#428

backend/app/controllers/materials_controller.rb

@@ -255,7 +255,8 @@ class MaterialsController < ApplicationController
   end
 
   def resolve_material_tag! locale, tag_name_raw
-    Tag.find_or_create_by_tag_name!(locale, tag_name_raw, category: :material)
+    Tag.find_or_create_by_tag_name!(locale, tag_name_raw, category: :material,
+                                   created_by_user: current_user)
   end
 
   def material_index_needs_tag_name? filters

backend/app/controllers/nico_tags_controller.rb

@@ -98,7 +98,8 @@ class NicoTagsController < ApplicationController
     ApplicationRecord.transaction do
       linked_tags = Tag.normalise_tags!(locale, linked_tag_names,
                                         with_tagme: false,
-                                        with_no_deerjikist: false)
+                                        with_no_deerjikist: false,
+                                        created_by_user: current_user)
 
       TagVersioning.record_tag_snapshots!(
           linked_tags,
@@ -140,10 +141,23 @@ class NicoTagsController < ApplicationController
   end
 
   def render_nico_tag_form_record_invalid record
-    if record.is_a?(TagName) || record.is_a?(Tag)
-      render_validation_error fields: { tags: record.errors.full_messages.map { |message|
-        "タグ名 “#{ record.name }”: #{ message }"
-      } }
+    names =
+        case record
+        when TagName
+          [record]
+        when Tag
+          record.tag_names.to_a
+        else
+          []
+        end
+    messages = names.flat_map do |tag_name|
+      tag_name.errors.full_messages.map do |message|
+        "タグ名 “#{ tag_name.name }”: #{ message }"
+      end
+    end
+
+    if messages.any?
+      render_validation_error fields: { tags: messages }
     else
       render_validation_error record
     end

backend/app/controllers/posts_controller.rb

@@ -818,7 +818,8 @@ class PostsController < ApplicationController
                         with_tagme: false,
                         with_no_deerjikist: false,
                         deny_deprecated: true,
-                        with_sections: true) => { tags:, sections: }
+                        with_sections: true,
+                        created_by_user: current_user) => { tags:, sections: }
 
     tags = Tag.expand_parent_tags(tags).reject(&:deprecated?)
     video_ms = normalise_video_ms(tags, video_ms_param:, duration_param:)
@@ -964,7 +965,8 @@ class PostsController < ApplicationController
     Tag.normalise_tags!(locale, snapshot[:tag_names],
                         with_tagme: false,
                         deny_deprecated: true,
-                        with_sections: true) => { tags:, sections: }
+                        with_sections: true,
+                        created_by_user: current_user) => { tags:, sections: }
     TagVersioning.record_tag_snapshots!(tags, created_by_user: current_user,
                                         language_code: locale.language_code)
 

backend/app/controllers/sitemap_entries_controller.rb

@@ -0,0 +1,57 @@
+class SitemapEntriesController < ApplicationController
+  PAGE_SIZE = 1_000
+  RESOURCES = [
+      'posts', 'tags', 'deerjikists', 'materials',
+      'descriptions', 'tag_groups', 'theatres'].freeze
+
+  def index
+    locale = resolve_locale!
+    resources = RESOURCES.map { |resource| { resource:, count: entries(resource, locale).count } }
+    render json: { resources:, page_size: PAGE_SIZE }
+  end
+
+  def show
+    locale = resolve_locale!
+    resource = params[:resource]
+    return head :not_found unless RESOURCES.include?(resource)
+
+    page = Integer(params.fetch(:page, '1'), exception: false)
+    return head :bad_request unless page && page.positive?
+
+    scope = entries(resource, locale)
+    return head :not_found if page > [(scope.count.to_f / PAGE_SIZE).ceil, 1].max
+
+    ids = scope.order(:id).offset((page - 1) * PAGE_SIZE).limit(PAGE_SIZE).pluck(:id)
+    render json: { ids: }
+  end
+
+  private
+
+  def entries resource, locale
+    named_tags = TagName.where(language_code: locale.language_code, primary_flg: true)
+        .select(:tag_id)
+    case resource
+    when 'posts'
+      Post.all
+    when 'tags'
+      Tag.where(id: named_tags)
+    when 'deerjikists'
+      Tag.where(id: named_tags).where(id: Deerjikist.select(:tag_id))
+    when 'materials'
+      Material.all
+    when 'descriptions'
+      TagDescription.where(language_code: locale.language_code, tag_id: named_tags)
+          .where.not(body: [nil, ''])
+          .where(TagDescriptionVersion
+              .where('tag_description_versions.tag_id = tag_descriptions.tag_id')
+              .where('tag_description_versions.language_code = tag_descriptions.language_code')
+              .where('tag_description_versions.version_no = tag_descriptions.version_no')
+              .arel.exists)
+    when 'tag_groups'
+      TagGroup.joins(:versions)
+          .where('tag_group_versions.version_no = tag_groups.version_no')
+    when 'theatres'
+      Theatre.kept
+    end
+  end
+end

backend/app/controllers/tags_controller.rb

@@ -844,7 +844,8 @@ class TagsController < ApplicationController
   def update_parent_tags! locale, tag, parent_names
     parent_tags = Tag.normalise_tags!(locale, parent_names,
                                       with_tagme: false,
-                                      with_no_deerjikist: false)
+                                      with_no_deerjikist: false,
+                                      created_by_user: current_user)
 
     old_parent_tags = tag.parents.to_a
 

backend/app/models/tag.rb

@@ -142,7 +142,8 @@ class Tag < ApplicationRecord
                              with_tagme: true,
                              with_no_deerjikist: true,
                              deny_deprecated: false,
-                             with_sections: false
+                             with_sections: false,
+                             created_by_user: nil
       if tag_names.any? { |n| n.downcase.start_with?('nico:') }
         raise NicoTagNormalisationError
       end
@@ -171,7 +172,8 @@ class Tag < ApplicationRecord
 
         name = TagName.canonicalise(locale, name).first
 
-        find_or_create_by_tag_name!(locale, name, category: (cat || :general)).tap do |tag|
+        find_or_create_by_tag_name!(locale, name, category: (cat || :general),
+                                   created_by_user:).tap do |tag|
           if deny_deprecated && tag.deprecated?
             raise DeprecatedTagNormalisationError, [tag.name(locale.language_code)]
           end
@@ -259,7 +261,7 @@ class Tag < ApplicationRecord
       [left_end_ms, right_end_ms].max
     end
 
-    def find_or_create_by_tag_name! locale, name, category:
+    def find_or_create_by_tag_name! locale, name, category:, created_by_user: nil
       language_code = locale.language_code
       name = name.to_s.strip
 
@@ -268,11 +270,10 @@ class Tag < ApplicationRecord
         tn = TagName.lock.find_by(language_code:, name:)
         next tn.tag if tn
 
-        tag = Tag.create!(category:)
-        TagName.create!(tag:, language_code:, name:,
-                        script_code: locale.script_code, primary_flg: true,
-                        auto_generated: false)
-        TagNameCompletion.for_tag!(tag)
+        tag = Tag.new(category:)
+        tag.tag_names.build(language_code:, name:, script_code: locale.script_code,
+                            primary_flg: true, auto_generated: false)
+        TagNameCompletion.for_tag!(tag, created_by_user:)
         tag.association(:tag_names).reset
 
         tag

backend/app/services/post_creator.rb

@@ -105,7 +105,7 @@ class PostCreator
       category = spec[:category] || spec['category']
       next if name.blank? || category.blank?
 
-      tag = Tag.find_or_create_by_tag_name!(locale, name, category:)
+      tag = Tag.find_or_create_by_tag_name!(locale, name, category:, created_by_user: @actor)
       tag.update!(category:) if tag.category.to_sym != category.to_sym
       tags[name] ||= tag
     end.values

backend/app/services/tag_name_completion.rb

@@ -11,13 +11,14 @@ class TagNameCompletion
             end
         Tag.where(id: certified_names.keys).lock.find_each(order: :asc) do |tag|
           for_tag!(tag, locales: [locale],
-                   certified_names: { locale.language_code => certified_names.fetch(tag.id) })
+                   certified_names: { locale.language_code => certified_names.fetch(tag.id) },
+                   created_by_user: nil)
         end
         named_tags =
             TagName.where(language_code: locale.language_code, primary_flg: true)
             .select(:tag_id)
         Tag.where.not(id: named_tags).lock.find_each(order: :asc) do |tag|
-          for_tag!(tag, locales: [locale])
+          for_tag!(tag, locales: [locale], created_by_user: nil)
         end
         true
       end
@@ -26,12 +27,15 @@ class TagNameCompletion
       end
     end
 
-    def for_tag! tag, locales: nil, certified_names: { }
+    def for_tag! tag, locales: nil, certified_names: { }, created_by_user: nil
       locales ||=
           Locale.where(deprecated_at: nil)
           .order(:language_code, :created_at, :script_code).lock
       Tag.transaction do
         SharedResourceIdAllocator.lock_space!(Tag, 'tags')
+        # Creation includes every language in its first snapshot.
+        creating = tag.new_record?
+        tag.save! if creating
         completed = tag.with_lock do
           primary_names = tag.tag_names.where(primary_flg: true).lock.index_by(&:language_code)
           certified_names.each do |language, name|
@@ -46,9 +50,9 @@ class TagNameCompletion
           missing_locales = locales.to_a.uniq(&:language_code).reject { |locale|
             primary_names.key?(locale.language_code)
           }
-          next true if missing_locales.empty?
+          next true if missing_locales.empty? && !creating
 
-          TagVersioning.ensure_snapshot!(tag, created_by_user: nil)
+          TagVersioning.ensure_snapshot!(tag, created_by_user:) unless creating
           missing_locales.each do |locale|
             primary_names[locale.language_code] =
                 if certified_names.key?(locale.language_code)
@@ -60,7 +64,8 @@ class TagNameCompletion
                 end
           end
           tag.association(:tag_names).reset
-          version = TagVersioning.record!(tag, event_type: :update, created_by_user: nil)
+          event_type = creating ? :create : :update
+          version = TagVersioning.record!(tag, event_type:, created_by_user:)
           unless version&.persisted?
             raise ActiveRecord::RecordNotSaved, 'Tag version was not persisted'
           end

backend/config/routes.rb

@@ -1,5 +1,6 @@
 Rails.application.routes.draw do
   resources :locales, only: [:index]
+  resources :sitemap_entries, only: [:index, :show], param: :resource
 
   resources :tag_groups, only: [:index, :show, :create, :update]
 

backend/spec/models/locale_spec.rb

@@ -57,6 +57,7 @@ RSpec.describe Locale, type: :model do
     tag = create(:tag, primary_name: 'already_named')
     existing = create(:tag_name, name: 'existing_ainu', tag:,
                                  language_code: 'ain', script_code: 'Kana')
+    versions_before = tag.tag_versions.order(:version_no).map(&:attributes)
 
     create_ainu_locale!
 
@@ -65,6 +66,7 @@ RSpec.describe Locale, type: :model do
     expect(existing.reload).to have_attributes(
         tag_id: tag.id, language_code: 'ain', script_code: 'Kana',
         primary_flg: true, auto_generated: false)
+    expect(tag.tag_versions.order(:version_no).map(&:attributes)).to eq(versions_before)
   end
 
   it 'adds the new language primary while preserving existing names and aliases' do
@@ -88,6 +90,7 @@ RSpec.describe Locale, type: :model do
     prepare_ainu_reference!
     first = create(:tag, primary_name: 'atomic_first')
     second = create(:tag, primary_name: 'atomic_second')
+    versions_before = TagVersion.order(:id).map(&:attributes)
     allow(TagName).to receive(:generate_name).and_call_original
     allow(TagName).to receive(:generate_name)
         .with(kind_of(described_class), second, primary_tag_name_for(second, 'ja'))
@@ -97,6 +100,69 @@ RSpec.describe Locale, type: :model do
 
     expect(described_class.exists?(code: 'ain-Kana')).to be(false)
     expect(TagName.where(language_code: 'ain', tag_id: [first.id, second.id])).to be_empty
+    expect(TagVersion.order(:id).map(&:attributes)).to eq(versions_before)
+  end
+
+  it 'records a separate automatic update for each tag without changing its authored create' do
+    author = create(:user, :admin)
+    tags = ['locale_history_first', 'locale_history_second'].map do |name|
+      Tag.find_or_create_by_tag_name!(Locale.nipponese, name, category: :general,
+                                     created_by_user: author)
+    end
+    originals = tags.map { |tag| tag.tag_versions.sole.attributes }
+
+    expect { create_ainu_locale! }.to change(TagVersion, :count).by(2)
+
+    tags.zip(originals).each do |tag, original|
+      versions = tag.tag_versions.order(:version_no).to_a
+      expect(versions.map(&:event_type)).to eq(['create', 'update'])
+      expect(versions.first.attributes).to eq(original)
+      expect(versions.first.created_by_user_id).to eq(author.id)
+      expect(versions.last).to have_attributes(version_no: 2, created_by_user_id: nil)
+      expect(versions.last.names.fetch('ain')).to eq(
+          'name' => tag.name('ja'), 'script_code' => 'Kana',
+          'auto_generated' => true, 'aliases' => [])
+      expect(versions.first.names.keys).to eq(['ja'])
+      expect(tag.reload.version_no).to eq(2)
+    end
+
+    expect { TagNameCompletion.for_locale!(Locale.find('ain-Kana')) }
+        .not_to change(TagVersion, :count)
+  end
+
+  it 'records automatic before and after snapshots for a tag without any history' do
+    tag = create(:tag, primary_name: 'legacy_before_locale')
+    expect(tag.tag_versions).to be_empty
+
+    create_ainu_locale!
+
+    versions = tag.tag_versions.order(:version_no).to_a
+    expect(versions.map(&:event_type)).to eq(['create', 'update'])
+    expect(versions.map(&:created_by_user_id)).to eq([nil, nil])
+    expect(versions.first.names.keys).to eq(['ja'])
+    expect(versions.last.names.keys).to match_array(['ja', 'ain'])
+    expect(versions.last.names.fetch('ja')).to eq(versions.first.names.fetch('ja'))
+  end
+
+  it 'rolls back earlier tag names and histories when a later history fails' do
+    first = create(:tag, primary_name: 'history_atomic_first')
+    second = create(:tag, primary_name: 'history_atomic_second')
+    names_before = TagName.order(:id).map(&:attributes)
+    versions_before = TagVersion.order(:id).map(&:attributes)
+    allow(TagVersioning).to receive(:record!).and_wrap_original do |original, tag, **options|
+      if tag.id == second.id && options[:event_type] == :update
+        raise ActiveRecord::RecordNotSaved, 'history failed'
+      end
+      original.call(tag, **options)
+    end
+
+    expect { create_ainu_locale! }
+        .to raise_error(ActiveRecord::RecordNotSaved, 'history failed')
+
+    expect(described_class.exists?(code: 'ain-Kana')).to be(false)
+    expect(TagName.order(:id).map(&:attributes)).to eq(names_before)
+    expect(TagVersion.order(:id).map(&:attributes)).to eq(versions_before)
+    expect([first.reload.version_no, second.reload.version_no]).to eq([1, 1])
   end
 
   it 'rejects a private locale code outside the supported locale set' do

backend/spec/requests/locale_write_paths_spec.rb

@@ -14,7 +14,19 @@ RSpec.describe 'Locale propagation on write paths', type: :request do
     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
+    tag = tag_name.tag
+    version = tag.tag_versions.sole
+    expect(version).to have_attributes(
+        event_type: 'create', version_no: 1, created_by_user_id: member.id)
+    expect(tag.reload.version_no).to eq(1)
+    expect(version.names.keys).to match_array(
+        Locale.where(deprecated_at: nil).distinct.pluck(:language_code))
+    tag.tag_names.where(primary_flg: true).each do |primary|
+      expect(version.names.fetch(primary.language_code)).to include(
+          'name' => primary.name, 'script_code' => primary.script_code,
+          'auto_generated' => primary.auto_generated, 'aliases' => [])
+    end
+    tag
   end
 
   it 'confirms a generated Nipponese primary when a human renames it' do

backend/spec/requests/nico_tags_spec.rb

@@ -231,11 +231,14 @@ RSpec.describe 'NicoTags', type: :request do
         replacement: 'valid'
       )
       nico_tag
+      before_counts = [Tag.count, TagName.count, TagVersion.count]
 
       expect {
         patch "/tags/nico/#{nico_tag.id}", params: { tags: 'created_first invalid' }
       }.not_to change(TagName, :count)
 
+      expect([Tag.count, TagName.count, TagVersion.count]).to eq(before_counts)
+
       expect(response).to have_http_status(:unprocessable_entity)
       expect(json.fetch('errors').fetch('tags')).to include(
           a_string_including('タグ名 “invalid”:', '名前に使用できない文字が含まれてゐます．'))

backend/spec/requests/sitemap_entries_spec.rb

@@ -0,0 +1,155 @@
+require 'rails_helper'
+
+RSpec.describe 'Sitemap entries API', type: :request do
+  include_context 'Ainu locale'
+
+  let(:user) { create(:user, :member) }
+
+  it 'serves public resource counts with the default locale and page size' do
+    create(:post)
+    create(:tag, primary_name: 'sitemap_count_tag')
+
+    get '/sitemap_entries'
+
+    expect(response).to have_http_status(:ok)
+    expect(json.fetch('page_size')).to eq(1_000)
+    counts = json.fetch('resources').to_h { |entry|
+      [entry.fetch('resource'), entry.fetch('count')]
+    }
+    expect(counts).to eq(
+        'posts' => Post.count, 'tags' => Tag.count, 'deerjikists' => 0,
+        'materials' => 0, 'descriptions' => 0, 'tag_groups' => 0, 'theatres' => 0)
+  end
+
+  it 'paginates public post IDs in ascending order without exposing post contents' do
+    stub_const('SitemapEntriesController::PAGE_SIZE', 2)
+    posts = create_list(:post, 3)
+
+    get '/sitemap_entries/posts'
+    expect(response).to have_http_status(:ok)
+    expect(json).to eq('ids' => posts.first(2).map(&:id))
+
+    get '/sitemap_entries/posts', params: { page: 2 }
+    expect(response).to have_http_status(:ok)
+    expect(json).to eq('ids' => [posts.last.id])
+
+    get '/sitemap_entries/posts', params: { page: 3 }
+    expect(response).to have_http_status(:not_found)
+  end
+
+  ['0', '-1', 'invalid', '1.5'].each do |page|
+    it "rejects invalid sitemap page #{ page.inspect }" do
+      get '/sitemap_entries/posts', params: { page: }
+
+      expect(response).to have_http_status(:bad_request)
+    end
+  end
+
+  it 'rejects unsupported resource names' do
+    get '/sitemap_entries/users'
+
+    expect(response).to have_http_status(:not_found)
+  end
+
+  it 'returns an empty first page for a resource without entries' do
+    get '/sitemap_entries/posts'
+
+    expect(response).to have_http_status(:ok)
+    expect(json).to eq('ids' => [])
+  end
+
+  it 'rejects unregistered, deprecated and unsupported locales' do
+    get '/sitemap_entries', params: { locale: 'ain-Kana' }
+    expect(response).to have_http_status(:not_found)
+
+    locale.update!(deprecated_at: Time.current)
+    ['/sitemap_entries', '/sitemap_entries/posts'].each do |path|
+      get path, params: { locale: 'ain-Kana' }
+      expect(response).to have_http_status(:not_found)
+
+      get path, params: { locale: 'en' }
+      expect(response).to have_http_status(:not_found)
+    end
+  end
+
+  it 'only lists live materials and theatres' do
+    material = Material.create!(url: 'https://example.com/sitemap-material')
+    discarded_material = Material.create!(url: 'https://example.com/sitemap-discarded')
+    discarded_material.discard!
+    theatre = create(:theatre)
+    create(:theatre).discard!
+
+    get '/sitemap_entries/materials'
+    expect(response).to have_http_status(:ok)
+    expect(json).to eq('ids' => [material.id])
+
+    get '/sitemap_entries/theatres'
+    expect(response).to have_http_status(:ok)
+    expect(json).to eq('ids' => [theatre.id])
+  end
+
+  context 'with an active Ainu locale' do
+    before { locale }
+
+    it 'uses tag IDs and only includes deerjikists with linked accounts' do
+      tagged = create(:tag, primary_name: 'sitemap_deer', category: :deerjikist)
+      unlinked = create(:tag, primary_name: 'sitemap_unlinked', category: :deerjikist)
+      Deerjikist.create!(tag: tagged, platform: 'youtube', code: 'sitemap-channel')
+      Deerjikist.create!(tag: tagged, platform: 'nico', code: 'sitemap-nico')
+
+      get '/sitemap_entries/tags', params: { locale: 'ain-Kana' }
+      expect(response).to have_http_status(:ok)
+      expect(json.fetch('ids')).to contain_exactly(tagged.id, unlinked.id)
+
+      get '/sitemap_entries/deerjikists', params: { locale: 'ain-Kana' }
+      expect(response).to have_http_status(:ok)
+      expect(json).to eq('ids' => [tagged.id])
+    end
+
+    it 'lists description IDs for the requested language with a nonempty current version' do
+      tag = create(:tag, primary_name: 'sitemap_description')
+      japanese = TagDescriptionOperation.create!(
+          Locale.nipponese, tag:, body: 'Japanese sitemap body', created_by_user: user)
+      ainu = TagDescriptionOperation.create!(
+          locale, tag:, body: 'Ainu sitemap body', created_by_user: user)
+      unversioned_tag = create(:tag, primary_name: 'sitemap_unversioned')
+      TagDescription.create!(tag: unversioned_tag, language_code: 'ain',
+                             body: 'No revision', version_no: 1)
+      empty_tag = create(:tag, primary_name: 'sitemap_empty')
+      # Legacy empty bodies can exist even though the write service rejects them.
+      empty = TagDescription.create!(tag: empty_tag, language_code: 'ain',
+                                     body: '', version_no: 1)
+      TagDescriptionVersion.create!(tag_id: empty_tag.id, language_code: 'ain',
+                                    body: '', version_no: 1, event_type: 'create',
+                                    created_by_user_id: user.id, created_at: Time.current)
+
+      get '/sitemap_entries/descriptions', params: { locale: 'ain-Kana' }
+      expect(response).to have_http_status(:ok)
+      expect(json).to eq('ids' => [ainu.id])
+      expect(json.fetch('ids')).not_to include(japanese.id, empty.id)
+
+      get '/sitemap_entries/descriptions', params: { locale: 'ja' }
+      expect(response).to have_http_status(:ok)
+      expect(json).to eq('ids' => [japanese.id])
+
+      get '/sitemap_entries', params: { locale: 'ain-Kana' }
+      expect(response).to have_http_status(:ok)
+      descriptions = json.fetch('resources').find { |entry|
+        entry.fetch('resource') == 'descriptions'
+      }
+      expect(descriptions.fetch('count')).to eq(1)
+    end
+
+    it 'excludes groups without a revision matching the current version' do
+      group = TagGroupOperation.create!(
+          Locale.nipponese, name: 'Sitemap group', description: 'Group description',
+          members: [], placements: [], actor: user)
+      TagGroup.create!(name: 'Unversioned sitemap group', version_no: 1)
+
+      get '/sitemap_entries/tag_groups', params: { locale: 'ain-Kana' }
+
+      expect(response).to have_http_status(:ok)
+      expect(json).to eq('ids' => [group.id])
+    end
+  end
+end

backend/spec/services/post_creator_spec.rb

@@ -95,7 +95,8 @@ RSpec.describe PostCreator do
         post = described_class.new(actor:, attributes:).create!(locale)
 
         expect(Tag).to have_received(:find_or_create_by_tag_name!)
-            .with(locale, 'locale_character', category: :character).at_least(:once)
+            .with(locale, 'locale_character', category: :character,
+                  created_by_user: actor).at_least(:once)
         tag_name = TagName.find_by!(language_code: 'ain', name: 'locale_character')
         expect(tag_name).to have_attributes(script_code: 'Kana', primary_flg: true)
         expect(post.tags).to include(tag_name.tag)

backend/spec/services/tag_name_completion_spec.rb

@@ -1,6 +1,7 @@
 require 'rails_helper'
 
 RSpec.describe TagNameCompletion do
+  let(:author) { create(:user, :member) }
   let!(:language) { Language.create!(code: 'ain', name: 'ain') }
   let!(:script) { Script.create!(code: 'Kana', name: 'Kana') }
   let(:locale) do
@@ -65,4 +66,62 @@ RSpec.describe TagNameCompletion do
         .to contain_exactly(['ja', 'アイヌ'], ['ain', 'アイヌ'])
     expect(Tag.find_or_create_by_tag_name!(locale, 'アイヌ', category: :general)).to eq(tag)
   end
+
+  ['ja', 'ain'].each do |language|
+    it "records one authored create with all names for a #{ language } origin" do
+      ainu_locale = locale
+      origin = language == 'ja' ? Locale.nipponese : ainu_locale
+      tag = nil
+
+      expect {
+        tag = Tag.find_or_create_by_tag_name!(origin, 'アイヌ', category: :general,
+                                             created_by_user: author)
+      }.to change(TagVersion, :count).by(1)
+
+      version = tag.tag_versions.sole
+      expect(version).to have_attributes(
+          event_type: 'create', version_no: 1, created_by_user_id: author.id)
+      expect(tag.reload.version_no).to eq(1)
+      expect(version.names).to eq(
+          'ja' => { 'name' => 'アイヌ', 'script_code' => 'Jpan',
+                    'auto_generated' => language != 'ja', 'aliases' => [] },
+          'ain' => { 'name' => 'アイヌ', 'script_code' => 'Kana',
+                     'auto_generated' => language != 'ain', 'aliases' => [] })
+
+      expect {
+        described_class.for_tag!(tag, created_by_user: author)
+        found = Tag.find_or_create_by_tag_name!(origin, 'アイヌ', category: :general,
+                                               created_by_user: author)
+        expect(found).to eq(tag)
+        TagVersioning.record_tag_snapshot!(tag, created_by_user: author)
+      }.not_to change(TagVersion, :count)
+      expect(version.reload.created_by_user_id).to eq(author.id)
+    end
+  end
+
+  it 'records the author even when no additional language needs completion' do
+    tag = build(:tag, primary_name: 'single_language_creation')
+
+    described_class.for_tag!(tag, created_by_user: author)
+
+    expect(tag).to be_persisted
+    expect(tag.tag_versions.sole).to have_attributes(
+        event_type: 'create', version_no: 1, created_by_user_id: author.id)
+    expect(tag.tag_versions.sole.names.keys).to eq(['ja'])
+  end
+
+  it 'rolls back a new tag and all names when its create history fails' do
+    locale
+    author
+    before_counts = [Tag.count, TagName.count, TagVersion.count]
+    allow(TagVersioning).to receive(:record!).and_raise('history failed')
+
+    expect {
+      Tag.find_or_create_by_tag_name!(Locale.nipponese, 'atomic_new_history',
+                                     category: :general, created_by_user: author)
+    }.to raise_error('history failed')
+
+    expect([Tag.count, TagName.count, TagVersion.count]).to eq(before_counts)
+    expect(TagName.where(name: 'atomic_new_history')).to be_empty
+  end
 end