タグ・グループを Wiki から分離 (#425) (#429)

Reviewed-on: #429
Co-authored-by: miteruzo <miteruzo@naver.com>

backend/spec/db/tag_group_constraints_spec.rb

@@ -0,0 +1,110 @@
+require 'rails_helper'
+
+RSpec.describe 'Tag group persistence constraints' do
+  include TagGroupRecords
+
+  let!(:user) { create_member_user! }
+  let!(:tag) { group_tag('制約確認') }
+  let!(:group_id) do
+    seed_group(
+        name: '制約確認',
+        members: [{ 'tag_id' => tag.id, 'version_no' => tag.version_no }])
+  end
+
+  def placement attributes
+    insert_group_row('tag_group_placements', {
+        tag_group_id: group_id, position: 1,
+        created_at: Time.current, updated_at: Time.current }.merge(attributes))
+  end
+
+  def reject_statement
+    before_state = group_state
+    expect { yield }.to raise_error(ActiveRecord::StatementInvalid)
+    expect(group_state).to eq(before_state)
+  end
+
+  it 'allows membership without placement' do
+    expect(group_rows('tag_group_tags', tag_group_id: group_id).size).to eq(1)
+    expect(group_rows('tag_group_placements', tag_group_id: group_id)).to be_empty
+  end
+
+  it 'allows repeated Tag placements with unique membership' do
+    placement(tag_id: tag.id)
+    placement(tag_id: tag.id, position: 2)
+    expect(group_rows('tag_group_tags', tag_group_id: group_id).size).to eq(1)
+    expect(group_rows('tag_group_placements', tag_group_id: group_id).size).to eq(2)
+  end
+
+  it 'rejects duplicate Tag membership' do
+    reject_statement do
+      insert_group_row('tag_group_tags', {
+          tag_group_id: group_id, tag_id: tag.id, created_at: Time.current })
+    end
+  end
+
+  it 'rejects duplicate child membership' do
+    child_id = seed_group(name: '子')
+    attributes = { tag_group_id: group_id, child_tag_group_id: child_id,
+                   created_at: Time.current }
+    insert_group_row('tag_group_groups', attributes)
+    reject_statement { insert_group_row('tag_group_groups', attributes) }
+  end
+
+  it 'rejects direct self membership' do
+    reject_statement do
+      insert_group_row('tag_group_groups', {
+          tag_group_id: group_id, child_tag_group_id: group_id, created_at: Time.current })
+    end
+  end
+
+  it 'rejects a placement without a kind' do
+    reject_statement { placement({ }) }
+  end
+
+  it 'rejects simultaneous Section and Tag kinds' do
+    reject_statement { placement(section_name: '区分', tag_id: tag.id) }
+  end
+
+  it 'rejects a description attached to a Tag placement' do
+    reject_statement { placement(tag_id: tag.id, description: '不正') }
+  end
+
+  it 'allows an optional description on a Section' do
+    placement(section_name: '区分', description: '説明')
+    expect(group_rows('tag_group_placements', tag_group_id: group_id).sole)
+        .to include('section_name' => '区分', 'description' => '説明')
+  end
+
+  it 'rejects a Tag placement absent from membership' do
+    other = group_tag('非メンバー')
+    reject_statement { placement(tag_id: other.id) }
+  end
+
+  it 'rejects a missing parent placement' do
+    reject_statement { placement(section_name: '子', parent_position: 9) }
+  end
+
+  it 'rejects a child ordered before its parent' do
+    placement(section_name: '親', position: 2)
+    reject_statement { placement(section_name: '子', position: 1, parent_position: 2) }
+  end
+
+  it 'rejects duplicate group names' do
+    reject_statement { seed_group(name: '制約確認') }
+  end
+
+  it 'rejects a missing mandatory group name' do
+    reject_statement { seed_group(name: nil) }
+  end
+
+  it 'rejects a six-level snapshot' do
+    nodes = []
+    6.times { nodes = [{ 'tag_id' => tag.id, 'children' => nodes }] }
+    reject_statement do
+      insert_group_row('tag_group_versions', {
+          tag_group_id: group_id, version_no: 2, event_type: 'update', name: '制約確認',
+          members: [{ 'tag_id' => tag.id, 'version_no' => tag.version_no }].to_json,
+          placements: nodes.to_json, created_at: Time.current })
+    end
+  end
+end

backend/spec/db/tag_group_migration_spec.rb

@@ -0,0 +1,119 @@
+require 'rails_helper'
+
+RSpec.describe 'Tag group migration identity and structure' do
+  include TagGroupRecords
+
+  let!(:user) { create_member_user! }
+
+  before { I18n.locale = :ja }
+
+  it 'preserves page and revision IDs, timestamps and repeated historical structures' do
+    tag = group_tag('洗澡鹿')
+    body = "説明文\n\n- 洗澡鹿\n- 洗澡鹿"
+    page = legacy_group('伊地知ニジカ亜種', body)
+    revisions = [page.current_revision]
+    [body, '# 空の区分', body].each do |text|
+      revisions << Wiki::Commit.legacy_content!(page:, body: text, created_user: user)
+    end
+    before_state = group_state.except(*TagGroupRecords::GROUP_TABLES)
+
+    migrate_groups
+
+    versions = group_rows('tag_group_versions', tag_group_id: page.id)
+        .sort_by { _1.fetch('version_no') }
+    expect(versions.map { _1.fetch('id') }).to eq(revisions.map(&:id))
+    expect(versions.map { _1.fetch('version_no') }).to eq([1, 2, 3, 4])
+    expect(versions.map { _1.fetch('created_at') }).to eq(revisions.map(&:created_at))
+    expect(versions.map { _1.fetch('created_by_user_id') }).to eq([user.id] * 4)
+    expect(versions.map { _1.fetch('event_type') }).to eq(['create', 'update', 'update', 'update'])
+    expect(group_version(page.id, 1).fetch('placements')).to eq(
+        group_version(page.id, 2).fetch('placements'))
+    expect(group_version(page.id, 3).fetch('placements')).to eq([
+        { 'section_name' => '空の区分', 'description' => nil, 'children' => [] }])
+    expect_group_snapshot(
+        page.id, number: 4, description: '説明文',
+        members: [{ 'tag_id' => tag.id, 'version_no' => tag.version_no }],
+        placements: [{ 'tag_id' => tag.id, 'children' => [] }] * 2)
+    expect(group_rows('tag_groups', id: page.id).sole).to include(
+        'created_at' => page.created_at, 'updated_at' => page.reload.updated_at)
+    expect(group_state.except(*TagGroupRecords::GROUP_TABLES)).to eq(before_state)
+  end
+
+  it 'migrates nested list Sections and child groups as different placement kinds' do
+    series = group_tag('ぼざろクリーチャーシリーズ')
+    deer = group_tag('洗澡鹿')
+    nijika = group_tag('伊地知ニジカ')
+    child = legacy_group('伊地知ニジカ亜種', <<~MARKDOWN)
+      - ぼざろクリーチャーシリーズ
+        - 伊地知ニジカ亜種:
+          - 洗澡鹿
+    MARKDOWN
+    parent = legacy_group('ぼざろクリーチャーシリーズのキャラクター', <<~MARKDOWN)
+      - ぼざろクリーチャーシリーズ
+        - 伊地知ニジカ
+          - タググループ:伊地知ニジカ亜種
+    MARKDOWN
+
+    migrate_groups
+
+    expect_group_snapshot(
+        child.id, number: 1,
+        members: [series, deer].map { { 'tag_id' => _1.id, 'version_no' => _1.version_no } },
+        placements: [{ 'tag_id' => series.id, 'children' => [
+            { 'section_name' => '伊地知ニジカ亜種', 'description' => nil,
+              'children' => [{ 'tag_id' => deer.id, 'children' => [] }] }] }])
+    expect_group_snapshot(
+        parent.id, number: 1,
+        members: [
+            { 'tag_id' => series.id, 'version_no' => series.version_no },
+            { 'tag_id' => nijika.id, 'version_no' => nijika.version_no },
+            { 'tag_group_id' => child.id, 'version_no' => 1 }],
+        placements: [{ 'tag_id' => series.id, 'children' => [
+            { 'tag_id' => nijika.id, 'children' => [
+                { 'tag_group_id' => child.id, 'children' => [] }] }] }])
+  end
+
+  it 'preserves heading order, group paragraphs and Section descriptions' do
+    names = ['タグ希望', 'キャラクター名希望', '楽曲情報希望', 'bot操作', 'ニジラー情報不詳']
+    tags = names.map { group_tag(_1) }
+    markdown = <<~MARKDOWN
+      全体の説明
+
+      # 要求
+      要求の説明
+
+      - タグ希望
+        - キャラクター名希望
+        - 楽曲情報希望
+
+      # 情報
+      - bot操作
+      - ニジラー情報不詳
+    MARKDOWN
+    page = legacy_group('メタタグ', markdown)
+    expect(page.current_revision.body).to eq(markdown.chomp)
+
+    migrate_groups
+
+    leaves = tags.map { { 'tag_id' => _1.id, 'children' => [] } }
+    leaves.first['children'] = leaves[1..2]
+    expect_group_snapshot(
+        page.id, number: 1, description: '全体の説明',
+        members: tags.map { { 'tag_id' => _1.id, 'version_no' => _1.version_no } },
+        placements: [
+            { 'section_name' => '要求', 'description' => '要求の説明',
+              'children' => [leaves.first] },
+            { 'section_name' => '情報', 'description' => nil,
+              'children' => leaves[3..4] }])
+  end
+
+  it 'leaves Help in the legacy domain' do
+    page = Wiki::Commit.create_legacy_content!(
+        tag_name: create(:tag_name, name: 'Help:移行対象外'),
+        body: 'Help 本文', created_by_user: user)
+    before_state = group_state
+    migrate_groups
+    expect(group_state).to eq(before_state)
+    expect(page.reload.body).to eq('Help 本文')
+  end
+end

backend/spec/requests/tag_group_markdown_spec.rb

@@ -0,0 +1,139 @@
+require 'rails_helper'
+
+RSpec.describe 'Tag group Markdown round trips through the Wiki facade', type: :request do
+  include TagGroupRecords
+
+  let!(:user) { create_member_user! }
+  let!(:series) { group_tag('ぼざろクリーチャーシリーズ') }
+  let!(:deer) { group_tag('洗澡鹿') }
+  let!(:nizika) { group_tag('伊地知ニジカ') }
+  let!(:wanted) { group_tag('タグ希望') }
+  let!(:character) { group_tag('キャラクター名希望') }
+  let!(:music) { group_tag('楽曲情報希望') }
+  let!(:bot) { group_tag('bot操作') }
+  let!(:unknown) { group_tag('ニジラー情報不詳') }
+  let!(:child_id) { seed_group(name: '伊地知ニジカ亜種', description: '子の説明') }
+
+  before { I18n.locale = :ja }
+
+  def tag_node tag, children = []
+    { 'tag_id' => tag.id, 'children' => children }
+  end
+
+  def tag_member tag
+    { 'tag_id' => tag.id, 'version_no' => tag.version_no }
+  end
+
+  def check_round_trip placements:, members:, markdown:, description: nil
+    id = seed_group(name: '変換元', placements:, members:, description:)
+    without_group_legacy_reads { get group_title_path('変換元') }
+    expect(response).to have_http_status(:ok)
+    expect(json).to include('id' => id)
+    body = json.fetch('body')
+    expect(body).not_to include("\r")
+    expect(body.lines.map(&:chomp)).to all(satisfy { |line| line == line.rstrip })
+    # A trailing LF or a blank line between blocks is semantically irrelevant.
+    expect(body.lines.map(&:chomp).reject(&:empty?)).to eq(
+        markdown.lines.map(&:chomp).reject(&:empty?))
+
+    post '/wiki', params: { title: 'タググループ:再解析', body: },
+         headers: { 'X-Transfer-Code' => user.inheritance_code }
+    expect(response).to have_http_status(:created)
+    parsed = group_rows('tag_groups', name: '再解析').sole
+    expect_group_snapshot(parsed.fetch('id'), number: 1, placements:, members:, description:)
+  end
+
+  it 'renders a list Section under a Tag with two-space indentation' do
+    check_round_trip(
+        members: [series, deer].map { tag_member(_1) },
+        placements: [tag_node(series, [
+            { 'section_name' => '伊地知ニジカ亜種', 'description' => nil,
+              'children' => [tag_node(deer)] }])],
+        markdown: <<~MARKDOWN)
+          - ぼざろクリーチャーシリーズ
+            - 伊地知ニジカ亜種:
+              - 洗澡鹿
+        MARKDOWN
+  end
+
+  it 'renders a child Tag Group distinctly from its parent Tags' do
+    check_round_trip(
+        members: [tag_member(series), tag_member(nizika),
+                  { 'tag_group_id' => child_id, 'version_no' => 1 }],
+        placements: [tag_node(series, [tag_node(nizika, [
+            { 'tag_group_id' => child_id, 'children' => [] }])])],
+        markdown: <<~MARKDOWN)
+          - ぼざろクリーチャーシリーズ
+            - 伊地知ニジカ
+              - タググループ:伊地知ニジカ亜種
+        MARKDOWN
+  end
+
+  it 'renders top-level heading Sections, descriptions and ordered nested Tags' do
+    check_round_trip(
+        description: '全体の説明',
+        members: [wanted, character, music, bot, unknown].map { tag_member(_1) },
+        placements: [
+            { 'section_name' => '要求', 'description' => '要求の説明',
+              'children' => [tag_node(wanted, [tag_node(character), tag_node(music)])] },
+            { 'section_name' => '情報', 'description' => nil,
+              'children' => [tag_node(bot), tag_node(unknown)] }],
+        markdown: <<~MARKDOWN)
+          全体の説明
+
+          ## 要求
+          要求の説明
+
+          - タグ希望
+            - キャラクター名希望
+            - 楽曲情報希望
+
+          ## 情報
+          - bot操作
+          - ニジラー情報不詳
+        MARKDOWN
+  end
+
+  it 'renders nested heading Sections and all repeated Tag placements' do
+    check_round_trip(
+        members: [tag_member(deer)],
+        placements: [
+            { 'section_name' => '親', 'description' => '親の説明', 'children' => [
+                tag_node(deer),
+                { 'section_name' => '子', 'description' => '子の説明',
+                  'children' => [tag_node(deer)] }] }],
+        markdown: <<~MARKDOWN)
+          ## 親
+          親の説明
+
+          - 洗澡鹿
+
+          ### 子
+          子の説明
+
+          - 洗澡鹿
+        MARKDOWN
+  end
+
+  it 'rejects mixed top-level heading Sections and Tags without losing structure' do
+    id = seed_group(
+        name: '混在構造', members: [tag_member(series)],
+        placements: [
+            { 'section_name' => '区分', 'description' => nil, 'children' => [] },
+            tag_node(series)])
+
+    get group_title_path('混在構造')
+
+    expect(response).to have_http_status(:unprocessable_entity)
+    expect(group_rows('tag_groups', id:).sole.fetch('id')).to eq(id)
+  end
+
+  it 'rejects membership without a placement instead of omitting it' do
+    id = seed_group(name: '未配置構造', members: [tag_member(series)])
+
+    get group_title_path('未配置構造')
+
+    expect(response).to have_http_status(:unprocessable_entity)
+    expect(group_rows('tag_groups', id:).sole.fetch('id')).to eq(id)
+  end
+end

backend/spec/requests/tag_group_wiki_spec.rb

@@ -0,0 +1,304 @@
+require 'rails_helper'
+
+RSpec.describe 'Tag group Wiki facade reads', type: :request do
+  include TagGroupRecords
+
+  let!(:user) { create_member_user! }
+  let!(:old_tag) { group_tag('旧タグ') }
+  let!(:new_tag) { group_tag('新タグ') }
+  let!(:page) { legacy_group('読取り契約', '- 旧タグ') }
+  let!(:first_revision) { page.current_revision }
+  let!(:last_revision) do
+    Wiki::Commit.legacy_content!(page:, body: '- 新タグ', created_user: user)
+  end
+
+  before do
+    I18n.locale = :ja
+    migrate_groups
+    page.update_columns(body: 'legacy stale current')
+    page.wiki_revisions.each do |revision|
+      revision.wiki_lines.update_all(body: 'legacy stale revision')
+    end
+    page.wiki_versions.update_all(body: 'legacy stale version')
+  end
+
+  [:id, :title].each do |lookup|
+    context "with #{ lookup } lookup" do
+      let(:path) { lookup == :id ? "/wiki/#{ page.id }" : group_title_path('読取り契約') }
+
+      it 'reads current structure without consulting migrated Wiki tables' do
+        without_group_legacy_reads { get path }
+        expect(response).to have_http_status(:ok)
+        expect(json).to include(
+            'id' => page.id, 'title' => 'タググループ:読取り契約',
+            'revision_id' => last_revision.id, 'pred' => first_revision.id, 'succ' => nil)
+        expect(json.fetch('body').strip).to eq('- 新タグ')
+      end
+
+      it 'reads the old snapshot rather than current membership or placement' do
+        without_group_legacy_reads { get path, params: { version: first_revision.id } }
+        expect(response).to have_http_status(:ok)
+        expect(json.fetch('body').strip).to eq('- 旧タグ')
+        expect(json).to include(
+            'revision_id' => first_revision.id, 'pred' => nil, 'succ' => last_revision.id,
+            'updated_at' => first_revision.created_at.iso8601(3))
+      end
+
+      it 'checks existence without consulting migrated Wiki tables' do
+        without_group_legacy_reads { get "#{ path }/exists" }
+        expect(response).to have_http_status(:no_content)
+      end
+
+      it 'does not fall back to legacy history when a group version is missing' do
+        group_connection.execute(
+            "DELETE FROM tag_group_versions WHERE id = #{ first_revision.id }")
+        without_group_legacy_reads { get path, params: { version: first_revision.id } }
+        expect(response).to have_http_status(:not_found)
+      end
+    end
+  end
+
+  ['/wiki', '/wiki/search'].each do |path|
+    it "lists migrated groups once with current titles at #{ path }" do
+      get path, params: { title: 'タググループ:読取り' }
+      expect(response).to have_http_status(:ok)
+      rows = json.select { _1.fetch('title') == 'タググループ:読取り契約' }
+      expect(rows.size).to eq(1)
+      expect(rows.sole).to include('id' => page.id)
+      expect(response.body).not_to include('legacy stale')
+    end
+  end
+
+  it 'combines Tag Groups, Help and Tag Descriptions in the unfiltered list' do
+    help = Wiki::Commit.create_legacy_content!(
+        tag_name: create(:tag_name, name: 'Help:混在'), body: 'help', created_by_user: user)
+    TagDescriptionOperation.create!(tag: new_tag, body: 'tag description', created_by_user: user)
+    get '/wiki'
+    expect(response).to have_http_status(:ok)
+    expect(json.map { _1.fetch('title') }).to include(
+        'タググループ:読取り契約', help.title, '新タグ')
+  end
+
+  it 'keeps Help readable when its ID collides with a new group' do
+    help = Wiki::Commit.create_legacy_content!(
+        tag_name: create(:tag_name, name: 'Help:ID重複'), body: 'help body',
+        created_by_user: user)
+    seed_group(name: '別 ID重複', id: help.id, description: 'group body')
+
+    get '/wiki'
+    expect(response).to have_http_status(:ok)
+    expect(json.map { _1.fetch('title') }).to include(help.title, 'タググループ:別 ID重複')
+
+    get "/wiki/title/#{ CGI.escapeURIComponent(help.title) }"
+    expect(response).to have_http_status(:ok)
+    expect(json.fetch('body')).to eq('help body')
+
+    get '/wiki/changes'
+    expect(response).to have_http_status(:ok)
+    expect(json.map { _1.dig('wiki_page', 'title') }).to include(
+        help.title, 'タググループ:別 ID重複')
+  end
+
+  it 'finds groups by a partial prefix of their displayed title' do
+    get '/wiki', params: { title: 'タググル' }
+
+    expect(response).to have_http_status(:ok)
+    expect(json.map { _1.fetch('title') }).to include('タググループ:読取り契約')
+    expect(json.find { _1.fetch('title') == 'タググループ:読取り契約' })
+        .to include('updated_at' => be_present)
+  end
+
+  it 'does not restore a stale namespaced Wiki page after a group rename' do
+    old_page = legacy_group('旧名称', '- 旧本文')
+    seed_group(name: '新名称', id: old_page.id, description: '正本')
+
+    get group_title_path('旧名称')
+    expect(response).to have_http_status(:not_found)
+    get "#{ group_title_path('旧名称') }/exists"
+    expect(response).to have_http_status(:not_found)
+    get group_title_path('新名称')
+    expect(response).to have_http_status(:ok)
+    expect(json.fetch('body').strip).to eq('正本')
+  end
+
+  it 'orders mixed resource history by timestamp rather than independent IDs' do
+    help = Wiki::Commit.create_legacy_content!(
+        tag_name: create(:tag_name, name: 'Help:時系列'), body: 'help',
+        created_by_user: user)
+    TagDescriptionOperation.create!(tag: new_tag, body: 'description', created_by_user: user)
+    TagGroupVersion.update_all(created_at: 3.days.ago)
+    WikiRevision.where(wiki_page_id: help.id).update_all(created_at: 2.days.ago)
+    TagDescriptionVersion.update_all(created_at: 1.day.ago)
+
+    get '/wiki/changes'
+
+    expect(response).to have_http_status(:ok)
+    timestamps = json.map { Time.iso8601(_1.fetch('timestamp')) }
+    expect(timestamps).to eq(timestamps.sort.reverse)
+    titles = json.map { _1.dig('wiki_page', 'title') }
+    expect(titles.index('新タグ')).to be < titles.index(help.title)
+    expect(titles.index(help.title)).to be < titles.index('タググループ:読取り契約')
+  end
+
+  it 'renders nullable group editors without raising' do
+    group_connection.execute(
+        "UPDATE tag_groups SET created_by_user_id = NULL, updated_by_user_id = NULL " +
+        "WHERE id = #{ page.id }")
+    group_connection.execute(
+        "UPDATE tag_group_versions SET created_by_user_id = NULL " +
+        "WHERE tag_group_id = #{ page.id }")
+
+    get "/tag_groups/#{ page.id }"
+    expect(response).to have_http_status(:ok)
+    expect(json).to include('created_by_user' => nil, 'updated_by_user' => nil)
+    get "/wiki/title/#{ CGI.escapeURIComponent('タググループ:読取り契約') }"
+    expect(response).to have_http_status(:ok)
+  end
+
+  it 'reads group version IDs, editor and timestamps in scoped changes' do
+    without_group_legacy_reads { get '/wiki/changes', params: { id: page.id } }
+    expect(response).to have_http_status(:ok)
+    expect(json.map { _1.fetch('revision_id') }).to eq([last_revision.id, first_revision.id])
+    expect(json.first).to include(
+        'pred' => first_revision.id, 'succ' => nil, 'kind' => 'content',
+        'timestamp' => last_revision.created_at.iso8601(3),
+        'user' => { 'id' => user.id, 'name' => user.name },
+        'wiki_page' => include('id' => page.id, 'title' => 'タググループ:読取り契約'))
+  end
+
+  it 'includes Help and group history but excludes legacy-only migrated revisions' do
+    extra = Wiki::Commit.legacy_content!(page:, body: 'legacy only', created_user: user)
+    help = Wiki::Commit.create_legacy_content!(
+        tag_name: create(:tag_name, name: 'Help:変更一覧'), body: 'help', created_by_user: user)
+    get '/wiki/changes'
+    expect(response).to have_http_status(:ok)
+    rows = json.select { _1.fetch('wiki_page').fetch('title') == 'タググループ:読取り契約' }
+    expect(rows.map { _1.fetch('revision_id') }).to eq([last_revision.id, first_revision.id])
+    expect(rows.map { _1.fetch('revision_id') }).not_to include(extra.id)
+    expect(json).to include(include(
+        'revision_id' => help.current_revision.id,
+        'wiki_page' => include('title' => help.title)))
+  end
+
+  [false, true].each do |explicit|
+    it "diffs structured snapshots with #{ explicit ? 'explicit' : 'current' } target" do
+      params = { from: first_revision.id }
+      params[:to] = last_revision.id if explicit
+      without_group_legacy_reads { get "/wiki/#{ page.id }/diff", params: }
+      expect(response).to have_http_status(:ok)
+      expect(json).to include(
+          'wiki_page_id' => page.id, 'older_revision_id' => first_revision.id,
+          'newer_revision_id' => last_revision.id)
+      differences = json.fetch('diff').map { [_1.fetch('type'), _1.fetch('content').strip] }
+      expect(differences).to include(['removed', '- 旧タグ'], ['added', '- 新タグ'])
+    end
+  end
+
+  it 'does not use a version belonging to another group' do
+    other_id = seed_group(name: '別グループ', description: '別本文')
+    other_version = group_version(other_id, 1)
+    get group_title_path('読取り契約'), params: { version: other_version.fetch('id') }
+    expect(response).to have_http_status(:not_found)
+    get "/wiki/#{ page.id }/diff",
+        params: { from: other_version.fetch('id'), to: last_revision.id }
+    expect(response).to have_http_status(:not_found)
+  end
+
+  it 'resolves a group without any compatibility Wiki page' do
+    id = seed_group(name: '独立グループ', description: '独立した説明')
+    without_group_legacy_reads { get group_title_path('独立グループ') }
+    expect(response).to have_http_status(:ok)
+    expect(json).to include('id' => id, 'title' => 'タググループ:独立グループ')
+    expect(json.fetch('body').strip).to eq('独立した説明')
+  end
+
+  context 'when Help, description and group share the same numeric ID' do
+    let(:colliding_help) do
+      Wiki::Commit.create_legacy_content!(
+          tag_name: create(:tag_name, name: 'Help:三者ID衝突'),
+          body: 'help', created_by_user: user)
+    end
+    let(:colliding_group_id) do
+      seed_group(name: '三者ID衝突', id: colliding_help.id, description: 'group')
+    end
+    let(:colliding_description) do
+      TagDescription.create!(
+          id: colliding_help.id, tag: new_tag, language_code: 'ja',
+          body: 'description', version_no: 1)
+    end
+    let(:colliding_description_version) do
+      TagDescriptionVersion.create!(
+          tag_id: new_tag.id, language_code: 'ja', version_no: 1,
+          event_type: 'create', body: 'description', created_by_user_id: user.id,
+          created_at: Time.current)
+    end
+
+    before do
+      colliding_group_id
+      colliding_description
+      colliding_description_version
+    end
+
+    it 'lists all three resources without deduplicating their numeric ID' do
+      get '/wiki'
+
+      expect(response).to have_http_status(:ok)
+      rows = json.select { _1.fetch('id') == colliding_help.id }
+      expect(rows.map { [_1.fetch('id'), _1.fetch('title')] }).to contain_exactly(
+          [colliding_help.id, colliding_help.title],
+          [colliding_description.id, '新タグ'],
+          [colliding_group_id, 'タググループ:三者ID衝突'])
+    end
+
+    it 'lists each resource history without deduplicating the shared resource ID' do
+      get '/wiki/changes'
+
+      expect(response).to have_http_status(:ok)
+      rows = json.select { _1.fetch('wiki_page').fetch('id') == colliding_help.id }
+      histories = rows.map do |row|
+        [row.fetch('revision_id'), row.fetch('wiki_page').fetch('title')]
+      end
+      expect(histories).to contain_exactly(
+          [colliding_help.current_revision.id, colliding_help.title],
+          [colliding_description_version.id, '新タグ'],
+          [group_version(colliding_group_id, 1).fetch('id'), 'タググループ:三者ID衝突'])
+    end
+
+    it 'still excludes legacy copies of an actually migrated group and its history' do
+      extra = Wiki::Commit.legacy_content!(page:, body: 'legacy only', created_user: user)
+
+      get '/wiki'
+
+      expect(response).to have_http_status(:ok)
+      rows = json.select { _1.fetch('id') == page.id }
+      expect(rows.map { _1.fetch('title') }).to eq(['タググループ:読取り契約'])
+
+      get '/wiki/changes'
+
+      expect(response).to have_http_status(:ok)
+      rows = json.select { _1.fetch('wiki_page').fetch('id') == page.id }
+      expect(rows.map { _1.fetch('revision_id') })
+          .to contain_exactly(first_revision.id, last_revision.id)
+      expect(rows.map { _1.fetch('revision_id') }).not_to include(extra.id)
+      expect(rows.map { _1.fetch('wiki_page').fetch('title') })
+          .to all(eq('タググループ:読取り契約'))
+    end
+  end
+
+  it 'resolves colliding group, Help and description IDs by title' do
+    help = Wiki::Commit.create_legacy_content!(
+        tag_name: create(:tag_name, name: 'Help:ID衝突'), body: 'help', created_by_user: user)
+    seed_group(name: 'ID衝突', id: help.id, description: 'group')
+    TagDescription.create!(
+        id: help.id, tag: new_tag, language_code: 'ja', body: 'description', version_no: 1)
+    TagDescriptionVersion.create!(
+        tag_id: new_tag.id, language_code: 'ja', version_no: 1,
+        event_type: 'create', body: 'description', created_at: Time.current)
+    { 'タググループ:ID衝突' => 'group', 'Help:ID衝突' => 'help', '新タグ' => 'description' }
+        .each do |title, body|
+      get "/wiki/title/#{ CGI.escapeURIComponent(title) }"
+      expect(response).to have_http_status(:ok)
+      expect(json.fetch('body').strip).to eq(body)
+    end
+  end
+end

backend/spec/requests/tag_group_wiki_write_spec.rb

@@ -0,0 +1,304 @@
+require 'rails_helper'
+
+RSpec.describe 'Tag group Wiki facade writes', type: :request do
+  include TagGroupRecords
+  include ActiveSupport::Testing::TimeHelpers
+
+  let!(:user) { create_member_user! }
+  let!(:tag) { group_tag('洗澡鹿') }
+  let!(:other_tag) { group_tag('伊地知ニジカ') }
+  let(:headers) { { 'X-Transfer-Code' => user.inheritance_code } }
+  let(:members) { [{ 'tag_id' => tag.id, 'version_no' => tag.version_no }] }
+  let(:placements) { [{ 'tag_id' => tag.id, 'children' => [] }] }
+
+  before { I18n.locale = :ja }
+
+  def create_group title: 'タググループ:新規', body: '- 洗澡鹿', request_headers: headers
+    post '/wiki', params: { title:, body: }, headers: request_headers
+  end
+
+  def expect_rejected_without_writes
+    before_state = group_state
+    yield
+    aggregate_failures do
+      expect(response).to have_http_status(:unprocessable_entity)
+      expect(group_state).to eq(before_state)
+      expect(response.media_type).to eq('application/json')
+      expect(response.body).not_to be_empty
+      next if response.body.empty?
+
+      expect(json).to include(
+          'type' => 'validation_error', 'errors' => a_kind_of(Hash),
+          'base_errors' => a_kind_of(Array))
+    end
+  end
+
+  it 'creates the group, first snapshot and compatibility Wiki history' do
+    create_group
+    expect(response).to have_http_status(:created)
+    group = group_rows('tag_groups', name: '新規').sole
+    expect(json).to include('id' => group.fetch('id'), 'title' => 'タググループ:新規')
+    expect_group_snapshot(group.fetch('id'), number: 1, members:, placements:)
+    version = group_version(group.fetch('id'), 1)
+    expect(version).to include('event_type' => 'create', 'created_by_user_id' => user.id)
+    expect(group).to include('created_by_user_id' => user.id, 'updated_by_user_id' => user.id)
+    page = WikiPage.joins(:tag_name).find_by!(tag_names: { name: 'タググループ:新規' })
+    expect(page.body.strip).to eq('- 洗澡鹿')
+    expect(page.current_revision.body).to eq(page.body)
+    expect(page.wiki_versions.sole.body).to eq(page.body)
+    # New IDs are independently allocated; no global identity assertion here.
+  end
+
+  it 'keeps repeated placements but only one membership and one snapshot member' do
+    create_group(body: "- 洗澡鹿\n# 再掲\n- 洗澡鹿")
+    expect(response).to have_http_status(:created)
+    id = group_rows('tag_groups', name: '新規').sole.fetch('id')
+    expect_group_snapshot(
+        id, number: 1, members:,
+        placements: placements + [
+            { 'section_name' => '再掲', 'description' => nil, 'children' => placements }])
+  end
+
+  it 'resolves a Japanese alias through tag_names.tag_id' do
+    create(:tag_name, :alias, tag:, name: '鹿の別名')
+    create_group(body: '- 鹿の別名')
+    expect(response).to have_http_status(:created)
+    id = group_rows('tag_groups', name: '新規').sole.fetch('id')
+    expect_group_snapshot(id, number: 1, members:, placements:)
+    get group_title_path('新規')
+    expect(response).to have_http_status(:ok)
+    expect(json.fetch('body').strip).to eq('- 洗澡鹿')
+  end
+
+  {
+      'unknown Tag' => '- 解決不能',
+      'unknown Tag Group' => '- タググループ:存在しない',
+      'empty Section' => '- :',
+      'unsupported placement syntax' => "```\n洗澡鹿\n```",
+      'six levels' => "- 洗澡鹿\n  - 洗澡鹿\n    - 洗澡鹿\n      - 洗澡鹿\n" +
+          "        - 洗澡鹿\n          - 洗澡鹿",
+      'blank body' => '',
+      'normalised blank body' => "\r\n\r\n" }.each do |label, body|
+    it "rejects #{ label } without fallback or partial create" do
+      expect_rejected_without_writes { create_group(body:) }
+    end
+  end
+
+  ['', 'タググループ:', "タググループ:#{ '長' * 256 }"].each do |title|
+    it "rejects an invalid required title of length #{ title.length }" do
+      expect_rejected_without_writes { create_group(title:) }
+    end
+  end
+
+  it 'rejects a duplicate group name even without a matching legacy Wiki' do
+    seed_group(name: '新規', description: '既存')
+    expect_rejected_without_writes { create_group }
+  end
+
+  it 'accepts the existing five-level placement depth boundary' do
+    body = (0...5).map { "#{ '  ' * _1 }- 洗澡鹿" }.join("\n")
+    create_group(body:)
+    expect(response).to have_http_status(:created)
+    id = group_rows('tag_groups', name: '新規').sole.fetch('id')
+    tree = []
+    5.times { tree = [{ 'tag_id' => tag.id, 'children' => tree }] }
+    expect_group_snapshot(id, number: 1, members:, placements: tree)
+  end
+
+  context 'updating a migrated group' do
+    let!(:page) { legacy_group('更新', '- 洗澡鹿') }
+    let!(:old_revision) { page.current_revision }
+
+    before { migrate_groups }
+
+    def update_group body: '- 伊地知ニジカ', title: 'タググループ:更新', request_headers: headers
+      put "/wiki/#{ page.id }", params: { title:, body: }, headers: request_headers
+    end
+
+    [1, 3].each do |repetitions|
+      it "keeps identical Markdown unchanged after #{ repetitions } Wiki PUTs" do
+        body = page.body
+        travel_to(1.hour.from_now) do
+          expect_noop_group_update(group_id: page.id, page:) do
+            repetitions.times do
+              update_group(body:)
+              expect(response).to have_http_status(:ok)
+            end
+          end
+        end
+      end
+    end
+
+    it 'keeps identical Markdown unchanged with a stale base_revision_id' do
+      update_group
+      expect(response).to have_http_status(:ok)
+      body = page.reload.body
+      expect(page.current_revision.id).not_to eq(old_revision.id)
+
+      travel_to(1.hour.from_now) do
+        expect_noop_group_update(group_id: page.id, page:) do
+          put "/wiki/#{ page.id }",
+              params: { title: page.title, body:, base_revision_id: old_revision.id },
+              headers: headers
+        end
+      end
+    end
+
+    it 'keeps the original editor on identical Markdown from another member' do
+      editor = create(:user, :member)
+      body = page.body
+      travel_to(1.hour.from_now) do
+        expect_noop_group_update(group_id: page.id, page:) do
+          update_group(body:, request_headers: { 'X-Transfer-Code' => editor.inheritance_code })
+        end
+      end
+    end
+
+    it 'does not add history for Wiki content already changed through Native' do
+      changed_members = [{ 'tag_id' => other_tag.id }]
+      changed_placements = [{ 'tag_id' => other_tag.id, 'children' => [] }]
+      put "/tag_groups/#{ page.id }",
+          params: { name: '更新', description: nil,
+                    members: changed_members, placements: changed_placements },
+          headers:, as: :json
+      expect(response).to have_http_status(:ok)
+      expect_group_snapshot(
+          page.id, number: 2,
+          members: [{ 'tag_id' => other_tag.id, 'version_no' => other_tag.version_no }],
+          placements: changed_placements)
+      body = page.reload.body
+      expect(body).to eq('- 伊地知ニジカ')
+
+      travel_to(1.hour.from_now) do
+        expect_noop_group_update(group_id: page.id, page:) { update_group(body:) }
+      end
+    end
+
+    it 'replaces current membership and placement, retaining the old snapshot' do
+      old = group_version(page.id, 1)
+      update_group
+      expect(response).to have_http_status(:ok)
+      expect_group_snapshot(
+          page.id, number: 2,
+          members: [{ 'tag_id' => other_tag.id, 'version_no' => other_tag.version_no }],
+          placements: [{ 'tag_id' => other_tag.id, 'children' => [] }])
+      expect(group_version(page.id, 1)).to eq(old)
+      expect(group_version(page.id, 2)).to include(
+          'event_type' => 'update', 'created_by_user_id' => user.id)
+      expect(page.reload.body.strip).to eq('- 伊地知ニジカ')
+      expect(page.wiki_revisions.count).to eq(2)
+      expect(page.wiki_versions.count).to eq(2)
+      expect(page.current_revision.body).to eq(page.body)
+      expect(page.wiki_versions.order(:version_no).last.body).to eq(page.body)
+    end
+
+    it 'accepts the current base_revision_id used by the existing frontend' do
+      put "/wiki/#{ page.id }",
+          params: { title: page.title, body: '- 伊地知ニジカ',
+                    base_revision_id: old_revision.id }, headers: headers
+      expect(response).to have_http_status(:ok)
+      expect(group_rows('tag_groups', id: page.id).sole.fetch('version_no')).to eq(2)
+    end
+
+    it 'ignores a stale base_revision_id without rejecting the update' do
+      update_group
+      expect(response).to have_http_status(:ok)
+
+      put "/wiki/#{ page.id }",
+          params: { title: page.title, body: '- 洗澡鹿',
+                    base_revision_id: old_revision.id }, headers: headers
+
+      expect(response).to have_http_status(:ok)
+      expect(group_rows('tag_groups', id: page.id).sole.fetch('version_no')).to eq(3)
+      expect(page.reload.body.strip).to eq('- 洗澡鹿')
+    end
+
+    it 'records the editor and update time' do
+      editor = create(:user, :member, name: '編輯者')
+      travel_to(Time.current + 1.hour) do
+        update_group(request_headers: { 'X-Transfer-Code' => editor.inheritance_code })
+        expect(response).to have_http_status(:ok)
+        current = group_rows('tag_groups', id: page.id).sole
+        version = group_version(page.id, 2)
+        expect(current).to include('updated_by_user_id' => editor.id)
+        expect(version).to include('created_by_user_id' => editor.id)
+        expect(current.fetch('updated_at')).to be_within(1.second).of(Time.current)
+        expect(version.fetch('created_at')).to be_within(1.second).of(Time.current)
+      end
+    end
+
+    ['- 不明なタグ', '- タググループ:不明', '', '- :'].each do |body|
+      it "rejects invalid update #{ body.inspect } atomically" do
+        expect_rejected_without_writes { update_group(body:) }
+      end
+    end
+
+    it 'rejects direct self inclusion' do
+      expect_rejected_without_writes { update_group(body: '- タググループ:更新') }
+    end
+
+    it 'rejects indirect cyclic membership' do
+      seed_group(
+          name: '子', members: [{ 'tag_group_id' => page.id, 'version_no' => 1 }],
+          placements: [{ 'tag_group_id' => page.id, 'children' => [] }])
+      expect_rejected_without_writes { update_group(body: '- タググループ:子') }
+    end
+
+    it 'rejects duplicate rename without retaining a partial title or version' do
+      seed_group(name: '既存', description: '既存')
+      expect_rejected_without_writes { update_group(title: 'タググループ:既存') }
+    end
+  end
+
+  [:create, :update].each do |operation|
+    context "#{ operation } access and atomicity" do
+      let!(:page) do
+        next unless operation == :update
+
+        legacy = legacy_group('更新', '- 洗澡鹿')
+        seed_group(name: '更新', id: legacy.id, members:, placements:)
+        legacy
+      end
+      let!(:child_id) { seed_group(name: '子グループ', description: '子') }
+
+      def write_group operation, request_headers
+        body = "- 伊地知ニジカ\n- タググループ:子グループ"
+        if operation == :create
+          create_group(body:, request_headers:)
+        else
+          put "/wiki/#{ page.id }",
+              params: { title: 'タググループ:更新', body: }, headers: request_headers
+        end
+      end
+
+      [nil, :guest, :banned].each do |role|
+        it "rejects #{ role || 'anonymous' } without writes" do
+          actor = case role
+          when :guest then create(:user, :guest)
+          when :banned then create(:user, :member, :banned)
+          end
+          request_headers = actor ? { 'X-Transfer-Code' => actor.inheritance_code } : { }
+          before_state = group_state
+          write_group(operation, request_headers)
+          expect(response).to have_http_status(role ? :forbidden : :unauthorized)
+          expect(group_state).to eq(before_state)
+        end
+      end
+
+      it 'rejects a banned IP even for a member' do
+        IpAddress.create!(ip_address: IPAddr.new('127.0.0.1').hton, banned_at: Time.current)
+        before_state = group_state
+        write_group(operation, headers)
+        expect(response).to have_http_status(:forbidden)
+        expect(group_state).to eq(before_state)
+      end
+
+      (TagGroupRecords::GROUP_TABLES + ['wiki_pages', 'wiki_revisions', 'wiki_versions'])
+          .each do |table|
+        it "rolls back all writes after a real #{ table } write fails" do
+          expect_atomic_group_write(table) { write_group(operation, headers) }
+        end
+      end
+    end
+  end
+end

backend/spec/requests/tag_group_write_integrity_spec.rb

@@ -0,0 +1,329 @@
+require 'rails_helper'
+
+RSpec.describe 'Tag group write integrity', type: :request do
+  include TagGroupRecords
+  include ActiveSupport::Testing::TimeHelpers
+
+  let!(:user) { create_member_user! }
+  let!(:tag) { group_tag('洗澡鹿') }
+  let!(:other_tag) { group_tag('伊地知ニジカ') }
+  let(:headers) { { 'X-Transfer-Code' => user.inheritance_code } }
+  let(:members) { [{ 'tag_id' => tag.id, 'version_no' => tag.version_no }] }
+  let(:placements) { [{ 'tag_id' => tag.id, 'children' => [] }] }
+
+  before { I18n.locale = :ja }
+
+  def native_payload name: '更新', nodes: placements, member_rows: members
+    { name:, description: nil, members: member_rows.map do |member|
+      member.except('version_no')
+    end, placements: nodes }
+  end
+
+  def put_wiki id, title:, body: '- 伊地知ニジカ', base: nil
+    put "/wiki/#{ id }", params: { title:, body:, base_revision_id: base }, headers: headers
+  end
+
+  def create_help body
+    Wiki::Commit.create_legacy_content!(
+        tag_name: create(:tag_name, name: 'Help:既存'), body:, created_by_user: user)
+  end
+
+  def expect_no_writes
+    before_state = group_state
+    yield
+    expect(response).to have_http_status(:unprocessable_entity)
+    expect(group_state).to eq(before_state)
+  end
+
+  context 'resource identity' do
+    it 'rejects removing the prefix from a migrated group atomically' do
+      page = legacy_group('更新', '- 洗澡鹿')
+      seed_group(name: '更新', id: page.id, members:, placements:)
+
+      expect_no_writes do
+        put_wiki(page.id, title: '更新', base: page.current_revision.id)
+      end
+    end
+
+    it 'rejects an unprefixed update to an independent group' do
+      id = seed_group(name: '独立', members:, placements:)
+      expect_no_writes { put_wiki(id, title: '独立') }
+    end
+
+    it 'does not revive legacy writes when the compatibility title is stale' do
+      page = legacy_group('更新', '- 洗澡鹿')
+      seed_group(name: '更新', id: page.id, members:, placements:)
+      page.tag_name.update!(name: '古い別名')
+
+      expect_no_writes { put_wiki(page.id, title: '古い別名') }
+    end
+
+    it 'renames the group and its compatibility page through the operation' do
+      page = legacy_group('更新', '- 洗澡鹿')
+      seed_group(name: '更新', id: page.id, members:, placements:)
+
+      put_wiki(page.id, title: 'タググループ:改名')
+
+      expect(response).to have_http_status(:ok)
+      expect(TagGroup.find(page.id)).to have_attributes(name: '改名', version_no: 2)
+      expect(page.reload.title).to eq('タググループ:改名')
+      expect(page.body).to eq('- 伊地知ニジカ')
+    end
+
+    it 'updates Help with a colliding group ID without altering the group' do
+      page = create_help('Help body')
+      id = seed_group(name: '別グループ', id: page.id, members:, placements:)
+      group_before = TagGroup.find(id).attributes
+      version_before = group_version(id, 1)
+
+      put_wiki(id, title: 'Help:改名', body: 'Help after')
+
+      expect(response).to have_http_status(:ok)
+      expect(page.reload.body).to eq('Help after')
+      expect(page.title).to eq('Help:改名')
+      expect(TagGroup.find(id).attributes).to eq(group_before)
+      expect(group_version(id, 1)).to eq(version_before)
+    end
+
+    it 'rejects an ambiguous unprefixed rename when Help and group IDs collide' do
+      page = create_help('Help body')
+      seed_group(name: '更新', id: page.id, members:, placements:)
+
+      expect_no_writes { put_wiki(page.id, title: '更新') }
+      expect_no_writes do
+        put_wiki(page.id, title: '更新', base: page.current_revision.id)
+      end
+    end
+
+    it 'keeps a description update separate from a colliding group' do
+      page = Wiki::Commit.create_content!(
+          tag_name: tag.tag_name('ja'), body: 'description before', created_by_user: user)
+      id = seed_group(name: '更新', id: page.id, members:, placements:)
+      group_before = TagGroup.find(id).attributes
+
+      put_wiki(id, title: '洗澡鹿', body: 'description after')
+
+      expect(response).to have_http_status(:ok)
+      expect(TagDescription.find(id).body).to eq('description after')
+      expect(page.reload.body).to eq('description after')
+      expect(TagGroup.find(id).attributes).to eq(group_before)
+    end
+
+    it 'does not route a colliding Help write into an unrelated description' do
+      page = create_help('Help before')
+      id = seed_group(name: '更新', id: page.id, members:, placements:)
+      description = TagDescription.create!(
+          id:, tag:, language_code: 'ja', version_no: 1, body: 'description')
+
+      put_wiki(id, title: 'Help:既存', body: 'Help after')
+
+      expect(response).to have_http_status(:ok)
+      expect(page.reload.body).to eq('Help after')
+      expect(description.reload.body).to eq('description')
+      expect(TagGroup.find(id).version_no).to eq(1)
+      expect_no_writes { put_wiki(id, title: '洗澡鹿', body: 'description after') }
+      put_wiki(id, title: 'タググループ:更新')
+      expect(response).to have_http_status(:ok)
+      expect(TagGroup.find(id).version_no).to eq(2)
+      expect(page.reload.body).to eq('Help after')
+      expect(description.reload.body).to eq('description')
+    end
+  end
+
+  context 'compatibility synchronisation' do
+    it 'synchronises a native rename without modifying an ID-colliding Help page' do
+      help = create_help('Help before')
+      id = seed_group(name: '更新', id: help.id, members:, placements:)
+      help_before = help.attributes
+
+      put "/tag_groups/#{ id }", params: native_payload(name: '改名'), headers:, as: :json
+
+      expect(response).to have_http_status(:ok)
+      page = WikiPage.joins(:tag_name).find_by!(tag_names: { name: 'タググループ:改名' })
+      expect(page.id).not_to eq(help.id)
+      expect(page.body).to eq('- 洗澡鹿')
+      expect(page.current_revision.body).to eq(page.body)
+      expect(page.wiki_versions.sole.body).to eq(page.body)
+      expect(help.reload.attributes).to eq(help_before)
+    end
+
+    ['wiki_lines', 'wiki_revision_lines'].each do |table|
+      it "rolls back native and compatibility state on #{ table } failure" do
+        expect_atomic_group_write(table) do
+          post '/tag_groups', params: native_payload, headers:, as: :json
+        end
+      end
+    end
+
+    it 'rolls back a renderer failure instead of treating it as unsupported structure' do
+      allow(TagGroupMarkdownRenderer).to receive(:render).and_raise('renderer failure')
+      before_state = group_state
+
+      expect do
+        post '/tag_groups', params: native_payload, headers:, as: :json
+      end.to raise_error(RuntimeError, 'renderer failure')
+
+      expect(group_state).to eq(before_state)
+    end
+
+    it 'preserves unplaced membership and reports the skipped sync with its version' do
+      page = legacy_group('更新', '- 洗澡鹿')
+      id = seed_group(name: '更新', id: page.id, members:, placements:)
+      wiki_before = group_state.slice(*TagGroupRecords::WRITE_TABLES.drop(5))
+      warnings = []
+      allow(Rails.logger).to receive(:warn) { warnings << _1 }
+
+      put "/tag_groups/#{ id }",
+          params: native_payload(member_rows: members + [{ 'tag_id' => other_tag.id }]),
+          headers:, as: :json
+
+      expect(response).to have_http_status(:ok)
+      expect(json.fetch('members').map { _1.fetch('tag').fetch('id') })
+          .to contain_exactly(tag.id, other_tag.id)
+      expect(group_version(id, 2).fetch('members')).to include(
+          { 'tag_id' => other_tag.id, 'version_no' => other_tag.version_no })
+      expect(group_state.slice(*TagGroupRecords::WRITE_TABLES.drop(5))).to eq(wiki_before)
+      payload = JSON.parse(warnings.grep(/tag_group_wiki_sync_skipped/).sole.split(' ', 2).last)
+      expect(payload).to include(
+          'status' => 'unsupported_structure', 'tag_group_id' => id,
+          'version_no' => 2, 'user_id' => user.id,
+          'reason' => '掲載位置のない membership は Markdown にできません．')
+    end
+
+    it 'preserves a list Section description and records why no Wiki was created' do
+      nodes = [{ 'tag_id' => tag.id, 'children' => [
+          { 'section_name' => '区分', 'description' => '構造化の説明', 'children' => [] }] }]
+      warnings = []
+      allow(Rails.logger).to receive(:warn) { warnings << _1 }
+      before_count = WikiPage.count
+
+      post '/tag_groups', params: native_payload(nodes:), headers:, as: :json
+
+      expect(response).to have_http_status(:created)
+      id = json.fetch('id')
+      expect(group_version(id, 1).fetch('placements')).to eq(nodes)
+      expect(json.fetch('placements').sole.fetch('children').sole)
+          .to include('description' => '構造化の説明')
+      expect(WikiPage.count).to eq(before_count)
+      expect(warnings.grep(/tag_group_wiki_sync_skipped/).sole)
+          .to include('リスト内 Section の説明文は Markdown にできません．')
+    end
+  end
+
+  context 'identifier Markdown' do
+    ['[洗澡鹿](https://example.com)', '*洗澡鹿*', '**洗澡鹿**', '`洗澡鹿`',
+     '![洗澡鹿](https://example.com/image.png)',
+     '[タググループ:子](https://example.com)', '*区分*:',
+     '[区分](https://example.com):'].each do |label|
+      [:create, :update].each do |operation|
+        it "rejects decorated #{ label } on #{ operation } without writes" do
+          seed_group(name: '子', description: '子')
+          id = seed_group(name: '更新', members:, placements:)
+          expect_no_writes do
+            if operation == :create
+              post '/wiki', params: { title: 'タググループ:新規', body: "- #{ label }" },
+                   headers: headers
+            else
+              put_wiki(id, title: 'タググループ:更新', body: "- #{ label }")
+            end
+          end
+        end
+      end
+    end
+
+    ['# [区分](https://example.com)', '# *区分*', '# `区分`', '# 区分 {#custom}',
+     '# ![区分](https://example.com/image.png)'].each do |heading|
+      it "rejects a decorated heading #{ heading } without writes" do
+        expect_no_writes do
+          post '/wiki', params: { title: 'タググループ:新規', body: "#{ heading }\n- 洗澡鹿" },
+               headers: headers
+        end
+      end
+    end
+
+    it 'preserves allowed markup in group and heading descriptions' do
+      description = '[参照](https://example.com "リンクの説明") と *強調* と ``a`b``'
+      body = "#{ description }\n\n# 区分\n#{ description }\n\n- 洗澡鹿"
+      post '/wiki', params: { title: 'タググループ:説明構文', body: }, headers: headers
+
+      expect(response).to have_http_status(:created)
+      id = json.fetch('id')
+      version = group_version(id, 1)
+      expect(version.fetch('description')).to eq(description)
+      expect(version.fetch('placements').sole.fetch('description')).to eq(description)
+    end
+  end
+
+  context 'structure audit information' do
+    let!(:child_id) { seed_group(name: '子', description: '子') }
+    let(:members) do
+      [{ 'tag_id' => tag.id, 'version_no' => tag.version_no },
+       { 'tag_group_id' => child_id, 'version_no' => 1 }]
+    end
+    let(:placements) do
+      [{ 'tag_id' => tag.id, 'children' => [
+          { 'tag_group_id' => child_id, 'children' => [] }] }]
+    end
+    let!(:id) { seed_group(name: '更新', members:, placements:) }
+    let!(:editor) { create(:user, :member) }
+    let(:headers) { { 'X-Transfer-Code' => editor.inheritance_code } }
+
+    it 'keeps all membership and placement audit fields on a name-only edit' do
+      before_rows = group_state.slice('tag_group_tags', 'tag_group_groups', 'tag_group_placements')
+      travel_to(1.hour.from_now) do
+        put "/tag_groups/#{ id }", params: native_payload(name: '改名'), headers:, as: :json
+      end
+
+      expect(response).to have_http_status(:ok)
+      expect(group_state.slice(*before_rows.keys)).to eq(before_rows)
+      expect(group_version(id, 2)).to include('name' => '改名', 'members' => members)
+    end
+
+    it 'keeps membership and placement audit fields on a description-only edit' do
+      before_rows = group_state.slice('tag_group_tags', 'tag_group_groups', 'tag_group_placements')
+      travel_to(1.hour.from_now) do
+        put "/tag_groups/#{ id }",
+            params: native_payload.merge(description: '説明を追加'), headers:, as: :json
+      end
+
+      expect(response).to have_http_status(:ok)
+      expect(group_state.slice(*before_rows.keys)).to eq(before_rows)
+      expect(group_version(id, 2)).to include('description' => '説明を追加', 'members' => members)
+    end
+
+    it 'rolls back membership removal and placement edits on a late sync failure' do
+      new_members = [{ 'tag_id' => tag.id }]
+      new_nodes = [{ 'tag_id' => tag.id, 'children' => [] }]
+      expect_atomic_group_write('wiki_versions') do
+        put "/tag_groups/#{ id }",
+            params: native_payload(nodes: new_nodes, member_rows: new_members), headers:, as: :json
+      end
+    end
+
+    it 'changes only added or removed membership and keeps placement creation audit' do
+      tag_row = TagGroupTag.find([id, tag.id]).attributes
+      placement_row = TagGroupPlacement.find([id, 1]).attributes
+      new_members = [{ 'tag_id' => tag.id }, { 'tag_id' => other_tag.id }]
+      new_nodes = [{ 'tag_id' => tag.id, 'children' => [
+          { 'tag_id' => other_tag.id, 'children' => [] }] }]
+      child_row = TagGroupPlacement.find([id, 2]).attributes
+      travel_to(1.hour.from_now) do
+        put "/tag_groups/#{ id }",
+            params: native_payload(nodes: new_nodes, member_rows: new_members), headers:, as: :json
+      end
+
+      expect(response).to have_http_status(:ok)
+      expect(TagGroupTag.find([id, tag.id]).attributes).to eq(tag_row)
+      expect(TagGroupGroup.exists?(tag_group_id: id, child_tag_group_id: child_id)).to be(false)
+      expect(TagGroupTag.find([id, other_tag.id]).created_by_user_id).to eq(editor.id)
+      expect(TagGroupPlacement.find([id, 1]).attributes).to eq(placement_row)
+      changed = TagGroupPlacement.find([id, 2])
+      expect(changed).to have_attributes(
+          tag_id: other_tag.id, child_tag_group_id: nil, updated_by_user_id: editor.id,
+          created_at: child_row.fetch('created_at'),
+          created_by_user_id: child_row.fetch('created_by_user_id'))
+      expect(changed.updated_at).to be > child_row.fetch('updated_at')
+      expect(group_version(id, 1).fetch('members')).to eq(members)
+    end
+  end
+end

backend/spec/requests/tag_groups_spec.rb

@@ -0,0 +1,457 @@
+require 'rails_helper'
+
+RSpec.describe 'Tag group native API', type: :request do
+  include TagGroupRecords
+  include ActiveSupport::Testing::TimeHelpers
+
+  let!(:user) { create_member_user! }
+  let!(:group_id) { seed_group(name: '専用API', description: '説明') }
+
+  before { I18n.locale = :ja }
+
+  def expect_native_group value
+    expect(value).to include(
+        'id' => group_id, 'name' => '専用API', 'description' => '説明',
+        'version_no' => 1, 'members' => [], 'placements' => [],
+        'created_by_user' => UserRepr.base(user), 'updated_by_user' => UserRepr.base(user))
+    current = group_rows('tag_groups', id: group_id).sole
+    expect(value).to include(
+        'created_at' => current.fetch('created_at').iso8601(3),
+        'updated_at' => current.fetch('updated_at').iso8601(3))
+  end
+
+  it 'serves the collection as JSON without reading Wiki tables' do
+    without_group_legacy_reads { get '/tag_groups' }
+    expect(response).to have_http_status(:ok)
+    expect(response.media_type).to eq('application/json')
+    expect(json).to be_a(Array)
+    expect_native_group(json.find { _1.fetch('id') == group_id })
+  end
+
+  it 'serves an independent group as JSON without reading Wiki tables' do
+    without_group_legacy_reads { get "/tag_groups/#{ group_id }" }
+    expect(response).to have_http_status(:ok)
+    expect(response.media_type).to eq('application/json')
+    expect_native_group(json)
+  end
+
+  it 'provides the confirmed PUT update route' do
+    route = Rails.application.routes.recognize_path("/tag_groups/#{ group_id }", method: :put)
+    expect(route).to include(action: 'update', id: group_id.to_s)
+  end
+
+  [:create, :update].each do |operation|
+    [nil, :guest, :banned].each do |role|
+      it "rejects #{ role || 'anonymous' } native #{ operation } without writes" do
+        actor = case role
+        when :guest then create(:user, :guest)
+        when :banned then create(:user, :member, :banned)
+        end
+        headers = actor ? { 'X-Transfer-Code' => actor.inheritance_code } : { }
+        before_state = group_state
+        if operation == :create
+          post '/tag_groups', params: { }, headers:, as: :json
+        else
+          put "/tag_groups/#{ group_id }", params: { }, headers:, as: :json
+        end
+        expect(response).to have_http_status(role ? :forbidden : :unauthorized)
+        expect(group_state).to eq(before_state)
+      end
+    end
+
+    it "rejects a banned IP for native #{ operation }" do
+      IpAddress.create!(ip_address: IPAddr.new('127.0.0.1').hton, banned_at: Time.current)
+      headers = { 'X-Transfer-Code' => user.inheritance_code }
+      before_state = group_state
+      if operation == :create
+        post '/tag_groups', params: { }, headers:, as: :json
+      else
+        put "/tag_groups/#{ group_id }", params: { }, headers:, as: :json
+      end
+      expect(response).to have_http_status(:forbidden)
+      expect(group_state).to eq(before_state)
+    end
+  end
+
+  context 'structured membership and placements' do
+    let!(:tag) { group_tag('掲載タグ') }
+    let!(:unplaced) { group_tag('未掲載タグ') }
+    let!(:child_id) { seed_group(name: '子', description: '子の説明') }
+    let(:headers) { { 'X-Transfer-Code' => user.inheritance_code } }
+    let(:members) do
+      [{ 'tag_id' => tag.id }, { 'tag_group_id' => child_id }, { 'tag_id' => unplaced.id }]
+    end
+    let(:snapshot_members) do
+      [{ 'tag_id' => tag.id, 'version_no' => tag.version_no },
+       { 'tag_group_id' => child_id, 'version_no' => 1 },
+       { 'tag_id' => unplaced.id, 'version_no' => unplaced.version_no }]
+    end
+    let(:placements) do
+      [{ 'section_name' => '区分', 'description' => '区分の説明', 'children' => [
+          { 'tag_id' => tag.id, 'children' => [
+              { 'tag_group_id' => child_id, 'children' => [] }] },
+          { 'tag_id' => tag.id, 'children' => [] }] }]
+    end
+    let(:payload) { { name: '構造化', description: '全体の説明', members:, placements: } }
+
+    def native_write operation, attributes = payload
+      if operation == :create
+        post '/tag_groups', params: attributes, headers:, as: :json
+      else
+        put "/tag_groups/#{ group_id }", params: attributes, headers:, as: :json
+      end
+    end
+
+    def expect_structured_response
+      tag_repr = { 'id' => tag.id, 'name' => '掲載タグ', 'category' => tag.category }
+      unplaced_repr = { 'id' => unplaced.id, 'name' => '未掲載タグ',
+                        'category' => unplaced.category }
+      expect(json.fetch('members')).to contain_exactly(
+          include('tag' => include(tag_repr)),
+          include('tag' => include(unplaced_repr)),
+          include('tag_group' => include('id' => child_id, 'name' => '子')))
+      expect(json.fetch('placements')).to match([
+          include('section_name' => '区分', 'description' => '区分の説明', 'children' => [
+              include('tag' => include(tag_repr), 'children' => [
+                  include('tag_group' => include('id' => child_id, 'name' => '子'),
+                          'children' => [])]),
+              include('tag' => include(tag_repr), 'children' => [])])])
+    end
+
+    [:create, :update].each do |operation|
+      it "#{ operation }s structured data and keeps unplaced membership" do
+        previous = group_version(group_id, 1)
+        native_write(operation)
+        expect(response).to have_http_status(operation == :create ? :created : :ok)
+        id = operation == :create ? json.fetch('id') : group_id
+        number = operation == :create ? 1 : 2
+        expect_group_snapshot(
+            id, number:, members: snapshot_members, placements:, description: '全体の説明')
+        expect(group_version(group_id, 1)).to eq(previous)
+        get "/tag_groups/#{ id }"
+        expect(response).to have_http_status(:ok)
+        expect(json).to include(
+            'id' => id, 'name' => '構造化', 'description' => '全体の説明', 'version_no' => number,
+            'created_by_user' => UserRepr.base(user), 'updated_by_user' => UserRepr.base(user))
+        expect_structured_response
+      end
+
+      {
+          'blank name' => { name: '' },
+          'missing name' => { name: nil },
+          'oversized name' => { name: '長' * 256 },
+          'duplicate name' => { name: '子' },
+          'placement without a kind' => { placements: [{ children: [] }] },
+          'empty Section name' => { placements: [{ section_name: '', children: [] }] } }
+          .each do |label, invalid|
+        it "rejects #{ label } on #{ operation } without partial writes" do
+          before_state = group_state
+          native_write(operation, payload.merge(invalid))
+          aggregate_failures do
+            expect(response).to have_http_status(:unprocessable_entity)
+            expect(group_state).to eq(before_state)
+          end
+        end
+      end
+
+      it "rejects multiple placement kinds on #{ operation }" do
+        before_state = group_state
+        invalid = [{ tag_id: tag.id, section_name: '不正', children: [] }]
+        native_write(operation, payload.merge(placements: invalid))
+        expect(response).to have_http_status(:unprocessable_entity)
+        expect(group_state).to eq(before_state)
+      end
+
+      it "rejects a missing referenced Tag on #{ operation }" do
+        missing = Tag.maximum(:id).to_i + 1
+        before_state = group_state
+        native_write(operation, payload.merge(
+            members: [{ tag_id: missing }], placements: [{ tag_id: missing, children: [] }]))
+        expect(response).to have_http_status(:unprocessable_entity)
+        expect(group_state).to eq(before_state)
+      end
+
+      it "rejects a missing referenced group on #{ operation }" do
+        missing = group_rows('tag_groups').map { _1.fetch('id') }.max + 1
+        before_state = group_state
+        native_write(operation, payload.merge(
+            members: [{ tag_group_id: missing }],
+            placements: [{ tag_group_id: missing, children: [] }]))
+        expect(response).to have_http_status(:unprocessable_entity)
+        expect(group_state).to eq(before_state)
+      end
+
+      it "rejects six descendant placement levels on #{ operation }" do
+        nodes = []
+        6.times { nodes = [{ tag_id: tag.id, children: nodes }] }
+        before_state = group_state
+        native_write(operation, payload.merge(placements: nodes))
+        expect(response).to have_http_status(:unprocessable_entity)
+        expect(group_state).to eq(before_state)
+      end
+    end
+
+    it 'preserves membership-only data in structured reads without inventing placements' do
+      id = seed_group(name: '未掲載のみ', members: [snapshot_members.last])
+      without_group_legacy_reads { get "/tag_groups/#{ id }" }
+      expect(response).to have_http_status(:ok)
+      expect(json.fetch('placements')).to eq([])
+      expect(json.fetch('members')).to match([
+          include('tag' => include('id' => unplaced.id, 'name' => '未掲載タグ'))])
+    end
+
+    it 'rejects indirect containment cycles' do
+      parent = seed_group(
+          name: '親', members: [{ 'tag_group_id' => group_id, 'version_no' => 1 }])
+      before_state = group_state
+      native_write(:update, payload.merge(
+          members: [{ tag_group_id: parent }], placements: []))
+      expect(response).to have_http_status(:unprocessable_entity)
+      expect(group_state).to eq(before_state)
+    end
+
+    it 'rejects direct containment even without a corresponding placement' do
+      before_state = group_state
+      native_write(:update, payload.merge(
+          members: [{ tag_group_id: group_id }], placements: []))
+      expect(response).to have_http_status(:unprocessable_entity)
+      expect(group_state).to eq(before_state)
+    end
+
+    it 'preserves list Section descriptions in native structured data' do
+      nodes = [{ tag_id: tag.id, children: [
+          { section_name: 'リスト内区分', description: '消してはいけない説明', children: [] }] }]
+      native_write(:update, payload.merge(placements: nodes))
+      expect(response).to have_http_status(:ok)
+      expect(group_version(group_id, 2).fetch('placements')).to eq(
+          JSON.parse(nodes.to_json))
+      get "/tag_groups/#{ group_id }"
+      expect(response).to have_http_status(:ok)
+      section = json.fetch('placements').sole.fetch('children').sole
+      expect(section).to include(
+          'section_name' => 'リスト内区分', 'description' => '消してはいけない説明')
+    end
+
+    context 'compatibility writes for representable structures' do
+      let(:group_id) do
+        page = legacy_group('専用API', '説明')
+        seed_group(name: '専用API', id: page.id, description: '説明')
+      end
+      let(:members) { [{ 'tag_id' => tag.id }, { 'tag_group_id' => child_id }] }
+      let(:snapshot_members) do
+        [{ 'tag_id' => tag.id, 'version_no' => tag.version_no },
+         { 'tag_group_id' => child_id, 'version_no' => 1 }]
+      end
+
+      it 'treats identical native content with unplaced membership as a no-op' do
+        unplaced_payload = payload.merge(
+            name: '専用API', members: members + [{ 'tag_id' => unplaced.id }])
+        native_write(:update, unplaced_payload)
+        expect(response).to have_http_status(:ok)
+        expect_group_snapshot(
+            group_id, number: 2, description: '全体の説明', placements:,
+            members: snapshot_members + [
+                { 'tag_id' => unplaced.id, 'version_no' => unplaced.version_no }])
+        page = WikiPage.joins(:tag_name).find_by!(tag_names: { name: 'タググループ:専用API' })
+
+        travel_to(1.hour.from_now) do
+          expect_noop_group_update(group_id:, page:) do
+            native_write(:update, unplaced_payload)
+          end
+        end
+      end
+
+      context 'no-op updates against synchronised state' do
+        let(:synchronised_payload) do
+          { name: '構造化', description: '全体の説明',
+            members: [{ 'tag_id' => tag.id }, { 'tag_group_id' => child_id }], placements: }
+        end
+        let(:additional_tag) { group_tag('追加対象タグ') }
+        let(:compatibility_page) do
+          WikiPage.joins(:tag_name).find_by!(tag_names: { name: 'タググループ:構造化' })
+        end
+
+        before do
+          native_write(:update, synchronised_payload)
+          expect(response).to have_http_status(:ok)
+          expect(compatibility_page.body).to include('- 掲載タグ', '- タググループ:子')
+        end
+
+        [1, 3].each do |repetitions|
+          it "keeps identical native content unchanged after #{ repetitions } PUTs" do
+            travel_to(1.hour.from_now) do
+              expect_noop_group_update(group_id:, page: compatibility_page) do
+                repetitions.times do
+                  native_write(:update, synchronised_payload)
+                  expect(response).to have_http_status(:ok)
+                end
+              end
+            end
+          end
+        end
+
+        it 'treats membership order alone as a no-op' do
+          travel_to(1.hour.from_now) do
+            expect_noop_group_update(group_id:, page: compatibility_page) do
+              native_write(:update, synchronised_payload.merge(
+                  members: synchronised_payload.fetch(:members).reverse))
+            end
+          end
+        end
+
+        it 'keeps the original editor when another member submits identical content' do
+          editor = create(:user, :member)
+          travel_to(1.hour.from_now) do
+            expect_noop_group_update(group_id:, page: compatibility_page) do
+              put "/tag_groups/#{ group_id }", params: synchronised_payload,
+                  headers: { 'X-Transfer-Code' => editor.inheritance_code }, as: :json
+            end
+          end
+        end
+
+        it 'does not add history for Native content already changed through Wiki' do
+          put "/wiki/#{ group_id }",
+              params: { title: 'タググループ:構造化', body: '- 未掲載タグ' }, headers: headers
+          expect(response).to have_http_status(:ok)
+          expect(compatibility_page.reload.body).to eq('- 未掲載タグ')
+          same_content = {
+              name: '構造化', description: nil, members: [{ 'tag_id' => unplaced.id }],
+              placements: [{ 'tag_id' => unplaced.id, 'children' => [] }] }
+          expect_group_snapshot(
+              group_id, number: 3, description: nil,
+              members: [{ 'tag_id' => unplaced.id, 'version_no' => unplaced.version_no }],
+              placements: same_content.fetch(:placements))
+
+          travel_to(1.hour.from_now) do
+            expect_noop_group_update(group_id:, page: compatibility_page) do
+              native_write(:update, same_content)
+            end
+          end
+        end
+
+        ['name', 'description', 'membership addition', 'membership removal',
+         'Section name', 'Section description', 'placement order', 'placement hierarchy']
+            .each do |change|
+          it "records a real #{ change } change in both histories" do
+            changed = synchronised_payload.deep_dup
+            section = changed.fetch(:placements).first
+            children = section.fetch('children')
+            case change
+            when 'name' then changed[:name] = '実際の改名'
+            when 'description' then changed[:description] = '実際の説明変更'
+            when 'membership addition'
+              expect(changed.fetch(:members)).not_to include('tag_id' => additional_tag.id)
+              changed[:members] << { 'tag_id' => additional_tag.id }
+              children << { 'tag_id' => additional_tag.id, 'children' => [] }
+            when 'membership removal'
+              changed[:members].reject! { _1.key?('tag_group_id') }
+              children.first['children'] = []
+            when 'Section name' then section['section_name'] = '別区分'
+            when 'Section description' then section['description'] = '別の区分説明'
+            when 'placement order' then children.reverse!
+            when 'placement hierarchy'
+              children << children.first.fetch('children').pop
+            end
+
+            old_versions = group_rows('tag_group_versions', tag_group_id: group_id)
+            group = TagGroup.find(group_id)
+            number = group.version_no
+            page = compatibility_page
+            old_revision_id = page.current_revision.id
+            old_wiki_version_id = page.wiki_versions.order(version_no: :desc).first.id
+            revision_count = page.wiki_revisions.count
+            version_count = page.wiki_versions.count
+            travel_to(1.hour.from_now) { native_write(:update, changed) }
+
+            expect(response).to have_http_status(:ok)
+            expected_members = changed.fetch(:members).map do |member|
+              target = if member.key?('tag_id')
+                Tag.find(member.fetch('tag_id'))
+              else
+                TagGroup.find(member.fetch('tag_group_id'))
+              end
+              member.merge('version_no' => target.version_no)
+            end
+            expect_group_snapshot(
+                group_id, number: number + 1, members: expected_members,
+                placements: changed.fetch(:placements), description: changed.fetch(:description))
+            expect(group.reload.name).to eq(changed.fetch(:name))
+            versions = group_rows('tag_group_versions', tag_group_id: group_id)
+            expect(versions.size).to eq(old_versions.size + 1)
+            expect(versions.select { _1.fetch('version_no') <= number }).to eq(old_versions)
+            expect(page.wiki_revisions.count).to eq(revision_count + 1)
+            expect(page.wiki_versions.count).to eq(version_count + 1)
+            expect(page.reload.current_revision.id).not_to eq(old_revision_id)
+            expect(page.wiki_versions.order(version_no: :desc).first.id)
+                .not_to eq(old_wiki_version_id)
+            get group_title_path(changed.fetch(:name))
+            expect(response).to have_http_status(:ok)
+            expect(json.fetch('body')).to eq(page.body)
+          end
+        end
+      end
+
+      [:create, :update].each do |operation|
+        it "synchronises Wiki current state and histories on native #{ operation }" do
+          native_write(operation)
+          expect(response).to have_http_status(operation == :create ? :created : :ok)
+          id = operation == :create ? json.fetch('id') : group_id
+          number = operation == :create ? 1 : 2
+          expect_group_snapshot(
+              id, number:, members: snapshot_members, placements:, description: '全体の説明')
+          page = WikiPage.joins(:tag_name).find_by!(tag_names: { name: 'タググループ:構造化' })
+          expect(page.body).to include('全体の説明', '# 区分', '- 掲載タグ', '- タググループ:子')
+          expect(page.current_revision.body).to eq(page.body)
+          expect(page.wiki_versions.order(:version_no).last.body).to eq(page.body)
+          expect(page.wiki_revisions.count).to eq(number)
+          expect(page.wiki_versions.count).to eq(number)
+          get group_title_path('構造化')
+          expect(response).to have_http_status(:ok)
+          expect(json.fetch('body')).to eq(page.body)
+        end
+
+        (TagGroupRecords::GROUP_TABLES + ['wiki_pages', 'wiki_revisions', 'wiki_versions'])
+            .each do |table|
+          it "rolls back native #{ operation } after #{ table } writes" do
+            expect_atomic_group_write(table) { native_write(operation) }
+          end
+        end
+      end
+
+      it 'uses AUTO_INCREMENT for a new group instead of supplying a compatibility ID' do
+        inserts = []
+        subscriber = lambda do |*args|
+          sql = args.last.fetch(:sql)
+          inserts << sql if sql.match?(/\A\s*INSERT INTO `?tag_groups`?\s/i)
+        end
+        ActiveSupport::Notifications.subscribed(subscriber, 'sql.active_record') do
+          native_write(:create)
+        end
+        expect(response).to have_http_status(:created)
+        expect(inserts.size).to eq(1)
+        columns = inserts.sole[/\((.*?)\)/, 1].split(',').map { _1.strip.delete('`') }
+        expect(columns).not_to include('id')
+      end
+
+      it 'updates a native group through Wiki and then reads structured current data' do
+        native_write(:create)
+        expect(response).to have_http_status(:created)
+        id = json.fetch('id')
+        previous = group_version(id, 1)
+        put "/wiki/#{ id }",
+            params: { title: 'タググループ:構造化', body: '- 未掲載タグ' }, headers: headers
+        expect(response).to have_http_status(:ok)
+        expect_group_snapshot(
+            id, number: 2,
+            members: [{ 'tag_id' => unplaced.id, 'version_no' => unplaced.version_no }],
+            placements: [{ 'tag_id' => unplaced.id, 'children' => [] }])
+        expect(group_version(id, 1)).to eq(previous)
+        get "/tag_groups/#{ id }"
+        expect(response).to have_http_status(:ok)
+        expect(json).to include('version_no' => 2)
+        expect(json.fetch('members')).to match([
+            include('tag' => include('id' => unplaced.id, 'name' => '未掲載タグ'))])
+      end
+    end
+  end
+end

backend/spec/support/tag_group_records.rb

@@ -0,0 +1,220 @@
+require 'cgi'
+
+# SQL fixtures use the migration contract without inventing application models.
+# Include explicitly; these helpers must not affect unrelated examples.
+module TagGroupRecords
+  GROUP_TABLES = [
+      'tag_groups', 'tag_group_tags', 'tag_group_groups',
+      'tag_group_placements', 'tag_group_versions'].freeze
+  WRITE_TABLES = GROUP_TABLES + [
+      'wiki_pages', 'wiki_revisions', 'wiki_versions', 'wiki_lines',
+      'wiki_revision_lines', 'tag_names', 'tag_description_versions',
+      'tag_descriptions']
+
+  def group_connection = ApplicationRecord.connection
+
+  def group_rows table, conditions = { }
+    clauses = conditions.map do |column, value|
+      "#{ group_connection.quote_column_name(column) } = #{ group_connection.quote(value) }"
+    end
+    sql = "SELECT * FROM #{ group_connection.quote_table_name(table) }"
+    sql += " WHERE #{ clauses.join(' AND ') }" if clauses.any?
+    group_connection.select_all(sql).to_a.sort_by { |row| row.values.map(&:to_s) }
+  end
+
+  def insert_group_row table, attributes
+    columns = attributes.keys.map { group_connection.quote_column_name(_1) }.join(', ')
+    values = attributes.values.map { group_connection.quote(_1) }.join(', ')
+    group_connection.insert(
+        "INSERT INTO #{ group_connection.quote_table_name(table) } (#{ columns }) " +
+        "VALUES (#{ values })")
+  end
+
+  def group_state
+    WRITE_TABLES.to_h { |table| [table, group_rows(table)] }
+  end
+
+  def expect_noop_group_update group_id:, page:
+    before_state = group_state
+    group = TagGroup.find(group_id)
+    version_id = TagGroupVersion.find_by!(
+        tag_group_id: group_id, version_no: group.version_no).id
+    revision_id = page.reload.current_revision.id
+    wiki_version_id = page.wiki_versions.order(version_no: :desc).first.id
+    writes = []
+    tables = Regexp.union(WRITE_TABLES)
+    subscriber = lambda do |*args|
+      sql = args.last.fetch(:sql)
+      if sql.match?(/\A\s*(?:INSERT INTO|UPDATE|DELETE FROM)\s+`?(?:#{ tables })`?\s/i)
+        writes << sql
+      end
+    end
+
+    aggregate_failures 'no-op current state, history and SQL writes' do
+      ActiveSupport::Notifications.subscribed(subscriber, 'sql.active_record') { yield }
+      expect(response).to have_http_status(:ok)
+      after_state = group_state
+      before_state.each do |table, rows|
+        expect(after_state.fetch(table)).to eq(rows), "No-op changed #{ table }"
+      end
+      expect(TagGroupVersion.find_by!(
+          tag_group_id: group_id, version_no: group.reload.version_no).id).to eq(version_id)
+      expect(page.reload.current_revision.id).to eq(revision_id)
+      expect(page.wiki_versions.order(version_no: :desc).first.id).to eq(wiki_version_id)
+      expect(writes).to be_empty
+    end
+  end
+
+  def expect_atomic_group_write table
+    before_state = group_state
+    failure = Class.new(StandardError)
+    injected = false
+    subscriber = lambda do |*args|
+      sql = args.last.fetch(:sql)
+      next unless sql.match?(/\A\s*(?:INSERT INTO|UPDATE)\s+`?#{ table }`?\s/i)
+
+      injected = true
+      raise failure, 'injected after SQL write'
+    end
+    begin
+      ActiveSupport::Notifications.subscribed(subscriber, 'sql.active_record') { yield }
+    rescue failure
+      # Inspect the database after the operation's transaction unwinds.
+    end
+    aggregate_failures do
+      expect(injected).to be(true), "No INSERT/UPDATE reached #{ table }"
+      expect(group_state).to eq(before_state)
+    end
+  end
+
+  def group_version group_id, number
+    row = group_rows('tag_group_versions', tag_group_id: group_id, version_no: number).sole
+    row.merge('members' => JSON.parse(row.fetch('members')),
+              'placements' => JSON.parse(row.fetch('placements')))
+  end
+
+  def group_tag name
+    tag = create(:tag, primary_name: name)
+    TagVersioning.ensure_snapshot!(tag, created_by_user: user)
+    tag.reload
+  end
+
+  def legacy_group name, body
+    # Historical fixtures preserve blank lines independently of today's writer.
+    body = body.sub(/\n+\z/, '')
+    page = WikiPage.create!(
+        tag_name: create(:tag_name, name: "タググループ:#{ name }"),
+        body:, created_user: user, updated_user: user)
+    WikiVersionRecorder.record!(page:, event_type: :create, created_by_user: user)
+    lines = body.split("\n")
+    shas = lines.map { Digest::SHA256.hexdigest(_1) }
+    revision = WikiRevision.create!(
+        wiki_page: page, kind: :content, created_user: user, lines_count: lines.size,
+        tree_sha256: Digest::SHA256.hexdigest(shas.join(',')))
+    lines.each_with_index do |line, position|
+      sha = shas.fetch(position)
+      line_id = WikiLine.find_by(sha256: sha)&.id || insert_group_row('wiki_lines', {
+          body: line, sha256: sha, created_at: Time.current, updated_at: Time.current })
+      WikiRevisionLine.create!(wiki_revision: revision, wiki_line_id: line_id, position:)
+    end
+    page
+  end
+
+  def seed_group name:, placements: [], members: [], description: nil, id: nil
+    now = Time.current.change(usec: 0)
+    attributes = {
+        name:, description:, version_no: 1,
+        created_by_user_id: user.id, updated_by_user_id: user.id,
+        created_at: now, updated_at: now }
+    attributes[:id] = id if id
+    group_id = insert_group_row('tag_groups', attributes)
+    insert_group_row('tag_group_versions', {
+        tag_group_id: group_id, version_no: 1, event_type: 'create',
+        name:, description:, members: members.to_json, placements: placements.to_json,
+        created_by_user_id: user.id, created_at: now })
+    members.each do |member|
+      tag_member = member.key?('tag_id')
+      table = tag_member ? 'tag_group_tags' : 'tag_group_groups'
+      key = tag_member ? :tag_id : :child_tag_group_id
+      value = member.fetch(tag_member ? 'tag_id' : 'tag_group_id')
+      insert_group_row(table, {
+          tag_group_id: group_id, key => value,
+          created_by_user_id: user.id, created_at: now })
+    end
+    position = 0
+    append = lambda do |nodes, parent|
+      nodes.each do |node|
+        position += 1
+        own_position = position
+        insert_group_row('tag_group_placements', {
+            tag_group_id: group_id, position:, parent_position: parent,
+            section_name: node['section_name'], description: node['description'],
+            tag_id: node['tag_id'], child_tag_group_id: node['tag_group_id'],
+            created_by_user_id: user.id, updated_by_user_id: user.id,
+            created_at: now, updated_at: now })
+        append.call(node.fetch('children'), own_position)
+      end
+    end
+    append.call(placements, nil)
+    group_id
+  end
+
+  def without_group_legacy_reads
+    queries = []
+    subscriber = lambda do |*args|
+      sql = args.last.fetch(:sql)
+      if (sql.match?(/\bSELECT\b/i) &&
+          sql.match?(/\bwiki_(pages|revisions|versions|lines|revision_lines)\b/i))
+        queries << sql
+      end
+    end
+    ActiveSupport::Notifications.subscribed(subscriber, 'sql.active_record') { yield }
+    expect(queries).to be_empty
+  end
+
+  def group_title_path name
+    "/wiki/title/#{ CGI.escapeURIComponent("タググループ:#{ name }") }"
+  end
+
+  def migrate_groups
+    require_relative '../../db/migrate/20261008010000_migrate_tag_groups_from_wiki_pages'
+    migration = MigrateTagGroupsFromWikiPages.new
+    @group_migration_messages = []
+    allow(migration).to receive(:say) do |message, *_args|
+      @group_migration_messages << message if message.start_with?('Wiki #', 'Tag Group')
+    end
+    migration.suppress_messages { migration.up }
+  end
+
+  def expect_group_snapshot group_id, number:, placements:, members:, description: nil
+    current = group_rows('tag_groups', id: group_id).sole
+    version = group_version(group_id, number)
+    expect(current).to include('version_no' => number, 'description' => description),
+                       @group_migration_messages&.join("\n")
+    expect(version).to include(
+        'name' => current.fetch('name'), 'description' => description,
+        'version_no' => number, 'placements' => placements)
+    expect(version.fetch('members')).to match_array(members)
+    expect(group_rows('tag_group_tags', tag_group_id: group_id).map { _1.fetch('tag_id') })
+        .to match_array(members.filter_map { _1['tag_id'] })
+    children = group_rows('tag_group_groups', tag_group_id: group_id)
+    expect(children.map { _1.fetch('child_tag_group_id') })
+        .to match_array(members.filter_map { _1['tag_group_id'] })
+
+    rows = group_rows('tag_group_placements', tag_group_id: group_id)
+    tree = lambda do |parent|
+      rows.select { _1['parent_position'] == parent }.sort_by { _1.fetch('position') }
+          .map do |row|
+        node = if row['tag_id']
+          { 'tag_id' => row.fetch('tag_id') }
+        elsif row['child_tag_group_id']
+          { 'tag_group_id' => row.fetch('child_tag_group_id') }
+        else
+          { 'section_name' => row.fetch('section_name'), 'description' => row['description'] }
+        end
+        node.merge('children' => tree.call(row.fetch('position')))
+      end
+    end
+    expect(tree.call(nil)).to eq(placements)
+  end
+end

backend/spec/tasks/nico_export_spec.rb

@@ -18,8 +18,8 @@ RSpec.describe 'nico:export' do
   before do
     task.reenable
 
-    allow(ENV).to receive(:fetch).with('MYSQL_USER').and_return('mysql-user')
-    allow(ENV).to receive(:fetch).with('MYSQL_PASS').and_return('mysql-pass')
+    allow(ENV).to receive(:fetch).with('NIZIKA_NICO_MYSQL_USER').and_return('mysql-user')
+    allow(ENV).to receive(:fetch).with('NIZIKA_NICO_MYSQL_PASS').and_return('mysql-pass')
     allow(ENV).to receive(:fetch).with('NIZIKA_NICO_PATH').and_return('/srv/nizika-nico')
   end
 
@@ -33,8 +33,8 @@ RSpec.describe 'nico:export' do
       expect(Open3).to receive(:capture3) do |env, *args, **kwargs|
         expect(env).to eq(
           {
-            'MYSQL_USER' => 'mysql-user',
-            'MYSQL_PASS' => 'mysql-pass',
+            'NIZIKA_NICO_MYSQL_USER' => 'mysql-user',
+            'NIZIKA_NICO_MYSQL_PASS' => 'mysql-pass',
           },
         )