#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/materials_controller.rb

@@ -72,7 +72,6 @@ class MaterialsController < ApplicationController
     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)
@@ -90,7 +89,7 @@ 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)
@@ -133,14 +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)
@@ -239,8 +236,10 @@ class MaterialsController < ApplicationController
     nil
   end
 
-  def resolve_material_tag! locale, tag_name_raw
+  def resolve_material_tag! tag_name_raw
-    Tag.find_or_create_by_tag_name!(locale, tag_name_raw, category: :material)
+    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

backend/app/controllers/nico_tags_controller.rb

@@ -81,8 +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)
@@ -91,9 +89,8 @@ class NicoTagsController < ApplicationController
     linked_tags = nil
 
     ApplicationRecord.transaction do
-      linked_tags = Tag.normalise_tags!(locale, linked_tag_names,
+      linked_tags = Tag.normalise_tags!(linked_tag_names, with_tagme: false,
-                                        with_tagme: false,
+                                                          with_no_deerjikist: false)
-                                        with_no_deerjikist: false)
 
       TagVersioning.record_tag_snapshots!(linked_tags, created_by_user: current_user)
 

backend/app/controllers/posts_controller.rb

@@ -213,12 +213,10 @@ class PostsController < ApplicationController
     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])
@@ -244,7 +242,7 @@ 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), status: :created
@@ -273,18 +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．'
@@ -317,7 +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]
@@ -339,8 +331,7 @@ class PostsController < ApplicationController
         base_snapshot = post_snapshot_from_version(base_version)
         current_snapshot = post_snapshot_from_record(post)
       end
-      incoming_snapshot = post_incoming_snapshot(locale:,
+      incoming_snapshot = post_incoming_snapshot(title:,
-                                                 title:,
                                                  original_created_from:,
                                                  original_created_before:,
                                                  tag_names:,
@@ -369,7 +360,7 @@ 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
@@ -710,14 +701,11 @@ class PostsController < ApplicationController
     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!(tag_names, with_tagme: false, deny_deprecated: true,
-    Tag.normalise_tags!(locale, tag_names,
+                                   with_sections: true) => { tags:, sections: }
-                        with_tagme: false,
-                        deny_deprecated: true,
-                        with_sections: true) => { tags:, sections: }
 
     tags = Tag.expand_parent_tags(tags).reject(&:deprecated?)
     video_ms = normalise_video_ms(tags, video_ms_param:, duration_param:)
@@ -852,7 +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],
@@ -860,7 +848,7 @@ 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: }

backend/app/controllers/tags_controller.rb

@@ -406,9 +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(tag, name)
-
-    return unless validate_tag_rename(locale, tag, name)
 
     alias_names = params[:aliases].to_s.split.uniq
     parent_names = params[:parent_tags].to_s.split.uniq
@@ -436,7 +434,7 @@ class TagsController < ApplicationController
       alias_names.delete(name)
 
       update_aliases!(tag, alias_names)
-      update_parent_tags!(locale, tag, parent_names)
+      update_parent_tags!(tag, parent_names)
 
       tag.reload
 
@@ -455,8 +453,6 @@ class TagsController < ApplicationController
     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)
@@ -464,7 +460,7 @@ 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
@@ -686,7 +682,7 @@ class TagsController < ApplicationController
         created_by_user:)
   end
 
-  def validate_tag_rename locale, tag, name
+  def validate_tag_rename tag, name
     return true if name.blank? || name == tag.name
 
     if tag.in?([Tag.tagme, Tag.bot, Tag.no_deerjikist, Tag.video, Tag.niconico])
@@ -694,8 +690,9 @@ class TagsController < ApplicationController
       return false
     end
 
-    target_tag_name = TagName.find_by(language_code: locale.language_code, name:)
+    target_tag_name = TagName.find_by(name:)
-    return true unless target_tag_name&.primary_flg
+    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
@@ -779,10 +776,9 @@ class TagsController < ApplicationController
     end
   end
 
-  def update_parent_tags! locale, tag, parent_names
+  def update_parent_tags! tag, parent_names
-    parent_tags = Tag.normalise_tags!(locale, parent_names,
+    parent_tags = Tag.normalise_tags!(parent_names, with_tagme: false,
-                                      with_tagme: false,
+                                                    with_no_deerjikist: false)
-                                      with_no_deerjikist: false)
 
     old_parent_tags = tag.parents.to_a
 

backend/app/models/language.rb

@@ -1,3 +0,0 @@
-class Language < ApplicationRecord
-  has_many :languages, class_name: 'Locale', foreign_key: :language_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),
-                      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/script.rb

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

backend/app/models/tag.rb

@@ -50,7 +50,6 @@ class Tag < ApplicationRecord
 
   has_many :tag_versions
 
-  has_many :tag_names
   belongs_to :tag_name
   delegate :wiki_page, to: :tag_name
 
@@ -96,19 +95,17 @@ 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.tagme = find_or_create_by_tag_name!('タグ希望', category: :meta)
-  def self.bot = find_or_create_by_tag_name!(Locale.nipponese, 'bot操作', category: :meta)
+  def self.bot = find_or_create_by_tag_name!('bot操作', category: :meta)
-  def self.no_deerjikist =
+  def self.no_deerjikist = find_or_create_by_tag_name!('ニジラー情報不詳', category: :meta)
-      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!('動画', 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!('ニコニコ', 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!('YouTube', category: :meta)
-  def self.youtube = find_or_create_by_tag_name!(Locale.nipponese, 'YouTube', category: :meta)
 
-  def self.normalise_tags! locale, tag_names,
+  def self.normalise_tags! tag_names, with_tagme: true,
-                           with_tagme: true,
+                                      with_no_deerjikist: true,
-                           with_no_deerjikist: true,
+                                      deny_deprecated: false,
-                           deny_deprecated: false,
+                                      with_sections: false
-                           with_sections: false
     if tag_names.any? { |n| n.downcase.start_with?('nico:') }
       raise NicoTagNormalisationError
     end
@@ -135,9 +132,9 @@ 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]
         end
@@ -225,22 +222,13 @@ class Tag < ApplicationRecord
     [left_end_ms, right_end_ms].max
   end
 
-  def self.find_or_create_by_tag_name! locale, name, category:
+  def self.find_or_create_by_tag_name! name, category:
-    language_code = locale.language_code
+    tn = TagName.find_or_create_by!(name: name.to_s.strip)
-    name = name.to_s.strip
+    tn = tn.canonical if tn.canonical_id?
 
-    tn = TagName.find_or_create_by!(language_code:, name:) do
+    Tag.find_or_create_by!(tag_name_id: tn.id) do |t|
-      _1.script_code = locale.script_code
+      t.category = category
-      _1.primary_flg = true
     end
-
-    tag = tn.tag
-    return tag if tag
-
-    tag = Tag.create!(tag_name: tn, category:)
-    tn.update!(tag:)
-
-    tag
   rescue ActiveRecord::RecordNotUnique
     retry
   end
@@ -276,8 +264,6 @@ class Tag < ApplicationRecord
         end
 
         TagVersioning.record!(source_tag, event_type: :discard, created_by_user:)
-        source_tag.tag_names.update_all(tag_id: source_tag.id, primary_key: false,
-                                        updated_at: Time.current)
         source_tag.destroy!
 
         source_tag_name.update_columns(canonical_id: target_tag.tag_name_id,

backend/app/models/tag_name.rb

@@ -1,55 +1,43 @@
 class TagName < ApplicationRecord
-  belongs_to :language, foreign_key: :language_code, primary_key: :code
+  has_one :tag
-  belongs_to :tag, optional: true
   has_one :wiki_page
 
-  validates :name, presence: true,
+  belongs_to :canonical, class_name: 'TagName', optional: true
-                   length: { maximum: 255 },
+  has_many :aliases, class_name: 'TagName', foreign_key: :canonical_id
-                   uniqueness: { scope: :language_code }
 
+  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
 
-  def primary? = primary_flg
+  def self.canonicalise names
-
-  def canonical = TagName.find_by(language:, tag:, primary_flg: true)
-  def aliases = TagName.where(language:, tag:, primary_flg: false)
-
-  def self.canonicalise locale, 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|
+    names.map { |name| tns[name]&.canonical&.name || name }.uniq
-      if tns[name].primary_flg
-        name
-      else
-        TagName.find_by(language_code: locale.language_code,
-                        tag_id: tns[name].tag_id,
-                        primary_flg: true).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 }"
   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
+  def canonical_must_not_be_present_with_tag_or_wiki_page
-    if !(primary?) && wiki_page
+    if canonical_id? && (tag || 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．'
+      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
 

backend/app/models/tag_name_sanitisation_rule.rb

@@ -15,38 +15,31 @@ class TagNameSanitisationRule < ApplicationRecord
     end
 
     def apply!
-      Language.find_each do |language|
+      TagName.find_each do |tn|
-        TagName.where(language:).find_each do |tn|
+        name = sanitise(tn.name)
-          name = sanitise(tn.name)
+        next if name == tn.name
-          next if name == tn.name
 
-          TagName.transaction do
+        TagName.transaction do
-            existing_tn = TagName.find_by(language:, name:)
+          existing_tn = TagName.find_by(name:)
-            if existing_tn
+          if existing_tn
-              unless existing_tn.primary_flg
+            existing_tn = existing_tn.canonical || existing_tn
-                existing_tn = TagName.find_by!(language:,
+            next if existing_tn.id == tn.id
-                                               tag_id: existing_tn.tag_id,
-                                               primary_flg: true)
-              end
-              next if existing_tn.id == tn.id
 
-              existing_tag = existing_tn.tag
+            existing_tag = Tag.find_by(tag_name_id: existing_tn.id)
-              source_tag = tn.tag
+            source_tag = Tag.find_by(tag_name_id: tn.id)
 
-              if existing_tag
+            if existing_tag
-                Tag.merge_tags!(existing_tag, source_tag) if tn.tag
+              Tag.merge_tags!(existing_tag, source_tag) if tn.tag
-              elsif source_tag
+            elsif source_tag
-                source_tag.update_columns(tag_name_id: existing_tn.id, 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!
-
-              next
             end
+            tn.destroy!
 
-            # TagName 側の自動サニタイズを回避
+            next
-            tn.update_columns(name:, updated_at: Time.current)
           end
+
+          # TagName 側の自動サニタイズを回避
+          tn.update_columns(name:, updated_at: Time.current)
         end
       end
     end

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,
@@ -61,7 +61,7 @@ class PostBulkCreator
 
   private
 
-  def create_row locale, actor, attributes, index
+  def create_row actor, attributes, index
     preflight =
         PostCreatePreflight.new(
             attributes: attributes,
@@ -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
+  def build!
-    direct_tag_specs, tag_sections = parse_direct_tag_specs(locale)
+    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!(snapshot_tag_specs.map { _1[:name] })
     validate_new_tag_specs!(snapshot_tag_specs)
-    post_tag_specs = expand_parent_tag_specs(locale, 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
@@ -42,13 +42,13 @@ 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)
+      tag_name, category, sections = parse_raw_tag_name(raw_name)
-      existing_tag = existing_tags_by_name(locale)[tag_name]
+      existing_tag = existing_tags_by_name[tag_name]
       raise Tag::DeprecatedTagNormalisationError, [existing_tag.name] if existing_tag&.deprecated?
 
       direct_tag_specs << {
@@ -65,7 +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 {
@@ -74,7 +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?
 
@@ -87,17 +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 }
@@ -131,10 +131,8 @@ class PostCreatePlan
     raise ActiveRecord::RecordInvalid, post
   end
 
-  def expand_parent_tag_specs locale, snapshot_tag_specs
+  def expand_parent_tag_specs snapshot_tag_specs
-    existing_snapshot_tags = snapshot_tag_specs.filter_map do
+    existing_snapshot_tags = snapshot_tag_specs.filter_map { existing_tags_by_name[_1[:name]] }
-      existing_tags_by_name(locale)[_1[:name]]
-    end
     expanded_parent_specs =
         Tag.expand_parent_tags(existing_snapshot_tags)
            .reject(&:deprecated?)
@@ -158,33 +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
+      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!(
+    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
+  def canonical_tag_name_without_sections raw_name
-    name, = parse_raw_tag_name(locale, 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
@@ -262,13 +260,10 @@ class PostCreatePlan
     end
   end
 
-  def resolved_tag_name locale, name
+  def resolved_tag_name name
-    tag_name = TagName.find_by!(language_code: locale.language_code, name:)
+    tag_name = TagName.includes(:canonical).find_by(name:)
-    unless tag_name.primary_flg
+    return name if tag_name.nil?
-      tag_name = TagName.find_by!(language_code: locale.language_code,
+
-                                  tag_id: tag_name.tag_id,
+    (tag_name.canonical || tag_name).name
-                                  primary_flg: true)
-    end
-    tag_name.name
   end
 end

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],
@@ -21,14 +21,14 @@ class PostCreator
     ApplicationRecord.transaction do
       post.save!
       post.thumbnail.attach(thumbnail_attachment) if thumbnail_attachment.present?
-      snapshot_tags = planned_snapshot_tags(locale)
+      snapshot_tags = planned_snapshot_tags
-      post_tags = planned_post_tags(locale)
+      post_tags = planned_post_tags
-      sections = planned_sections(locale)
+      sections = planned_sections
       TagVersioning.record_tag_snapshots!(snapshot_tags, created_by_user: @actor)
-      post.video_ms = planned_video_ms(locale)
+      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
@@ -45,25 +45,23 @@ 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
+  def planned_parent_post_ids = planned_create_attributes[:normalised_parent_post_ids]
-    planned_create_attributes(locale)[:normalised_parent_post_ids]
+
+  def planned_video_ms
+    planned_create_attributes[:video_ms]
   end
 
-  def planned_video_ms locale
+  def planned_create_attributes
-    planned_create_attributes(locale)[:video_ms]
-  end
-
-  def planned_create_attributes locale
     @planned_create_attributes ||= begin
       if @attributes.key?(:snapshot_tag_specs)
-        snapshot_tags = materialise_tags(locale, @attributes[:snapshot_tag_specs] || [])
+        snapshot_tags = materialise_tags(@attributes[:snapshot_tag_specs] || [])
-        post_tags = materialise_tags(locale, @attributes[:post_tag_specs] || [])
+        post_tags = materialise_tags(@attributes[:post_tag_specs] || [])
         {
             snapshot_tags: snapshot_tags,
             post_tags: post_tags,
@@ -94,13 +92,13 @@ class PostCreator
         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

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/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_030000) 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_030000) 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_030000) 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
@@ -445,20 +420,12 @@ ActiveRecord::Schema[8.0].define(version: 2026_09_22_030000) 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.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 ["name"], name: "index_tag_names_on_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"
   end
 
   create_table "tag_similarities", primary_key: ["tag_id", "target_tag_id"], charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
@@ -734,8 +701,6 @@ ActiveRecord::Schema[8.0].define(version: 2026_09_22_030000) 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"
@@ -769,10 +734,7 @@ ActiveRecord::Schema[8.0].define(version: 2026_09_22_030000) 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

@@ -1,12 +1,5 @@
 FactoryBot.define do
   factory :tag_name do
-    language_code { 'ja' }
+    name { "tag-#{SecureRandom.hex(4)}" }
-    script_code { 'Jpan' }
-    primary_flg { true }
-    sequence(:name) { |number| "tag-#{ SecureRandom.hex(4) }-#{ number }" }
-
-    trait :alias do
-      primary_flg { false }
-    end
   end
 end

backend/spec/factories/tags.rb

@@ -6,15 +6,10 @@ FactoryBot.define do
 
     category { :general }
     post_count { 0 }
-
     association :tag_name
 
     after(:build) do |tag, evaluator|
       tag.name = evaluator.name if evaluator.name.present?
     end
-
-    after(:create) do |tag|
-      tag.tag_name.update!(tag:) if tag.tag_name.tag_id != tag.id
-    end
   end
 end

backend/spec/models/locale_spec.rb

@@ -1,69 +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, name: 'first_existing_tag')
-    second = create(:tag, 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, first.name)
-        .and_return('name_from_generator')
-
-    locale = create_french_locale!
-
-    expect(TagName).to have_received(:generate_name).with(locale, first, first.name)
-    expect(TagName).to have_received(:generate_name).with(locale, second, second.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, 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, 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, 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_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_name) { TagName.create!(name: 'post_version_spec_tag') }
-  let!(:tag) { create(:tag, tag_name: tag_name, category: :general) }
+  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_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, name: 'foobar')
-        english_name = create(:tag_name, name: 'temporary',
-                                        language_code: 'en', script_code: 'Latn')
-        english = create(:tag, 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(japanese.reload.tag_name).to have_attributes(
-            name: 'foobar', language_code: 'ja', tag_id: japanese.id)
-        expect(english.reload.tag_name_id).to eq(english_name.id)
-      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
+    context 'when a conflicting canonical tag_name exists' do
-      let!(:existing) { create(:tag_name, name: 'foobar') }
+      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
@@ -95,7 +63,7 @@ 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!(:existing) { TagName.create!(name: 'foobar') }
       let!(:source_tag) { create(:tag, name: 'tmp', category: :general) }
       let!(:source_tag_name_id) { source_tag.tag_name_id }
 
@@ -105,7 +73,8 @@ RSpec.describe TagNameSanitisationRule, type: :model do
 
       it 'moves the tag to the existing tag_name' do
         described_class.apply!
-        expect(source_tag.reload.tag_name_id).to eq(existing.id)
+        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
@@ -113,33 +82,29 @@ RSpec.describe TagNameSanitisationRule, type: :model do
     context 'when the sanitised name is an alias of an existing tag' do
       let!(:existing_tag) { create(:tag) }
       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(
+        expect(alias_name.reload.canonical).to eq(existing_tag.tag_name)
-            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_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_tn) { TagName.create!(name: 'foobar') }
-      let!(:existing_tag) { create(:tag, tag_name: existing_tn, category: :general) }
+      let!(:existing_tag) { Tag.create!(tag_name: existing_tn, category: :general) }
 
-      let!(:source_tn) { create(:tag_name, name: 'tmp') }
+      let!(:source_tn) { TagName.create!(name: 'tmp') }
-      let!(:source_tag) { create(:tag, tag_name: source_tn, category: :general) }
+      let!(:source_tag) { Tag.create!(tag_name: source_tn, category: :general) }
       let!(:source_tag_name_id) { source_tn.id }
 
       before do

backend/spec/models/tag_name_spec.rb

@@ -1,94 +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
-    tag = create(:tag)
-
-    expect(tag.reload.tag_name.reload.tag_id).to eq(tag.id)
-    expect(tag.tag_name.tag).to eq(tag)
-    expect(described_class.find_by!(tag_id: tag.id, language_code: 'ja', primary_flg: true))
-        .to eq(tag.tag_name)
-  end
-
-  it 'persists an alias owned by the same tag as its primary name' do
-    tag = create(:tag)
-    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(tag.tag_name)
-  end
-
-  describe '.canonicalise' do
-    it 'resolves the primary name of the alias language on the same tag' do
-      tag = create(:tag, 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, name: 'japanese_canonical')
-      english_name = create(:tag_name, name: 'english_canonical',
-                                      language_code: 'en', script_code: 'Latn')
-      english = create(:tag, 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

@@ -9,7 +9,7 @@ RSpec.describe Tag, type: :model do
         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
@@ -25,48 +25,19 @@ 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, name: 'japanese_canonical')
-      english_name = create(:tag_name, name: 'english_canonical',
-                                      language_code: 'en', script_code: 'Latn')
-      english = create(:tag, 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')
+      tag_name = TagName.create!(name: 'normalise deprecated tag')
-      deprecated_tag = create(:tag,
+      deprecated_tag = Tag.create!(
-          tag_name:,
+        tag_name:,
-          category: :general,
+        category: :general,
-          deprecated_at: 1.day.from_now)
+        deprecated_at: 1.day.from_now
+      )
 
       expect {
-        described_class.normalise_tags!(Locale.nipponese,
+        described_class.normalise_tags!(
-            [deprecated_tag.name],
+          [deprecated_tag.name],
-            deny_deprecated: true)
+          deny_deprecated: true
+        )
       }.to raise_error(Tag::DeprecatedTagNormalisationError) { |error|
         expect(error.tag_names).to eq([deprecated_tag.name])
       }
@@ -74,79 +45,88 @@ RSpec.describe Tag, type: :model do
 
     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]'],
+          ['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-]'],
+        ['伊地知ニジカ[1:00-]'],
-          with_sections: true)
+        with_sections: true
+      )
 
       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]'],
+        ['伊地知ニジカ[-1:00]'],
-          with_sections: true)
+        with_sections: true
+      )
 
       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[-]'],
+        ['伊地知ニジカ[-]'],
-          with_sections: true)
+        with_sections: true
+      )
 
       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-]'],
+        ['伊地知ニジカ[0:00-]'],
-          with_sections: true)
+        with_sections: true
+      )
 
       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]'],
+        ['伊地知ニジカ[1:00-1:00]'],
-          with_sections: true)
+        with_sections: true
+      )
 
       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]'],
+        ['伊地知ニジカ[2:00-1:00]'],
-          with_sections: true)
+        with_sections: true
+      )
 
       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]'],
+        ['伊地知ニジカ[1:00-][2:00-3:00]'],
-          with_sections: true)
+        with_sections: true
+      )
 
       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-]'],
+        ['伊地知ニジカ[1:00-3:00][3:00-]'],
-          with_sections: true)
+        with_sections: true
+      )
 
       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]])
@@ -203,65 +183,11 @@ 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(tag.tag_name.reload).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(english.tag_name.language_code).to eq('en')
-        expect(japanese.tag_name.language_code).to eq('ja')
-        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, 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(tags.first.tag_name).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)
 
@@ -269,42 +195,31 @@ RSpec.describe Tag, type: :model do
       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 = TagName.create!(name: 'lookup_alias', canonical: tag.tag_name)
-      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')
       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
+    it 'creates a tag for an existing canonical name reached through an alias' do
-      tag = create(:tag)
+      canonical = create(:tag_name)
-      primary = tag.tag_name
+      alias_name = TagName.create!(name: 'lookup_alias', canonical:)
-      alias_name = create(:tag_name, :alias, name: 'lookup_alias', tag:)
+      tag = nil
-      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'))
 
       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(1).and change(TagName, :count).by(0)
-      }.to change(Tag, :count).by(0).and change(TagName, :count).by(0)
 
-      expect(tag.reload.tag_name).to eq(primary)
+      expect(tag.tag_name).to eq(canonical)
     end
   end
 
@@ -328,8 +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(
+        expect(source_tag_name.reload.canonical_id).to eq(target_tag.tag_name_id)
-            tag_id: target_tag.id, language_code: 'ja', primary_flg: false)
         expect(target_tag.reload.post_count).to eq(1)
       end
     end
@@ -355,8 +269,7 @@ 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(
+        expect(source_tag_name.reload.canonical_id).to eq(target_tag.tag_name_id)
-            tag_id: target_tag.id, language_code: 'ja', primary_flg: false)
         expect(target_tag.reload.post_count).to eq(1)
       end
     end
@@ -364,7 +277,7 @@ RSpec.describe Tag, type: :model do
     it 'keeps source history and records the new target alias after deleting the source' do
       user = create_member_user!
       source_name = source_tag.name
-      source_alias = create(:tag_name, :alias, name: 'merge_alias', tag: source_tag)
+      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
 
@@ -434,8 +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(
+        expect(source_tag_name.reload.canonical_id).to eq(target_tag.tag_name_id)
-            tag_id: target_tag.id, language_code: 'ja', primary_flg: false)
         expect(target_tag.reload.post_count).to eq(1)
       end
     end
@@ -466,8 +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(
+        expect(source_tag_name.reload.canonical_id).to eq(target_tag.tag_name_id)
-            tag_id: target_tag.id, language_code: 'ja', primary_flg: false)
         expect(target_tag.reload.post_count).to eq(1)
       end
     end
@@ -496,8 +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(
+        expect(earlier_name.reload.canonical_id).to be_nil
-            tag_id: earlier_source.id, language_code: 'ja', primary_flg: true)
         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)
@@ -506,8 +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(
+        expect(source_tag_name.reload.canonical_id).to be_nil
-            tag_id: source_tag.id, language_code: 'ja', primary_flg: true)
         expect(target_tag.reload.post_count).to eq(0)
       end
     end

backend/spec/requests/gekanator_learning_spec.rb

@@ -898,11 +898,12 @@ RSpec.describe 'Gekanator learning API', type: :request do
 
   describe 'GET /gekanator/questions' do
     it 'omits questions for deprecated tags' do
-      active_tag = create(:tag, name: 'active_question_tag', category: :general)
+      active_tag = Tag.create!(name: 'active_question_tag', category: :general)
-      deprecated_tag = create(:tag,
+      deprecated_tag = Tag.create!(
-          name: 'deprecated_question_tag',
+        name: 'deprecated_question_tag',
-          category: :general,
+        category: :general,
-          deprecated_at: Time.current)
+        deprecated_at: Time.current
+      )
 
       [active_tag, deprecated_tag].each do |question_tag|
         GekanatorQuestion.create!(

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, name: 'active tag', category: :general)
+      active_tag = Tag.create!(name: 'active tag', category: :general)
-      deprecated_tag = create(:tag,
+      deprecated_tag = Tag.create!(
-          name: 'deprecated tag',
+        name: 'deprecated tag',
-          category: :general,
+        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

@@ -1,236 +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
-    expect(tag_name.tag.tag_name_id).to eq(tag_name.id)
-    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: tag.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, tag_name: english_name, category: :material) }
-    let!(:japanese_tag) do
-      create(:tag, name: 'temporary_japanese', category: :general).tap do |tag|
-        # Isolate lookup from the separately tested uniqueness validation.
-        tag.tag_name.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: child.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, tag_name: english_name) }
-
-    it 'allows a rename to a name already used in Japanese' do
-      japanese = create(:tag, name: 'rename_target')
-
-      patch "/tags/#{ tag.id }", params: { locale: 'en', name: 'rename_target' }
-
-      expect(response).to have_http_status(:ok), response.body
-      expect(tag.reload.tag_name).to have_attributes(
-          name: 'rename_target', language_code: 'en', tag_id: tag.id)
-      expect(japanese.reload.tag_name).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: tag.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')
-      expect(tag.reload.tag_name_id).to eq(english_name.id)
-      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, 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: tag.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, 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, 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, name: 'material_scope_root',
+          Tag.create!(tag_name: TagName.create!(name: 'material_scope_root'),
                       category: :material)
       child_b =
-          create(:tag, name: 'material_scope_b',
+          Tag.create!(tag_name: TagName.create!(name: 'material_scope_b'),
                       category: :material)
       child_a =
-          create(:tag, name: 'material_scope_a',
+          Tag.create!(tag_name: TagName.create!(name: 'material_scope_a'),
                       category: :material)
       deprecated =
-          create(:tag, name: 'material_scope_old',
+          Tag.create!(tag_name: TagName.create!(name: 'material_scope_old'),
                       category: :material,
                       deprecated_at: Time.current)
       grandchild =
-          create(:tag, 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, 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'))
@@ -323,8 +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')
+        general_tag_name = TagName.create!(name: 'material_create_general_tag')
-        create(:tag, tag_name: general_tag_name, category: :general)
+        Tag.create!(tag_name: general_tag_name, category: :general)
 
         post '/materials', params: {
           tag: 'material_create_general_tag',
@@ -384,7 +384,7 @@ RSpec.describe 'Materials API', type: :request do
 
   describe 'PUT /materials/:id' do
     let!(:tag) do
-      create(:tag, 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'))
@@ -508,7 +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, 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
@@ -531,7 +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, 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
@@ -651,8 +651,8 @@ RSpec.describe 'Materials API', type: :request do
   end
 
   describe 'GET /materials/download.zip' do
-    let!(:tag_a) { create(:tag, name: 'zip_a', category: :material) }
+    let!(:tag_a) { Tag.create!(tag_name: TagName.create!(name: 'zip_a'), category: :material) }
-    let!(:tag_b) { create(:tag, name: 'zip_b', 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'))
@@ -701,7 +701,7 @@ RSpec.describe 'Materials API', type: :request do
 
   describe 'GET /materials/versions' do
     let!(:tag) do
-      create(:tag, 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'))
@@ -776,7 +776,7 @@ RSpec.describe 'Materials API', type: :request do
 
   describe 'DELETE /materials/:id' do
     let!(:tag) do
-      create(:tag, 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

@@ -162,11 +162,11 @@ 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_name = TagName.create!(name: 'nico_linked_a')
-      linked_a = create(:tag, tag_name: linked_a_name, category: :general)
+      linked_a = Tag.create!(tag_name: linked_a_name, category: :general)
 
-      linked_b_name = create(:tag_name, name: 'nico_linked_b')
+      linked_b_name = TagName.create!(name: 'nico_linked_b')
-      linked_b = create(:tag, tag_name: linked_b_name, category: :general)
+      linked_b = Tag.create!(tag_name: linked_b_name, category: :general)
 
       NicoTagVersionRecorder.record!(external_tag: nico_tag,
                                      event_type: :create, created_by_user: admin)

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_name) { TagName.create!(name: 'spec_tag') }
-  let!(:tag)      { create(:tag, tag_name: tag_name, category: :general) }
+  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_name) { TagName.create!(name: 'spec_tag') }
-    let!(:tag) { create(:tag, tag_name:, category: :general) }
+    let!(:tag) { Tag.create!(tag_name:, category: :general) }
-    let!(:tag_name2) { create(:tag_name, name: 'unko') }
+    let!(:tag_name2) { TagName.create!(name: 'unko') }
-    let!(:tag2) { create(:tag, tag_name: tag_name2, category: :deerjikist) }
+    let!(:tag2) { Tag.create!(tag_name: tag_name2, category: :deerjikist) }
-    let!(:alias_tag_name) { create(:tag_name, :alias, name: 'manko', tag:) }
+    let!(:alias_tag_name) { TagName.create!(name: 'manko', canonical: tag_name) }
 
     let!(:hit_post) do
       Post.create!(uploaded_user: user, title: 'hello spec world',
@@ -341,17 +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_name) { TagName.create!(name: 'not_spec_foo') }
-      let!(:foo_tag) { create(:tag, tag_name: foo_tag_name, category: :general) }
+      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_name) { TagName.create!(name: 'not_spec_bar') }
-      let!(:bar_tag) { create(:tag, tag_name: bar_tag_name, category: :general) }
+      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_name) { TagName.create!(name: 'not_spec_baz') }
-      let!(:baz_tag) { create(:tag, tag_name: baz_tag_name, category: :general) }
+      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
@@ -772,10 +772,11 @@ RSpec.describe 'Posts API', type: :request do
       end
 
       it 'omits deprecated tags' do
-        deprecated_tag = create(:tag,
+        deprecated_tag = Tag.create!(
-            name: 'deprecated_post_tag',
+          name: 'deprecated_post_tag',
-            category: :general,
+          category: :general,
-            deprecated_at: Time.current)
+          deprecated_at: Time.current
+        )
         PostTag.create!(post: post_record, tag: deprecated_tag)
 
         request
@@ -852,9 +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_name = TagName.create!(name: "show_query_tag_#{ i }")
-              tag = create(:tag, tag_name:, category: :general)
+              tag = Tag.create!(tag_name:, category: :general)
-              create(:tag_name, :alias, name: "show_query_alias_#{ i }", tag:)
+              TagName.create!(name: "show_query_alias_#{ i }", canonical: tag_name)
               PostTag.create!(post: post_record, tag:)
               tag
             end
@@ -999,7 +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
@@ -1156,10 +1157,11 @@ RSpec.describe 'Posts API', type: :request do
     end
 
     it 'rejects a deprecated tag specified directly' do
-      create(:tag,
+      Tag.create!(
-          name: 'deprecated_direct_tag',
+        name: 'deprecated_direct_tag',
-          category: :general,
+        category: :general,
-          deprecated_at: Time.current)
+        deprecated_at: Time.current
+      )
       sign_in_as(member)
 
       post '/posts', params: post_write_params(
@@ -1176,16 +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, name: 'active_child', category: :general)
+      child = Tag.create!(name: 'active_child', category: :general)
-      deprecated_parent = create(:tag,
+      deprecated_parent = Tag.create!(
-          name: 'deprecated_parent',
+        name: 'deprecated_parent',
-          category: :general,
+        category: :general,
-          deprecated_at: Time.current)
+        deprecated_at: Time.current
-      deprecated_grandparent = create(:tag,
+      )
-          name: 'deprecated_grandparent',
+      deprecated_grandparent = Tag.create!(
-          category: :general,
+        name: 'deprecated_grandparent',
-          deprecated_at: Time.current)
+        category: :general,
-      active_grandparent = create(:tag, 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)
@@ -1618,7 +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
@@ -1655,8 +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')
+      tn2 = TagName.create!(name: 'spec_tag_2')
-      replacement_tag = create(:tag, tag_name: tn2, category: :general)
+      replacement_tag = Tag.create!(tag_name: tn2, category: :general)
 
       put "/posts/#{post_record.id}", params: post_update_params(
           post_record,
@@ -1704,10 +1707,11 @@ RSpec.describe 'Posts API', type: :request do
     end
 
     it 'rejects a deprecated tag specified directly' do
-      create(:tag,
+      Tag.create!(
-          name: 'deprecated_update_tag',
+        name: 'deprecated_update_tag',
-          category: :general,
+        category: :general,
-          deprecated_at: Time.current)
+        deprecated_at: Time.current
+      )
       sign_in_as(member)
 
       put "/posts/#{ post_record.id }", params: post_update_params(
@@ -1982,8 +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!(
+        current_tag = Tag.find_or_create_by_tag_name!('current_added_tag', category: :general)
-            Locale.nipponese, 'current_added_tag', category: :general)
         PostTag.create!(post: post_record, tag: current_tag, created_user: member)
 
         PostVersionRecorder.record!(
@@ -2012,8 +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!(
+        current_tag = Tag.find_or_create_by_tag_name!('current_merge_tag', category: :general)
-            Locale.nipponese, 'current_merge_tag', category: :general)
         PostTag.create!(post: post_record, tag: current_tag, created_user: member)
 
         PostVersionRecorder.record!(
@@ -2100,8 +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!(
+        linked_tag = Tag.find_or_create_by_tag_name!('relation_linked_tag', category: :general)
-            Locale.nipponese, 'relation_linked_tag', category: :general)
 
         NicoTagRelation.create!(nico_tag:, tag: linked_tag)
         PostExternalTag.create!(post: post_record, external_tag: nico_tag)
@@ -2190,8 +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!(:tag_name2) { TagName.create!(name: 'spec_tag_2') }
-    let!(:tag2) { create(:tag, tag_name: tag_name2, category: :general) }
+    let!(:tag2) { Tag.create!(tag_name: tag_name2, category: :general) }
 
     def snapshot_tags(post)
       post.snapshot_tag_names.join(' ')
@@ -2549,8 +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')
+      tag_name2 = TagName.create!(name: 'spec_tag_2')
-      create(:tag, tag_name: tag_name2, category: :general)
+      Tag.create!(tag_name: tag_name2, category: :general)
 
       expect do
         put "/posts/#{post_record.id}", params: post_write_params(
@@ -2714,8 +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')
+      tag_name2 = TagName.create!(name: 'spec_tag_2')
-      tag2 = create(:tag, tag_name: tag_name2, category: :general)
+      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

@@ -232,8 +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_name = TagName.create!(name: 'tag_versions_from_wiki')
-      wiki_tag = create(:tag, tag_name: wiki_tag_name, category: :general)
+      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

@@ -8,8 +8,8 @@ RSpec.describe 'Tag and wiki history integrity', type: :request do
   end
 
   def create_tag! name:, category: :general
-    tag_name = create(:tag_name, name:)
+    tag_name = TagName.create!(name:)
-    create(:tag, tag_name:, category:)
+    Tag.create!(tag_name:, category:)
   end
 
   def create_wiki_for_tag! tag:, body: 'wiki body', user: member_user

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!(:tn) { TagName.create!(name: 'spec_tag') }
-  let!(:tag) { create(:tag, tag_name: tn, category: :general) }
+  let!(:tag) { Tag.create!(tag_name: tn, category: :general) }
-  let!(:alias_tn) { create(:tag_name, :alias, name: 'unko', tag:) }
+  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!(:tn2) { TagName.create!(name: 'unknown') }
-  let!(:tag2) { create(:tag, tag_name: tn2, category: :general) }
+  let!(:tag2) { Tag.create!(tag_name: tn2, category: :general) }
 
   def response_tags
     json.fetch('tags')
@@ -91,7 +91,7 @@ RSpec.describe 'Tags API', type: :request do
     end
 
     it 'filters tags by category' do
-      meme = create(:tag, name: 'meme_only', category: :meme)
+      meme = Tag.create!(tag_name: TagName.create!(name: 'meme_only'), category: :meme)
 
       get '/tags', params: { category: 'meme' }
 
@@ -101,11 +101,12 @@ RSpec.describe 'Tags API', type: :request do
     end
 
     it 'filters tags by deprecated state' do
-      deprecated_tag = create(:tag,
+      deprecated_tag = Tag.create!(
-          name: 'deprecated_filter',
+        name: 'deprecated_filter',
-          category: :general,
+        category: :general,
-          deprecated_at: 1.day.from_now)
+        deprecated_at: 1.day.from_now
-      active_tag = create(:tag, name: 'active_filter', category: :general)
+      )
+      active_tag = Tag.create!(name: 'active_filter', category: :general)
 
       get '/tags', params: { name: '_filter', deprecated: '1' }
 
@@ -121,9 +122,9 @@ RSpec.describe 'Tags API', type: :request do
     end
 
     it 'filters tags by post_count range' do
-      low = create(:tag, name: 'pc_low', category: :general)
+      low = Tag.create!(tag_name: TagName.create!(name: 'pc_low'), category: :general)
-      mid = create(:tag, name: 'pc_mid', category: :general)
+      mid = Tag.create!(tag_name: TagName.create!(name: 'pc_mid'), category: :general)
-      high = create(:tag, name: 'pc_high', 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)
@@ -141,8 +142,8 @@ RSpec.describe 'Tags API', type: :request do
     end
 
     it 'filters tags by created_at range' do
-      old_tag = create(:tag, name: 'created_old', category: :general)
+      old_tag = Tag.create!(tag_name: TagName.create!(name: 'created_old'), category: :general)
-      new_tag = create(:tag, name: 'created_new', 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)
@@ -161,8 +162,8 @@ RSpec.describe 'Tags API', type: :request do
     end
 
     it 'filters tags by updated_at range' do
-      old_tag = create(:tag, name: 'updated_old', category: :general)
+      old_tag = Tag.create!(tag_name: TagName.create!(name: 'updated_old'), category: :general)
-      new_tag = create(:tag, name: 'updated_new', 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)
@@ -181,12 +182,12 @@ RSpec.describe 'Tags API', type: :request do
     end
 
     it 'orders tags by custom category order' do
-      create(:tag, name: 'cat_deerjikist', category: :deerjikist)
+      Tag.create!(tag_name: TagName.create!(name: 'cat_deerjikist'), category: :deerjikist)
-      create(:tag, name: 'cat_meme', category: :meme)
+      Tag.create!(tag_name: TagName.create!(name: 'cat_meme'), category: :meme)
-      create(:tag, name: 'cat_character', category: :character)
+      Tag.create!(tag_name: TagName.create!(name: 'cat_character'), category: :character)
-      create(:tag, name: 'cat_general', category: :general)
+      Tag.create!(tag_name: TagName.create!(name: 'cat_general'), category: :general)
-      create(:tag, name: 'cat_material', category: :material)
+      Tag.create!(tag_name: TagName.create!(name: 'cat_material'), category: :material)
-      create(:tag, name: 'cat_meta', category: :meta)
+      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 }
@@ -201,20 +202,20 @@ RSpec.describe 'Tags API', type: :request do
     context 'with mixed legacy pagination' do
       let!(:first_tag) do
         create(:tag,
-            tag_name: create(:tag_name, name: 'a_mixed_page'),
+               tag_name: create(:tag_name, name: 'a_mixed_page'),
-            category: :meme)
+               category: :meme)
       end
 
       let!(:middle_tag) do
         create(:tag,
-            tag_name: create(:tag_name, name: 'm_mixed_page'),
+               tag_name: create(:tag_name, name: 'm_mixed_page'),
-            category: :meta)
+               category: :meta)
       end
 
       let!(:last_tag) do
         create(:tag,
-            tag_name: create(:tag_name, name: 'z_mixed_page'),
+               tag_name: create(:tag_name, name: 'z_mixed_page'),
-            category: :general)
+               category: :general)
       end
 
       let!(:first_external) do
@@ -264,7 +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, 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 }
@@ -275,8 +276,8 @@ RSpec.describe 'Tags API', type: :request do
     end
 
     it 'falls back to default ordering when order is invalid' do
-      low = create(:tag, name: 'fallback_low', category: :general)
+      low = Tag.create!(tag_name: TagName.create!(name: 'fallback_low'), category: :general)
-      high = create(:tag, name: 'fallback_high', 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)
@@ -289,7 +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, 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 }
@@ -301,9 +302,10 @@ RSpec.describe 'Tags API', type: :request do
     end
 
     it 'returns aliases and parent tags' do
-      parent_tag = create(:tag,
+      parent_tag = Tag.create!(
-          tag_name: create(:tag_name, name: 'index_parent_tag'),
+        tag_name: TagName.create!(name: 'index_parent_tag'),
-          category: :meme)
+        category: :meme
+      )
       TagImplication.create!(tag:, parent_tag:)
 
       get '/tags', params: { name: 'spec_tag' }
@@ -347,9 +349,10 @@ RSpec.describe 'Tags API', type: :request do
       end
 
       it 'returns aliases and parent tags' do
-        parent_tag = create(:tag,
+        parent_tag = Tag.create!(
-            tag_name: create(:tag_name, name: 'show_parent_tag'),
+          tag_name: TagName.create!(name: 'show_parent_tag'),
-            category: :character)
+          category: :character
+        )
         TagImplication.create!(tag:, parent_tag:)
 
         request
@@ -413,7 +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, 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)
 
@@ -452,7 +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, name:, post_count: 1)
+        Tag.create!(category: :general, name:, post_count: 1)
         create(:external_tag, name:, post_count: 1)
       end
 
@@ -464,9 +467,9 @@ 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, name: 'switch_internal', post_count: 1)
+      internal = Tag.create!(category: :general, name: 'switch_internal', post_count: 1)
-      alias_target = create(:tag, category: :general, name: 'alias_target', post_count: 1)
+      alias_target = Tag.create!(category: :general, name: 'alias_target', post_count: 1)
-      create(:tag_name, :alias, name: 'switch_alias', tag: alias_target)
+      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' }
@@ -479,15 +482,13 @@ RSpec.describe 'Tags API', type: :request do
     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, name: literal, post_count: 1)
+        Tag.create!(category: :general, name: literal, post_count: 1)
-        alias_target = create(
+        alias_target = Tag.create!(category: :general, name: 'literal_alias_target', post_count: 1)
-            :tag, category: :general, name: 'literal_alias_target', post_count: 1)
+        TagName.create!(name: "#{ literal }_alias", canonical: alias_target.tag_name)
-        create(:tag_name, :alias, name: "#{ literal }_alias",
-                                  tag: alias_target)
         create(:external_tag, name: literal, post_count: 1)
-        create(:tag, category: :general, 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 }" }
@@ -509,7 +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)
@@ -522,10 +523,11 @@ RSpec.describe 'Tags API', type: :request do
     end
 
     it 'omits deprecated tags' do
-      deprecated_tag = create(:tag,
+      deprecated_tag = Tag.create!(
-          name: 'spec_deprecated',
+        name: 'spec_deprecated',
-          category: :general,
+        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' }
@@ -772,8 +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'))
+        expect(TagName.find_by!(name: 'spec_tag').canonical).to eq(tag.reload.tag_name)
-            .to have_attributes(tag_id: tag.id, primary_flg: false)
 
         patch "/tags/#{ tag.id }", params: { name: 'spec_tag' }
 
@@ -782,10 +783,8 @@ RSpec.describe 'Tags API', type: :request do
         tag.reload
 
         expect(tag.name).to eq('spec_tag')
-        expect(tag.tag_name).to have_attributes(
+        expect(tag.tag_name.canonical_id).to be_nil
-            tag_id: tag.id, language_code: 'ja', primary_flg: true)
+        expect(TagName.find_by!(name: 'patch_roundtrip_target').canonical).to eq(tag.tag_name)
-        expect(TagName.find_by!(language_code: 'ja', name: 'patch_roundtrip_target'))
-            .to have_attributes(tag_id: tag.id, primary_flg: false)
       end
 
       it '別 tag の正規名には変更できない' do
@@ -804,8 +803,7 @@ RSpec.describe 'Tags API', type: :request do
         )
 
         expect(tag.reload.name).to eq('spec_tag')
-        expect(TagName.where(tag_id: tag.id, language_code: 'ja', primary_flg: false).pluck(:name))
+        expect(tag.tag_name.aliases.map(&:name)).to contain_exactly('unko')
-            .to contain_exactly('unko')
         expect(wiki_page.reload.tag_name).to eq(tag.tag_name)
       end
 
@@ -822,27 +820,27 @@ RSpec.describe 'Tags API', type: :request do
 
   describe 'GET /tags/with-depth' do
     let!(:root_meme) do
-      create(:tag, 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, 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, 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, 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, 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, name: 'depth_child_general', category: :general)
+      Tag.create!(tag_name: TagName.create!(name: 'depth_child_general'), category: :general)
     end
 
     before do
@@ -885,13 +883,15 @@ RSpec.describe 'Tags API', type: :request do
     end
 
     it 'passes through deprecated tags when finding children' do
-      deprecated_middle = create(:tag,
+      deprecated_middle = Tag.create!(
-          name: 'depth_deprecated_middle',
+        name: 'depth_deprecated_middle',
-          category: :character,
+        category: :character,
-          deprecated_at: Time.current)
+        deprecated_at: Time.current
-      visible_descendant = create(:tag,
+      )
-          name: 'depth_visible_descendant',
+      visible_descendant = Tag.create!(
-          category: :material)
+        name: 'depth_visible_descendant',
+        category: :material
+      )
       TagImplication.create!(parent_tag: root_material, tag: deprecated_middle)
       TagImplication.create!(parent_tag: deprecated_middle, tag: visible_descendant)
 
@@ -903,20 +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,
+      active_child = Tag.create!(
-          name: 'depth_active_child_below_deprecated',
+        name: 'depth_active_child_below_deprecated',
-          category: :character)
+        category: :character
-      deprecated_parent = create(:tag,
+      )
-          name: 'depth_deprecated_parent',
+      deprecated_parent = Tag.create!(
-          category: :character,
+        name: 'depth_deprecated_parent',
-          deprecated_at: Time.current)
+        category: :character,
-      deprecated_grandparent = create(:tag,
+        deprecated_at: Time.current
-          name: 'depth_deprecated_grandparent',
+      )
-          category: :material,
+      deprecated_grandparent = Tag.create!(
-          deprecated_at: Time.current)
+        name: 'depth_deprecated_grandparent',
-      active_ancestor = create(:tag,
+        category: :material,
-          name: 'depth_active_ancestor',
+        deprecated_at: Time.current
-          category: :meme)
+      )
+      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)
@@ -941,13 +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,
+      active_child = Tag.create!(
-          name: 'depth_root_below_deprecated',
+        name: 'depth_root_below_deprecated',
-          category: :character)
+        category: :character
-      deprecated_parent = create(:tag,
+      )
-          name: 'depth_root_deprecated_parent',
+      deprecated_parent = Tag.create!(
-          category: :material,
+        name: 'depth_root_deprecated_parent',
-          deprecated_at: Time.current)
+        category: :material,
+        deprecated_at: Time.current
+      )
       TagImplication.create!(tag: active_child, parent_tag: deprecated_parent)
 
       get '/tags/with-depth'
@@ -961,14 +967,16 @@ RSpec.describe 'Tags API', type: :request do
     end
 
     it 'terminates when deprecated implications contain a cycle' do
-      first = create(:tag,
+      first = Tag.create!(
-          name: 'depth_cycle_first',
+        name: 'depth_cycle_first',
-          category: :character,
+        category: :character,
-          deprecated_at: Time.current)
+        deprecated_at: Time.current
-      second = create(:tag,
+      )
-          name: 'depth_cycle_second',
+      second = Tag.create!(
-          category: :material,
+        name: 'depth_cycle_second',
-          deprecated_at: Time.current)
+        category: :material,
+        deprecated_at: Time.current
+      )
       TagImplication.create!(tag: first, parent_tag: root_material)
       TagImplication.create!(tag: second, parent_tag: first)
       now = Time.current
@@ -994,19 +1002,19 @@ RSpec.describe 'Tags API', type: :request do
     let!(:material_user) { create_member_user! }
 
     let!(:root_tag) do
-      create(:tag, name: 'materials_root', category: :material)
+      Tag.create!(tag_name: TagName.create!(name: 'materials_root'), category: :material)
     end
 
     let!(:child_a_tag) do
-      create(:tag, 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, 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, name: 'materials_grandchild', category: :material)
+      Tag.create!(tag_name: TagName.create!(name: 'materials_grandchild'), category: :material)
     end
 
     let!(:root_material) do
@@ -1150,12 +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,
+        old_parent = Tag.create!(
-            tag_name: create(:tag_name, name: 'put_old_parent'),
+          tag_name: TagName.create!(name: 'put_old_parent'),
-            category: :general)
+          category: :general
-        kept_parent = create(:tag,
+        )
-            tag_name: create(:tag_name, name: 'put_kept_parent'),
+        kept_parent = Tag.create!(
-            category: :general)
+          tag_name: TagName.create!(name: 'put_kept_parent'),
+          category: :general
+        )
         TagImplication.create!(tag:, parent_tag: old_parent)
         TagImplication.create!(tag:, parent_tag: kept_parent)
 
@@ -1174,17 +1184,14 @@ RSpec.describe 'Tags API', type: :request do
         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'))
+        expect(TagName.find_by(name: 'put_alias_a').canonical).to eq(tag.tag_name)
-            .to have_attributes(tag_id: tag.id, primary_flg: false)
+        expect(TagName.find_by(name: 'put_alias_b').canonical).to eq(tag.tag_name)
-        expect(TagName.find_by!(language_code: 'ja', name: 'put_alias_b'))
-            .to have_attributes(tag_id: tag.id, primary_flg: false)
 
         old_name_alias = TagName.find_by(name: 'spec_tag')
         expect(old_name_alias).to be_present
-        expect(old_name_alias).to have_attributes(
+        expect(old_name_alias.canonical).to eq(tag.tag_name)
-            tag_id: tag.id, language_code: 'ja', primary_flg: false)
 
-        expect(alias_tn.reload.tag_id).to be_nil
+        expect(alias_tn.reload.canonical).to be_nil
 
         expect(tag.parents.map(&:name)).to contain_exactly(
           'put_kept_parent',
@@ -1219,8 +1226,7 @@ RSpec.describe 'Tags API', type: :request do
 
         tag.reload
 
-        expect(TagName.find_by!(language_code: 'ja', name: 'put_alias_self_test'))
+        expect(TagName.find_by(name: 'put_alias_self_test').canonical).to eq(tag.tag_name)
-            .to have_attributes(tag_id: tag.id, primary_flg: false)
         expect(json['aliases']).to include('put_alias_self_test')
         expect(json['aliases']).not_to include('spec_tag')
       end
@@ -1291,14 +1297,10 @@ RSpec.describe 'Tags API', type: :request do
         tag.reload
 
         expect(tag.name).to eq('spec_tag')
-        expect(TagName.find_by!(language_code: 'ja', name: 'put_roundtrip_b'))
+        expect(TagName.find_by!(name: 'put_roundtrip_b').canonical).to eq(tag.tag_name)
-            .to have_attributes(tag_id: tag.id, primary_flg: false)
+        expect(tag.tag_name.aliases.map(&:name)).to contain_exactly('put_roundtrip_b', 'unko')
-        expect(TagName.where(tag_id: tag.id, language_code: 'ja', primary_flg: false).pluck(:name))
+        expect(tag.tag_name.aliases.map(&:name)).not_to include('spec_tag')
-            .to contain_exactly('put_roundtrip_b', 'unko')
+        expect(alias_tn.reload.canonical).to eq(tag.tag_name)
-        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)
 
         version = tag.tag_versions.order(:version_no).last
 
@@ -1308,12 +1310,14 @@ RSpec.describe 'Tags API', type: :request do
       end
 
       it 'parent tag の snapshot も作成する' do
-        old_parent = create(:tag,
+        old_parent = Tag.create!(
-            tag_name: create(:tag_name, name: 'put_snapshot_old_parent'),
+          tag_name: TagName.create!(name: 'put_snapshot_old_parent'),
-            category: :general)
+          category: :general
-        new_parent = create(:tag,
+        )
-            tag_name: create(:tag_name, name: 'put_snapshot_new_parent'),
+        new_parent = Tag.create!(
-            category: :general)
+          tag_name: TagName.create!(name: 'put_snapshot_new_parent'),
+          category: :general
+        )
         TagImplication.create!(tag:, parent_tag: old_parent)
 
         put "/tags/#{ tag.id }", params: {
@@ -1407,7 +1411,7 @@ 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: tag.tag_name,
@@ -1441,8 +1445,7 @@ RSpec.describe 'Tags API', type: :request do
 
         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!(language_code: 'ja', name: 'put_wiki_roundtrip_b'))
+        expect(TagName.find_by!(name: 'put_wiki_roundtrip_b').canonical).to eq(tag.tag_name)
-            .to have_attributes(tag_id: tag.id, primary_flg: false)
 
         versions = wiki_page.wiki_versions.order(:version_no).last(2)
 
@@ -1451,16 +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,
+        old_owner = Tag.create!(
-            tag_name: create(:tag_name, name: 'put_alias_old_owner'),
+          tag_name: TagName.create!(name: 'put_alias_old_owner'),
-            category: :general)
+          category: :general
-        stolen_alias = create(:tag_name, :alias,
+        )
-            name: 'put_stolen_alias',
+        stolen_alias = TagName.create!(
-            tag: old_owner)
+          name: 'put_stolen_alias',
+          canonical: old_owner.tag_name
+        )
 
-        expect(TagName.where(tag_id: old_owner.id, language_code: 'ja',
+        expect(old_owner.tag_name.aliases.map(&:name)).to include('put_stolen_alias')
-                              primary_flg: false).pluck(:name))
-            .to include('put_stolen_alias')
 
         expect {
           put "/tags/#{ tag.id }", params: {
@@ -1476,11 +1479,8 @@ RSpec.describe 'Tags API', type: :request do
 
         expect(response).to have_http_status(:ok)
 
-        expect(stolen_alias.reload).to have_attributes(
+        expect(stolen_alias.reload.canonical).to eq(tag.tag_name)
-            tag_id: tag.id, language_code: 'ja', primary_flg: false)
+        expect(old_owner.reload.tag_name.aliases.map(&:name)).not_to include('put_stolen_alias')
-        expect(TagName.where(tag_id: old_owner.id, language_code: 'ja',
-                              primary_flg: false).pluck(:name))
-            .not_to include('put_stolen_alias')
 
         old_owner_versions = old_owner.tag_versions.order(:version_no)
 
@@ -1492,12 +1492,14 @@ RSpec.describe 'Tags API', type: :request do
       end
 
       it '別 tag の alias 名を rename で奪へる' do
-        old_owner = create(:tag,
+        old_owner = Tag.create!(
-            tag_name: create(:tag_name, name: 'put_alias_collision_owner'),
+          tag_name: TagName.create!(name: 'put_alias_collision_owner'),
-            category: :general)
+          category: :general
-        stolen_alias = create(:tag_name, :alias,
+        )
-            name: 'put_alias_collision_name',
+        stolen_alias = TagName.create!(
-            tag: old_owner)
+          name: 'put_alias_collision_name',
+          canonical: old_owner.tag_name
+        )
         wiki_page =
             Wiki::Commit.create_content!(
                 tag_name: tag.tag_name,
@@ -1513,20 +1515,16 @@ 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(tag.name).to eq('put_alias_collision_name')
-        expect(stolen_alias).to have_attributes(
+        expect(stolen_alias.canonical_id).to be_nil
-            tag_id: tag.id, language_code: 'ja', primary_flg: true)
+        expect(TagName.find_by!(name: 'spec_tag').canonical).to eq(tag.tag_name)
-        expect(TagName.find_by!(language_code: 'ja', name: 'spec_tag'))
+        expect(old_owner.tag_name.aliases.map(&:name)).not_to include('put_alias_collision_name')
-            .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')
 
         old_owner_versions = old_owner.tag_versions.order(:version_no)
 
@@ -1536,9 +1534,10 @@ RSpec.describe 'Tags API', type: :request do
       end
 
       it 'parent_tags に指定すると循環する tag は 422 にする' do
-        child = create(:tag,
+        child = Tag.create!(
-            tag_name: create(:tag_name, name: 'put_cycle_child'),
+          tag_name: TagName.create!(name: 'put_cycle_child'),
-            category: :general)
+          category: :general
+        )
 
         TagImplication.create!(tag: child, parent_tag: tag)
 

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,
+    Tag.create!(
-        tag_name: tn,
+      tag_name: tn,
-        category: :general,
+      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_name = TagName.create!(name: 'wiki_body_only_tag')
-        linked_tag = create(:tag, tag_name: linked_tag_name, category: :general)
+        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_name = TagName.create!(name: 'wiki_linked_tag_for_version')
-    linked_tag = create(:tag, tag_name: linked_tag_name, category: :general)
+    linked_tag = Tag.create!(tag_name: linked_tag_name, category: :general)
 
     linked_page =
         Wiki::Commit.create_content!(

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, 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, 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)
+        thumbnails: { }).run.fetch(:results)
-
-    expect(creators.length).to eq(posts.length)
-    creators.each do |creator|
-      expect(creator).to have_received(:create!).with(locale).once
-    end
 
     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, name:, category:)
+    Tag.create!(name:, category:)
   end
 
   before do
@@ -10,55 +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, tag_name: english_name, category: :character)
-      japanese = create(:tag, name: 'temporary_japanese', category: :general)
-      # The DB permits this identity; validation has its own contract spec.
-      japanese.tag_name.update_columns(name: 'shared_name')
-      english_parent = create(:tag, name: 'english_parent', category: :material)
-      japanese_parent = create(:tag, 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: english_parent.name, category: :material })
-      expect(plan[:post_tag_specs].pluck(:name)).not_to include(japanese_parent.name)
-    end
-
-    it 'resolves aliases within the requested language' do
-      japanese = create(:tag, name: 'japanese_canonical')
-      english_name = create(:tag_name, name: 'english_canonical',
-                                      language_code: 'en', script_code: 'Latn')
-      english = create(:tag, 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, category: :character }])
-    end
-  end
-
   it 'plans direct and existing default tags without persisting records' do
     counts = [TagName.count, Tag.count]
 
@@ -67,7 +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(
@@ -78,9 +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
+  it 'resolves aliases and keeps tag sections separate from canonical names' do
-    tag = create_tag!('虹夏', :character)
+    canonical = create_tag!('虹夏', :character)
-    create(:tag_name, :alias, name: 'にじか', tag:)
+    TagName.create!(name: 'にじか', canonical: canonical.tag_name)
     create_tag!('動画', :meta)
 
     plan = described_class.new(
@@ -89,7 +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(
@@ -104,7 +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
     }
@@ -122,7 +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
     }
@@ -136,7 +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) }
+    expect { creator.create! }.to raise_error(Post::RemoteThumbnailFetchFailed)
-        .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, 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/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_name = TagName.create!(name: 'commit_integrity_linked_tag')
-      tag = create(:tag, tag_name:, category: :general)
+      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_name = TagName.create!(name: 'commit_linked_tag_without_versions')
-      tag = create(:tag, tag_name:, category: :general)
+      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_name = TagName.create!(name: 'commit_linked_tag_without_versions')
-      tag = create(:tag, tag_name:, category: :general)
+      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!(
+      deerjikist_tag = Tag.find_or_create_by_tag_name!('テスト投稿者', category: :deerjikist)
-          Locale.nipponese, '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!(
+      deerjikist_tag = Tag.find_or_create_by_tag_name!('後から判明した投稿者', category: :deerjikist)
-          Locale.nipponese, '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/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)

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, name: 't1')
+    t1 = Tag.create!(name: "t1")
-    t2 = create(:tag, name: 't2')
+    t2 = Tag.create!(name: "t2")
-    t3 = create(:tag, name: 't3')
+    t3 = Tag.create!(name: "t3")
-    deprecated_tag = create(:tag, name: 'deprecated', deprecated_at: Time.current)
+    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, name: 't1')
+    t1 = Tag.create!(name: "t1")
-    t2 = create(:tag, name: 't2')
+    t2 = Tag.create!(name: "t2")
-    t3 = create(:tag, name: 't3')
+    t3 = Tag.create!(name: "t3")
-    deprecated_tag = create(:tag, name: 'deprecated', deprecated_at: Time.current)
+    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")