = TagName.find_by!(tag_id: tag.id, language_code: 'en', primary_flg: true)
-      expect(primary).to have_attributes(name: 'english_original', script_code: 'Latn')
-    end
-
-    it 'does not take an alias from another language' do
-      japanese = create(:tag, primary_name: 'japanese_owner')
-      japanese_alias = create(:tag_name, :alias, name: 'shared_alias',
-                                                tag: japanese)
-      expect(japanese_alias.reload).to have_attributes(
-          tag_id: japanese.id,
-          primary_flg: false, language_code: 'ja')
-
-      put "/tags/#{ tag.id }", params: {
-          locale: 'en', name: english_name.name,
-          category: tag.category, deprecated: false,
-          aliases: 'shared_alias', parent_tags: '' }
-
-      expect(response).to have_http_status(:ok), response.body
-      expect(japanese_alias.reload).to have_attributes(
-          tag_id: japanese.id,
-          primary_flg: false, language_code: 'ja')
-      expect(TagName.find_by!(language_code: 'en', name: 'shared_alias'))
-          .to have_attributes(
-              tag_id: tag.id, script_code: 'Latn',
-              primary_flg: false, language_code: 'en')
-      expect(TagName.where(name: 'shared_alias').pluck(:language_code, :tag_id))
-          .to contain_exactly(['ja', japanese.id], ['en', tag.id])
-    end
-  end
-end

backend/spec/requests/materials_spec.rb

@@ -26,10 +26,10 @@ RSpec.describe 'Materials API', type: :request do
 
   describe 'GET /materials' do
     let!(:tag_a) do
-      create(:tag, primary_name: 'material_index_a', category: :material)
+      Tag.create!(tag_name: TagName.create!(name: 'material_index_a'), category: :material)
     end
     let!(:tag_b) do
-      create(:tag, primary_name: 'material_index_b', category: :material)
+      Tag.create!(tag_name: TagName.create!(name: 'material_index_b'), category: :material)
     end
 
     let!(:material_a) do
@@ -116,20 +116,20 @@ RSpec.describe 'Materials API', type: :request do
 
     it 'filters by descendant tags and returns stable parent tag groups' do
       root =
-          create(:tag, primary_name: 'material_scope_root',
+          Tag.create!(tag_name: TagName.create!(name: 'material_scope_root'),
                       category: :material)
       child_b =
-          create(:tag, primary_name: 'material_scope_b',
+          Tag.create!(tag_name: TagName.create!(name: 'material_scope_b'),
                       category: :material)
       child_a =
-          create(:tag, primary_name: 'material_scope_a',
+          Tag.create!(tag_name: TagName.create!(name: 'material_scope_a'),
                       category: :material)
       deprecated =
-          create(:tag, primary_name: 'material_scope_old',
+          Tag.create!(tag_name: TagName.create!(name: 'material_scope_old'),
                       category: :material,
                       deprecated_at: Time.current)
       grandchild =
-          create(:tag, primary_name: 'material_scope_grandchild',
+          Tag.create!(tag_name: TagName.create!(name: 'material_scope_grandchild'),
                       category: :material)
       root_material =
           build_material(tag: root, user: member_user,
@@ -179,7 +179,7 @@ RSpec.describe 'Materials API', type: :request do
 
   describe 'GET /materials/:id' do
     let!(:tag) do
-      create(:tag, primary_name: 'material_show', category: :material)
+      Tag.create!(tag_name: TagName.create!(name: 'material_show'), category: :material)
     end
     let!(:material) do
       build_material(tag:, user: member_user, file: dummy_upload(filename: 'show.png'))
@@ -269,7 +269,7 @@ RSpec.describe 'Materials API', type: :request do
         expect(response).to have_http_status(:created)
 
         material = Material.order(:id).last
-        expect(primary_tag_name_for(material.tag, 'ja').name).to eq('material_create_new')
+        expect(material.tag.name).to eq('material_create_new')
         expect(material.tag.category).to eq('material')
         expect(material.created_by_user).to eq(member_user)
         expect(material.updated_by_user).to eq(member_user)
@@ -297,8 +297,7 @@ RSpec.describe 'Materials API', type: :request do
 
         expect(response).to have_http_status(:created)
 
-        tag = TagName.find_by!(name: 'material_create_versioned_tag',
-                               language_code: 'ja', primary_flg: true).tag
+        tag = Tag.joins(:tag_name).find_by!(tag_names: { name: 'material_create_versioned_tag' })
         version = tag.tag_versions.order(:version_no).last
 
         expect(version.event_type).to eq('create')
@@ -324,8 +323,8 @@ RSpec.describe 'Materials API', type: :request do
       end
 
       it 'returns 422 when the existing tag is not material/character' do
-        general_tag_name = create(:tag_name, name: 'material_create_general_tag')
-        create(:tag, primary_tag_name: general_tag_name, category: :general)
+        general_tag_name = TagName.create!(name: 'material_create_general_tag')
+        Tag.create!(tag_name: general_tag_name, category: :general)
 
         post '/materials', params: {
           tag: 'material_create_general_tag',
@@ -346,7 +345,7 @@ RSpec.describe 'Materials API', type: :request do
         expect(response).to have_http_status(:created)
 
         material = Material.order(:id).last
-        expect(primary_tag_name_for(material.tag, 'ja').name).to eq('material_create_url_only')
+        expect(material.tag.name).to eq('material_create_url_only')
         expect(material.url).to eq('https://example.com/material-source')
         expect(material.file.attached?).to be(false)
       end
@@ -385,7 +384,7 @@ RSpec.describe 'Materials API', type: :request do
 
   describe 'PUT /materials/:id' do
     let!(:tag) do
-      create(:tag, primary_name: 'material_update_old', category: :material)
+      Tag.create!(tag_name: TagName.create!(name: 'material_update_old'), category: :material)
     end
     let!(:material) do
       build_material(tag:, user: member_user, file: dummy_upload(filename: 'old.png'))
@@ -464,7 +463,7 @@ RSpec.describe 'Materials API', type: :request do
         expect(response).to have_http_status(:ok)
 
         material.reload
-        expect(primary_tag_name_for(material.tag, 'ja').name).to eq('material_update_new')
+        expect(material.tag.name).to eq('material_update_new')
         expect(material.tag.category).to eq('material')
         expect(material.url).to eq('https://example.com/updated-source')
         expect(material.updated_by_user).to eq(member_user)
@@ -498,8 +497,7 @@ RSpec.describe 'Materials API', type: :request do
 
         expect(response).to have_http_status(:ok)
 
-        tag = TagName.find_by!(name: 'material_update_versioned_tag',
-                               language_code: 'ja', primary_flg: true).tag
+        tag = Tag.joins(:tag_name).find_by!(tag_names: { name: 'material_update_versioned_tag' })
         version = tag.tag_versions.order(:version_no).last
 
         expect(version.event_type).to eq('create')
@@ -510,7 +508,7 @@ RSpec.describe 'Materials API', type: :request do
 
       it 'backfills a create tag_version for an existing material tag without history' do
         existing_tag =
-            create(:tag, primary_name: 'material_update_existing_no_history',
+            Tag.create!(tag_name: TagName.create!(name: 'material_update_existing_no_history'),
                         category: :material)
 
         expect(existing_tag.tag_versions).to be_empty
@@ -533,7 +531,7 @@ RSpec.describe 'Materials API', type: :request do
 
       it 'backfills a create tag_version for an existing character tag without history' do
         existing_tag =
-            create(:tag, primary_name: 'material_update_character_no_history',
+            Tag.create!(tag_name: TagName.create!(name: 'material_update_character_no_history'),
                         category: :character)
 
         expect(existing_tag.tag_versions).to be_empty
@@ -565,7 +563,7 @@ RSpec.describe 'Materials API', type: :request do
         expect(response).to have_http_status(:ok)
 
         material.reload
-        expect(primary_tag_name_for(material.tag, 'ja').name).to eq('material_update_remove_file')
+        expect(material.tag.name).to eq('material_update_remove_file')
         expect(material.url).to eq('https://example.com/updated-source')
         expect(material.updated_by_user).to eq(member_user)
         expect(material.file.attached?).to be(false)
@@ -653,8 +651,8 @@ RSpec.describe 'Materials API', type: :request do
   end
 
   describe 'GET /materials/download.zip' do
-    let!(:tag_a) { create(:tag, primary_name: 'zip_a', category: :material) }
-    let!(:tag_b) { create(:tag, primary_name: 'zip_b', category: :material) }
+    let!(:tag_a) { Tag.create!(tag_name: TagName.create!(name: 'zip_a'), category: :material) }
+    let!(:tag_b) { Tag.create!(tag_name: TagName.create!(name: 'zip_b'), category: :material) }
     let!(:material_a) do
       build_material(tag: tag_a, user: member_user,
                      file: dummy_upload(filename: 'a.png', body: 'zip-a'))
@@ -703,7 +701,7 @@ RSpec.describe 'Materials API', type: :request do
 
   describe 'GET /materials/versions' do
     let!(:tag) do
-      create(:tag, primary_name: 'material_history', category: :material)
+      Tag.create!(tag_name: TagName.create!(name: 'material_history'), category: :material)
     end
     let!(:material) do
       build_material(tag:, user: member_user, file: dummy_upload(filename: 'history.png'))
@@ -778,7 +776,7 @@ RSpec.describe 'Materials API', type: :request do
 
   describe 'DELETE /materials/:id' do
     let!(:tag) do
-      create(:tag, primary_name: 'material_destroy', category: :material)
+      Tag.create!(tag_name: TagName.create!(name: 'material_destroy'), category: :material)
     end
     let!(:material) do
       build_material(tag:, user: member_user, file: dummy_upload(filename: 'destroy.png'))

backend/spec/requests/nico_tags_spec.rb

@@ -44,10 +44,10 @@ RSpec.describe 'NicoTags', type: :request do
       unlinked.update!(name: 'search_unlinked')
       other = create(:external_tag)
       other.update!(name: 'other')
-      destination = create(:tag, category: :general)
-      primary_tag_name_for(destination, 'ja').update!(name: 'destination_search')
+      destination = create(:tag, :general)
+      destination.tag_name.update!(name: 'destination_search')
       NicoTagRelation.create!(nico_tag: linked, tag: destination)
-      NicoTagRelation.create!(nico_tag: other, tag: create(:tag, category: :general))
+      NicoTagRelation.create!(nico_tag: other, tag: create(:tag, :general))
 
       get '/tags/nico', params: {
         name: 'search_',
@@ -151,7 +151,7 @@ RSpec.describe 'NicoTags', type: :request do
 
     it '404 when only an internal tag exists for the target id' do
       sign_in_as(member)
-      non_nico = create(:tag, category: :general)
+      non_nico = create(:tag, :general)
       expect(ExternalTag.exists?(non_nico.id)).to be(false)
       patch "/tags/nico/#{non_nico.id}", params: { tags: 'a b' }
       expect(response).to have_http_status(:not_found)
@@ -162,18 +162,18 @@ RSpec.describe 'NicoTags', type: :request do
 
       nico_tag = create(:external_tag, name: 'nico_tags_spec_source')
 
-      linked_a_name = create(:tag_name, name: 'nico_linked_a')
-      linked_a = create(:tag, primary_tag_name: linked_a_name, category: :general)
+      linked_a_name = TagName.create!(name: 'nico_linked_a')
+      linked_a = Tag.create!(tag_name: linked_a_name, category: :general)
 
-      linked_b_name = create(:tag_name, name: 'nico_linked_b')
-      linked_b = create(:tag, primary_tag_name: linked_b_name, category: :general)
+      linked_b_name = TagName.create!(name: 'nico_linked_b')
+      linked_b = Tag.create!(tag_name: linked_b_name, category: :general)
 
       NicoTagVersionRecorder.record!(external_tag: nico_tag,
                                      event_type: :create, created_by_user: admin)
 
       expect {
         patch "/tags/nico/#{nico_tag.id}", params: {
-          tags: "  #{ linked_a_name.name }\n#{ linked_b_name.name }  "
+          tags: "  #{linked_a.name}\n#{linked_b.name}  "
         }
       }.to change(TagVersion, :count).by(2)
        .and change(NicoTagVersion, :count).by(1)

backend/spec/requests/posts_spec.rb

@@ -113,8 +113,8 @@ RSpec.describe 'Posts API', type: :request do
         'sections' => [])
   end
 
-  let!(:tag_name) { create(:tag_name, name: 'spec_tag') }
-  let!(:tag)      { create(:tag, primary_tag_name: tag_name, category: :general) }
+  let!(:tag_name) { TagName.create!(name: 'spec_tag') }
+  let!(:tag)      { Tag.create!(tag_name: tag_name, category: :general) }
 
   let!(:post_record) do
     Post.create!(title: 'spec post', url: 'https://example.com/spec').tap do |p|
@@ -125,11 +125,11 @@ RSpec.describe 'Posts API', type: :request do
   describe 'GET /posts' do
     let!(:user) { create_member_user! }
 
-    let!(:tag_name) { create(:tag_name, name: 'spec_tag') }
-    let!(:tag) { create(:tag, primary_tag_name: tag_name, category: :general) }
-    let!(:tag_name2) { create(:tag_name, name: 'unko') }
-    let!(:tag2) { create(:tag, primary_tag_name: tag_name2, category: :deerjikist) }
-    let!(:alias_tag_name) { create(:tag_name, :alias, name: 'manko', tag:) }
+    let!(:tag_name) { TagName.create!(name: 'spec_tag') }
+    let!(:tag) { Tag.create!(tag_name:, category: :general) }
+    let!(:tag_name2) { TagName.create!(name: 'unko') }
+    let!(:tag2) { Tag.create!(tag_name: tag_name2, category: :deerjikist) }
+    let!(:alias_tag_name) { TagName.create!(name: 'manko', canonical: tag_name) }
 
     let!(:hit_post) do
       Post.create!(uploaded_user: user, title: 'hello spec world',
@@ -267,7 +267,7 @@ RSpec.describe 'Posts API', type: :request do
       end
 
       it 'keeps internal name searches independent of colliding external ids' do
-        get '/posts', params: { tags: primary_tag_name_for(tag, 'ja').name }
+        get '/posts', params: { tags: tag.name }
 
         expect(response).to have_http_status(:ok)
         expect(json.fetch('count')).to eq(3)
@@ -286,7 +286,7 @@ RSpec.describe 'Posts API', type: :request do
 
       [nil, 'all'].each do |match|
         it "intersects internal and external matches with match=#{ match || 'omitted' }" do
-          params = { tags: "#{ primary_tag_name_for(tag, 'ja').name } nico:search_external" }
+          params = { tags: "#{ tag.name } nico:search_external" }
           params[:match] = match if match
 
           get '/posts', params: params
@@ -307,8 +307,7 @@ RSpec.describe 'Posts API', type: :request do
       end
 
       it 'excludes external matches from an internal tag search' do
-        get '/posts', params: {
-            tags: "#{ primary_tag_name_for(tag, 'ja').name } not:nico:search_external" }
+        get '/posts', params: { tags: "#{ tag.name } not:nico:search_external" }
 
         expect(response).to have_http_status(:ok)
         expect(json.fetch('count')).to eq(2)
@@ -317,9 +316,7 @@ RSpec.describe 'Posts API', type: :request do
       end
 
       it 'unions an external match with a negated internal match' do
-        get '/posts', params: {
-            tags: "nico:search_external not:#{ primary_tag_name_for(tag, 'ja').name }",
-            match: 'any' }
+        get '/posts', params: { tags: "nico:search_external not:#{ tag.name }", match: 'any' }
 
         expect(response).to have_http_status(:ok)
         expect(json.fetch('count')).to eq(2)
@@ -336,9 +333,7 @@ RSpec.describe 'Posts API', type: :request do
       end
 
       it 'applies the same mixed name search to the existing random endpoint' do
-        get '/posts/random', params: {
-            tags: "#{ primary_tag_name_for(tag, 'ja').name } nico:search_external",
-            match: 'all' }
+        get '/posts/random', params: { tags: "#{ tag.name } nico:search_external", match: 'all' }
 
         expect(response).to have_http_status(:ok)
         expect(json.fetch('id')).to eq(both_post.id)
@@ -346,17 +341,17 @@ RSpec.describe 'Posts API', type: :request do
     end
 
     context 'when tags contain not:' do
-      let!(:foo_tag_name) { create(:tag_name, name: 'not_spec_foo') }
-      let!(:foo_tag) { create(:tag, primary_tag_name: foo_tag_name, category: :general) }
+      let!(:foo_tag_name) { TagName.create!(name: 'not_spec_foo') }
+      let!(:foo_tag) { Tag.create!(tag_name: foo_tag_name, category: :general) }
 
-      let!(:bar_tag_name) { create(:tag_name, name: 'not_spec_bar') }
-      let!(:bar_tag) { create(:tag, primary_tag_name: bar_tag_name, category: :general) }
+      let!(:bar_tag_name) { TagName.create!(name: 'not_spec_bar') }
+      let!(:bar_tag) { Tag.create!(tag_name: bar_tag_name, category: :general) }
 
-      let!(:baz_tag_name) { create(:tag_name, name: 'not_spec_baz') }
-      let!(:baz_tag) { create(:tag, primary_tag_name: baz_tag_name, category: :general) }
+      let!(:baz_tag_name) { TagName.create!(name: 'not_spec_baz') }
+      let!(:baz_tag) { Tag.create!(tag_name: baz_tag_name, category: :general) }
 
       let!(:foo_alias_tag_name) do
-        create(:tag_name, :alias, name: 'not_spec_foo_alias', tag: foo_tag)
+        TagName.create!(name: 'not_spec_foo_alias', canonical: foo_tag_name)
       end
 
       let!(:foo_only_post) do
@@ -744,9 +739,7 @@ RSpec.describe 'Posts API', type: :request do
           .find { _1['name'] == 'nico:post_index_external' }
 
       expect(post_json.fetch('tags')).to include(
-          a_hash_including('id' => tag.id,
-                           'name' => primary_tag_name_for(tag, 'ja').name,
-                           'category' => 'general'))
+          a_hash_including('id' => tag.id, 'name' => tag.name, 'category' => 'general'))
       expect(external_json).not_to be_nil
       expect_external_tag_json(external_json, external_tag)
     end
@@ -779,10 +772,11 @@ RSpec.describe 'Posts API', type: :request do
       end
 
       it 'omits deprecated tags' do
-        deprecated_tag = create(:tag,
-            primary_name: 'deprecated_post_tag',
+        deprecated_tag = Tag.create!(
+          name: 'deprecated_post_tag',
           category: :general,
-            deprecated_at: Time.current)
+          deprecated_at: Time.current
+        )
         PostTag.create!(post: post_record, tag: deprecated_tag)
 
         request
@@ -859,9 +853,9 @@ RSpec.describe 'Posts API', type: :request do
 
         tags =
             15.times.map do |i|
-              tag_name = create(:tag_name, name: "show_query_tag_#{ i }")
-              tag = create(:tag, primary_tag_name: tag_name, category: :general)
-              create(:tag_name, :alias, name: "show_query_alias_#{ i }", tag:)
+              tag_name = TagName.create!(name: "show_query_tag_#{ i }")
+              tag = Tag.create!(tag_name:, category: :general)
+              TagName.create!(name: "show_query_alias_#{ i }", canonical: tag_name)
               PostTag.create!(post: post_record, tag:)
               tag
             end
@@ -916,9 +910,7 @@ RSpec.describe 'Posts API', type: :request do
         expect(response).to have_http_status(:ok)
 
         expect(json.fetch('tags')).to include(
-            a_hash_including('id' => tag.id,
-                             'name' => primary_tag_name_for(tag, 'ja').name,
-                             'category' => 'general'))
+            a_hash_including('id' => tag.id, 'name' => tag.name, 'category' => 'general'))
         external_json =
             json
             .fetch('tags')
@@ -1008,7 +1000,7 @@ RSpec.describe 'Posts API', type: :request do
 
   describe 'POST /posts' do
     let(:member) { create(:user, :member) }
-    let!(:alias_tag_name) { create(:tag_name, :alias, name: 'manko', tag:) }
+    let!(:alias_tag_name) { TagName.create!(name: 'manko', canonical: tag_name) }
 
     it '401 when not logged in' do
       sign_out
@@ -1165,10 +1157,11 @@ RSpec.describe 'Posts API', type: :request do
     end
 
     it 'rejects a deprecated tag specified directly' do
-      create(:tag,
-          primary_name: 'deprecated_direct_tag',
+      Tag.create!(
+        name: 'deprecated_direct_tag',
         category: :general,
-          deprecated_at: Time.current)
+        deprecated_at: Time.current
+      )
       sign_in_as(member)
 
       post '/posts', params: post_write_params(
@@ -1185,16 +1178,18 @@ RSpec.describe 'Posts API', type: :request do
     end
 
     it 'expands through multiple deprecated parent tags and saves active ancestors' do
-      child = create(:tag, primary_name: 'active_child', category: :general)
-      deprecated_parent = create(:tag,
-          primary_name: 'deprecated_parent',
+      child = Tag.create!(name: 'active_child', category: :general)
+      deprecated_parent = Tag.create!(
+        name: 'deprecated_parent',
         category: :general,
-          deprecated_at: Time.current)
-      deprecated_grandparent = create(:tag,
-          primary_name: 'deprecated_grandparent',
+        deprecated_at: Time.current
+      )
+      deprecated_grandparent = Tag.create!(
+        name: 'deprecated_grandparent',
         category: :general,
-          deprecated_at: Time.current)
-      active_grandparent = create(:tag, primary_name: 'active_grandparent', category: :general)
+        deprecated_at: Time.current
+      )
+      active_grandparent = Tag.create!(name: 'active_grandparent', category: :general)
       TagImplication.create!(tag: child, parent_tag: deprecated_parent)
       TagImplication.create!(tag: deprecated_parent, parent_tag: deprecated_grandparent)
       TagImplication.create!(tag: deprecated_grandparent, parent_tag: active_grandparent)
@@ -1208,8 +1203,7 @@ RSpec.describe 'Posts API', type: :request do
       )
 
       expect(response).to have_http_status(:created)
-      saved_names = TagName.where(tag_id: Post.find(json.fetch('id')).tags.select(:id),
-                                  language_code: 'ja', primary_flg: true).pluck(:name)
+      saved_names = Post.find(json.fetch('id')).tags.map(&:name)
       expect(saved_names).to include('active_child', 'active_grandparent')
       expect(saved_names).not_to include('deprecated_parent', 'deprecated_grandparent')
     end
@@ -1312,8 +1306,7 @@ RSpec.describe 'Posts API', type: :request do
       expect(response).to have_http_status(:created)
 
       created_post = Post.find(json.fetch('id'))
-      tag = TagName.find_by!(name: '伊地知ニジカ',
-                             language_code: 'ja', primary_flg: true).tag
+      tag = Tag.joins(:tag_name).find_by!(tag_names: { name: '伊地知ニジカ' })
       section = PostTagSection.find_by!(post: created_post, tag:)
 
       expect(section.begin_ms).to eq(60_000)
@@ -1333,8 +1326,7 @@ RSpec.describe 'Posts API', type: :request do
       expect(response).to have_http_status(:created)
 
       created_post = Post.find(json.fetch('id'))
-      tag = TagName.find_by!(name: '伊地知ニジカ',
-                             language_code: 'ja', primary_flg: true).tag
+      tag = Tag.joins(:tag_name).find_by!(tag_names: { name: '伊地知ニジカ' })
       expect(PostTagSection.find_by(post: created_post, tag:)).to be_nil
     end
 
@@ -1351,8 +1343,7 @@ RSpec.describe 'Posts API', type: :request do
       expect(response).to have_http_status(:created)
 
       created_post = Post.find(json.fetch('id'))
-      tag = TagName.find_by!(name: '伊地知ニジカ',
-                             language_code: 'ja', primary_flg: true).tag
+      tag = Tag.joins(:tag_name).find_by!(tag_names: { name: '伊地知ニジカ' })
       expect(PostTagSection.find_by(post: created_post, tag:)).to be_nil
     end
 
@@ -1631,7 +1622,6 @@ RSpec.describe 'Posts API', type: :request do
         expect(arguments[:thumbnails].keys).to eq([0])
         expect(arguments[:host]).to eq('http://www.example.com')
       end
-      expect(creator).to have_received(:run).with(Locale.nipponese)
     end
 
     it 'rejects malformed manifests as a request-level error' do
@@ -1668,8 +1658,8 @@ RSpec.describe 'Posts API', type: :request do
       create(:post_tag_section, post: post_record, tag:,
                                 begin_ms: 1000, end_ms: 2000)
 
-      tn2 = create(:tag_name, name: 'spec_tag_2')
-      replacement_tag = create(:tag, primary_tag_name: tn2, category: :general)
+      tn2 = TagName.create!(name: 'spec_tag_2')
+      replacement_tag = Tag.create!(tag_name: tn2, category: :general)
 
       put "/posts/#{post_record.id}", params: post_update_params(
           post_record,
@@ -1717,10 +1707,11 @@ RSpec.describe 'Posts API', type: :request do
     end
 
     it 'rejects a deprecated tag specified directly' do
-      create(:tag,
-          primary_name: 'deprecated_update_tag',
+      Tag.create!(
+        name: 'deprecated_update_tag',
         category: :general,
-          deprecated_at: Time.current)
+        deprecated_at: Time.current
+      )
       sign_in_as(member)
 
       put "/posts/#{ post_record.id }", params: post_update_params(
@@ -1975,7 +1966,7 @@ RSpec.describe 'Posts API', type: :request do
         put "/posts/#{post_record.id}", params: post_write_params(
             base_version_no: base_version.version_no,
             title: 'updated by me',
-            tags: "spec_tag #{primary_tag_name_for(Tag.no_deerjikist, 'ja').name}")
+            tags: "spec_tag #{Tag.no_deerjikist.name}")
 
         expect(response).to have_http_status(:conflict)
 
@@ -1995,8 +1986,7 @@ RSpec.describe 'Posts API', type: :request do
 
         base_version = create_post_version_for!(post_record.reload)
 
-        current_tag = Tag.find_or_create_by_tag_name!(
-            Locale.nipponese, 'current_added_tag', category: :general)
+        current_tag = Tag.find_or_create_by_tag_name!('current_added_tag', category: :general)
         PostTag.create!(post: post_record, tag: current_tag, created_user: member)
 
         PostVersionRecorder.record!(
@@ -2007,8 +1997,7 @@ RSpec.describe 'Posts API', type: :request do
         put "/posts/#{post_record.id}", params: post_write_params(
             base_version_no: base_version.version_no,
             title: post_record.title,
-            tags: ['spec_tag', primary_tag_name_for(Tag.no_deerjikist, 'ja').name,
-                   'incoming_added_tag'].join(' '))
+            tags: "spec_tag #{Tag.no_deerjikist.name} incoming_added_tag")
 
         expect(response).to have_http_status(:conflict)
 
@@ -2026,8 +2015,7 @@ RSpec.describe 'Posts API', type: :request do
 
         base_version = create_post_version_for!(post_record.reload)
 
-        current_tag = Tag.find_or_create_by_tag_name!(
-            Locale.nipponese, 'current_merge_tag', category: :general)
+        current_tag = Tag.find_or_create_by_tag_name!('current_merge_tag', category: :general)
         PostTag.create!(post: post_record, tag: current_tag, created_user: member)
 
         PostVersionRecorder.record!(
@@ -2038,17 +2026,15 @@ RSpec.describe 'Posts API', type: :request do
         put "/posts/#{post_record.id}", params: post_write_params(
             base_version_no: base_version.version_no,
             title: post_record.title,
-            tags: ['spec_tag', primary_tag_name_for(Tag.no_deerjikist, 'ja').name,
-                   'incoming_merge_tag'].join(' '),
+            tags: "spec_tag #{Tag.no_deerjikist.name} incoming_merge_tag",
             merge: '1')
 
         expect(response).to have_http_status(:ok)
 
-        names = TagName.where(tag_id: post_record.reload.tags.select(:id),
-                              language_code: 'ja', primary_flg: true).pluck(:name)
+        names = post_record.reload.tags.map(&:name)
 
         expect(names).to include('spec_tag')
-        expect(names).to include(primary_tag_name_for(Tag.no_deerjikist, 'ja').name)
+        expect(names).to include(Tag.no_deerjikist.name)
         expect(names).to include('current_merge_tag')
         expect(names).to include('incoming_merge_tag')
       end
@@ -2071,15 +2057,14 @@ RSpec.describe 'Posts API', type: :request do
         put "/posts/#{post_record.id}", params: post_write_params(
             base_version_no: base_version.version_no,
             title: post_record.title,
-            tags: "spec_tag #{ primary_tag_name_for(Tag.no_deerjikist, 'ja').name }")
+            tags: "spec_tag #{ Tag.no_deerjikist.name }")
 
         expect(response).to have_http_status(:ok)
 
-        names = TagName.where(tag_id: post_record.reload.tags.select(:id),
-                              language_code: 'ja', primary_flg: true).pluck(:name)
+        names = post_record.reload.tags.map(&:name)
 
         expect(names).to include('spec_tag')
-        expect(names).to include(primary_tag_name_for(Tag.no_deerjikist, 'ja').name)
+        expect(names).to include(Tag.no_deerjikist.name)
         expect(post_record.external_tags).to contain_exactly(nico_tag)
       end
 
@@ -2094,15 +2079,14 @@ RSpec.describe 'Posts API', type: :request do
         put "/posts/#{post_record.id}", params: post_write_params(
             base_version_no: base_version.version_no,
             title: 'updated title',
-            tags: "spec_tag #{ primary_tag_name_for(Tag.no_deerjikist, 'ja').name }")
+            tags: "spec_tag #{ Tag.no_deerjikist.name }")
 
         expect(response).to have_http_status(:ok)
 
-        names = TagName.where(tag_id: post_record.reload.tags.select(:id),
-                              language_code: 'ja', primary_flg: true).pluck(:name)
+        names = post_record.reload.tags.map(&:name)
 
         expect(names).to include('spec_tag')
-        expect(names).to include(primary_tag_name_for(Tag.no_deerjikist, 'ja').name)
+        expect(names).to include(Tag.no_deerjikist.name)
         expect(post_record.external_tags).to contain_exactly(nico_tag)
 
         external_json =
@@ -2118,8 +2102,7 @@ RSpec.describe 'Posts API', type: :request do
         sign_in_as(member)
 
         nico_tag = create_nico_tag!('nico:relation_source')
-        linked_tag = Tag.find_or_create_by_tag_name!(
-            Locale.nipponese, 'relation_linked_tag', category: :general)
+        linked_tag = Tag.find_or_create_by_tag_name!('relation_linked_tag', category: :general)
 
         NicoTagRelation.create!(nico_tag:, tag: linked_tag)
         PostExternalTag.create!(post: post_record, external_tag: nico_tag)
@@ -2130,17 +2113,16 @@ RSpec.describe 'Posts API', type: :request do
         put "/posts/#{post_record.id}", params: post_write_params(
             base_version_no: base_version.version_no,
             title: post_record.title,
-            tags: "spec_tag #{ primary_tag_name_for(Tag.no_deerjikist, 'ja').name }")
+            tags: "spec_tag #{ Tag.no_deerjikist.name }")
 
         expect(response).to have_http_status(:ok)
 
-        names = TagName.where(tag_id: post_record.reload.tags.select(:id),
-                              language_code: 'ja', primary_flg: true).pluck(:name)
+        names = post_record.reload.tags.map(&:name)
 
         expect(post_record.external_tags).to contain_exactly(nico_tag)
         expect(names).to include('spec_tag')
-        expect(names).to include(primary_tag_name_for(Tag.no_deerjikist, 'ja').name)
-        expect(names).not_to include(primary_tag_name_for(linked_tag, 'ja').name)
+        expect(names).to include(Tag.no_deerjikist.name)
+        expect(names).not_to include(linked_tag.name)
       end
 
       it 'force-updates stale posts without base_version_no' do
@@ -2156,7 +2138,7 @@ RSpec.describe 'Posts API', type: :request do
 
         put "/posts/#{post_record.id}", params: post_write_params(
             title: 'forced title',
-            tags: "spec_tag #{primary_tag_name_for(Tag.no_deerjikist, 'ja').name}",
+            tags: "spec_tag #{Tag.no_deerjikist.name}",
             force: '1')
 
         expect(response).to have_http_status(:ok)
@@ -2209,8 +2191,8 @@ RSpec.describe 'Posts API', type: :request do
     let(:oc_from) { Time.zone.local(2019, 12, 31, 0, 0, 0) }
     let(:oc_before) { Time.zone.local(2020, 1, 1, 0, 0, 0) }
 
-    let!(:tag_name2) { create(:tag_name, name: 'spec_tag_2') }
-    let!(:tag2) { create(:tag, primary_tag_name: tag_name2, category: :general) }
+    let!(:tag_name2) { TagName.create!(name: 'spec_tag_2') }
+    let!(:tag2) { Tag.create!(tag_name: tag_name2, category: :general) }
 
     def snapshot_tags(post)
       post.snapshot_tag_names.join(' ')
@@ -2435,7 +2417,7 @@ RSpec.describe 'Posts API', type: :request do
       expect(response).to have_http_status(:ok)
       expect(json.fetch('count')).to eq(3)
       expect(json.fetch('versions').first.fetch('tags')).to include(
-          'name' => primary_tag_name_for(tag2, 'ja').name, 'type' => 'context')
+          'name' => tag2.name, 'type' => 'context')
     end
 
     it 'filters versions by tag when the current snapshot includes the tag' do
@@ -2568,8 +2550,8 @@ RSpec.describe 'Posts API', type: :request do
       sign_in_as(member)
       base_version = create_post_version_for!(post_record)
 
-      tag_name2 = create(:tag_name, name: 'spec_tag_2')
-      create(:tag, primary_tag_name: tag_name2, category: :general)
+      tag_name2 = TagName.create!(name: 'spec_tag_2')
+      Tag.create!(tag_name: tag_name2, category: :general)
 
       expect do
         put "/posts/#{post_record.id}", params: post_write_params(
@@ -2733,8 +2715,8 @@ RSpec.describe 'Posts API', type: :request do
 
       base_version = create_post_version_for!(post_record.reload)
 
-      tag_name2 = create(:tag_name, name: 'spec_tag_2')
-      tag2 = create(:tag, primary_tag_name: tag_name2, category: :general)
+      tag_name2 = TagName.create!(name: 'spec_tag_2')
+      tag2 = Tag.create!(tag_name: tag_name2, category: :general)
 
       expect {
         put "/posts/#{post_record.id}", params: post_write_params(

backend/spec/requests/tag_versions_spec.rb

@@ -3,13 +3,13 @@ require 'rails_helper'
 RSpec.describe 'TagVersions API', type: :request do
   let(:member) { create(:user, :member, name: 'version member') }
 
-  let!(:tag) { create(:tag, primary_name: 'tag_versions_target', category: :general) }
-  let!(:other_tag) { create(:tag, primary_name: 'tag_versions_other', category: :general) }
+  let!(:tag) { create(:tag, name: 'tag_versions_target', category: :general) }
+  let!(:other_tag) { create(:tag, name: 'tag_versions_other', category: :general) }
 
-  let!(:parent_shared) { create(:tag, primary_name: 'parent_shared', category: :general) }
-  let!(:parent_old) { create(:tag, primary_name: 'parent_old', category: :general) }
-  let!(:parent_new) { create(:tag, primary_name: 'parent_new', category: :general) }
-  let!(:other_parent) { create(:tag, primary_name: 'other_parent', category: :general) }
+  let!(:parent_shared) { create(:tag, name: 'parent_shared', category: :general) }
+  let!(:parent_old) { create(:tag, name: 'parent_old', category: :general) }
+  let!(:parent_new) { create(:tag, name: 'parent_new', category: :general) }
+  let!(:other_parent) { create(:tag, name: 'other_parent', category: :general) }
 
   let(:t_v1) { Time.zone.local(2020, 1, 1, 12, 0, 0) }
   let(:t_v2) { Time.zone.local(2020, 1, 2, 12, 0, 0) }
@@ -36,12 +36,6 @@ RSpec.describe 'TagVersions API', type: :request do
             category: category,
             deprecated_at: deprecated_at,
             aliases: Array(aliases).join(' '),
-            names: [{ language_code: 'ja', name:, script_code: 'Jpan',
-                      primary_flg: true,
-                      auto_generated: false }] + Array(aliases).map { |alias_name|
-              { language_code: 'ja', name: alias_name, script_code: 'Jpan',
-                primary_flg: false, auto_generated: false }
-            },
             parent_tag_ids: Array(parent_tags).map(&:id).join(' '),
             created_by_user: created_by_user,
             created_at: created_at)
@@ -217,7 +211,7 @@ RSpec.describe 'TagVersions API', type: :request do
     end
 
     it 'returns empty when the specified tag has no versions' do
-      fresh_tag = create(:tag, primary_name: 'no_versions_tag', category: :general)
+      fresh_tag = create(:tag, name: 'no_versions_tag', category: :general)
 
       get '/tags/versions', params: { id: fresh_tag.id }
 
@@ -238,8 +232,8 @@ RSpec.describe 'TagVersions API', type: :request do
     end
 
     it 'does not create tag versions by wiki updates when tag has no versions yet' do
-      wiki_tag_name = create(:tag_name, name: 'tag_versions_from_wiki')
-      wiki_tag = create(:tag, primary_tag_name: wiki_tag_name, category: :general)
+      wiki_tag_name = TagName.create!(name: 'tag_versions_from_wiki')
+      wiki_tag = Tag.create!(tag_name: wiki_tag_name, category: :general)
 
       wiki_page =
           Wiki::Commit.create_content!(

backend/spec/requests/tag_wiki_history_integrity_spec.rb

@@ -8,13 +8,13 @@ RSpec.describe 'Tag and wiki history integrity', type: :request do
   end
 
   def create_tag! name:, category: :general
-    tag_name = create(:tag_name, name:)
-    create(:tag, primary_tag_name: tag_name, category:)
+    tag_name = TagName.create!(name:)
+    Tag.create!(tag_name:, category:)
   end
 
   def create_wiki_for_tag! tag:, body: 'wiki body', user: member_user
     Wiki::Commit.create_content!(
-        tag_name: primary_tag_name_for(tag, 'ja'),
+        tag_name: tag.tag_name,
         body:,
         created_by_user: user,
         message: 'init')
@@ -43,7 +43,7 @@ RSpec.describe 'Tag and wiki history integrity', type: :request do
       wiki_page.reload
       version = wiki_page.wiki_versions.order(:version_no).last
 
-      expect(primary_tag_name_for(tag, 'ja').name).to eq('patch_tag_wiki_after')
+      expect(tag.name).to eq('patch_tag_wiki_after')
       expect(wiki_page.title).to eq('patch_tag_wiki_after')
 
       expect(version).to have_attributes(
@@ -72,7 +72,7 @@ RSpec.describe 'Tag and wiki history integrity', type: :request do
       tag.reload
       wiki_page.reload
 
-      expect(primary_tag_name_for(tag, 'ja').name).to eq('patch_tag_category_only')
+      expect(tag.name).to eq('patch_tag_category_only')
       expect(tag.category).to eq('meme')
       expect(wiki_page.wiki_versions.count).to eq(before_wiki_versions)
     end
@@ -101,7 +101,7 @@ RSpec.describe 'Tag and wiki history integrity', type: :request do
       wiki_page.reload
       version = wiki_page.wiki_versions.order(:version_no).last
 
-      expect(primary_tag_name_for(tag, 'ja').name).to eq('put_tag_wiki_after')
+      expect(tag.name).to eq('put_tag_wiki_after')
       expect(wiki_page.title).to eq('put_tag_wiki_after')
 
       expect(version).to have_attributes(
@@ -134,7 +134,7 @@ RSpec.describe 'Tag and wiki history integrity', type: :request do
       tag.reload
       wiki_page.reload
 
-      expect(primary_tag_name_for(tag, 'ja').name).to eq('put_tag_category_only')
+      expect(tag.name).to eq('put_tag_category_only')
       expect(tag.category).to eq('meme')
       expect(wiki_page.wiki_versions.count).to eq(before_wiki_versions)
     end

backend/spec/requests/tags_deerjikists_spec.rb

@@ -12,7 +12,7 @@ RSpec.describe 'Tags deerjikists API', type: :request do
   let(:guest) { create(:user, role: :guest) }
 
   before do
-    primary_tag_name_for(tag, 'ja').update!(name: 'deerjika')
+    tag.tag_name.update!(name: 'deerjika')
   end
 
   describe 'GET /tags/:id/deerjikists' do
@@ -344,7 +344,7 @@ RSpec.describe 'Tags deerjikists API', type: :request do
         end
 
         before do
-          primary_tag_name_for(other_tag, 'ja').update!(name: 'existing-deerjikist')
+          other_tag.tag_name.update!(name: 'existing-deerjikist')
         end
 
         it 'returns an indexed 422 error and rolls back the complete replacement' do

backend/spec/requests/tags_spec.rb

@@ -2,13 +2,13 @@ require 'cgi'
 require 'rails_helper'
 
 RSpec.describe 'Tags API', type: :request do
-  let!(:tn) { create(:tag_name, name: 'spec_tag') }
-  let!(:tag) { create(:tag, primary_tag_name: tn, category: :general) }
-  let!(:alias_tn) { create(:tag_name, :alias, name: 'unko', tag:) }
+  let!(:tn) { TagName.create!(name: 'spec_tag') }
+  let!(:tag) { Tag.create!(tag_name: tn, category: :general) }
+  let!(:alias_tn) { TagName.create!(name: 'unko', canonical: tn) }
   let!(:post) { Post.create!(url: 'https://example.com/unkounkounko') }
   let!(:post_tag) { PostTag.create!(post:, tag:) }
-  let!(:tn2) { create(:tag_name, name: 'unknown') }
-  let!(:tag2) { create(:tag, primary_tag_name: tn2, category: :general) }
+  let!(:tn2) { TagName.create!(name: 'unknown') }
+  let!(:tag2) { Tag.create!(tag_name: tn2, category: :general) }
 
   def response_tags
     json.fetch('tags')
@@ -18,18 +18,6 @@ RSpec.describe 'Tags API', type: :request do
     response_tags.map { |t| t.fetch('name') }
   end
 
-  def version_primary_name(version, language_code)
-    version.names.find { |name|
-      name['language_code'] == language_code && name['primary_flg']
-    }.fetch('name')
-  end
-
-  def version_alias_names(version, language_code)
-    version.names.filter_map { |name|
-      name['name'] if name['language_code'] == language_code && !name['primary_flg']
-    }
-  end
-
   def dummy_material_upload(filename: 'dummy.png', type: 'image/png', body: 'dummy')
     Rack::Test::UploadedFile.new(StringIO.new(body), type, original_filename: filename)
   end
@@ -50,9 +38,7 @@ RSpec.describe 'Tags API', type: :request do
       expect(response).to have_http_status(:ok)
       expect(json.fetch('count')).to eq(2)
       expect(response_tags).to contain_exactly(
-          a_hash_including('id' => tag.id,
-                           'name' => primary_tag_name_for(tag, 'ja').name,
-                           'category' => 'general'),
+          a_hash_including('id' => tag.id, 'name' => tag.name, 'category' => 'general'),
           a_hash_including(
               'id' => external.id,
               'name' => 'nico:spec_external',
@@ -105,7 +91,7 @@ RSpec.describe 'Tags API', type: :request do
     end
 
     it 'filters tags by category' do
-      meme = create(:tag, primary_name: 'meme_only', category: :meme)
+      meme = Tag.create!(tag_name: TagName.create!(name: 'meme_only'), category: :meme)
 
       get '/tags', params: { category: 'meme' }
 
@@ -115,29 +101,30 @@ RSpec.describe 'Tags API', type: :request do
     end
 
     it 'filters tags by deprecated state' do
-      deprecated_tag = create(:tag,
-          primary_name: 'deprecated_filter',
+      deprecated_tag = Tag.create!(
+        name: 'deprecated_filter',
         category: :general,
-          deprecated_at: 1.day.from_now)
-      active_tag = create(:tag, primary_name: 'active_filter', category: :general)
+        deprecated_at: 1.day.from_now
+      )
+      active_tag = Tag.create!(name: 'active_filter', category: :general)
 
       get '/tags', params: { name: '_filter', deprecated: '1' }
 
       expect(response).to have_http_status(:ok)
-      expect(response_names).to include(primary_tag_name_for(deprecated_tag, 'ja').name)
-      expect(response_names).not_to include(primary_tag_name_for(active_tag, 'ja').name)
+      expect(response_names).to include(deprecated_tag.name)
+      expect(response_names).not_to include(active_tag.name)
 
       get '/tags', params: { name: '_filter', deprecated: '0' }
 
       expect(response).to have_http_status(:ok)
-      expect(response_names).to include(primary_tag_name_for(active_tag, 'ja').name)
-      expect(response_names).not_to include(primary_tag_name_for(deprecated_tag, 'ja').name)
+      expect(response_names).to include(active_tag.name)
+      expect(response_names).not_to include(deprecated_tag.name)
     end
 
     it 'filters tags by post_count range' do
-      low = create(:tag, primary_name: 'pc_low', category: :general)
-      mid = create(:tag, primary_name: 'pc_mid', category: :general)
-      high = create(:tag, primary_name: 'pc_high', category: :general)
+      low = Tag.create!(tag_name: TagName.create!(name: 'pc_low'), category: :general)
+      mid = Tag.create!(tag_name: TagName.create!(name: 'pc_mid'), category: :general)
+      high = Tag.create!(tag_name: TagName.create!(name: 'pc_high'), category: :general)
 
       low.update_columns(post_count: 1)
       mid.update_columns(post_count: 3)
@@ -155,8 +142,8 @@ RSpec.describe 'Tags API', type: :request do
     end
 
     it 'filters tags by created_at range' do
-      old_tag = create(:tag, primary_name: 'created_old', category: :general)
-      new_tag = create(:tag, primary_name: 'created_new', category: :general)
+      old_tag = Tag.create!(tag_name: TagName.create!(name: 'created_old'), category: :general)
+      new_tag = Tag.create!(tag_name: TagName.create!(name: 'created_new'), category: :general)
 
       old_time = Time.zone.local(2024, 1, 1, 0, 0, 0)
       new_time = Time.zone.local(2024, 2, 1, 0, 0, 0)
@@ -175,8 +162,8 @@ RSpec.describe 'Tags API', type: :request do
     end
 
     it 'filters tags by updated_at range' do
-      old_tag = create(:tag, primary_name: 'updated_old', category: :general)
-      new_tag = create(:tag, primary_name: 'updated_new', category: :general)
+      old_tag = Tag.create!(tag_name: TagName.create!(name: 'updated_old'), category: :general)
+      new_tag = Tag.create!(tag_name: TagName.create!(name: 'updated_new'), category: :general)
 
       old_time = Time.zone.local(2024, 3, 1, 0, 0, 0)
       new_time = Time.zone.local(2024, 4, 1, 0, 0, 0)
@@ -195,12 +182,12 @@ RSpec.describe 'Tags API', type: :request do
     end
 
     it 'orders tags by custom category order' do
-      create(:tag, primary_name: 'cat_deerjikist', category: :deerjikist)
-      create(:tag, primary_name: 'cat_meme', category: :meme)
-      create(:tag, primary_name: 'cat_character', category: :character)
-      create(:tag, primary_name: 'cat_general', category: :general)
-      create(:tag, primary_name: 'cat_material', category: :material)
-      create(:tag, primary_name: 'cat_meta', category: :meta)
+      Tag.create!(tag_name: TagName.create!(name: 'cat_deerjikist'), category: :deerjikist)
+      Tag.create!(tag_name: TagName.create!(name: 'cat_meme'), category: :meme)
+      Tag.create!(tag_name: TagName.create!(name: 'cat_character'), category: :character)
+      Tag.create!(tag_name: TagName.create!(name: 'cat_general'), category: :general)
+      Tag.create!(tag_name: TagName.create!(name: 'cat_material'), category: :material)
+      Tag.create!(tag_name: TagName.create!(name: 'cat_meta'), category: :meta)
       create(:external_tag, name: 'cat_nico')
 
       get '/tags', params: { name: 'cat_', order: 'category:asc', limit: 20 }
@@ -215,19 +202,19 @@ RSpec.describe 'Tags API', type: :request do
     context 'with mixed legacy pagination' do
       let!(:first_tag) do
         create(:tag,
-            primary_tag_name: create(:tag_name, name: 'a_mixed_page'),
+               tag_name: create(:tag_name, name: 'a_mixed_page'),
                category: :meme)
       end
 
       let!(:middle_tag) do
         create(:tag,
-            primary_tag_name: create(:tag_name, name: 'm_mixed_page'),
+               tag_name: create(:tag_name, name: 'm_mixed_page'),
                category: :meta)
       end
 
       let!(:last_tag) do
         create(:tag,
-            primary_tag_name: create(:tag_name, name: 'z_mixed_page'),
+               tag_name: create(:tag_name, name: 'z_mixed_page'),
                category: :general)
       end
 
@@ -278,7 +265,7 @@ RSpec.describe 'Tags API', type: :request do
 
     it 'paginates and keeps total count' do
       %w[pag_a pag_b pag_c].each do |name|
-        create(:tag, primary_tag_name: create(:tag_name, name:), category: :general)
+        Tag.create!(tag_name: TagName.create!(name:), category: :general)
       end
 
       get '/tags', params: { name: 'pag_', order: 'name:asc', page: 2, limit: 2 }
@@ -289,8 +276,8 @@ RSpec.describe 'Tags API', type: :request do
     end
 
     it 'falls back to default ordering when order is invalid' do
-      low = create(:tag, primary_name: 'fallback_low', category: :general)
-      high = create(:tag, primary_name: 'fallback_high', category: :general)
+      low = Tag.create!(tag_name: TagName.create!(name: 'fallback_low'), category: :general)
+      high = Tag.create!(tag_name: TagName.create!(name: 'fallback_high'), category: :general)
 
       low.update_columns(post_count: 1)
       high.update_columns(post_count: 9)
@@ -303,7 +290,7 @@ RSpec.describe 'Tags API', type: :request do
 
     it 'normalises invalid page and limit' do
       %w[norm_a norm_b].each do |name|
-        create(:tag, primary_tag_name: create(:tag_name, name:), category: :general)
+        Tag.create!(tag_name: TagName.create!(name:), category: :general)
       end
 
       get '/tags', params: { name: 'norm_', order: 'name:asc', page: 0, limit: 0 }
@@ -315,9 +302,10 @@ RSpec.describe 'Tags API', type: :request do
     end
 
     it 'returns aliases and parent tags' do
-      parent_tag = create(:tag,
-          primary_tag_name: create(:tag_name, name: 'index_parent_tag'),
-          category: :meme)
+      parent_tag = Tag.create!(
+        tag_name: TagName.create!(name: 'index_parent_tag'),
+        category: :meme
+      )
       TagImplication.create!(tag:, parent_tag:)
 
       get '/tags', params: { name: 'spec_tag' }
@@ -361,9 +349,10 @@ RSpec.describe 'Tags API', type: :request do
       end
 
       it 'returns aliases and parent tags' do
-        parent_tag = create(:tag,
-            primary_tag_name: create(:tag_name, name: 'show_parent_tag'),
-            category: :character)
+        parent_tag = Tag.create!(
+          tag_name: TagName.create!(name: 'show_parent_tag'),
+          category: :character
+        )
         TagImplication.create!(tag:, parent_tag:)
 
         request
@@ -409,7 +398,7 @@ RSpec.describe 'Tags API', type: :request do
     it 'prefers Tag when Tag and ExternalTag have the same id' do
       internal = create(
           :tag,
-          primary_tag_name: create(:tag_name, name: 'internal_collision'))
+          tag_name: create(:tag_name, name: 'internal_collision'))
       create(
           :external_tag,
           id: internal.id,
@@ -427,7 +416,7 @@ RSpec.describe 'Tags API', type: :request do
 
   describe 'GET /tags/autocomplete' do
     it 'combines internal and external matches without conflating equal ids' do
-      internal = create(:tag, category: :general, primary_name: 'mixed_internal', post_count: 2)
+      internal = Tag.create!(category: :general, name: 'mixed_internal', post_count: 2)
       external = create(:external_tag, id: internal.id,
                                        name: 'mixed_external', post_count: 3)
 
@@ -466,7 +455,7 @@ RSpec.describe 'Tags API', type: :request do
     it 'limits the combined results to 20 and sorts ties by displayed name' do
       11.times do |i|
         name = "combined_#{ i.to_s.rjust(2, '0') }"
-        create(:tag, category: :general, primary_name: name, post_count: 1)
+        Tag.create!(category: :general, name:, post_count: 1)
         create(:external_tag, name:, post_count: 1)
       end
 
@@ -478,39 +467,34 @@ RSpec.describe 'Tags API', type: :request do
     end
 
     it 'excludes external tags but preserves internal alias matches when nico is false' do
-      internal = create(:tag, category: :general, primary_name: 'switch_internal', post_count: 1)
-      alias_target = create(:tag, category: :general, primary_name: 'alias_target', post_count: 1)
-      create(:tag_name, :alias, name: 'switch_alias', tag: alias_target)
+      internal = Tag.create!(category: :general, name: 'switch_internal', post_count: 1)
+      alias_target = Tag.create!(category: :general, name: 'alias_target', post_count: 1)
+      TagName.create!(name: 'switch_alias', canonical: alias_target.tag_name)
       create(:external_tag, name: 'switch_external', post_count: 1)
 
       get '/tags/autocomplete', params: { q: 'switch', nico: '0' }
 
       expect(response).to have_http_status(:ok)
       expect(json).to contain_exactly(
-          a_hash_including('id' => internal.id,
-                           'name' => primary_tag_name_for(internal, 'ja').name),
-          a_hash_including('id' => alias_target.id,
-                           'name' => primary_tag_name_for(alias_target, 'ja').name,
+          a_hash_including('id' => internal.id, 'name' => internal.name),
+          a_hash_including('id' => alias_target.id, 'name' => alias_target.name,
                            'matched_alias' => 'switch_alias'))
     end
 
     ['%', '_'].each do |wildcard|
-      it "treats #{ wildcard } literally for primary, alias, and external names" do
+      it "treats #{ wildcard } literally for canonical, alias, and external names" do
         literal = "literal#{ wildcard }match"
-        create(:tag, category: :general, primary_name: literal, post_count: 1)
-        alias_target = create(
-            :tag, category: :general, primary_name: 'literal_alias_target', post_count: 1)
-        create(:tag_name, :alias, name: "#{ literal }_alias",
-                                  tag: alias_target)
+        Tag.create!(category: :general, name: literal, post_count: 1)
+        alias_target = Tag.create!(category: :general, name: 'literal_alias_target', post_count: 1)
+        TagName.create!(name: "#{ literal }_alias", canonical: alias_target.tag_name)
         create(:external_tag, name: literal, post_count: 1)
-        create(:tag, category: :general, primary_name: 'literalXmatch', post_count: 2)
+        Tag.create!(category: :general, name: 'literalXmatch', post_count: 2)
         create(:external_tag, name: 'literalXmatch', post_count: 2)
 
         get '/tags/autocomplete', params: { q: "literal#{ wildcard }" }
 
         expect(json.map { |row| row.fetch('name') })
-            .to contain_exactly(
-                literal, primary_tag_name_for(alias_target, 'ja').name, "nico:#{ literal }")
+            .to contain_exactly(literal, alias_target.name, "nico:#{ literal }")
       end
     end
 
@@ -526,7 +510,7 @@ RSpec.describe 'Tags API', type: :request do
       expect(t['matched_alias']).to be(nil)
     end
 
-    it 'returns matching primary tag names by q with aliases' do
+    it 'returns matching canonical tags by q with aliases' do
       get '/tags/autocomplete', params: { q: 'unk' }
 
       expect(response).to have_http_status(:ok)
@@ -539,10 +523,11 @@ RSpec.describe 'Tags API', type: :request do
     end
 
     it 'omits deprecated tags' do
-      deprecated_tag = create(:tag,
-          primary_name: 'spec_deprecated',
+      deprecated_tag = Tag.create!(
+        name: 'spec_deprecated',
         category: :general,
-          deprecated_at: Time.current)
+        deprecated_at: Time.current
+      )
       deprecated_tag.update_columns(post_count: 1)
 
       get '/tags/autocomplete', params: { q: 'spec_', present: '0' }
@@ -636,7 +621,7 @@ RSpec.describe 'Tags API', type: :request do
         expect(response).to have_http_status(:ok)
 
         tag.reload
-        expect(primary_tag_name_for(tag, 'ja').name).to eq('new')
+        expect(tag.name).to eq('new')
         expect(tag.category).to eq('general')
 
         body = JSON.parse(response.body)
@@ -651,7 +636,7 @@ RSpec.describe 'Tags API', type: :request do
         expect(response).to have_http_status(:ok)
 
         tag.reload
-        expect(primary_tag_name_for(tag, 'ja').name).to eq('spec_tag')
+        expect(tag.name).to eq('spec_tag')
         expect(tag.category).to eq('meme')
       end
 
@@ -661,7 +646,7 @@ RSpec.describe 'Tags API', type: :request do
         expect(response).to have_http_status(:ok)
 
         tag.reload
-        expect(primary_tag_name_for(tag, 'ja').name).to eq('spec_tag')
+        expect(tag.name).to eq('spec_tag')
         expect(tag.category).to eq('general')
       end
 
@@ -671,7 +656,7 @@ RSpec.describe 'Tags API', type: :request do
         expect(response).to have_http_status(:ok)
 
         tag.reload
-        expect(primary_tag_name_for(tag, 'ja').name).to eq('n')
+        expect(tag.name).to eq('n')
         expect(tag.category).to eq('meta')
       end
 
@@ -684,7 +669,7 @@ RSpec.describe 'Tags API', type: :request do
         patch "/tags/#{tag.id}", params: { name: 'new', category: 'nico' }
 
         expect(response).to have_http_status(:unprocessable_entity)
-        expect(primary_tag_name_for(tag.reload, 'ja').name).to eq('spec_tag')
+        expect(tag.reload.name).to eq('spec_tag')
         expect(tag.category).to eq('general')
       end
 
@@ -699,11 +684,11 @@ RSpec.describe 'Tags API', type: :request do
 
         expect(versions.map(&:event_type)).to eq(['create', 'update'])
 
-        expect(version_primary_name(versions.first, 'ja')).to eq('spec_tag')
+        expect(versions.first.name).to eq('spec_tag')
         expect(versions.first.category).to eq('general')
-        expect(version_alias_names(versions.first, 'ja')).to include('unko')
+        expect(versions.first.aliases.split).to include('unko')
 
-        expect(version_primary_name(versions.second, 'ja')).to eq('new_tag_name')
+        expect(versions.second.name).to eq('new_tag_name')
         expect(versions.second.category).to eq('meme')
         expect(versions.second.created_by_user_id).to eq(member_user.id)
       end
@@ -734,7 +719,7 @@ RSpec.describe 'Tags API', type: :request do
       it 'PATCH で tag の name を変更すると対応する wiki version を作成する' do
         wiki_page =
             Wiki::Commit.create_content!(
-                tag_name: primary_tag_name_for(tag, 'ja'),
+                tag_name: tag.tag_name,
                 body: 'wiki body before',
                 created_by_user: member_user,
                 message: 'init')
@@ -762,7 +747,7 @@ RSpec.describe 'Tags API', type: :request do
       it 'tag の category だけを変更しても wiki version は作成しない' do
         wiki_page =
             Wiki::Commit.create_content!(
-                tag_name: primary_tag_name_for(tag, 'ja'),
+                tag_name: tag.tag_name,
                 body: 'wiki body before',
                 created_by_user: member_user,
                 message: 'init')
@@ -789,8 +774,7 @@ RSpec.describe 'Tags API', type: :request do
         }
 
         expect(response).to have_http_status(:ok)
-        expect(TagName.find_by!(language_code: 'ja', name: 'spec_tag'))
-            .to have_attributes(tag_id: tag.id, primary_flg: false)
+        expect(TagName.find_by!(name: 'spec_tag').canonical).to eq(tag.reload.tag_name)
 
         patch "/tags/#{ tag.id }", params: { name: 'spec_tag' }
 
@@ -798,17 +782,15 @@ RSpec.describe 'Tags API', type: :request do
 
         tag.reload
 
-        expect(primary_tag_name_for(tag, 'ja').name).to eq('spec_tag')
-        expect(primary_tag_name_for(tag, 'ja')).to have_attributes(
-            tag_id: tag.id, language_code: 'ja', primary_flg: true)
-        expect(TagName.find_by!(language_code: 'ja', name: 'patch_roundtrip_target'))
-            .to have_attributes(tag_id: tag.id, primary_flg: false)
+        expect(tag.name).to eq('spec_tag')
+        expect(tag.tag_name.canonical_id).to be_nil
+        expect(TagName.find_by!(name: 'patch_roundtrip_target').canonical).to eq(tag.tag_name)
       end
 
       it '別 tag の正規名には変更できない' do
         wiki_page =
             Wiki::Commit.create_content!(
-                tag_name: primary_tag_name_for(tag, 'ja'),
+                tag_name: tag.tag_name,
                 body: 'patch collision wiki',
                 created_by_user: member_user,
                 message: 'init')
@@ -820,10 +802,9 @@ RSpec.describe 'Tags API', type: :request do
           'name' => ['その名前は既に使はれてゐます．']
         )
 
-        expect(primary_tag_name_for(tag.reload, 'ja').name).to eq('spec_tag')
-        expect(TagName.where(tag_id: tag.id, language_code: 'ja', primary_flg: false).pluck(:name))
-            .to contain_exactly('unko')
-        expect(wiki_page.reload.tag_name).to eq(primary_tag_name_for(tag, 'ja'))
+        expect(tag.reload.name).to eq('spec_tag')
+        expect(tag.tag_name.aliases.map(&:name)).to contain_exactly('unko')
+        expect(wiki_page.reload.tag_name).to eq(tag.tag_name)
       end
 
       it 'system tag の name は変更できない' do
@@ -832,34 +813,34 @@ RSpec.describe 'Tags API', type: :request do
         patch "/tags/#{ system_tag.id }", params: { name: 'patch_system_tag_renamed' }
 
         expect(response).to have_http_status(:unprocessable_entity)
-        expect(primary_tag_name_for(system_tag.reload, 'ja').name).to eq('bot操作')
+        expect(system_tag.reload.name).to eq('bot操作')
       end
     end
   end
 
   describe 'GET /tags/with-depth' do
     let!(:root_meme) do
-      create(:tag, primary_name: 'depth_a_root_meme', category: :meme)
+      Tag.create!(tag_name: TagName.create!(name: 'depth_a_root_meme'), category: :meme)
     end
 
     let!(:root_material) do
-      create(:tag, primary_name: 'depth_b_root_material', category: :material)
+      Tag.create!(tag_name: TagName.create!(name: 'depth_b_root_material'), category: :material)
     end
 
     let!(:hidden_general_root) do
-      create(:tag, primary_name: 'depth_hidden_general_root', category: :general)
+      Tag.create!(tag_name: TagName.create!(name: 'depth_hidden_general_root'), category: :general)
     end
 
     let!(:child_character) do
-      create(:tag, primary_name: 'depth_child_character', category: :character)
+      Tag.create!(tag_name: TagName.create!(name: 'depth_child_character'), category: :character)
     end
 
     let!(:grandchild_material) do
-      create(:tag, primary_name: 'depth_grandchild_material', category: :material)
+      Tag.create!(tag_name: TagName.create!(name: 'depth_grandchild_material'), category: :material)
     end
 
     let!(:child_general) do
-      create(:tag, primary_name: 'depth_child_general', category: :general)
+      Tag.create!(tag_name: TagName.create!(name: 'depth_child_general'), category: :general)
     end
 
     before do
@@ -902,13 +883,15 @@ RSpec.describe 'Tags API', type: :request do
     end
 
     it 'passes through deprecated tags when finding children' do
-      deprecated_middle = create(:tag,
-          primary_name: 'depth_deprecated_middle',
+      deprecated_middle = Tag.create!(
+        name: 'depth_deprecated_middle',
         category: :character,
-          deprecated_at: Time.current)
-      visible_descendant = create(:tag,
-          primary_name: 'depth_visible_descendant',
-          category: :material)
+        deprecated_at: Time.current
+      )
+      visible_descendant = Tag.create!(
+        name: 'depth_visible_descendant',
+        category: :material
+      )
       TagImplication.create!(parent_tag: root_material, tag: deprecated_middle)
       TagImplication.create!(parent_tag: deprecated_middle, tag: visible_descendant)
 
@@ -920,20 +903,24 @@ RSpec.describe 'Tags API', type: :request do
     end
 
     it 'passes through multiple deprecated tags for roots and has_children' do
-      active_child = create(:tag,
-          primary_name: 'depth_active_child_below_deprecated',
-          category: :character)
-      deprecated_parent = create(:tag,
-          primary_name: 'depth_deprecated_parent',
+      active_child = Tag.create!(
+        name: 'depth_active_child_below_deprecated',
+        category: :character
+      )
+      deprecated_parent = Tag.create!(
+        name: 'depth_deprecated_parent',
         category: :character,
-          deprecated_at: Time.current)
-      deprecated_grandparent = create(:tag,
-          primary_name: 'depth_deprecated_grandparent',
+        deprecated_at: Time.current
+      )
+      deprecated_grandparent = Tag.create!(
+        name: 'depth_deprecated_grandparent',
         category: :material,
-          deprecated_at: Time.current)
-      active_ancestor = create(:tag,
-          primary_name: 'depth_active_ancestor',
-          category: :meme)
+        deprecated_at: Time.current
+      )
+      active_ancestor = Tag.create!(
+        name: 'depth_active_ancestor',
+        category: :meme
+      )
       TagImplication.create!(tag: active_child, parent_tag: deprecated_parent)
       TagImplication.create!(tag: deprecated_parent, parent_tag: deprecated_grandparent)
       TagImplication.create!(tag: deprecated_grandparent, parent_tag: active_ancestor)
@@ -958,13 +945,15 @@ RSpec.describe 'Tags API', type: :request do
     end
 
     it 'treats an active tag with only deprecated ancestors as a root' do
-      active_child = create(:tag,
-          primary_name: 'depth_root_below_deprecated',
-          category: :character)
-      deprecated_parent = create(:tag,
-          primary_name: 'depth_root_deprecated_parent',
+      active_child = Tag.create!(
+        name: 'depth_root_below_deprecated',
+        category: :character
+      )
+      deprecated_parent = Tag.create!(
+        name: 'depth_root_deprecated_parent',
         category: :material,
-          deprecated_at: Time.current)
+        deprecated_at: Time.current
+      )
       TagImplication.create!(tag: active_child, parent_tag: deprecated_parent)
 
       get '/tags/with-depth'
@@ -978,14 +967,16 @@ RSpec.describe 'Tags API', type: :request do
     end
 
     it 'terminates when deprecated implications contain a cycle' do
-      first = create(:tag,
-          primary_name: 'depth_cycle_first',
+      first = Tag.create!(
+        name: 'depth_cycle_first',
         category: :character,
-          deprecated_at: Time.current)
-      second = create(:tag,
-          primary_name: 'depth_cycle_second',
+        deprecated_at: Time.current
+      )
+      second = Tag.create!(
+        name: 'depth_cycle_second',
         category: :material,
-          deprecated_at: Time.current)
+        deprecated_at: Time.current
+      )
       TagImplication.create!(tag: first, parent_tag: root_material)
       TagImplication.create!(tag: second, parent_tag: first)
       now = Time.current
@@ -1011,19 +1002,19 @@ RSpec.describe 'Tags API', type: :request do
     let!(:material_user) { create_member_user! }
 
     let!(:root_tag) do
-      create(:tag, primary_name: 'materials_root', category: :material)
+      Tag.create!(tag_name: TagName.create!(name: 'materials_root'), category: :material)
     end
 
     let!(:child_a_tag) do
-      create(:tag, primary_name: 'materials_child_a', category: :material)
+      Tag.create!(tag_name: TagName.create!(name: 'materials_child_a'), category: :material)
     end
 
     let!(:child_b_tag) do
-      create(:tag, primary_name: 'materials_child_b', category: :character)
+      Tag.create!(tag_name: TagName.create!(name: 'materials_child_b'), category: :character)
     end
 
     let!(:grandchild_tag) do
-      create(:tag, primary_name: 'materials_grandchild', category: :material)
+      Tag.create!(tag_name: TagName.create!(name: 'materials_grandchild'), category: :material)
     end
 
     let!(:root_material) do
@@ -1045,7 +1036,7 @@ RSpec.describe 'Tags API', type: :request do
     end
 
     it 'returns a tag tree with nested materials sorted by child name' do
-      get "/tags/name/#{ CGI.escape(primary_tag_name_for(root_tag, 'ja').name) }/materials"
+      get "/tags/name/#{ CGI.escape(root_tag.name) }/materials"
 
       expect(response).to have_http_status(:ok)
 
@@ -1136,7 +1127,7 @@ RSpec.describe 'Tags API', type: :request do
         }
 
         expect(response).to have_http_status(:unprocessable_entity)
-        expect(primary_tag_name_for(tag.reload, 'ja').name).to eq('spec_tag')
+        expect(tag.reload.name).to eq('spec_tag')
       end
 
       it 'category が空なら 422 を返す' do
@@ -1148,7 +1139,7 @@ RSpec.describe 'Tags API', type: :request do
         }
 
         expect(response).to have_http_status(:unprocessable_entity)
-        expect(primary_tag_name_for(tag.reload, 'ja').name).to eq('spec_tag')
+        expect(tag.reload.name).to eq('spec_tag')
         expect(tag.category).to eq('general')
       end
 
@@ -1167,12 +1158,14 @@ RSpec.describe 'Tags API', type: :request do
       end
 
       it 'name, category, aliases, parent tags をまとめて更新できる' do
-        old_parent = create(:tag,
-            primary_tag_name: create(:tag_name, name: 'put_old_parent'),
-            category: :general)
-        kept_parent = create(:tag,
-            primary_tag_name: create(:tag_name, name: 'put_kept_parent'),
-            category: :general)
+        old_parent = Tag.create!(
+          tag_name: TagName.create!(name: 'put_old_parent'),
+          category: :general
+        )
+        kept_parent = Tag.create!(
+          tag_name: TagName.create!(name: 'put_kept_parent'),
+          category: :general
+        )
         TagImplication.create!(tag:, parent_tag: old_parent)
         TagImplication.create!(tag:, parent_tag: kept_parent)
 
@@ -1188,24 +1181,22 @@ RSpec.describe 'Tags API', type: :request do
 
         tag.reload
 
-        expect(primary_tag_name_for(tag, 'ja').name).to eq('put_renamed_tag')
+        expect(tag.name).to eq('put_renamed_tag')
         expect(tag.category).to eq('meme')
 
-        expect(TagName.find_by!(language_code: 'ja', name: 'put_alias_a'))
-            .to have_attributes(tag_id: tag.id, primary_flg: false)
-        expect(TagName.find_by!(language_code: 'ja', name: 'put_alias_b'))
-            .to have_attributes(tag_id: tag.id, primary_flg: false)
+        expect(TagName.find_by(name: 'put_alias_a').canonical).to eq(tag.tag_name)
+        expect(TagName.find_by(name: 'put_alias_b').canonical).to eq(tag.tag_name)
 
-        old_name_alias = TagName.find_by(language_code: 'ja', name: 'spec_tag')
+        old_name_alias = TagName.find_by(name: 'spec_tag')
         expect(old_name_alias).to be_present
-        expect(old_name_alias).to have_attributes(
-            tag_id: tag.id, language_code: 'ja', primary_flg: false)
+        expect(old_name_alias.canonical).to eq(tag.tag_name)
 
-        expect(alias_tn.reload.tag_id).to be_nil
+        expect(alias_tn.reload.canonical).to be_nil
 
-        expect(TagName.where(tag_id: tag.parents.select(:id),
-                             language_code: 'ja', primary_flg: true).pluck(:name))
-            .to contain_exactly('put_kept_parent', 'put_new_parent')
+        expect(tag.parents.map(&:name)).to contain_exactly(
+          'put_kept_parent',
+          'put_new_parent'
+        )
 
         expect(TagImplication.where(tag:, parent_tag: old_parent)).not_to exist
 
@@ -1235,8 +1226,7 @@ RSpec.describe 'Tags API', type: :request do
 
         tag.reload
 
-        expect(TagName.find_by!(language_code: 'ja', name: 'put_alias_self_test'))
-            .to have_attributes(tag_id: tag.id, primary_flg: false)
+        expect(TagName.find_by(name: 'put_alias_self_test').canonical).to eq(tag.tag_name)
         expect(json['aliases']).to include('put_alias_self_test')
         expect(json['aliases']).not_to include('spec_tag')
       end
@@ -1273,13 +1263,13 @@ RSpec.describe 'Tags API', type: :request do
 
         expect(versions.map(&:event_type)).to eq(['create', 'update'])
 
-        expect(version_primary_name(versions.first, 'ja')).to eq('spec_tag')
+        expect(versions.first.name).to eq('spec_tag')
         expect(versions.first.category).to eq('general')
-        expect(version_alias_names(versions.first, 'ja')).to include('unko')
+        expect(versions.first.aliases.split).to include('unko')
 
-        expect(version_primary_name(versions.second, 'ja')).to eq('put_versioned_tag')
+        expect(versions.second.name).to eq('put_versioned_tag')
         expect(versions.second.category).to eq('meta')
-        expect(version_alias_names(versions.second, 'ja')).to include('spec_tag')
+        expect(versions.second.aliases.split).to include('spec_tag')
         expect(versions.second.created_by_user_id).to eq(member_user.id)
       end
 
@@ -1306,37 +1296,35 @@ RSpec.describe 'Tags API', type: :request do
 
         tag.reload
 
-        expect(primary_tag_name_for(tag, 'ja').name).to eq('spec_tag')
-        expect(TagName.find_by!(language_code: 'ja', name: 'put_roundtrip_b'))
-            .to have_attributes(tag_id: tag.id, primary_flg: false)
-        expect(TagName.where(tag_id: tag.id, language_code: 'ja', primary_flg: false).pluck(:name))
-            .to contain_exactly('put_roundtrip_b', 'unko')
-        expect(TagName.where(tag_id: tag.id, language_code: 'ja', primary_flg: false).pluck(:name))
-            .not_to include('spec_tag')
-        expect(alias_tn.reload).to have_attributes(
-            tag_id: tag.id, language_code: 'ja', primary_flg: false)
+        expect(tag.name).to eq('spec_tag')
+        expect(TagName.find_by!(name: 'put_roundtrip_b').canonical).to eq(tag.tag_name)
+        expect(tag.tag_name.aliases.map(&:name)).to contain_exactly('put_roundtrip_b', 'unko')
+        expect(tag.tag_name.aliases.map(&:name)).not_to include('spec_tag')
+        expect(alias_tn.reload.canonical).to eq(tag.tag_name)
 
         version = tag.tag_versions.order(:version_no).last
 
         expect(version.event_type).to eq('update')
-        expect(version_primary_name(version, 'ja')).to eq('spec_tag')
-        expect(version_alias_names(version, 'ja')).to contain_exactly('put_roundtrip_b', 'unko')
+        expect(version.name).to eq('spec_tag')
+        expect(version.aliases.split).to contain_exactly('put_roundtrip_b', 'unko')
       end
 
       it 'parent tag の snapshot も作成する' do
-        old_parent = create(:tag,
-            primary_tag_name: create(:tag_name, name: 'put_snapshot_old_parent'),
-            category: :general)
-        new_parent = create(:tag,
-            primary_tag_name: create(:tag_name, name: 'put_snapshot_new_parent'),
-            category: :general)
+        old_parent = Tag.create!(
+          tag_name: TagName.create!(name: 'put_snapshot_old_parent'),
+          category: :general
+        )
+        new_parent = Tag.create!(
+          tag_name: TagName.create!(name: 'put_snapshot_new_parent'),
+          category: :general
+        )
         TagImplication.create!(tag:, parent_tag: old_parent)
 
         put "/tags/#{ tag.id }", params: {
           name: 'spec_tag',
           category: 'general',
           aliases: 'unko',
-          parent_tags: primary_tag_name_for(new_parent, 'ja').name,
+          parent_tags: new_parent.name,
           deprecated: '0',
         }
 
@@ -1359,13 +1347,13 @@ RSpec.describe 'Tags API', type: :request do
 
         expect(response).to have_http_status(:unprocessable_entity)
 
-        expect(primary_tag_name_for(tag.reload, 'ja').name).to eq('spec_tag')
+        expect(tag.reload.name).to eq('spec_tag')
         expect(tag.category).to eq('general')
       end
 
       it 'system tag の name は変更できない' do
         system_tag = Tag.tagme
-        old_name = primary_tag_name_for(system_tag, 'ja').name
+        old_name = system_tag.name
         old_category = system_tag.category
 
         expect {
@@ -1380,14 +1368,14 @@ RSpec.describe 'Tags API', type: :request do
 
         expect(response).to have_http_status(:unprocessable_entity)
 
-        expect(primary_tag_name_for(system_tag.reload, 'ja').name).to eq(old_name)
+        expect(system_tag.reload.name).to eq(old_name)
         expect(system_tag.category).to eq(old_category)
       end
 
       it 'wiki を持つ tag を更新すると wiki version も作成する' do
         wiki_page =
             Wiki::Commit.create_content!(
-                tag_name: primary_tag_name_for(tag, 'ja'),
+                tag_name: tag.tag_name,
                 body: 'wiki body before',
                 created_by_user: member_user,
                 message: 'init')
@@ -1423,10 +1411,10 @@ RSpec.describe 'Tags API', type: :request do
         )
       end
 
-      it 'wiki を持つ tag を旧 alias へ戻しても wiki を新しい正本名へ移す' do
+      it 'wiki を持つ tag を旧 alias へ戻しても wiki を新 canonical へ移す' do
         wiki_page =
             Wiki::Commit.create_content!(
-                tag_name: primary_tag_name_for(tag, 'ja'),
+                tag_name: tag.tag_name,
                 body: 'wiki body before',
                 created_by_user: member_user,
                 message: 'init')
@@ -1455,11 +1443,9 @@ RSpec.describe 'Tags API', type: :request do
 
         tag.reload
 
-        expect(wiki_page.reload.tag_name).to eq(primary_tag_name_for(tag, 'ja'))
-        expect(TagName.find_by!(language_code: 'ja', name: 'put_wiki_roundtrip_b').wiki_page)
-            .to be_nil
-        expect(TagName.find_by!(language_code: 'ja', name: 'put_wiki_roundtrip_b'))
-            .to have_attributes(tag_id: tag.id, primary_flg: false)
+        expect(wiki_page.reload.tag_name).to eq(tag.tag_name)
+        expect(TagName.find_by!(name: 'put_wiki_roundtrip_b').wiki_page).to be_nil
+        expect(TagName.find_by!(name: 'put_wiki_roundtrip_b').canonical).to eq(tag.tag_name)
 
         versions = wiki_page.wiki_versions.order(:version_no).last(2)
 
@@ -1468,16 +1454,16 @@ RSpec.describe 'Tags API', type: :request do
       end
 
       it '別名を他 tag から奪った場合、奪はれた側の tag version も作成する' do
-        old_owner = create(:tag,
-            primary_tag_name: create(:tag_name, name: 'put_alias_old_owner'),
-            category: :general)
-        stolen_alias = create(:tag_name, :alias,
+        old_owner = Tag.create!(
+          tag_name: TagName.create!(name: 'put_alias_old_owner'),
+          category: :general
+        )
+        stolen_alias = TagName.create!(
           name: 'put_stolen_alias',
-            tag: old_owner)
+          canonical: old_owner.tag_name
+        )
 
-        expect(TagName.where(tag_id: old_owner.id, language_code: 'ja',
-                              primary_flg: false).pluck(:name))
-            .to include('put_stolen_alias')
+        expect(old_owner.tag_name.aliases.map(&:name)).to include('put_stolen_alias')
 
         expect {
           put "/tags/#{ tag.id }", params: {
@@ -1493,32 +1479,30 @@ RSpec.describe 'Tags API', type: :request do
 
         expect(response).to have_http_status(:ok)
 
-        expect(stolen_alias.reload).to have_attributes(
-            tag_id: tag.id, language_code: 'ja', primary_flg: false)
-        expect(TagName.where(tag_id: old_owner.id, language_code: 'ja',
-                              primary_flg: false).pluck(:name))
-            .not_to include('put_stolen_alias')
+        expect(stolen_alias.reload.canonical).to eq(tag.tag_name)
+        expect(old_owner.reload.tag_name.aliases.map(&:name)).not_to include('put_stolen_alias')
 
         old_owner_versions = old_owner.tag_versions.order(:version_no)
 
         expect(old_owner_versions.first.event_type).to eq('create')
-        expect(version_alias_names(old_owner_versions.first, 'ja')).to include('put_stolen_alias')
+        expect(old_owner_versions.first.aliases.split).to include('put_stolen_alias')
 
         expect(old_owner_versions.second.event_type).to eq('update')
-        expect(version_alias_names(old_owner_versions.second, 'ja'))
-            .not_to include('put_stolen_alias')
+        expect(old_owner_versions.second.aliases.split).not_to include('put_stolen_alias')
       end
 
       it '別 tag の alias 名を rename で奪へる' do
-        old_owner = create(:tag,
-            primary_tag_name: create(:tag_name, name: 'put_alias_collision_owner'),
-            category: :general)
-        stolen_alias = create(:tag_name, :alias,
+        old_owner = Tag.create!(
+          tag_name: TagName.create!(name: 'put_alias_collision_owner'),
+          category: :general
+        )
+        stolen_alias = TagName.create!(
           name: 'put_alias_collision_name',
-            tag: old_owner)
+          canonical: old_owner.tag_name
+        )
         wiki_page =
             Wiki::Commit.create_content!(
-                tag_name: primary_tag_name_for(tag, 'ja'),
+                tag_name: tag.tag_name,
                 body: 'put collision wiki',
                 created_by_user: member_user,
                 message: 'init')
@@ -1531,33 +1515,29 @@ RSpec.describe 'Tags API', type: :request do
           deprecated: '0',
         }
 
-        expect(response).to have_http_status(:ok), response.body
+        expect(response).to have_http_status(:ok)
 
         tag.reload
         old_owner.reload
         stolen_alias.reload
 
-        expect(primary_tag_name_for(tag, 'ja').name).to eq('put_alias_collision_name')
-        expect(stolen_alias).to have_attributes(
-            tag_id: tag.id, language_code: 'ja', primary_flg: true)
-        expect(TagName.find_by!(language_code: 'ja', name: 'spec_tag'))
-            .to have_attributes(tag_id: tag.id, primary_flg: false)
-        expect(TagName.where(tag_id: old_owner.id, language_code: 'ja',
-                              primary_flg: false).pluck(:name))
-            .not_to include('put_alias_collision_name')
+        expect(tag.name).to eq('put_alias_collision_name')
+        expect(stolen_alias.canonical_id).to be_nil
+        expect(TagName.find_by!(name: 'spec_tag').canonical).to eq(tag.tag_name)
+        expect(old_owner.tag_name.aliases.map(&:name)).not_to include('put_alias_collision_name')
 
         old_owner_versions = old_owner.tag_versions.order(:version_no)
 
         expect(old_owner_versions.last.event_type).to eq('update')
-        expect(version_alias_names(old_owner_versions.last, 'ja'))
-            .not_to include('put_alias_collision_name')
-        expect(wiki_page.reload.tag_name).to eq(primary_tag_name_for(tag, 'ja'))
+        expect(old_owner_versions.last.aliases.split).not_to include('put_alias_collision_name')
+        expect(wiki_page.reload.tag_name).to eq(tag.tag_name)
       end
 
       it 'parent_tags に指定すると循環する tag は 422 にする' do
-        child = create(:tag,
-            primary_tag_name: create(:tag_name, name: 'put_cycle_child'),
-            category: :general)
+        child = Tag.create!(
+          tag_name: TagName.create!(name: 'put_cycle_child'),
+          category: :general
+        )
 
         TagImplication.create!(tag: child, parent_tag: tag)
 
@@ -1565,7 +1545,7 @@ RSpec.describe 'Tags API', type: :request do
           name: 'spec_tag',
           category: 'general',
           aliases: 'unko',
-          parent_tags: primary_tag_name_for(child, 'ja').name,
+          parent_tags: child.name,
           deprecated: '0',
         }
 
@@ -1577,7 +1557,7 @@ RSpec.describe 'Tags API', type: :request do
       it 'tag の name を変更すると対応する wiki version を作成する' do
         wiki_page =
             Wiki::Commit.create_content!(
-                tag_name: primary_tag_name_for(tag, 'ja'),
+                tag_name: tag.tag_name,
                 body: 'wiki body before',
                 created_by_user: member_user,
                 message: 'init')

backend/spec/requests/theatres_spec.rb

@@ -396,7 +396,7 @@ RSpec.describe 'Theatres API', type: :request do
     end
 
     it 'finalizes skip when votes reach majority and stores voters and tag snapshots' do
-      tag = create(:tag, primary_name: 'skip-target')
+      tag = create(:tag, name: 'skip-target')
       PostTag.create!(post: niconico_post, tag:)
 
       TheatreSkipVote.create!(theatre:, post: niconico_post, user: member)
@@ -503,7 +503,7 @@ RSpec.describe 'Theatres API', type: :request do
     end
 
     it 'returns tag penalties and candidate weights for the current watchers' do
-      tag = create(:tag, primary_name: 'heavy-tag')
+      tag = create(:tag, name: 'heavy-tag')
       PostTag.create!(post: second_niconico_post, tag:)
       event = TheatreSkipEvent.create!(
         theatre:,

backend/spec/requests/wiki_conflict_spec.rb

@@ -10,7 +10,7 @@ RSpec.describe 'Wiki conflict handling', type: :request do
   it 'returns 409 when base_revision_id is stale' do
     page =
         Wiki::Commit.create_content!(
-            tag_name: create(:tag_name, name: 'wiki_conflict_request'),
+            tag_name: TagName.create!(name: 'wiki_conflict_request'),
             body: 'first',
             created_by_user: user,
             message: 'init')

backend/spec/requests/wiki_history_integrity_spec.rb

@@ -10,7 +10,7 @@ RSpec.describe 'Wiki history integrity', type: :request do
 
   def create_wiki_page title:, body: 'body', message: 'init', user: self.user
     Wiki::Commit.create_content!(
-        tag_name: create(:tag_name, name: title),
+        tag_name: TagName.create!(name: title),
         body:,
         created_by_user: user,
         message:)

backend/spec/requests/wiki_spec.rb

@@ -10,7 +10,7 @@ RSpec.describe 'Wiki API', type: :request do
 
   let!(:user) { create_member_user! }
 
-  let!(:tn) { create(:tag_name, name: 'spec_wiki_title') }
+  let!(:tn) { TagName.create!(name: 'spec_wiki_title') }
   let!(:page) do
     Wiki::Commit.create_content!(
         tag_name: tn,
@@ -19,10 +19,11 @@ RSpec.describe 'Wiki API', type: :request do
         message: 'init')
   end
   let!(:tag) do
-    create(:tag,
-        primary_tag_name: tn,
+    Tag.create!(
+      tag_name: tn,
       category: :general,
-        deprecated_at: Time.zone.local(2026, 6, 1))
+      deprecated_at: Time.zone.local(2026, 6, 1)
+    )
   end
 
   describe 'GET /wiki' do
@@ -207,7 +208,7 @@ RSpec.describe 'Wiki API', type: :request do
       { 'X-Transfer-Code' => user.inheritance_code }
     end
 
-    let!(:test_tag_name) { create(:tag_name, name: 'TestPage') }
+    let!(:test_tag_name) { TagName.create!(name: 'TestPage') }
 
     let!(:page) do
       Wiki::Commit.create_content!(
@@ -274,8 +275,8 @@ RSpec.describe 'Wiki API', type: :request do
       end
 
       it 'wiki body だけを変更しても tag version は作成しない' do
-        linked_tag_name = create(:tag_name, name: 'wiki_body_only_tag')
-        linked_tag = create(:tag, primary_tag_name: linked_tag_name, category: :general)
+        linked_tag_name = TagName.create!(name: 'wiki_body_only_tag')
+        linked_tag = Tag.create!(tag_name: linked_tag_name, category: :general)
 
         TagVersionRecorder.record!(
             tag: linked_tag,
@@ -358,13 +359,13 @@ RSpec.describe 'Wiki API', type: :request do
   describe 'GET /wiki/search' do
     before do
       Wiki::Commit.create_content!(
-          tag_name: create(:tag_name, name: 'spec_wiki_title_2'),
+          tag_name: TagName.create!(name: 'spec_wiki_title_2'),
           body: 'search body 2',
           created_by_user: user,
           message: 'init')
 
       Wiki::Commit.create_content!(
-          tag_name: create(:tag_name, name: 'unrelated_title'),
+          tag_name: TagName.create!(name: 'unrelated_title'),
           body: 'unrelated body',
           created_by_user: user,
           message: 'init')
@@ -433,7 +434,7 @@ RSpec.describe 'Wiki API', type: :request do
 
     it 'returns empty array when page has no revisions and filtered by id' do
       # 別ページを作って revision 無し
-      tn2 = create(:tag_name, name: 'spec_no_rev')
+      tn2 = TagName.create!(name: 'spec_no_rev')
       # 異常データ: revision 無し WikiPage を直接作る
       p2 = WikiPage.create!(
           tag_name: tn2,
@@ -513,7 +514,7 @@ RSpec.describe 'Wiki API', type: :request do
 
   describe 'Wiki::Commit.redirect!' do
     it 'raises because redirect revisions are deprecated' do
-      target_tag_name = create(:tag_name, name: 'redirect_deprecated_target')
+      target_tag_name = TagName.create!(name: 'redirect_deprecated_target')
       target =
           Wiki::Commit.create_content!(
               tag_name: target_tag_name,
@@ -534,8 +535,8 @@ RSpec.describe 'Wiki API', type: :request do
   end
 
   it 'wiki title を変更すると対応する tag の version を作成する' do
-    linked_tag_name = create(:tag_name, name: 'wiki_linked_tag_for_version')
-    linked_tag = create(:tag, primary_tag_name: linked_tag_name, category: :general)
+    linked_tag_name = TagName.create!(name: 'wiki_linked_tag_for_version')
+    linked_tag = Tag.create!(tag_name: linked_tag_name, category: :general)
 
     linked_page =
         Wiki::Commit.create_content!(
@@ -563,8 +564,7 @@ RSpec.describe 'Wiki API', type: :request do
     expect(response).to have_http_status(:ok)
 
     linked_tag.reload
-    expect(primary_tag_name_for(linked_tag, 'ja').name)
-        .to eq('wiki_linked_tag_for_version_renamed')
+    expect(linked_tag.name).to eq('wiki_linked_tag_for_version_renamed')
 
     versions = linked_tag.tag_versions.order(:version_no)
 

backend/spec/requests/wiki_title_collision_spec.rb

@@ -9,7 +9,7 @@ RSpec.describe 'Wiki title collision', type: :request do
 
   def create_wiki_page title:, body:
     Wiki::Commit.create_content!(
-        tag_name: create(:tag_name, name: title),
+        tag_name: TagName.create!(name: title),
         body:,
         created_by_user: user,
         message: 'init')

backend/spec/services/material_sync_importer_spec.rb

@@ -2,7 +2,7 @@ require 'rails_helper'
 
 RSpec.describe MaterialSyncImporter do
   let(:user) { create(:user, :member) }
-  let(:tag) { create(:tag, primary_name: 'sync_tag', category: :material) }
+  let(:tag) { Tag.create!(tag_name: TagName.create!(name: 'sync_tag'), category: :material) }
 
   def tempfile_for body
     Tempfile.new(['material-sync-importer', '.png']).tap do |file|

backend/spec/services/nico_tag_version_recorder_spec.rb

@@ -65,7 +65,7 @@ RSpec.describe NicoTagVersionRecorder do
   end
 
   it 'records sorted linked internal names and later link removal' do
-    tags = ['z_link', 'a_link'].map { |name| create(:tag, primary_name: name, category: :general) }
+    tags = ['z_link', 'a_link'].map { |name| Tag.create!(name:, category: :general) }
     tags.each { |tag| NicoTagRelation.create!(nico_tag: external_tag, tag:) }
 
     expect(record(:create).linked_tags).to eq('a_link z_link')

backend/spec/services/post_bulk_creator_spec.rb

@@ -1,8 +1,6 @@
 require 'rails_helper'
 
 RSpec.describe PostBulkCreator do
-  include_context 'English locale'
-
   it 'limits workers to two and keeps failures in their request slots' do
     actor = instance_double(User, id: 123)
     allow(User).to receive(:find).with(123) {
@@ -11,7 +9,6 @@ RSpec.describe PostBulkCreator do
     mutex = Mutex.new
     active = 0
     maximum_active = 0
-    creators = []
 
     allow(PostCreatePreflight).to receive(:new) do |attributes:, **|
       preflight = instance_double(PostCreatePreflight)
@@ -31,7 +28,6 @@ RSpec.describe PostBulkCreator do
     end
     allow(PostCreator).to receive(:new) do |attributes:, **|
       creator = instance_double(PostCreator)
-      mutex.synchronize { creators << creator }
       if attributes[:title] == 'broken'
         allow(creator).to receive(:create!).and_raise(StandardError, 'broken')
       else
@@ -49,12 +45,7 @@ RSpec.describe PostBulkCreator do
     results = described_class.new(
         actor:,
         posts:,
-        thumbnails: { }).run(locale).fetch(:results)
-
-    expect(creators.length).to eq(posts.length)
-    creators.each do |creator|
-      expect(creator).to have_received(:create!).with(locale).once
-    end
+        thumbnails: { }).run.fetch(:results)
 
     expect(maximum_active).to eq(2)
     expect(results.length).to eq(posts.length)

backend/spec/services/post_create_plan_spec.rb

@@ -2,7 +2,7 @@ require 'rails_helper'
 
 RSpec.describe PostCreatePlan do
   def create_tag! name, category
-    create(:tag, primary_name: name, category:)
+    Tag.create!(name:, category:)
   end
 
   before do
@@ -10,59 +10,6 @@ RSpec.describe PostCreatePlan do
     create_tag!('ニジラー情報不詳', :meta)
   end
 
-  context 'with an explicit locale' do
-    include_context 'English locale'
-
-    it 'resolves the matching language identity and its parents' do
-      english_name = create(:tag_name, name: 'shared_name',
-                                      language_code: 'en', script_code: 'Latn')
-      english = create(:tag, primary_tag_name: english_name, category: :character)
-      japanese = create(:tag, primary_name: 'temporary_japanese', category: :general)
-      # The DB permits this identity; validation has its own contract spec.
-      primary_tag_name_for(japanese, 'ja').update_columns(name: 'shared_name')
-      english_parent_name = create(:tag_name, name: 'english_parent',
-                                            language_code: 'en', script_code: 'Latn')
-      english_parent = create(:tag, primary_tag_name: english_parent_name,
-                                    category: :material)
-      japanese_parent = create(:tag, primary_name: 'japanese_parent', category: :general)
-      TagImplication.create!(tag: english, parent_tag: english_parent)
-      TagImplication.create!(tag: japanese, parent_tag: japanese_parent)
-
-      plan = described_class.new(attributes: { tags: 'shared_name' }).build!(locale)
-
-      expect(plan[:direct_tag_specs]).to eq(
-          [{ name: 'shared_name', category: :character }])
-      expect(plan[:post_tag_specs]).to include(
-          { name: primary_tag_name_for(english_parent, 'en').name, category: :material })
-      expect(plan[:post_tag_specs].pluck(:name))
-          .not_to include(primary_tag_name_for(japanese_parent, 'ja').name)
-    end
-
-    it 'resolves aliases within the requested language' do
-      japanese = create(:tag, primary_name: 'japanese_canonical')
-      english_name = create(:tag_name, name: 'english_canonical',
-                                      language_code: 'en', script_code: 'Latn')
-      english = create(:tag, primary_tag_name: english_name, category: :character)
-      japanese_alias = create(:tag_name, :alias, name: 'shared_alias',
-                                                tag: japanese)
-      english_alias = create(:tag_name, :alias, name: 'shared_alias',
-                                               tag: english,
-                                               language_code: 'en', script_code: 'Latn')
-
-      expect(japanese_alias.reload).to have_attributes(
-          tag_id: japanese.id,
-          primary_flg: false, language_code: 'ja')
-      expect(english_alias.reload).to have_attributes(
-          tag_id: english.id,
-          primary_flg: false, language_code: 'en')
-
-      plan = described_class.new(attributes: { tags: 'shared_alias' }).build!(locale)
-
-      expect(plan[:direct_tag_specs]).to eq(
-          [{ name: english_name.name, category: :character }])
-    end
-  end
-
   it 'plans direct and existing default tags without persisting records' do
     counts = [TagName.count, Tag.count]
 
@@ -71,7 +18,7 @@ RSpec.describe PostCreatePlan do
             url: 'https://example.com/post',
             title: 'title',
             tags: 'character:new_character',
-            parent_post_ids: '' }).build!(Locale.nipponese)
+            parent_post_ids: '' }).build!
 
     expect(plan[:tags]).to eq('new_character')
     expect(plan[:direct_tag_specs]).to eq(
@@ -82,9 +29,9 @@ RSpec.describe PostCreatePlan do
     expect([TagName.count, Tag.count]).to eq(counts)
   end
 
-  it 'resolves aliases and keeps tag sections separate from primary names' do
-    tag = create_tag!('虹夏', :character)
-    create(:tag_name, :alias, name: 'にじか', tag:)
+  it 'resolves aliases and keeps tag sections separate from canonical names' do
+    canonical = create_tag!('虹夏', :character)
+    TagName.create!(name: 'にじか', canonical: canonical.tag_name)
     create_tag!('動画', :meta)
 
     plan = described_class.new(
@@ -93,7 +40,7 @@ RSpec.describe PostCreatePlan do
             title: 'video',
             tags: '動画 にじか[0:10-0:20]',
             duration: '1:00',
-            parent_post_ids: '' }).build!(Locale.nipponese)
+            parent_post_ids: '' }).build!
 
     expect(plan[:tags].split).to include('動画', '虹夏[0:10-0:20]')
     expect(plan[:display_tags]).to include(
@@ -108,7 +55,7 @@ RSpec.describe PostCreatePlan do
     counts = [Tag.count, TagName.count, ExternalTag.count]
 
     expect {
-      described_class.new(attributes: { tags: 'NiCo:reserved' }).build!(Locale.nipponese)
+      described_class.new(attributes: { tags: 'NiCo:reserved' }).build!
     }.to raise_error(ActiveRecord::RecordInvalid) { |error|
       expect(error.record.errors[:tags]).to be_present
     }
@@ -126,7 +73,7 @@ RSpec.describe PostCreatePlan do
               url: 'https://example.com/post',
               title: 'title',
               tags: long_name,
-              parent_post_ids: '' }).build!(Locale.nipponese)
+              parent_post_ids: '' }).build!
     }.to raise_error(ActiveRecord::RecordInvalid) { |error|
       expect(error.record.errors[:tags]).not_to be_empty
     }
@@ -140,7 +87,7 @@ RSpec.describe PostCreatePlan do
             title: 'title',
             tags: 'ordinary_tag',
             duration: 'invalid',
-            parent_post_ids: '' }).build!(Locale.nipponese)
+            parent_post_ids: '' }).build!
 
     expect(plan[:duration]).to eq('invalid')
     expect(plan[:video_ms]).to be_nil

backend/spec/services/post_creator_spec.rb

@@ -14,6 +14,7 @@ RSpec.describe PostCreator do
   end
 
   before do
+    allow(Tag).to receive(:normalise_tags!).and_return({ tags: [], sections: {} })
     allow(TagVersioning).to receive(:record_tag_snapshots!)
     allow(Tag).to receive(:expand_parent_tags).and_return([])
     allow(PostVersionRecorder).to receive(:record!)
@@ -33,7 +34,7 @@ RSpec.describe PostCreator do
           url: 'https://example.com/post',
           thumbnail: real_thumbnail_upload,
           thumbnail_base: 'https://example.com/thumb.jpg',
-          tags: '' }).create!(Locale.nipponese)
+          tags: '' }).create!
 
     expect(post.thumbnail).to be_attached
     expect(post.thumbnail_base).to eq('https://example.com/thumb.jpg')
@@ -53,7 +54,7 @@ RSpec.describe PostCreator do
           title: 'title',
           url: 'https://example.com/post',
           thumbnail_base: 'https://example.com/thumb.jpg',
-          tags: '' }).create!(Locale.nipponese)
+          tags: '' }).create!
 
     expect(post.thumbnail_base).to eq('https://example.com/thumb.jpg')
     expect(post.thumbnail).to be_attached
@@ -71,34 +72,7 @@ RSpec.describe PostCreator do
           tags: '' })
 
     post_count = Post.count
-    expect { creator.create!(Locale.nipponese) }
-        .to raise_error(Post::RemoteThumbnailFetchFailed)
+    expect { creator.create! }.to raise_error(Post::RemoteThumbnailFetchFailed)
     expect(Post.count).to eq(post_count)
   end
-
-  context 'with an explicit locale' do
-    include_context 'English locale'
-
-    [false, true].each do |planned|
-      it "passes locale to tag creation with planned attributes: #{ planned }" do
-        attributes = {
-            title: 'Locale propagation',
-            url: 'https://example.com/locale-post',
-            tags: 'character:locale_character' }
-        if planned
-          specs = [{ name: 'locale_character', category: :character }]
-          attributes.merge!(snapshot_tag_specs: specs, post_tag_specs: specs)
-        end
-        allow(Tag).to receive(:find_or_create_by_tag_name!).and_call_original
-
-        post = described_class.new(actor:, attributes:).create!(locale)
-
-        expect(Tag).to have_received(:find_or_create_by_tag_name!)
-            .with(locale, 'locale_character', category: :character).at_least(:once)
-        tag_name = TagName.find_by!(language_code: 'en', name: 'locale_character')
-        expect(tag_name).to have_attributes(script_code: 'Latn', primary_flg: true)
-        expect(post.tags).to include(tag_name.tag)
-      end
-    end
-  end
 end

backend/spec/services/post_import_previewer_spec.rb

@@ -64,7 +64,7 @@ RSpec.describe PostImportPreviewer do
     end
 
     it 'applies metadata to automatic fields and recognises metadata tags' do
-      create(:tag, primary_name: 'known-tag', category: :general)
+      Tag.create!(name: 'known-tag', category: :general)
       allow(PostMetadataFetcher).to receive(:fetch).and_return(
         title: 'metadata title',
         thumbnail_base: 'https://example.com/thumb.jpg',

backend/spec/services/tag_version_recorder_spec.rb

@@ -1,53 +0,0 @@
-require 'rails_helper'
-
-RSpec.describe TagVersionRecorder do
-  let(:user) { create_member_user! }
-  let(:tag) { create(:tag, primary_name: '日本語名') }
-
-  before do
-    Language.insert_all!([{ code: 'en', name: 'English', created_at: Time.current }])
-    Script.insert_all!([{ code: 'Latn', name: 'Latin', created_at: Time.current }])
-    Locale.insert_all!([{ code: 'en', language_code: 'en', script_code: 'Latn',
-                          name: 'English', created_at: Time.current }])
-    create(:tag_name, :alias, tag:, name: '別名')
-    create(:tag_name, tag:, language_code: 'en', script_code: 'Latn', name: 'English name')
-    create(:tag_name, :alias, tag:, language_code: 'en', script_code: 'Latn',
-                              name: 'English alias')
-  end
-
-  it 'snapshots every language primary name and alias deterministically' do
-    version = described_class.record!(tag:, event_type: :create, created_by_user: user)
-
-    expect(version.names).to eq([
-      { 'language_code' => 'en', 'name' => 'English name', 'script_code' => 'Latn',
-        'primary_flg' => true, 'auto_generated' => false },
-      { 'language_code' => 'en', 'name' => 'English alias', 'script_code' => 'Latn',
-        'primary_flg' => false, 'auto_generated' => false },
-      { 'language_code' => 'ja', 'name' => '日本語名', 'script_code' => 'Jpan',
-        'primary_flg' => true, 'auto_generated' => false },
-      { 'language_code' => 'ja', 'name' => '別名', 'script_code' => 'Jpan',
-        'primary_flg' => false, 'auto_generated' => false }
-    ])
-  end
-
-  it 'creates a version for an English-only name change and preserves prior names' do
-    original = described_class.record!(tag:, event_type: :create, created_by_user: user)
-    TagName.find_by!(tag:, language_code: 'en', primary_flg: true).update!(name: 'Renamed')
-
-    updated = described_class.record!(tag:, event_type: :update, created_by_user: user)
-
-    expect(updated.version_no).to eq(2)
-    expect(original.reload.names).to include(
-      hash_including('language_code' => 'en', 'name' => 'English name'))
-    expect(updated.names).to include(hash_including('language_code' => 'en', 'name' => 'Renamed'))
-  end
-
-  it 'does not create a version for an unchanged multilingual snapshot' do
-    described_class.record!(tag:, event_type: :create, created_by_user: user)
-
-    unchanged = described_class.record!(tag:, event_type: :update, created_by_user: user)
-
-    expect(unchanged.version_no).to eq(1)
-    expect(tag.reload.tag_versions.count).to eq(1)
-  end
-end

backend/spec/services/wiki/commit_integrity_spec.rb

@@ -6,7 +6,7 @@ RSpec.describe Wiki::Commit do
 
   def create_page title:, body: 'initial body'
     described_class.create_content!(
-        tag_name: create(:tag_name, name: title),
+        tag_name: TagName.create!(name: title),
         body:,
         created_by_user: user,
         message: 'init')
@@ -16,7 +16,7 @@ RSpec.describe Wiki::Commit do
     it 'creates page, revision, and version with normalised body' do
       expect {
         described_class.create_content!(
-            tag_name: create(:tag_name, name: 'commit_integrity_create'),
+            tag_name: TagName.create!(name: 'commit_integrity_create'),
             body: "a\r\nb\r\n\r\n",
             created_by_user: user,
             message: 'init')
@@ -36,7 +36,7 @@ RSpec.describe Wiki::Commit do
     end
 
     it 'rejects body that becomes blank after normalisation' do
-      tag_name = create(:tag_name, name: 'commit_integrity_blank')
+      tag_name = TagName.create!(name: 'commit_integrity_blank')
 
       expect {
         described_class.create_content!(
@@ -76,8 +76,8 @@ RSpec.describe Wiki::Commit do
     end
 
     it 'does not record tag_version on body-only wiki update' do
-      tag_name = create(:tag_name, name: 'commit_integrity_linked_tag')
-      tag = create(:tag, primary_tag_name: tag_name, category: :general)
+      tag_name = TagName.create!(name: 'commit_integrity_linked_tag')
+      tag = Tag.create!(tag_name:, category: :general)
 
       page =
           described_class.create_content!(

backend/spec/services/wiki/commit_spec.rb

@@ -4,7 +4,7 @@ RSpec.describe Wiki::Commit do
   let(:user) { create_member_user! }
 
   def create_page(title: 'commit_spec_page', body: 'initial body')
-    tag_name = create(:tag_name, name: title)
+    tag_name = TagName.create!(name: title)
 
     Wiki::Commit.create_content!(
         tag_name:,
@@ -80,8 +80,8 @@ RSpec.describe Wiki::Commit do
     end
 
     it 'does not record tag version when corresponding tag has no versions' do
-      tag_name = create(:tag_name, name: 'commit_linked_tag_without_versions')
-      tag = create(:tag, primary_tag_name: tag_name, category: :general)
+      tag_name = TagName.create!(name: 'commit_linked_tag_without_versions')
+      tag = Tag.create!(tag_name:, category: :general)
 
       page =
           described_class.create_content!(
@@ -107,8 +107,8 @@ RSpec.describe Wiki::Commit do
     end
 
     it 'does not record tag version when corresponding tag has no versions' do
-      tag_name = create(:tag_name, name: 'commit_linked_tag_without_versions')
-      tag = create(:tag, primary_tag_name: tag_name, category: :general)
+      tag_name = TagName.create!(name: 'commit_linked_tag_without_versions')
+      tag = Tag.create!(tag_name:, category: :general)
 
       page =
           described_class.create_content!(

backend/spec/services/wiki_version_recorder_spec.rb

@@ -5,7 +5,7 @@ RSpec.describe WikiVersionRecorder do
 
   def create_page title:, body: 'body'
     Wiki::Commit.create_content!(
-        tag_name: create(:tag_name, name: title),
+        tag_name: TagName.create!(name: title),
         body:,
         created_by_user: user,
         message: 'init')

backend/spec/services/youtube/sync_spec.rb

@@ -172,8 +172,7 @@ RSpec.describe Youtube::Sync do
       Tag.video
       Tag.no_deerjikist
 
-      deerjikist_tag = Tag.find_or_create_by_tag_name!(
-          Locale.nipponese, 'テスト投稿者', category: :deerjikist)
+      deerjikist_tag = Tag.find_or_create_by_tag_name!('テスト投稿者', category: :deerjikist)
       Deerjikist.create!(
         platform: 'youtube',
         code: 'UC_MAPPED',
@@ -227,8 +226,7 @@ RSpec.describe Youtube::Sync do
       )
       PostTag.create!(post:, tag: Tag.no_deerjikist)
 
-      deerjikist_tag = Tag.find_or_create_by_tag_name!(
-          Locale.nipponese, '後から判明した投稿者', category: :deerjikist)
+      deerjikist_tag = Tag.find_or_create_by_tag_name!('後から判明した投稿者', category: :deerjikist)
       Deerjikist.create!(
         platform: 'youtube',
         code: 'UC_MAPPED_LATER',

backend/spec/support/locale_context.rb

@@ -1,13 +0,0 @@
-RSpec.shared_context 'English locale' do
-  let!(:locale) do
-    Language.find_or_create_by!(code: 'en') { _1.name = 'English' }
-    Script.find_or_create_by!(code: 'Latn') { _1.name = 'Latin' }
-    unless Locale.exists?(code: 'en')
-      # Reference data only: do not generate names for unrelated existing tags.
-      Locale.insert_all!([
-          { code: 'en', language_code: 'en', script_code: 'Latn',
-            name: 'English', created_at: Time.current }])
-    end
-    Locale.find('en')
-  end
-end

backend/spec/support/test_records.rb

@@ -1,8 +1,4 @@
 module TestRecords
-  def primary_tag_name_for(tag, language_code)
-    TagName.find_by!(tag_id: tag.id, language_code:, primary_flg: true)
-  end
-
   def create_member_user!
     User.create!(name: 'spec user',
                  inheritance_code: SecureRandom.hex(16),

backend/spec/tasks/nico_sync_spec.rb

@@ -8,7 +8,7 @@ RSpec.describe 'nico:sync' do
   end
 
   def create_tag!(name, category:)
-    Tag.find_or_create_by_tag_name!(Locale.nipponese, name, category:)
+    Tag.find_or_create_by_tag_name!(name, category:)
   end
 
   def link_nico_to_tag!(nico_tag, tag)
@@ -64,8 +64,7 @@ RSpec.describe 'nico:sync' do
     run_rake_task('nico:sync')
 
     post.reload
-    active_tag_names = TagName.where(tag_id: post.tags.select(:id),
-                                     language_code: 'ja', primary_flg: true).pluck(:name)
+    active_tag_names = post.tags.joins(:tag_name).pluck('tag_names.name')
 
     expect(active_tag_names).to include('spec_kept')
     expect(post.external_tags).to contain_exactly(nico)
@@ -435,9 +434,7 @@ RSpec.describe 'nico:sync' do
 
     external = post.external_tags.sole
     expect(external.name).to eq('raw tag[]')
-    expect(TagName.where(tag_id: post.tags.select(:id),
-                         language_code: 'ja', primary_flg: true).pluck(:name))
-        .not_to include('bot操作')
+    expect(post.tags.map(&:name)).not_to include('bot操作')
     expect(post.post_versions.order(:version_no).last.tags_json)
         .to include('external_tag_id' => external.id)
 
@@ -449,9 +446,7 @@ RSpec.describe 'nico:sync' do
       run_nico_sync_with_tags!([])
     }.to change(PostVersion, :count).by(1)
     expect(post.reload.external_tags).to be_empty
-    expect(TagName.where(tag_id: post.tags.select(:id),
-                         language_code: 'ja', primary_flg: true).pluck(:name))
-        .not_to include('bot操作')
+    expect(post.tags.map(&:name)).not_to include('bot操作')
   end
 
   it 'サニタイズ後の既存外部タグを再利用し、その連携タグを記載する' do
@@ -568,9 +563,7 @@ RSpec.describe 'nico:sync' do
         name: 'AAA')
     expect(ExternalTag.exists?(platform: :nico, name: 'AAA?')).to be(false)
 
-    expect(TagName.where(tag_id: post.tags.select(:id),
-                         language_code: 'ja', primary_flg: true).pluck(:name))
-        .not_to include('bot操作')
+    expect(post.tags.map(&:name)).not_to include('bot操作')
     expect(post.post_versions.order(:version_no).last.tags_json)
         .to include('external_tag_id' => external.id)
 
@@ -584,9 +577,7 @@ RSpec.describe 'nico:sync' do
     }.to change(PostVersion, :count).by(1)
 
     expect(post.reload.external_tags).to be_empty
-    expect(TagName.where(tag_id: post.tags.select(:id),
-                         language_code: 'ja', primary_flg: true).pluck(:name))
-        .not_to include('bot操作')
+    expect(post.tags.map(&:name)).not_to include('bot操作')
   end
 
   it 'nico: prefix を含む従来の規則で外部タグ名をサニタイズする' do

backend/spec/tasks/post_similarity_calc_spec.rb

@@ -6,10 +6,10 @@ RSpec.describe 'post_similarity:calc' do
 
   it 'calculates similarities from active tags only' do
     # 必要最低限のデータ
-    t1 = create(:tag, primary_name: 't1')
-    t2 = create(:tag, primary_name: 't2')
-    t3 = create(:tag, primary_name: 't3')
-    deprecated_tag = create(:tag, primary_name: 'deprecated', deprecated_at: Time.current)
+    t1 = Tag.create!(name: "t1")
+    t2 = Tag.create!(name: "t2")
+    t3 = Tag.create!(name: "t3")
+    deprecated_tag = Tag.create!(name: 'deprecated', deprecated_at: Time.current)
 
     p1 = Post.create!(url: "https://example.com/1")
     p2 = Post.create!(url: "https://example.com/2")

backend/spec/tasks/tag_similarity_calc_spec.rb

@@ -6,10 +6,10 @@ RSpec.describe 'tag_similarity:calc' do
 
   it 'calculates similarities for active tags only' do
     # 必要最低限のデータ
-    t1 = create(:tag, primary_name: 't1')
-    t2 = create(:tag, primary_name: 't2')
-    t3 = create(:tag, primary_name: 't3')
-    deprecated_tag = create(:tag, primary_name: 'deprecated', deprecated_at: Time.current)
+    t1 = Tag.create!(name: "t1")
+    t2 = Tag.create!(name: "t2")
+    t3 = Tag.create!(name: "t3")
+    deprecated_tag = Tag.create!(name: 'deprecated', deprecated_at: Time.current)
 
     p1 = Post.create!(url: "https://example.com/1")
     p2 = Post.create!(url: "https://example.com/2")