AI: address issue #450

backend/app/controllers/posts_controller.rb

@@ -37,8 +37,6 @@ class PostsController < ApplicationController
 
     offset = (page - 1) * limit
 
-    needs_history_join = order[0] == 'updated_at' || updated_between.any?(&:present?)
-
     q =
         filtered_posts(locale)
         .preload(:external_tags, :uploaded_user, :parents, :children,
@@ -56,25 +54,9 @@ class PostsController < ApplicationController
     end
     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]
+    q = q.where('posts.updated_at >= ?', updated_between[0]) if updated_between[0]
+    q = q.where('posts.updated_at <= ?', updated_between[1]) if updated_between[1]
     count_scope = q
-    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')
-      updated_at_all_sql = 'GREATEST(posts.updated_at, ' +
-          'COALESCE(history_times.latest_at, posts.updated_at))'
-    end
-    if updated_between[0]
-      q = q.where("#{ updated_at_all_sql } >= ?", updated_between[0])
-    end
-    if updated_between[1]
-      q = q.where("#{ updated_at_all_sql } <= ?", updated_between[1])
-    end
-    count_scope = q if updated_between.any?(&:present?)
-    if needs_history_join
-      q = q.select('posts.*', "#{ updated_at_all_sql } AS updated_at")
-    end
 
     sort_sql =
         case order[0]
@@ -82,8 +64,6 @@ class PostsController < ApplicationController
           'COALESCE(posts.original_created_before - INTERVAL 1 MINUTE,' +
           'posts.original_created_from,' +
           'posts.created_at) '
-        when 'updated_at'
-          updated_at_all_sql
         else
           "posts.#{ order[0] }"
         end
@@ -91,20 +71,11 @@ class PostsController < ApplicationController
              .limit(limit)
              .offset(offset)
              .to_a
-    latest_version_times =
-        if needs_history_join
-          { }
-        else
-          HistoryAccess.visible(PostVersion.where(post_id: posts.map(&:id)))
-              .group(:post_id).maximum(:created_at)
-        end
 
     count_scope = count_scope.except(:select, :order)
 
     render json: { posts: posts.map { |post|
-      updated_at = [post.updated_at, latest_version_times[post.id]].compact.max
-      PostRepr.base(post, language_code: locale.language_code)
-          .merge('updated_at' => updated_at).tap do |json|
+      PostRepr.base(post, language_code: locale.language_code).tap do |json|
         json['thumbnail'] =
             if post.thumbnail.attached?
               rails_storage_proxy_url(post.thumbnail, only_path: false)

backend/app/controllers/tag_descriptions_controller.rb

@@ -49,7 +49,6 @@ 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 = HistoryAccess.current(TagGroup.all, TagGroupVersion).includes(:created_by_user, :updated_by_user).order(:id)
+    groups = TagGroup.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

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

@@ -147,29 +147,6 @@ 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/representations/tag_group_repr.rb

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

backend/app/representations/wiki_page_repr.rb

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

backend/app/services/post_tag_search.rb

@@ -3,8 +3,8 @@ class PostTagSearch
   def self.literals(locale, raw)
     tokens = raw.split.reject { _1.downcase == 'type:or' }
     names = tokens.map { _1.sub(/\Anot:/i, '') }
-    registered = matching_names(TagName.where(language_code: locale.language_code),
-        names, 'tag_names.name', :tag_id).to_h
+    registered = TagName.where(language_code: locale.language_code, name: names)
+        .pluck(:name, :tag_id).to_h
     primary = TagName.where(language_code: locale.language_code,
         tag_id: registered.values, primary_flg: true).pluck(:tag_id, :name).to_h
     tokens.zip(names).map do |token, name|
@@ -19,25 +19,12 @@ class PostTagSearch
 
   def self.references_for(locale, literals)
     names = literals.map { _1[:name] }.uniq
-    internal = matching_names(TagName.where(language_code: locale.language_code),
-        names, 'tag_names.name', :tag_id).group_by(&:first)
-    external = matching_names(ExternalTag.all, names,
-        "CONCAT(external_tags.platform, ':', external_tags.name)", :id).group_by(&:first)
+    internal = TagName.where(language_code: locale.language_code, name: names)
+        .pluck(:name, :tag_id).group_by(&:first)
+    external = names.empty? ? {} : ExternalTag.where(
+        "CONCAT(platform, ':', name) IN (?)", names)
+        .pluck(Arel.sql("CONCAT(platform, ':', name)"), :id).group_by(&:first)
     names.to_h { |name| [name, [internal.fetch(name, []).map(&:last).uniq,
                               external.fetch(name, []).map(&:last).uniq]] }
   end
-
-  def self.matching_names(scope, names, expression, identifier)
-    return [] if names.empty?
-
-    queries = names.uniq.map do |name|
-      scope.klass.sanitize_sql_array(['SELECT ? AS name', name])
-    end
-    # Return the input spelling so Ruby does not recheck database equivalence.
-    scope.joins(<<~SQL).pluck(Arel.sql('search_names.name'), identifier)
-      INNER JOIN (#{ queries.join(' UNION ALL ') }) AS search_names
-        ON #{ expression } = search_names.name COLLATE utf8mb4_0900_ai_ci
-    SQL
-  end
-  private_class_method :matching_names
 end