AI: address review on PR #469

backend/app/controllers/posts_controller.rb

@@ -37,7 +37,7 @@ class PostsController < ApplicationController
 
     offset = (page - 1) * limit
 
-    history_join_required = order[0] == 'updated_at' || updated_between.any?(&:present?)
+    needs_history_join = order[0] == 'updated_at' || updated_between.any?(&:present?)
 
     q =
         filtered_posts(locale)
@@ -57,8 +57,8 @@ class PostsController < ApplicationController
     q = q.where('posts.created_at >= ?', created_between[0]) if created_between[0]
     q = q.where('posts.created_at <= ?', created_between[1]) if created_between[1]
     count_scope = q
-    if history_join_required
-      history_times = PostVersion.all
+    if needs_history_join
+      history_times = HistoryAccess.visible(PostVersion.all)
           .select('post_id, MAX(created_at) AS latest_at').group(:post_id)
       q = q.joins("LEFT JOIN (#{ history_times.to_sql }) history_times " +
                   'ON history_times.post_id = posts.id')
@@ -72,7 +72,7 @@ class PostsController < ApplicationController
       q = q.where("#{ updated_at_all_sql } <= ?", updated_between[1])
     end
     count_scope = q if updated_between.any?(&:present?)
-    if history_join_required
+    if needs_history_join
       q = q.select('posts.*', "#{ updated_at_all_sql } AS updated_at")
     end
 
@@ -92,10 +92,10 @@ class PostsController < ApplicationController
              .offset(offset)
              .to_a
     latest_version_times =
-        if history_join_required
+        if needs_history_join
           { }
         else
-          PostVersion.where(post_id: posts.map(&:id))
+          HistoryAccess.visible(PostVersion.where(post_id: posts.map(&:id)))
               .group(:post_id).maximum(:created_at)
         end
 

backend/app/controllers/tag_descriptions_controller.rb

@@ -49,6 +49,7 @@ class TagDescriptionsController < ApplicationController
   private
 
   def representation description
+    HistoryAccess.require_current!(description, TagDescriptionVersion)
     description.as_json(only: [
         :tag_id,
         :language_code,

backend/app/controllers/tag_groups_controller.rb

@@ -1,7 +1,7 @@
 class TagGroupsController < ApplicationController
   def index
     locale = resolve_locale!
-    groups = TagGroup.includes(:created_by_user, :updated_by_user).order(:id)
+    groups = HistoryAccess.current(TagGroup.all, TagGroupVersion).includes(:created_by_user, :updated_by_user).order(:id)
     render json: TagGroupRepr.many(locale, groups.to_a)
   end
 

backend/app/controllers/wiki_pages_controller.rb

@@ -8,11 +8,12 @@ class WikiPagesController < ApplicationController
 
     title = params[:title].to_s.strip
     descriptions =
-        TagDescription.where(language_code: locale.language_code)
+        HistoryAccess.current(TagDescription.all, TagDescriptionVersion)
+        .where(language_code: locale.language_code)
         .includes(tag: :tag_names)
 
     descriptions = descriptions.order(updated_at: :desc, id: :asc)
-    tag_groups = TagGroup.order(updated_at: :desc, id: :asc)
+    tag_groups = HistoryAccess.current(TagGroup.all, TagGroupVersion).order(updated_at: :desc, id: :asc)
     if title.present?
       pattern = "%#{ ApplicationRecord.sanitize_sql_like(title) }%"
       descriptions =
@@ -40,13 +41,13 @@ class WikiPagesController < ApplicationController
     return head :not_found unless language.is_a?(String)
     return head :not_found unless Language.exists?(code: language)
 
-    names = TagDescription.joins(tag: :tag_names)
+    names = HistoryAccess.current(TagDescription.all, TagDescriptionVersion).joins(tag: :tag_names)
         .where(language_code: locale.language_code, tag_names: { language_code: language })
         .pluck('tag_descriptions.tag_id', 'tag_descriptions.id', 'tag_names.name')
     candidates = names.map do |tag_id, description_id, name|
       WikiPageRepr.autolink_tag(locale, tag_id:, description_id:, name:, language:)
     end
-    candidates.concat(TagGroup.order(:id).pluck(:id, :name).map do |id, name|
+    candidates.concat(HistoryAccess.current(TagGroup.all, TagGroupVersion).order(:id).pluck(:id, :name).map do |id, name|
       WikiPageRepr.autolink_group(locale, id:, name:, language:)
     end)
     render json: candidates
@@ -410,7 +411,7 @@ class WikiPagesController < ApplicationController
   end
 
   def tag_description_by_title locale, title
-    TagDescription.joins(tag: :tag_names)
+    HistoryAccess.current(TagDescription.all, TagDescriptionVersion).joins(tag: :tag_names)
         .find_by(language_code: locale.language_code,
                  tag_names: { language_code: locale.language_code, name: title })
   end

backend/app/models/history_access.rb

@@ -147,6 +147,29 @@ class HistoryAccess < ActiveSupport::CurrentAttributes
     scope.where(Arel.sql(sql(scope.klass, row)))
   end
 
+  def self.current(scope, version_model)
+    return scope if admin?
+
+    table = scope.klass.table_name
+    keys = KEYS.fetch(version_model.table_name)
+    matches = keys.map do |key|
+      column = scope.klass.column_names.include?(key) ? key : 'id'
+      "current_snapshot.#{ key } = #{ table }.#{ column }"
+    end.join(' AND ')
+    boundary = "#{ matches } AND current_snapshot.version_no >= #{ table }.version_no " +
+        "AND current_snapshot.event_type = 'discard'"
+    scope = scope.where(Arel.sql("NOT EXISTS (SELECT 1 FROM #{ version_model.table_name } " +
+        "current_snapshot WHERE #{ boundary })"))
+    condition = "#{ matches } AND current_snapshot.version_no = #{ table }.version_no"
+    scope.where(Arel.sql("NOT EXISTS (SELECT 1 FROM #{ version_model.table_name } " +
+        "current_snapshot WHERE #{ condition } AND NOT (#{ sql(version_model, 'current_snapshot') }))"))
+  end
+
+  def self.require_current!(record, version_model)
+    return if admin?
+    raise Forbidden unless current(record.class.where(id: record.id), version_model).exists?
+  end
+
   def self.blob_visible?(blob, seen = [])
     return true if admin?
     return false if seen.include?(blob.id)

backend/app/models/post_implication.rb

@@ -8,6 +8,7 @@ class PostImplication < ApplicationRecord
   validates :parent_post_id, presence: true
 
   validate :parent_post_mustnt_be_itself
+  validate :parent_post_mustnt_create_cycle
 
   private
 
@@ -16,4 +17,24 @@ class PostImplication < ApplicationRecord
       errors.add :parent_post_id, '親投稿に同じ投稿を設定することはできません．'
     end
   end
+
+  def parent_post_mustnt_create_cycle
+    return if post_id.blank? || parent_post_id.blank?
+    return if errors[:parent_post_id].present?
+
+    ancestor_ids = Set.new
+    frontier_ids = [parent_post_id]
+
+    until frontier_ids.empty?
+      if frontier_ids.include?(post_id)
+        errors.add :parent_post_id, :invalid
+        return
+      end
+
+      ancestor_ids.merge(frontier_ids)
+      frontier_ids = PostImplication.where(post_id: frontier_ids)
+          .distinct.pluck(:parent_post_id)
+          .reject { ancestor_ids.include?(_1) }
+    end
+  end
 end

backend/app/representations/tag_group_repr.rb

@@ -44,6 +44,7 @@ module TagGroupRepr
   end
 
   def one locale, group
+    HistoryAccess.require_current!(group, TagGroupVersion)
     many(locale, [group]).first
   end
 

backend/app/representations/wiki_page_repr.rb

@@ -5,6 +5,7 @@ module WikiPageRepr
   module_function
 
   def tag_description locale, description
+    HistoryAccess.require_current!(description, TagDescriptionVersion)
     tag = description.tag
 
     { 'id' => description.id,

backend/spec/models/post_implication_spec.rb

@@ -48,4 +48,47 @@ RSpec.describe PostImplication, type: :model do
     expect(duplicate).not_to be_valid
     expect(duplicate.errors[:post_id]).to be_present
   end
+
+  it 'rejects a parent that would create a two-post cycle' do
+    described_class.create!(post: post_record, parent_post:)
+
+    implication = described_class.new(
+        post: parent_post, parent_post: post_record)
+
+    expect(implication).not_to be_valid
+    expect(implication.errors.of_kind?(:parent_post_id, :invalid)).to be true
+  end
+
+  it 'rejects a parent that would create a three-post cycle' do
+    ancestor_post = create(:post)
+    described_class.create!(post: post_record, parent_post:)
+    described_class.create!(post: parent_post, parent_post: ancestor_post)
+
+    implication = described_class.new(
+        post: ancestor_post, parent_post: post_record)
+
+    expect(implication).not_to be_valid
+    expect(implication.errors.of_kind?(:parent_post_id, :invalid)).to be true
+  end
+
+  it 'allows a parent with an ancestor when no cycle would result' do
+    ancestor_post = create(:post)
+    described_class.create!(post: parent_post, parent_post: ancestor_post)
+
+    implication = described_class.new(post: post_record, parent_post:)
+
+    expect(implication).to be_valid
+  end
+
+  it 'terminates when existing ancestors already contain a cycle' do
+    ancestor_post = create(:post)
+    described_class.create!(post: parent_post, parent_post: ancestor_post)
+    legacy_implication = described_class.new(
+        post: ancestor_post, parent_post:)
+    legacy_implication.save!(validate: false)
+
+    implication = described_class.new(post: post_record, parent_post:)
+
+    expect(implication).to be_valid
+  end
 end

backend/spec/requests/counts_history_boundaries_spec.rb

@@ -14,7 +14,7 @@ RSpec.describe 'History boundaries shared with Counts', type: :request do
     end
   end
 
-  it 'keeps discarded history private while exposing the current description' do
+  it 'denies the same discarded description through Counts, the facade and the ordinary API' do
     get '/counts/query', params: { resource: 'tag_descriptions', definition: 'history',
         mode: 'details', locale: 'ja', execution_at: '2025-01-01T00:00:00Z' }
     expect(response).to have_http_status(:ok)
@@ -22,8 +22,8 @@ RSpec.describe 'History boundaries shared with Counts', type: :request do
         'excluded_count' => 2, 'versions' => [])
     ["/wiki/#{ description.id }", "/tags/#{ tag.id }/description"].each do |path|
       get path, params: { locale: 'ja' }
-      expect(response).to have_http_status(:ok)
-      expect(response.parsed_body.fetch('body')).to eq(description.body)
+      expect(response).to have_http_status(:not_found)
+      expect(response.body).not_to include('private body')
     end
     get '/sitemap_entries/descriptions', params: { locale: 'ja' }
     expect(response).to have_http_status(:ok)

backend/spec/requests/post_history_privacy_spec.rb

@@ -69,38 +69,40 @@ RSpec.describe 'Post history privacy', type: :request do
         sign_in_as(create(:user, role.to_sym)) unless role == 'anonymous'
       end
 
-      it 'uses the latest version timestamp for display regardless of role' do
+      it 'uses only authorised history timestamps for display' do
         get '/posts'
         expect(response).to have_http_status(:ok)
         row = response.parsed_body.fetch('posts').find { _1.fetch('id') == post_record.id }
-        expected = origin + 4.days
+        expected = origin + (role == 'admin' ? 4 : 3).days
         expect(Time.zone.parse(row.fetch('updated_at'))).to eq(expected)
       end
 
-      it 'uses the latest version timestamp for date bounds and count regardless of role' do
+      it 'uses the same visibility for date bounds and count' do
         get '/posts', params: { updated_from: (origin + 4.days).iso8601,
                                 updated_to: (origin + 4.days).iso8601 }
         expect(response).to have_http_status(:ok)
         ids = response.parsed_body.fetch('posts').pluck('id')
-        expect(ids).to eq([post_record.id])
+        expect(ids).to eq(role == 'admin' ? [post_record.id] : [])
         expect(response.parsed_body.fetch('count')).to eq(ids.length)
       end
 
-      it 'sorts using the latest version timestamps in both directions regardless of role' do
+      it 'sorts using authorised timestamps in both directions' do
         ['asc', 'desc'].each do |direction|
           get '/posts', params: { order: "updated_at:#{ direction }" }
           expect(response).to have_http_status(:ok)
-          expected = [other_post.id, post_record.id]
+          expected = role == 'admin' ? [other_post.id, post_record.id] :
+              [post_record.id, other_post.id]
           expected.reverse! if direction == 'desc'
           expect(response.parsed_body.fetch('posts').pluck('id')).to eq(expected)
         end
       end
 
-      it 'applies latest version timestamp ordering before pagination regardless of role' do
+      it 'applies authorised timestamp ordering before pagination' do
         get '/posts', params: { order: 'updated_at:desc', limit: 1 }
 
         expect(response).to have_http_status(:ok)
-        expect(response.parsed_body.fetch('posts').pluck('id')).to eq([post_record.id])
+        expected = role == 'admin' ? post_record.id : other_post.id
+        expect(response.parsed_body.fetch('posts').pluck('id')).to eq([expected])
         expect(response.parsed_body.fetch('count')).to eq(2)
       end