多言語化の基盤作り (#55) (#421)

Reviewed-on: #421
Co-authored-by: miteruzo <miteruzo@naver.com>

backend/spec/requests/deerjikists_spec.rb

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

backend/spec/requests/error_responses_spec.rb

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

backend/spec/requests/gekanator_learning_spec.rb

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

backend/spec/requests/gekanator_posts_spec.rb

@@ -4,12 +4,11 @@ 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 = Tag.create!(name: 'active tag', category: :general)
-      deprecated_tag = Tag.create!(
-        name: 'deprecated tag',
-        category: :general,
-        deprecated_at: Time.current
-      )
+      active_tag = create(:tag, primary_name: 'active tag', category: :general)
+      deprecated_tag = create(:tag,
+          primary_name: 'deprecated tag',
+          category: :general,
+          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

@@ -0,0 +1,363 @@
+require 'rails_helper'
+
+RSpec.describe 'Locale propagation on write paths', type: :request do
+  include_context 'English locale'
+
+  let(:member) { create(:user, :member) }
+
+  before do
+    sign_in_as(member)
+  end
+
+  def expect_localised_tag(name, expected_locale)
+    tag_name = TagName.find_by!(name:, language_code: expected_locale.language_code)
+    expect(tag_name).to have_attributes(
+        script_code: expected_locale.script_code, primary_flg: true)
+    expect(tag_name.tag_id).to be_present
+    tag_name.tag
+  end
+
+  it 'confirms a generated Nipponese primary when a human renames it' do
+    tag = create(:tag, primary_name: 'generated_source')
+    primary = primary_tag_name_for(tag, 'ja')
+    primary.update!(name: "Tag_##{ tag.id }", auto_generated: true)
+
+    patch "/tags/#{ tag.id }", params: { locale: 'ja', name: '人間が確定した名称' }
+
+    expect(response).to have_http_status(:ok), response.body
+    expect(primary.reload).to have_attributes(
+        name: '人間が確定した名称', auto_generated: false)
+  end
+
+  it 'rolls back Nipponese edits when an alias conflicts with another primary' do
+    tag = create(:tag, primary_name: 'target_before_collision')
+    create(:tag_name, :alias, tag:, name: 'existing_alias')
+    other_tag = create(:tag, primary_name: 'other_primary')
+    other_primary = primary_tag_name_for(other_tag, 'ja')
+    primary_name_before = primary_tag_name_for(tag, 'ja').name
+    aliases_before = tag.tag_names.where(primary_flg: false).order(:name).pluck(:name)
+    category_before = tag.category
+
+    put "/tags/#{ tag.id }", params: {
+        locale: 'ja', name: 'renamed_before_collision', category: 'character',
+        deprecated: false, aliases: 'other_primary', parent_tags: '' }
+
+    aggregate_failures do
+      expect(response).to have_http_status(:unprocessable_entity)
+      expect(other_primary.reload).to have_attributes(tag_id: other_tag.id, primary_flg: true)
+      expect(TagName.where(tag: other_tag, language_code: 'ja', primary_flg: true))
+          .to contain_exactly(other_primary)
+      expect(primary_tag_name_for(tag.reload, 'ja').name).to eq(primary_name_before)
+      expect(tag.category).to eq(category_before)
+      expect(tag.tag_names.where(primary_flg: false).order(:name).pluck(:name))
+          .to eq(aliases_before)
+    end
+  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 Nipponese fallback' do
+        pending '日本語以外の Locale 有効化は別課題で実装する' if requested_locale
+        locale if requested_locale
+        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 Nipponese fallback' do
+        pending '日本語以外の Locale 有効化は別課題で実装する' if requested_locale
+        locale if requested_locale
+        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
+        pending '日本語以外の Locale 有効化は別課題で実装する' if requested_locale
+        locale if requested_locale
+        # 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
+        pending '日本語以外の Locale 有効化は別課題で実装する' if requested_locale
+        locale if requested_locale
+        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
+        pending '日本語以外の Locale 有効化は別課題で実装する' if requested_locale
+        locale if requested_locale
+        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
+        pending '日本語以外の Locale 有効化は別課題で実装する' if requested_locale
+        locale if requested_locale
+        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
+        pending '日本語以外の Locale 有効化は別課題で実装する' if requested_locale
+        locale if requested_locale
+        tag = create(:tag)
+
+        put "/tags/#{ tag.id }", params: locale_params.merge(
+            name: primary_tag_name_for(tag, 'ja').name, category: tag.category, deprecated: false,
+            aliases: '', parent_tags: 'locale_parent')
+
+        expect(response).to have_http_status(:ok), response.body
+        parent = expect_localised_tag('locale_parent', expected_locale)
+        expect(TagImplication.where(tag:).pluck(:parent_tag_id)).to eq([parent.id])
+      end
+    end
+  end
+
+  context 'with existing names in both languages' do
+    let(:english_name) do
+      create(:tag_name, name: 'shared_name', language_code: 'en', script_code: 'Latn')
+    end
+    let(:english_tag) { create(:tag, primary_tag_name: english_name, category: :material) }
+    let(:nipponese_tag) do
+      create(:tag, primary_name: 'temporary_nipponese', category: :general).tap do |tag|
+        # Isolate lookup from the separately tested uniqueness validation.
+        primary_tag_name_for(tag, 'ja').update_columns(name: 'shared_name')
+      end
+    end
+
+    it 'plans and creates the post using the English identity and category' do
+      pending '日本語以外の Locale 有効化は別課題で実装する'
+      locale
+      english_tag
+      nipponese_tag
+      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(nipponese_tag)
+      expect(english_tag.reload.category).to eq('material')
+      expect(nipponese_tag.reload.category).to eq('general')
+    end
+
+    it 'updates the post using the English identity' do
+      pending '日本語以外の Locale 有効化は別課題で実装する'
+      locale
+      english_tag
+      nipponese_tag
+      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(nipponese_tag)
+    end
+
+    it 'resolves the English material tag' do
+      pending '日本語以外の Locale 有効化は別課題で実装する'
+      locale
+      english_tag
+      nipponese_tag
+      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: nipponese_tag)).to be_empty
+    end
+
+    it 'resolves the English parent tag' do
+      pending '日本語以外の Locale 有効化は別課題で実装する'
+      locale
+      english_tag
+      nipponese_tag
+      child = create(:tag)
+
+      put "/tags/#{ child.id }", params: {
+          locale: 'en', name: primary_tag_name_for(child, 'ja').name,
+          category: child.category, deprecated: false,
+          aliases: '', parent_tags: 'shared_name' }
+
+      expect(response).to have_http_status(:ok), response.body
+      expect(TagImplication.where(tag: child).pluck(:parent_tag_id)).to eq([english_tag.id])
+    end
+
+    it 'resolves the English internal tag for a Nico link' do
+      pending '日本語以外の Locale 有効化は別課題で実装する'
+      locale
+      english_tag
+      nipponese_tag
+      external = create(:external_tag)
+      NicoTagVersionRecorder.record!(
+          external_tag: external, event_type: :create, created_by_user: member)
+
+      put "/tags/nico/#{ external.id }", params: { locale: 'en', tags: 'shared_name' }
+
+      expect(response).to have_http_status(:ok), response.body
+      expect(external.reload.linked_tags).to contain_exactly(english_tag)
+    end
+  end
+
+  context 'when renaming or updating aliases in English' do
+    let(:english_name) do
+      create(:tag_name, name: 'english_original', language_code: 'en', script_code: 'Latn')
+    end
+    let(:tag) { create(:tag, primary_tag_name: english_name) }
+
+    it 'marks a human-renamed generated primary as no longer auto-generated' do
+      pending '日本語以外の Locale 有効化は別課題で実装する'
+      locale
+      generated_tag = create(:tag, primary_name: 'rename_generated_source')
+      generated_name = primary_tag_name_for(generated_tag, 'en')
+      expect(generated_name.auto_generated).to be(true)
+
+      patch "/tags/#{ generated_tag.id }", params: {
+          locale: 'en', name: 'human_english_name' }
+
+      expect(response).to have_http_status(:ok), response.body
+      expect(generated_name.reload).to have_attributes(
+          name: 'human_english_name', auto_generated: false)
+    end
+
+    it 'does not steal another tag primary for an alias' do
+      pending '日本語以外の Locale 有効化は別課題で実装する'
+      locale
+      other_tag = create(:tag, primary_name: 'other_nipponese')
+      other_primary = primary_tag_name_for(other_tag, 'en')
+      other_primary.update!(name: 'other_english_primary', auto_generated: false)
+      create(:tag_name, :alias, tag:, name: 'existing_english_alias',
+                                language_code: 'en', script_code: 'Latn')
+      primary_name_before = primary_tag_name_for(tag, 'en').name
+      aliases_before =
+          tag.tag_names.where(language_code: 'en', primary_flg: false)
+              .order(:name).pluck(:name)
+      category_before = tag.category
+
+      put "/tags/#{ tag.id }", params: {
+          locale: 'en', name: 'renamed_before_alias_collision',
+          category: 'character', deprecated: false,
+          aliases: 'other_english_primary', parent_tags: '' }
+
+      aggregate_failures do
+        expect(response).to have_http_status(:unprocessable_entity)
+        expect(other_primary.reload).to have_attributes(
+            tag_id: other_tag.id, language_code: 'en', primary_flg: true)
+        expect(TagName.where(tag: other_tag, language_code: 'en', primary_flg: true))
+            .to contain_exactly(other_primary)
+        expect(primary_tag_name_for(tag.reload, 'en').name).to eq(primary_name_before)
+        expect(tag.category).to eq(category_before)
+        aliases_after =
+            tag.tag_names.where(language_code: 'en', primary_flg: false)
+                .order(:name).pluck(:name)
+        expect(aliases_after).to eq(aliases_before)
+      end
+    end
+
+    it 'allows a rename to a name already used in Nipponese' do
+      pending '日本語以外の Locale 有効化は別課題で実装する'
+      locale
+      nipponese = create(:tag, primary_name: 'rename_target')
+
+      patch "/tags/#{ tag.id }", params: { locale: 'en', name: 'rename_target' }
+
+      expect(response).to have_http_status(:ok), response.body
+      expect(primary_tag_name_for(tag.reload, 'en')).to have_attributes(
+          name: 'rename_target', language_code: 'en', tag_id: tag.id)
+      expect(primary_tag_name_for(nipponese.reload, 'ja')).to have_attributes(
+          name: 'rename_target', language_code: 'ja', tag_id: nipponese.id)
+    end
+
+    it 'creates aliases in the requested language' do
+      pending '日本語以外の Locale 有効化は別課題で実装する'
+      locale
+      put "/tags/#{ tag.id }", params: {
+          locale: 'en', name: english_name.name,
+          category: tag.category, deprecated: false,
+          aliases: 'english_alias', parent_tags: '' }
+
+      expect(response).to have_http_status(:ok), response.body
+      expect(TagName.find_by!(language_code: 'en', name: 'english_alias'))
+          .to have_attributes(
+              script_code: 'Latn',
+              tag_id: tag.id, primary_flg: false, language_code: 'en')
+      primary = TagName.find_by!(tag_id: tag.id, language_code: 'en', primary_flg: true)
+      expect(primary).to have_attributes(name: 'english_original', script_code: 'Latn')
+    end
+
+    it 'does not take an alias from another language' do
+      pending '日本語以外の Locale 有効化は別課題で実装する'
+      locale
+      nipponese = create(:tag, primary_name: 'nipponese_owner')
+      nipponese_alias = create(:tag_name, :alias, name: 'shared_alias',
+                                                  tag: nipponese)
+      expect(nipponese_alias.reload).to have_attributes(
+          tag_id: nipponese.id,
+          primary_flg: false, language_code: 'ja')
+
+      put "/tags/#{ tag.id }", params: {
+          locale: 'en', name: english_name.name,
+          category: tag.category, deprecated: false,
+          aliases: 'shared_alias', parent_tags: '' }
+
+      expect(response).to have_http_status(:ok), response.body
+      expect(nipponese_alias.reload).to have_attributes(
+          tag_id: nipponese.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', nipponese.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
-      Tag.create!(tag_name: TagName.create!(name: 'material_index_a'), category: :material)
+      create(:tag, primary_name: 'material_index_a', category: :material)
     end
     let!(:tag_b) do
-      Tag.create!(tag_name: TagName.create!(name: 'material_index_b'), category: :material)
+      create(:tag, primary_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 =
-          Tag.create!(tag_name: TagName.create!(name: 'material_scope_root'),
+          create(:tag, primary_name: 'material_scope_root',
                       category: :material)
       child_b =
-          Tag.create!(tag_name: TagName.create!(name: 'material_scope_b'),
+          create(:tag, primary_name: 'material_scope_b',
                       category: :material)
       child_a =
-          Tag.create!(tag_name: TagName.create!(name: 'material_scope_a'),
+          create(:tag, primary_name: 'material_scope_a',
                       category: :material)
       deprecated =
-          Tag.create!(tag_name: TagName.create!(name: 'material_scope_old'),
+          create(:tag, primary_name: 'material_scope_old',
                       category: :material,
                       deprecated_at: Time.current)
       grandchild =
-          Tag.create!(tag_name: TagName.create!(name: 'material_scope_grandchild'),
+          create(:tag, primary_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
-      Tag.create!(tag_name: TagName.create!(name: 'material_show'), category: :material)
+      create(:tag, primary_name: 'material_show', category: :material)
     end
     let!(:material) do
       build_material(tag:, user: member_user, file: dummy_upload(filename: 'show.png'))
@@ -269,7 +269,7 @@ RSpec.describe 'Materials API', type: :request do
         expect(response).to have_http_status(:created)
 
         material = Material.order(:id).last
-        expect(material.tag.name).to eq('material_create_new')
+        expect(primary_tag_name_for(material.tag, 'ja').name).to eq('material_create_new')
         expect(material.tag.category).to eq('material')
         expect(material.created_by_user).to eq(member_user)
         expect(material.updated_by_user).to eq(member_user)
@@ -297,7 +297,8 @@ RSpec.describe 'Materials API', type: :request do
 
         expect(response).to have_http_status(:created)
 
-        tag = Tag.joins(:tag_name).find_by!(tag_names: { name: 'material_create_versioned_tag' })
+        tag = TagName.find_by!(name: 'material_create_versioned_tag',
+                               language_code: 'ja', primary_flg: true).tag
         version = tag.tag_versions.order(:version_no).last
 
         expect(version.event_type).to eq('create')
@@ -323,8 +324,8 @@ RSpec.describe 'Materials API', type: :request do
       end
 
       it 'returns 422 when the existing tag is not material/character' do
-        general_tag_name = TagName.create!(name: 'material_create_general_tag')
-        Tag.create!(tag_name: general_tag_name, category: :general)
+        general_tag_name = create(:tag_name, name: 'material_create_general_tag')
+        create(:tag, primary_tag_name: general_tag_name, category: :general)
 
         post '/materials', params: {
           tag: 'material_create_general_tag',
@@ -345,7 +346,7 @@ RSpec.describe 'Materials API', type: :request do
         expect(response).to have_http_status(:created)
 
         material = Material.order(:id).last
-        expect(material.tag.name).to eq('material_create_url_only')
+        expect(primary_tag_name_for(material.tag, 'ja').name).to eq('material_create_url_only')
         expect(material.url).to eq('https://example.com/material-source')
         expect(material.file.attached?).to be(false)
       end
@@ -384,7 +385,7 @@ RSpec.describe 'Materials API', type: :request do
 
   describe 'PUT /materials/:id' do
     let!(:tag) do
-      Tag.create!(tag_name: TagName.create!(name: 'material_update_old'), category: :material)
+      create(:tag, primary_name: 'material_update_old', category: :material)
     end
     let!(:material) do
       build_material(tag:, user: member_user, file: dummy_upload(filename: 'old.png'))
@@ -463,7 +464,7 @@ RSpec.describe 'Materials API', type: :request do
         expect(response).to have_http_status(:ok)
 
         material.reload
-        expect(material.tag.name).to eq('material_update_new')
+        expect(primary_tag_name_for(material.tag, 'ja').name).to eq('material_update_new')
         expect(material.tag.category).to eq('material')
         expect(material.url).to eq('https://example.com/updated-source')
         expect(material.updated_by_user).to eq(member_user)
@@ -497,7 +498,8 @@ RSpec.describe 'Materials API', type: :request do
 
         expect(response).to have_http_status(:ok)
 
-        tag = Tag.joins(:tag_name).find_by!(tag_names: { name: 'material_update_versioned_tag' })
+        tag = TagName.find_by!(name: 'material_update_versioned_tag',
+                               language_code: 'ja', primary_flg: true).tag
         version = tag.tag_versions.order(:version_no).last
 
         expect(version.event_type).to eq('create')
@@ -508,7 +510,7 @@ RSpec.describe 'Materials API', type: :request do
 
       it 'backfills a create tag_version for an existing material tag without history' do
         existing_tag =
-            Tag.create!(tag_name: TagName.create!(name: 'material_update_existing_no_history'),
+            create(:tag, primary_name: 'material_update_existing_no_history',
                         category: :material)
 
         expect(existing_tag.tag_versions).to be_empty
@@ -531,7 +533,7 @@ RSpec.describe 'Materials API', type: :request do
 
       it 'backfills a create tag_version for an existing character tag without history' do
         existing_tag =
-            Tag.create!(tag_name: TagName.create!(name: 'material_update_character_no_history'),
+            create(:tag, primary_name: 'material_update_character_no_history',
                         category: :character)
 
         expect(existing_tag.tag_versions).to be_empty
@@ -563,7 +565,7 @@ RSpec.describe 'Materials API', type: :request do
         expect(response).to have_http_status(:ok)
 
         material.reload
-        expect(material.tag.name).to eq('material_update_remove_file')
+        expect(primary_tag_name_for(material.tag, 'ja').name).to eq('material_update_remove_file')
         expect(material.url).to eq('https://example.com/updated-source')
         expect(material.updated_by_user).to eq(member_user)
         expect(material.file.attached?).to be(false)
@@ -651,8 +653,8 @@ RSpec.describe 'Materials API', type: :request do
   end
 
   describe 'GET /materials/download.zip' do
-    let!(:tag_a) { Tag.create!(tag_name: TagName.create!(name: 'zip_a'), category: :material) }
-    let!(:tag_b) { Tag.create!(tag_name: TagName.create!(name: 'zip_b'), category: :material) }
+    let!(:tag_a) { create(:tag, primary_name: 'zip_a', category: :material) }
+    let!(:tag_b) { create(:tag, primary_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 +703,7 @@ RSpec.describe 'Materials API', type: :request do
 
   describe 'GET /materials/versions' do
     let!(:tag) do
-      Tag.create!(tag_name: TagName.create!(name: 'material_history'), category: :material)
+      create(:tag, primary_name: 'material_history', category: :material)
     end
     let!(:material) do
       build_material(tag:, user: member_user, file: dummy_upload(filename: 'history.png'))
@@ -776,7 +778,7 @@ RSpec.describe 'Materials API', type: :request do
 
   describe 'DELETE /materials/:id' do
     let!(:tag) do
-      Tag.create!(tag_name: TagName.create!(name: 'material_destroy'), category: :material)
+      create(:tag, primary_name: 'material_destroy', category: :material)
     end
     let!(:material) do
       build_material(tag:, user: member_user, file: dummy_upload(filename: 'destroy.png'))

backend/spec/requests/nico_tags_spec.rb

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

backend/spec/requests/posts_spec.rb

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

backend/spec/requests/tag_versions_spec.rb

@@ -3,13 +3,13 @@ require 'rails_helper'
 RSpec.describe 'TagVersions API', type: :request do
   let(:member) { create(:user, :member, name: 'version member') }
 
-  let!(:tag) { create(:tag, name: 'tag_versions_target', category: :general) }
-  let!(:other_tag) { create(:tag, name: 'tag_versions_other', category: :general) }
+  let!(:tag) { create(:tag, primary_name: 'tag_versions_target', category: :general) }
+  let!(:other_tag) { create(:tag, primary_name: 'tag_versions_other', category: :general) }
 
-  let!(:parent_shared) { create(:tag, name: 'parent_shared', category: :general) }
-  let!(:parent_old) { create(:tag, name: 'parent_old', category: :general) }
-  let!(:parent_new) { create(:tag, name: 'parent_new', category: :general) }
-  let!(:other_parent) { create(:tag, name: 'other_parent', category: :general) }
+  let!(:parent_shared) { create(:tag, primary_name: 'parent_shared', category: :general) }
+  let!(:parent_old) { create(:tag, primary_name: 'parent_old', category: :general) }
+  let!(:parent_new) { create(:tag, primary_name: 'parent_new', category: :general) }
+  let!(:other_parent) { create(:tag, primary_name: 'other_parent', category: :general) }
 
   let(:t_v1) { Time.zone.local(2020, 1, 1, 12, 0, 0) }
   let(:t_v2) { Time.zone.local(2020, 1, 2, 12, 0, 0) }
@@ -36,6 +36,10 @@ RSpec.describe 'TagVersions API', type: :request do
             category: category,
             deprecated_at: deprecated_at,
             aliases: Array(aliases).join(' '),
+            names: { ja: { name:, script_code: 'Jpan', auto_generated: false,
+                           aliases: Array(aliases).sort.map { |alias_name|
+                             { name: alias_name, script_code: 'Jpan' }
+                           } } },
             parent_tag_ids: Array(parent_tags).map(&:id).join(' '),
             created_by_user: created_by_user,
             created_at: created_at)
@@ -211,7 +215,7 @@ RSpec.describe 'TagVersions API', type: :request do
     end
 
     it 'returns empty when the specified tag has no versions' do
-      fresh_tag = create(:tag, name: 'no_versions_tag', category: :general)
+      fresh_tag = create(:tag, primary_name: 'no_versions_tag', category: :general)
 
       get '/tags/versions', params: { id: fresh_tag.id }
 
@@ -232,8 +236,8 @@ 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 = TagName.create!(name: 'tag_versions_from_wiki')
-      wiki_tag = Tag.create!(tag_name: wiki_tag_name, category: :general)
+      wiki_tag_name = create(:tag_name, name: 'tag_versions_from_wiki')
+      wiki_tag = create(:tag, primary_tag_name: wiki_tag_name, category: :general)
 
       wiki_page =
           Wiki::Commit.create_content!(

backend/spec/requests/tag_wiki_history_integrity_spec.rb

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

backend/spec/requests/tags_deerjikists_spec.rb

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

backend/spec/requests/tags_spec.rb

@@ -2,13 +2,13 @@ require 'cgi'
 require 'rails_helper'
 
 RSpec.describe 'Tags API', type: :request do
-  let!(:tn) { TagName.create!(name: 'spec_tag') }
-  let!(:tag) { Tag.create!(tag_name: tn, category: :general) }
-  let!(:alias_tn) { TagName.create!(name: 'unko', canonical: tn) }
+  let!(:tn) { create(:tag_name, name: 'spec_tag') }
+  let!(:tag) { create(:tag, primary_tag_name: tn, category: :general) }
+  let!(:alias_tn) { create(:tag_name, :alias, name: 'unko', tag:) }
   let!(:post) { Post.create!(url: 'https://example.com/unkounkounko') }
   let!(:post_tag) { PostTag.create!(post:, tag:) }
-  let!(:tn2) { TagName.create!(name: 'unknown') }
-  let!(:tag2) { Tag.create!(tag_name: tn2, category: :general) }
+  let!(:tn2) { create(:tag_name, name: 'unknown') }
+  let!(:tag2) { create(:tag, primary_tag_name: tn2, category: :general) }
 
   def response_tags
     json.fetch('tags')
@@ -18,6 +18,14 @@ RSpec.describe 'Tags API', type: :request do
     response_tags.map { |t| t.fetch('name') }
   end
 
+  def version_primary_name(version, language_code)
+    version.names.fetch(language_code).fetch('name')
+  end
+
+  def version_alias_names(version, language_code)
+    version.names.fetch(language_code).fetch('aliases').pluck('name')
+  end
+
   def dummy_material_upload(filename: 'dummy.png', type: 'image/png', body: 'dummy')
     Rack::Test::UploadedFile.new(StringIO.new(body), type, original_filename: filename)
   end
@@ -38,7 +46,9 @@ RSpec.describe 'Tags API', type: :request do
       expect(response).to have_http_status(:ok)
       expect(json.fetch('count')).to eq(2)
       expect(response_tags).to contain_exactly(
-          a_hash_including('id' => tag.id, 'name' => tag.name, 'category' => 'general'),
+          a_hash_including('id' => tag.id,
+                           'name' => primary_tag_name_for(tag, 'ja').name,
+                           'category' => 'general'),
           a_hash_including(
               'id' => external.id,
               'name' => 'nico:spec_external',
@@ -91,7 +101,7 @@ RSpec.describe 'Tags API', type: :request do
     end
 
     it 'filters tags by category' do
-      meme = Tag.create!(tag_name: TagName.create!(name: 'meme_only'), category: :meme)
+      meme = create(:tag, primary_name: 'meme_only', category: :meme)
 
       get '/tags', params: { category: 'meme' }
 
@@ -101,30 +111,29 @@ RSpec.describe 'Tags API', type: :request do
     end
 
     it 'filters tags by deprecated state' do
-      deprecated_tag = Tag.create!(
-        name: 'deprecated_filter',
-        category: :general,
-        deprecated_at: 1.day.from_now
-      )
-      active_tag = Tag.create!(name: 'active_filter', category: :general)
+      deprecated_tag = create(:tag,
+          primary_name: 'deprecated_filter',
+          category: :general,
+          deprecated_at: 1.day.from_now)
+      active_tag = create(:tag, primary_name: 'active_filter', category: :general)
 
       get '/tags', params: { name: '_filter', deprecated: '1' }
 
       expect(response).to have_http_status(:ok)
-      expect(response_names).to include(deprecated_tag.name)
-      expect(response_names).not_to include(active_tag.name)
+      expect(response_names).to include(primary_tag_name_for(deprecated_tag, 'ja').name)
+      expect(response_names).not_to include(primary_tag_name_for(active_tag, 'ja').name)
 
       get '/tags', params: { name: '_filter', deprecated: '0' }
 
       expect(response).to have_http_status(:ok)
-      expect(response_names).to include(active_tag.name)
-      expect(response_names).not_to include(deprecated_tag.name)
+      expect(response_names).to include(primary_tag_name_for(active_tag, 'ja').name)
+      expect(response_names).not_to include(primary_tag_name_for(deprecated_tag, 'ja').name)
     end
 
     it 'filters tags by post_count range' do
-      low = Tag.create!(tag_name: TagName.create!(name: 'pc_low'), category: :general)
-      mid = Tag.create!(tag_name: TagName.create!(name: 'pc_mid'), category: :general)
-      high = Tag.create!(tag_name: TagName.create!(name: 'pc_high'), category: :general)
+      low = create(:tag, primary_name: 'pc_low', category: :general)
+      mid = create(:tag, primary_name: 'pc_mid', category: :general)
+      high = create(:tag, primary_name: 'pc_high', category: :general)
 
       low.update_columns(post_count: 1)
       mid.update_columns(post_count: 3)
@@ -142,8 +151,8 @@ RSpec.describe 'Tags API', type: :request do
     end
 
     it 'filters tags by created_at range' do
-      old_tag = Tag.create!(tag_name: TagName.create!(name: 'created_old'), category: :general)
-      new_tag = Tag.create!(tag_name: TagName.create!(name: 'created_new'), category: :general)
+      old_tag = create(:tag, primary_name: 'created_old', category: :general)
+      new_tag = create(:tag, primary_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)
@@ -162,8 +171,8 @@ RSpec.describe 'Tags API', type: :request do
     end
 
     it 'filters tags by updated_at range' do
-      old_tag = Tag.create!(tag_name: TagName.create!(name: 'updated_old'), category: :general)
-      new_tag = Tag.create!(tag_name: TagName.create!(name: 'updated_new'), category: :general)
+      old_tag = create(:tag, primary_name: 'updated_old', category: :general)
+      new_tag = create(:tag, primary_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)
@@ -182,12 +191,12 @@ RSpec.describe 'Tags API', type: :request do
     end
 
     it 'orders tags by custom category order' do
-      Tag.create!(tag_name: TagName.create!(name: 'cat_deerjikist'), category: :deerjikist)
-      Tag.create!(tag_name: TagName.create!(name: 'cat_meme'), category: :meme)
-      Tag.create!(tag_name: TagName.create!(name: 'cat_character'), category: :character)
-      Tag.create!(tag_name: TagName.create!(name: 'cat_general'), category: :general)
-      Tag.create!(tag_name: TagName.create!(name: 'cat_material'), category: :material)
-      Tag.create!(tag_name: TagName.create!(name: 'cat_meta'), category: :meta)
+      create(:tag, primary_name: 'cat_deerjikist', category: :deerjikist)
+      create(:tag, primary_name: 'cat_meme', category: :meme)
+      create(:tag, primary_name: 'cat_character', category: :character)
+      create(:tag, primary_name: 'cat_general', category: :general)
+      create(:tag, primary_name: 'cat_material', category: :material)
+      create(:tag, primary_name: 'cat_meta', category: :meta)
       create(:external_tag, name: 'cat_nico')
 
       get '/tags', params: { name: 'cat_', order: 'category:asc', limit: 20 }
@@ -202,20 +211,20 @@ 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'),
-               category: :meme)
+            primary_tag_name: create(:tag_name, name: 'a_mixed_page'),
+            category: :meme)
       end
 
       let!(:middle_tag) do
         create(:tag,
-               tag_name: create(:tag_name, name: 'm_mixed_page'),
-               category: :meta)
+            primary_tag_name: create(:tag_name, name: 'm_mixed_page'),
+            category: :meta)
       end
 
       let!(:last_tag) do
         create(:tag,
-               tag_name: create(:tag_name, name: 'z_mixed_page'),
-               category: :general)
+            primary_tag_name: create(:tag_name, name: 'z_mixed_page'),
+            category: :general)
       end
 
       let!(:first_external) do
@@ -265,7 +274,7 @@ RSpec.describe 'Tags API', type: :request do
 
     it 'paginates and keeps total count' do
       %w[pag_a pag_b pag_c].each do |name|
-        Tag.create!(tag_name: TagName.create!(name:), category: :general)
+        create(:tag, primary_tag_name: create(:tag_name, name:), category: :general)
       end
 
       get '/tags', params: { name: 'pag_', order: 'name:asc', page: 2, limit: 2 }
@@ -276,8 +285,8 @@ RSpec.describe 'Tags API', type: :request do
     end
 
     it 'falls back to default ordering when order is invalid' do
-      low = Tag.create!(tag_name: TagName.create!(name: 'fallback_low'), category: :general)
-      high = Tag.create!(tag_name: TagName.create!(name: 'fallback_high'), category: :general)
+      low = create(:tag, primary_name: 'fallback_low', category: :general)
+      high = create(:tag, primary_name: 'fallback_high', category: :general)
 
       low.update_columns(post_count: 1)
       high.update_columns(post_count: 9)
@@ -290,7 +299,7 @@ RSpec.describe 'Tags API', type: :request do
 
     it 'normalises invalid page and limit' do
       %w[norm_a norm_b].each do |name|
-        Tag.create!(tag_name: TagName.create!(name:), category: :general)
+        create(:tag, primary_tag_name: create(:tag_name, name:), category: :general)
       end
 
       get '/tags', params: { name: 'norm_', order: 'name:asc', page: 0, limit: 0 }
@@ -302,10 +311,9 @@ RSpec.describe 'Tags API', type: :request do
     end
 
     it 'returns aliases and parent tags' do
-      parent_tag = Tag.create!(
-        tag_name: TagName.create!(name: 'index_parent_tag'),
-        category: :meme
-      )
+      parent_tag = create(:tag,
+          primary_tag_name: create(:tag_name, name: 'index_parent_tag'),
+          category: :meme)
       TagImplication.create!(tag:, parent_tag:)
 
       get '/tags', params: { name: 'spec_tag' }
@@ -349,10 +357,9 @@ RSpec.describe 'Tags API', type: :request do
       end
 
       it 'returns aliases and parent tags' do
-        parent_tag = Tag.create!(
-          tag_name: TagName.create!(name: 'show_parent_tag'),
-          category: :character
-        )
+        parent_tag = create(:tag,
+            primary_tag_name: create(:tag_name, name: 'show_parent_tag'),
+            category: :character)
         TagImplication.create!(tag:, parent_tag:)
 
         request
@@ -398,7 +405,7 @@ RSpec.describe 'Tags API', type: :request do
     it 'prefers Tag when Tag and ExternalTag have the same id' do
       internal = create(
           :tag,
-          tag_name: create(:tag_name, name: 'internal_collision'))
+          primary_tag_name: create(:tag_name, name: 'internal_collision'))
       create(
           :external_tag,
           id: internal.id,
@@ -416,7 +423,7 @@ RSpec.describe 'Tags API', type: :request do
 
   describe 'GET /tags/autocomplete' do
     it 'combines internal and external matches without conflating equal ids' do
-      internal = Tag.create!(category: :general, name: 'mixed_internal', post_count: 2)
+      internal = create(:tag, category: :general, primary_name: 'mixed_internal', post_count: 2)
       external = create(:external_tag, id: internal.id,
                                        name: 'mixed_external', post_count: 3)
 
@@ -455,7 +462,7 @@ 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') }"
-        Tag.create!(category: :general, name:, post_count: 1)
+        create(:tag, category: :general, primary_name: name, post_count: 1)
         create(:external_tag, name:, post_count: 1)
       end
 
@@ -467,34 +474,39 @@ RSpec.describe 'Tags API', type: :request do
     end
 
     it 'excludes external tags but preserves internal alias matches when nico is false' do
-      internal = Tag.create!(category: :general, name: 'switch_internal', post_count: 1)
-      alias_target = Tag.create!(category: :general, name: 'alias_target', post_count: 1)
-      TagName.create!(name: 'switch_alias', canonical: alias_target.tag_name)
+      internal = create(:tag, category: :general, primary_name: 'switch_internal', post_count: 1)
+      alias_target = create(:tag, category: :general, primary_name: 'alias_target', post_count: 1)
+      create(:tag_name, :alias, name: 'switch_alias', tag: alias_target)
       create(:external_tag, name: 'switch_external', post_count: 1)
 
       get '/tags/autocomplete', params: { q: 'switch', nico: '0' }
 
       expect(response).to have_http_status(:ok)
       expect(json).to contain_exactly(
-          a_hash_including('id' => internal.id, 'name' => internal.name),
-          a_hash_including('id' => alias_target.id, 'name' => alias_target.name,
+          a_hash_including('id' => internal.id,
+                           'name' => primary_tag_name_for(internal, 'ja').name),
+          a_hash_including('id' => alias_target.id,
+                           'name' => primary_tag_name_for(alias_target, 'ja').name,
                            'matched_alias' => 'switch_alias'))
     end
 
     ['%', '_'].each do |wildcard|
-      it "treats #{ wildcard } literally for canonical, alias, and external names" do
+      it "treats #{ wildcard } literally for primary, alias, and external names" do
         literal = "literal#{ wildcard }match"
-        Tag.create!(category: :general, name: literal, post_count: 1)
-        alias_target = Tag.create!(category: :general, name: 'literal_alias_target', post_count: 1)
-        TagName.create!(name: "#{ literal }_alias", canonical: alias_target.tag_name)
+        create(:tag, category: :general, primary_name: literal, post_count: 1)
+        alias_target = create(
+            :tag, category: :general, primary_name: 'literal_alias_target', post_count: 1)
+        create(:tag_name, :alias, name: "#{ literal }_alias",
+                                  tag: alias_target)
         create(:external_tag, name: literal, post_count: 1)
-        Tag.create!(category: :general, name: 'literalXmatch', post_count: 2)
+        create(:tag, category: :general, primary_name: 'literalXmatch', post_count: 2)
         create(:external_tag, name: 'literalXmatch', post_count: 2)
 
         get '/tags/autocomplete', params: { q: "literal#{ wildcard }" }
 
         expect(json.map { |row| row.fetch('name') })
-            .to contain_exactly(literal, alias_target.name, "nico:#{ literal }")
+            .to contain_exactly(
+                literal, primary_tag_name_for(alias_target, 'ja').name, "nico:#{ literal }")
       end
     end
 
@@ -510,7 +522,7 @@ RSpec.describe 'Tags API', type: :request do
       expect(t['matched_alias']).to be(nil)
     end
 
-    it 'returns matching canonical tags by q with aliases' do
+    it 'returns matching primary tag names by q with aliases' do
       get '/tags/autocomplete', params: { q: 'unk' }
 
       expect(response).to have_http_status(:ok)
@@ -523,11 +535,10 @@ RSpec.describe 'Tags API', type: :request do
     end
 
     it 'omits deprecated tags' do
-      deprecated_tag = Tag.create!(
-        name: 'spec_deprecated',
-        category: :general,
-        deprecated_at: Time.current
-      )
+      deprecated_tag = create(:tag,
+          primary_name: 'spec_deprecated',
+          category: :general,
+          deprecated_at: Time.current)
       deprecated_tag.update_columns(post_count: 1)
 
       get '/tags/autocomplete', params: { q: 'spec_', present: '0' }
@@ -621,7 +632,7 @@ RSpec.describe 'Tags API', type: :request do
         expect(response).to have_http_status(:ok)
 
         tag.reload
-        expect(tag.name).to eq('new')
+        expect(primary_tag_name_for(tag, 'ja').name).to eq('new')
         expect(tag.category).to eq('general')
 
         body = JSON.parse(response.body)
@@ -636,7 +647,7 @@ RSpec.describe 'Tags API', type: :request do
         expect(response).to have_http_status(:ok)
 
         tag.reload
-        expect(tag.name).to eq('spec_tag')
+        expect(primary_tag_name_for(tag, 'ja').name).to eq('spec_tag')
         expect(tag.category).to eq('meme')
       end
 
@@ -646,7 +657,7 @@ RSpec.describe 'Tags API', type: :request do
         expect(response).to have_http_status(:ok)
 
         tag.reload
-        expect(tag.name).to eq('spec_tag')
+        expect(primary_tag_name_for(tag, 'ja').name).to eq('spec_tag')
         expect(tag.category).to eq('general')
       end
 
@@ -656,7 +667,7 @@ RSpec.describe 'Tags API', type: :request do
         expect(response).to have_http_status(:ok)
 
         tag.reload
-        expect(tag.name).to eq('n')
+        expect(primary_tag_name_for(tag, 'ja').name).to eq('n')
         expect(tag.category).to eq('meta')
       end
 
@@ -669,7 +680,7 @@ RSpec.describe 'Tags API', type: :request do
         patch "/tags/#{tag.id}", params: { name: 'new', category: 'nico' }
 
         expect(response).to have_http_status(:unprocessable_entity)
-        expect(tag.reload.name).to eq('spec_tag')
+        expect(primary_tag_name_for(tag.reload, 'ja').name).to eq('spec_tag')
         expect(tag.category).to eq('general')
       end
 
@@ -684,11 +695,11 @@ RSpec.describe 'Tags API', type: :request do
 
         expect(versions.map(&:event_type)).to eq(['create', 'update'])
 
-        expect(versions.first.name).to eq('spec_tag')
+        expect(version_primary_name(versions.first, 'ja')).to eq('spec_tag')
         expect(versions.first.category).to eq('general')
-        expect(versions.first.aliases.split).to include('unko')
+        expect(version_alias_names(versions.first, 'ja')).to include('unko')
 
-        expect(versions.second.name).to eq('new_tag_name')
+        expect(version_primary_name(versions.second, 'ja')).to eq('new_tag_name')
         expect(versions.second.category).to eq('meme')
         expect(versions.second.created_by_user_id).to eq(member_user.id)
       end
@@ -719,7 +730,7 @@ RSpec.describe 'Tags API', type: :request do
       it 'PATCH で tag の name を変更すると対応する wiki version を作成する' do
         wiki_page =
             Wiki::Commit.create_content!(
-                tag_name: tag.tag_name,
+                tag_name: primary_tag_name_for(tag, 'ja'),
                 body: 'wiki body before',
                 created_by_user: member_user,
                 message: 'init')
@@ -747,7 +758,7 @@ RSpec.describe 'Tags API', type: :request do
       it 'tag の category だけを変更しても wiki version は作成しない' do
         wiki_page =
             Wiki::Commit.create_content!(
-                tag_name: tag.tag_name,
+                tag_name: primary_tag_name_for(tag, 'ja'),
                 body: 'wiki body before',
                 created_by_user: member_user,
                 message: 'init')
@@ -774,7 +785,8 @@ RSpec.describe 'Tags API', type: :request do
         }
 
         expect(response).to have_http_status(:ok)
-        expect(TagName.find_by!(name: 'spec_tag').canonical).to eq(tag.reload.tag_name)
+        expect(TagName.find_by!(language_code: 'ja', name: 'spec_tag'))
+            .to have_attributes(tag_id: tag.id, primary_flg: false)
 
         patch "/tags/#{ tag.id }", params: { name: 'spec_tag' }
 
@@ -782,15 +794,17 @@ RSpec.describe 'Tags API', type: :request do
 
         tag.reload
 
-        expect(tag.name).to eq('spec_tag')
-        expect(tag.tag_name.canonical_id).to be_nil
-        expect(TagName.find_by!(name: 'patch_roundtrip_target').canonical).to eq(tag.tag_name)
+        expect(primary_tag_name_for(tag, 'ja').name).to eq('spec_tag')
+        expect(primary_tag_name_for(tag, 'ja')).to have_attributes(
+            tag_id: tag.id, language_code: 'ja', primary_flg: true)
+        expect(TagName.find_by!(language_code: 'ja', name: 'patch_roundtrip_target'))
+            .to have_attributes(tag_id: tag.id, primary_flg: false)
       end
 
       it '別 tag の正規名には変更できない' do
         wiki_page =
             Wiki::Commit.create_content!(
-                tag_name: tag.tag_name,
+                tag_name: primary_tag_name_for(tag, 'ja'),
                 body: 'patch collision wiki',
                 created_by_user: member_user,
                 message: 'init')
@@ -802,9 +816,10 @@ RSpec.describe 'Tags API', type: :request do
           'name' => ['その名前は既に使はれてゐます．']
         )
 
-        expect(tag.reload.name).to eq('spec_tag')
-        expect(tag.tag_name.aliases.map(&:name)).to contain_exactly('unko')
-        expect(wiki_page.reload.tag_name).to eq(tag.tag_name)
+        expect(primary_tag_name_for(tag.reload, 'ja').name).to eq('spec_tag')
+        expect(TagName.where(tag_id: tag.id, language_code: 'ja', primary_flg: false).pluck(:name))
+            .to contain_exactly('unko')
+        expect(wiki_page.reload.tag_name).to eq(primary_tag_name_for(tag, 'ja'))
       end
 
       it 'system tag の name は変更できない' do
@@ -813,34 +828,34 @@ RSpec.describe 'Tags API', type: :request do
         patch "/tags/#{ system_tag.id }", params: { name: 'patch_system_tag_renamed' }
 
         expect(response).to have_http_status(:unprocessable_entity)
-        expect(system_tag.reload.name).to eq('bot操作')
+        expect(primary_tag_name_for(system_tag.reload, 'ja').name).to eq('bot操作')
       end
     end
   end
 
   describe 'GET /tags/with-depth' do
     let!(:root_meme) do
-      Tag.create!(tag_name: TagName.create!(name: 'depth_a_root_meme'), category: :meme)
+      create(:tag, primary_name: 'depth_a_root_meme', category: :meme)
     end
 
     let!(:root_material) do
-      Tag.create!(tag_name: TagName.create!(name: 'depth_b_root_material'), category: :material)
+      create(:tag, primary_name: 'depth_b_root_material', category: :material)
     end
 
     let!(:hidden_general_root) do
-      Tag.create!(tag_name: TagName.create!(name: 'depth_hidden_general_root'), category: :general)
+      create(:tag, primary_name: 'depth_hidden_general_root', category: :general)
     end
 
     let!(:child_character) do
-      Tag.create!(tag_name: TagName.create!(name: 'depth_child_character'), category: :character)
+      create(:tag, primary_name: 'depth_child_character', category: :character)
     end
 
     let!(:grandchild_material) do
-      Tag.create!(tag_name: TagName.create!(name: 'depth_grandchild_material'), category: :material)
+      create(:tag, primary_name: 'depth_grandchild_material', category: :material)
     end
 
     let!(:child_general) do
-      Tag.create!(tag_name: TagName.create!(name: 'depth_child_general'), category: :general)
+      create(:tag, primary_name: 'depth_child_general', category: :general)
     end
 
     before do
@@ -883,15 +898,13 @@ RSpec.describe 'Tags API', type: :request do
     end
 
     it 'passes through deprecated tags when finding children' do
-      deprecated_middle = Tag.create!(
-        name: 'depth_deprecated_middle',
-        category: :character,
-        deprecated_at: Time.current
-      )
-      visible_descendant = Tag.create!(
-        name: 'depth_visible_descendant',
-        category: :material
-      )
+      deprecated_middle = create(:tag,
+          primary_name: 'depth_deprecated_middle',
+          category: :character,
+          deprecated_at: Time.current)
+      visible_descendant = create(:tag,
+          primary_name: 'depth_visible_descendant',
+          category: :material)
       TagImplication.create!(parent_tag: root_material, tag: deprecated_middle)
       TagImplication.create!(parent_tag: deprecated_middle, tag: visible_descendant)
 
@@ -903,24 +916,20 @@ RSpec.describe 'Tags API', type: :request do
     end
 
     it 'passes through multiple deprecated tags for roots and has_children' do
-      active_child = Tag.create!(
-        name: 'depth_active_child_below_deprecated',
-        category: :character
-      )
-      deprecated_parent = Tag.create!(
-        name: 'depth_deprecated_parent',
-        category: :character,
-        deprecated_at: Time.current
-      )
-      deprecated_grandparent = Tag.create!(
-        name: 'depth_deprecated_grandparent',
-        category: :material,
-        deprecated_at: Time.current
-      )
-      active_ancestor = Tag.create!(
-        name: 'depth_active_ancestor',
-        category: :meme
-      )
+      active_child = create(:tag,
+          primary_name: 'depth_active_child_below_deprecated',
+          category: :character)
+      deprecated_parent = create(:tag,
+          primary_name: 'depth_deprecated_parent',
+          category: :character,
+          deprecated_at: Time.current)
+      deprecated_grandparent = create(:tag,
+          primary_name: 'depth_deprecated_grandparent',
+          category: :material,
+          deprecated_at: Time.current)
+      active_ancestor = create(:tag,
+          primary_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)
@@ -945,15 +954,13 @@ RSpec.describe 'Tags API', type: :request do
     end
 
     it 'treats an active tag with only deprecated ancestors as a root' do
-      active_child = Tag.create!(
-        name: 'depth_root_below_deprecated',
-        category: :character
-      )
-      deprecated_parent = Tag.create!(
-        name: 'depth_root_deprecated_parent',
-        category: :material,
-        deprecated_at: Time.current
-      )
+      active_child = create(:tag,
+          primary_name: 'depth_root_below_deprecated',
+          category: :character)
+      deprecated_parent = create(:tag,
+          primary_name: 'depth_root_deprecated_parent',
+          category: :material,
+          deprecated_at: Time.current)
       TagImplication.create!(tag: active_child, parent_tag: deprecated_parent)
 
       get '/tags/with-depth'
@@ -967,16 +974,14 @@ RSpec.describe 'Tags API', type: :request do
     end
 
     it 'terminates when deprecated implications contain a cycle' do
-      first = Tag.create!(
-        name: 'depth_cycle_first',
-        category: :character,
-        deprecated_at: Time.current
-      )
-      second = Tag.create!(
-        name: 'depth_cycle_second',
-        category: :material,
-        deprecated_at: Time.current
-      )
+      first = create(:tag,
+          primary_name: 'depth_cycle_first',
+          category: :character,
+          deprecated_at: Time.current)
+      second = create(:tag,
+          primary_name: 'depth_cycle_second',
+          category: :material,
+          deprecated_at: Time.current)
       TagImplication.create!(tag: first, parent_tag: root_material)
       TagImplication.create!(tag: second, parent_tag: first)
       now = Time.current
@@ -1002,19 +1007,19 @@ RSpec.describe 'Tags API', type: :request do
     let!(:material_user) { create_member_user! }
 
     let!(:root_tag) do
-      Tag.create!(tag_name: TagName.create!(name: 'materials_root'), category: :material)
+      create(:tag, primary_name: 'materials_root', category: :material)
     end
 
     let!(:child_a_tag) do
-      Tag.create!(tag_name: TagName.create!(name: 'materials_child_a'), category: :material)
+      create(:tag, primary_name: 'materials_child_a', category: :material)
     end
 
     let!(:child_b_tag) do
-      Tag.create!(tag_name: TagName.create!(name: 'materials_child_b'), category: :character)
+      create(:tag, primary_name: 'materials_child_b', category: :character)
     end
 
     let!(:grandchild_tag) do
-      Tag.create!(tag_name: TagName.create!(name: 'materials_grandchild'), category: :material)
+      create(:tag, primary_name: 'materials_grandchild', category: :material)
     end
 
     let!(:root_material) do
@@ -1036,7 +1041,7 @@ RSpec.describe 'Tags API', type: :request do
     end
 
     it 'returns a tag tree with nested materials sorted by child name' do
-      get "/tags/name/#{ CGI.escape(root_tag.name) }/materials"
+      get "/tags/name/#{ CGI.escape(primary_tag_name_for(root_tag, 'ja').name) }/materials"
 
       expect(response).to have_http_status(:ok)
 
@@ -1127,7 +1132,7 @@ RSpec.describe 'Tags API', type: :request do
         }
 
         expect(response).to have_http_status(:unprocessable_entity)
-        expect(tag.reload.name).to eq('spec_tag')
+        expect(primary_tag_name_for(tag.reload, 'ja').name).to eq('spec_tag')
       end
 
       it 'category が空なら 422 を返す' do
@@ -1139,7 +1144,7 @@ RSpec.describe 'Tags API', type: :request do
         }
 
         expect(response).to have_http_status(:unprocessable_entity)
-        expect(tag.reload.name).to eq('spec_tag')
+        expect(primary_tag_name_for(tag.reload, 'ja').name).to eq('spec_tag')
         expect(tag.category).to eq('general')
       end
 
@@ -1158,14 +1163,12 @@ 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 = Tag.create!(
-          tag_name: TagName.create!(name: 'put_old_parent'),
-          category: :general
-        )
-        kept_parent = Tag.create!(
-          tag_name: TagName.create!(name: 'put_kept_parent'),
-          category: :general
-        )
+        old_parent = create(:tag,
+            primary_tag_name: create(:tag_name, name: 'put_old_parent'),
+            category: :general)
+        kept_parent = create(:tag,
+            primary_tag_name: create(:tag_name, name: 'put_kept_parent'),
+            category: :general)
         TagImplication.create!(tag:, parent_tag: old_parent)
         TagImplication.create!(tag:, parent_tag: kept_parent)
 
@@ -1181,22 +1184,24 @@ RSpec.describe 'Tags API', type: :request do
 
         tag.reload
 
-        expect(tag.name).to eq('put_renamed_tag')
+        expect(primary_tag_name_for(tag, 'ja').name).to eq('put_renamed_tag')
         expect(tag.category).to eq('meme')
 
-        expect(TagName.find_by(name: 'put_alias_a').canonical).to eq(tag.tag_name)
-        expect(TagName.find_by(name: 'put_alias_b').canonical).to eq(tag.tag_name)
+        expect(TagName.find_by!(language_code: 'ja', name: 'put_alias_a'))
+            .to have_attributes(tag_id: tag.id, primary_flg: false)
+        expect(TagName.find_by!(language_code: 'ja', name: 'put_alias_b'))
+            .to have_attributes(tag_id: tag.id, primary_flg: false)
 
-        old_name_alias = TagName.find_by(name: 'spec_tag')
+        old_name_alias = TagName.find_by(language_code: 'ja', name: 'spec_tag')
         expect(old_name_alias).to be_present
-        expect(old_name_alias.canonical).to eq(tag.tag_name)
+        expect(old_name_alias).to have_attributes(
+            tag_id: tag.id, language_code: 'ja', primary_flg: false)
 
-        expect(alias_tn.reload.canonical).to be_nil
+        expect(alias_tn.reload.tag_id).to be_nil
 
-        expect(tag.parents.map(&:name)).to contain_exactly(
-          'put_kept_parent',
-          'put_new_parent'
-        )
+        expect(TagName.where(tag_id: tag.parents.select(:id),
+                             language_code: 'ja', primary_flg: true).pluck(:name))
+            .to contain_exactly('put_kept_parent', 'put_new_parent')
 
         expect(TagImplication.where(tag:, parent_tag: old_parent)).not_to exist
 
@@ -1226,7 +1231,8 @@ RSpec.describe 'Tags API', type: :request do
 
         tag.reload
 
-        expect(TagName.find_by(name: 'put_alias_self_test').canonical).to eq(tag.tag_name)
+        expect(TagName.find_by!(language_code: 'ja', name: 'put_alias_self_test'))
+            .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
@@ -1263,13 +1269,13 @@ RSpec.describe 'Tags API', type: :request do
 
         expect(versions.map(&:event_type)).to eq(['create', 'update'])
 
-        expect(versions.first.name).to eq('spec_tag')
+        expect(version_primary_name(versions.first, 'ja')).to eq('spec_tag')
         expect(versions.first.category).to eq('general')
-        expect(versions.first.aliases.split).to include('unko')
+        expect(version_alias_names(versions.first, 'ja')).to include('unko')
 
-        expect(versions.second.name).to eq('put_versioned_tag')
+        expect(version_primary_name(versions.second, 'ja')).to eq('put_versioned_tag')
         expect(versions.second.category).to eq('meta')
-        expect(versions.second.aliases.split).to include('spec_tag')
+        expect(version_alias_names(versions.second, 'ja')).to include('spec_tag')
         expect(versions.second.created_by_user_id).to eq(member_user.id)
       end
 
@@ -1296,35 +1302,37 @@ RSpec.describe 'Tags API', type: :request do
 
         tag.reload
 
-        expect(tag.name).to eq('spec_tag')
-        expect(TagName.find_by!(name: 'put_roundtrip_b').canonical).to eq(tag.tag_name)
-        expect(tag.tag_name.aliases.map(&:name)).to contain_exactly('put_roundtrip_b', 'unko')
-        expect(tag.tag_name.aliases.map(&:name)).not_to include('spec_tag')
-        expect(alias_tn.reload.canonical).to eq(tag.tag_name)
+        expect(primary_tag_name_for(tag, 'ja').name).to eq('spec_tag')
+        expect(TagName.find_by!(language_code: 'ja', name: 'put_roundtrip_b'))
+            .to have_attributes(tag_id: tag.id, primary_flg: false)
+        expect(TagName.where(tag_id: tag.id, language_code: 'ja', primary_flg: false).pluck(:name))
+            .to contain_exactly('put_roundtrip_b', 'unko')
+        expect(TagName.where(tag_id: tag.id, language_code: 'ja', primary_flg: false).pluck(:name))
+            .not_to include('spec_tag')
+        expect(alias_tn.reload).to have_attributes(
+            tag_id: tag.id, language_code: 'ja', primary_flg: false)
 
         version = tag.tag_versions.order(:version_no).last
 
         expect(version.event_type).to eq('update')
-        expect(version.name).to eq('spec_tag')
-        expect(version.aliases.split).to contain_exactly('put_roundtrip_b', 'unko')
+        expect(version_primary_name(version, 'ja')).to eq('spec_tag')
+        expect(version_alias_names(version, 'ja')).to contain_exactly('put_roundtrip_b', 'unko')
       end
 
       it 'parent tag の snapshot も作成する' do
-        old_parent = Tag.create!(
-          tag_name: TagName.create!(name: 'put_snapshot_old_parent'),
-          category: :general
-        )
-        new_parent = Tag.create!(
-          tag_name: TagName.create!(name: 'put_snapshot_new_parent'),
-          category: :general
-        )
+        old_parent = create(:tag,
+            primary_tag_name: create(:tag_name, name: 'put_snapshot_old_parent'),
+            category: :general)
+        new_parent = create(:tag,
+            primary_tag_name: create(:tag_name, name: 'put_snapshot_new_parent'),
+            category: :general)
         TagImplication.create!(tag:, parent_tag: old_parent)
 
         put "/tags/#{ tag.id }", params: {
           name: 'spec_tag',
           category: 'general',
           aliases: 'unko',
-          parent_tags: new_parent.name,
+          parent_tags: primary_tag_name_for(new_parent, 'ja').name,
           deprecated: '0',
         }
 
@@ -1347,13 +1355,13 @@ RSpec.describe 'Tags API', type: :request do
 
         expect(response).to have_http_status(:unprocessable_entity)
 
-        expect(tag.reload.name).to eq('spec_tag')
+        expect(primary_tag_name_for(tag.reload, 'ja').name).to eq('spec_tag')
         expect(tag.category).to eq('general')
       end
 
       it 'system tag の name は変更できない' do
         system_tag = Tag.tagme
-        old_name = system_tag.name
+        old_name = primary_tag_name_for(system_tag, 'ja').name
         old_category = system_tag.category
 
         expect {
@@ -1368,14 +1376,14 @@ RSpec.describe 'Tags API', type: :request do
 
         expect(response).to have_http_status(:unprocessable_entity)
 
-        expect(system_tag.reload.name).to eq(old_name)
+        expect(primary_tag_name_for(system_tag.reload, 'ja').name).to eq(old_name)
         expect(system_tag.category).to eq(old_category)
       end
 
       it 'wiki を持つ tag を更新すると wiki version も作成する' do
         wiki_page =
             Wiki::Commit.create_content!(
-                tag_name: tag.tag_name,
+                tag_name: primary_tag_name_for(tag, 'ja'),
                 body: 'wiki body before',
                 created_by_user: member_user,
                 message: 'init')
@@ -1411,10 +1419,10 @@ RSpec.describe 'Tags API', type: :request do
         )
       end
 
-      it 'wiki を持つ tag を旧 alias へ戻しても wiki を新 canonical へ移す' do
+      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
         wiki_page =
             Wiki::Commit.create_content!(
-                tag_name: tag.tag_name,
+                tag_name: primary_tag_name_for(tag, 'ja'),
                 body: 'wiki body before',
                 created_by_user: member_user,
                 message: 'init')
@@ -1443,9 +1451,11 @@ RSpec.describe 'Tags API', type: :request do
 
         tag.reload
 
-        expect(wiki_page.reload.tag_name).to eq(tag.tag_name)
-        expect(TagName.find_by!(name: 'put_wiki_roundtrip_b').wiki_page).to be_nil
-        expect(TagName.find_by!(name: 'put_wiki_roundtrip_b').canonical).to eq(tag.tag_name)
+        expect(wiki_page.reload.tag_name).to eq(primary_tag_name_for(tag, 'ja'))
+        expect(TagName.find_by!(language_code: 'ja', name: 'put_wiki_roundtrip_b').wiki_page)
+            .to be_nil
+        expect(TagName.find_by!(language_code: 'ja', name: 'put_wiki_roundtrip_b'))
+            .to have_attributes(tag_id: tag.id, primary_flg: false)
 
         versions = wiki_page.wiki_versions.order(:version_no).last(2)
 
@@ -1454,16 +1464,16 @@ 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 = Tag.create!(
-          tag_name: TagName.create!(name: 'put_alias_old_owner'),
-          category: :general
-        )
-        stolen_alias = TagName.create!(
-          name: 'put_stolen_alias',
-          canonical: old_owner.tag_name
-        )
+        old_owner = create(:tag,
+            primary_tag_name: create(:tag_name, name: 'put_alias_old_owner'),
+            category: :general)
+        stolen_alias = create(:tag_name, :alias,
+            name: 'put_stolen_alias',
+            tag: old_owner)
 
-        expect(old_owner.tag_name.aliases.map(&:name)).to include('put_stolen_alias')
+        expect(TagName.where(tag_id: old_owner.id, language_code: 'ja',
+                              primary_flg: false).pluck(:name))
+            .to include('put_stolen_alias')
 
         expect {
           put "/tags/#{ tag.id }", params: {
@@ -1479,30 +1489,32 @@ RSpec.describe 'Tags API', type: :request do
 
         expect(response).to have_http_status(:ok)
 
-        expect(stolen_alias.reload.canonical).to eq(tag.tag_name)
-        expect(old_owner.reload.tag_name.aliases.map(&:name)).not_to include('put_stolen_alias')
+        expect(stolen_alias.reload).to have_attributes(
+            tag_id: tag.id, language_code: 'ja', primary_flg: false)
+        expect(TagName.where(tag_id: old_owner.id, language_code: 'ja',
+                              primary_flg: false).pluck(:name))
+            .not_to include('put_stolen_alias')
 
         old_owner_versions = old_owner.tag_versions.order(:version_no)
 
         expect(old_owner_versions.first.event_type).to eq('create')
-        expect(old_owner_versions.first.aliases.split).to include('put_stolen_alias')
+        expect(version_alias_names(old_owner_versions.first, 'ja')).to include('put_stolen_alias')
 
         expect(old_owner_versions.second.event_type).to eq('update')
-        expect(old_owner_versions.second.aliases.split).not_to include('put_stolen_alias')
+        expect(version_alias_names(old_owner_versions.second, 'ja'))
+            .not_to include('put_stolen_alias')
       end
 
       it '別 tag の alias 名を rename で奪へる' do
-        old_owner = Tag.create!(
-          tag_name: TagName.create!(name: 'put_alias_collision_owner'),
-          category: :general
-        )
-        stolen_alias = TagName.create!(
-          name: 'put_alias_collision_name',
-          canonical: old_owner.tag_name
-        )
+        old_owner = create(:tag,
+            primary_tag_name: create(:tag_name, name: 'put_alias_collision_owner'),
+            category: :general)
+        stolen_alias = create(:tag_name, :alias,
+            name: 'put_alias_collision_name',
+            tag: old_owner)
         wiki_page =
             Wiki::Commit.create_content!(
-                tag_name: tag.tag_name,
+                tag_name: primary_tag_name_for(tag, 'ja'),
                 body: 'put collision wiki',
                 created_by_user: member_user,
                 message: 'init')
@@ -1515,29 +1527,33 @@ RSpec.describe 'Tags API', type: :request do
           deprecated: '0',
         }
 
-        expect(response).to have_http_status(:ok)
+        expect(response).to have_http_status(:ok), response.body
 
         tag.reload
         old_owner.reload
         stolen_alias.reload
 
-        expect(tag.name).to eq('put_alias_collision_name')
-        expect(stolen_alias.canonical_id).to be_nil
-        expect(TagName.find_by!(name: 'spec_tag').canonical).to eq(tag.tag_name)
-        expect(old_owner.tag_name.aliases.map(&:name)).not_to include('put_alias_collision_name')
+        expect(primary_tag_name_for(tag, 'ja').name).to eq('put_alias_collision_name')
+        expect(stolen_alias).to have_attributes(
+            tag_id: tag.id, language_code: 'ja', primary_flg: true)
+        expect(TagName.find_by!(language_code: 'ja', name: 'spec_tag'))
+            .to have_attributes(tag_id: tag.id, primary_flg: false)
+        expect(TagName.where(tag_id: old_owner.id, language_code: 'ja',
+                              primary_flg: false).pluck(:name))
+            .not_to include('put_alias_collision_name')
 
         old_owner_versions = old_owner.tag_versions.order(:version_no)
 
         expect(old_owner_versions.last.event_type).to eq('update')
-        expect(old_owner_versions.last.aliases.split).not_to include('put_alias_collision_name')
-        expect(wiki_page.reload.tag_name).to eq(tag.tag_name)
+        expect(version_alias_names(old_owner_versions.last, 'ja'))
+            .not_to include('put_alias_collision_name')
+        expect(wiki_page.reload.tag_name).to eq(primary_tag_name_for(tag, 'ja'))
       end
 
       it 'parent_tags に指定すると循環する tag は 422 にする' do
-        child = Tag.create!(
-          tag_name: TagName.create!(name: 'put_cycle_child'),
-          category: :general
-        )
+        child = create(:tag,
+            primary_tag_name: create(:tag_name, name: 'put_cycle_child'),
+            category: :general)
 
         TagImplication.create!(tag: child, parent_tag: tag)
 
@@ -1545,7 +1561,7 @@ RSpec.describe 'Tags API', type: :request do
           name: 'spec_tag',
           category: 'general',
           aliases: 'unko',
-          parent_tags: child.name,
+          parent_tags: primary_tag_name_for(child, 'ja').name,
           deprecated: '0',
         }
 
@@ -1557,7 +1573,7 @@ RSpec.describe 'Tags API', type: :request do
       it 'tag の name を変更すると対応する wiki version を作成する' do
         wiki_page =
             Wiki::Commit.create_content!(
-                tag_name: tag.tag_name,
+                tag_name: primary_tag_name_for(tag, 'ja'),
                 body: 'wiki body before',
                 created_by_user: member_user,
                 message: 'init')

backend/spec/requests/theatres_spec.rb

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

backend/spec/requests/wiki_conflict_spec.rb

@@ -10,7 +10,7 @@ RSpec.describe 'Wiki conflict handling', type: :request do
   it 'returns 409 when base_revision_id is stale' do
     page =
         Wiki::Commit.create_content!(
-            tag_name: TagName.create!(name: 'wiki_conflict_request'),
+            tag_name: create(:tag_name, 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: TagName.create!(name: title),
+        tag_name: create(:tag_name, 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) { TagName.create!(name: 'spec_wiki_title') }
+  let!(:tn) { create(:tag_name, name: 'spec_wiki_title') }
   let!(:page) do
     Wiki::Commit.create_content!(
         tag_name: tn,
@@ -19,11 +19,10 @@ RSpec.describe 'Wiki API', type: :request do
         message: 'init')
   end
   let!(:tag) do
-    Tag.create!(
-      tag_name: tn,
-      category: :general,
-      deprecated_at: Time.zone.local(2026, 6, 1)
-    )
+    create(:tag,
+        primary_tag_name: tn,
+        category: :general,
+        deprecated_at: Time.zone.local(2026, 6, 1))
   end
 
   describe 'GET /wiki' do
@@ -208,7 +207,7 @@ RSpec.describe 'Wiki API', type: :request do
       { 'X-Transfer-Code' => user.inheritance_code }
     end
 
-    let!(:test_tag_name) { TagName.create!(name: 'TestPage') }
+    let!(:test_tag_name) { create(:tag_name, name: 'TestPage') }
 
     let!(:page) do
       Wiki::Commit.create_content!(
@@ -275,8 +274,8 @@ 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 = TagName.create!(name: 'wiki_body_only_tag')
-        linked_tag = Tag.create!(tag_name: linked_tag_name, category: :general)
+        linked_tag_name = create(:tag_name, name: 'wiki_body_only_tag')
+        linked_tag = create(:tag, primary_tag_name: linked_tag_name, category: :general)
 
         TagVersionRecorder.record!(
             tag: linked_tag,
@@ -359,13 +358,13 @@ RSpec.describe 'Wiki API', type: :request do
   describe 'GET /wiki/search' do
     before do
       Wiki::Commit.create_content!(
-          tag_name: TagName.create!(name: 'spec_wiki_title_2'),
+          tag_name: create(:tag_name, name: 'spec_wiki_title_2'),
           body: 'search body 2',
           created_by_user: user,
           message: 'init')
 
       Wiki::Commit.create_content!(
-          tag_name: TagName.create!(name: 'unrelated_title'),
+          tag_name: create(:tag_name, name: 'unrelated_title'),
           body: 'unrelated body',
           created_by_user: user,
           message: 'init')
@@ -434,7 +433,7 @@ 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 = TagName.create!(name: 'spec_no_rev')
+      tn2 = create(:tag_name, name: 'spec_no_rev')
       # 異常データ: revision 無し WikiPage を直接作る
       p2 = WikiPage.create!(
           tag_name: tn2,
@@ -514,7 +513,7 @@ RSpec.describe 'Wiki API', type: :request do
 
   describe 'Wiki::Commit.redirect!' do
     it 'raises because redirect revisions are deprecated' do
-      target_tag_name = TagName.create!(name: 'redirect_deprecated_target')
+      target_tag_name = create(:tag_name, name: 'redirect_deprecated_target')
       target =
           Wiki::Commit.create_content!(
               tag_name: target_tag_name,
@@ -535,8 +534,8 @@ 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 = TagName.create!(name: 'wiki_linked_tag_for_version')
-    linked_tag = Tag.create!(tag_name: linked_tag_name, category: :general)
+    linked_tag_name = create(:tag_name, name: 'wiki_linked_tag_for_version')
+    linked_tag = create(:tag, primary_tag_name: linked_tag_name, category: :general)
 
     linked_page =
         Wiki::Commit.create_content!(
@@ -564,7 +563,8 @@ RSpec.describe 'Wiki API', type: :request do
     expect(response).to have_http_status(:ok)
 
     linked_tag.reload
-    expect(linked_tag.name).to eq('wiki_linked_tag_for_version_renamed')
+    expect(primary_tag_name_for(linked_tag, 'ja').name)
+        .to eq('wiki_linked_tag_for_version_renamed')
 
     versions = linked_tag.tag_versions.order(:version_no)
 

backend/spec/requests/wiki_title_collision_spec.rb

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