#399

backend/db/migrate/20260727123600_add_tags_json_to_post_versions.rb

@@ -1,279 +0,0 @@
-class AddTagsJsonToPostVersions < ActiveRecord::Migration[8.0]
-  RESOLUTION_GRACE = 1.second
-  SECTION_LITERAL_PATTERN = /\[[^\[\]\s]*-[^\[\]\s]*\]\z/
-
-  class MigrationPostVersion < ActiveRecord::Base
-    self.table_name = 'post_versions'
-  end
-
-  class MigrationTag < ActiveRecord::Base
-    self.table_name = 'tags'
-  end
-
-  class MigrationTagName < ActiveRecord::Base
-    self.table_name = 'tag_names'
-  end
-
-  class MigrationTagVersion < ActiveRecord::Base
-    self.table_name = 'tag_versions'
-  end
-
-  class MigrationNicoTagVersion < ActiveRecord::Base
-    self.table_name = 'nico_tag_versions'
-  end
-
-  def up
-    add_column :post_versions, :tags_json, :json, after: :tags
-    MigrationPostVersion.reset_column_information
-
-    backfill_missing_initial_tag_versions!
-    intervals_by_name = build_intervals_by_name
-
-    say_with_time 'Backfilling post_versions.tags_json' do
-      MigrationPostVersion
-          .where(tags_json: nil)
-          .find_each(batch_size: 500) do |version|
-        version.update_columns(
-            tags_json: build_tags_json(version, intervals_by_name))
-      end
-    end
-
-    assert_backfill_complete!
-    change_column_null :post_versions, :tags_json, false
-  end
-
-  def down
-    remove_column :post_versions, :tags_json
-  end
-
-  private
-
-  def backfill_missing_initial_tag_versions!
-    say_with_time 'Backfilling missing initial tag versions' do
-      tag_rows = missing_initial_version_rows(MigrationTagVersion, nico: false)
-      nico_rows = missing_initial_version_rows(MigrationNicoTagVersion, nico: true)
-
-      MigrationTagVersion.insert_all!(tag_rows) if tag_rows.any?
-      MigrationNicoTagVersion.insert_all!(nico_rows) if nico_rows.any?
-
-      tag_rows.length + nico_rows.length
-    end
-  end
-
-  def missing_initial_version_rows version_class, nico:
-    first_versions =
-        version_class
-        .order(:tag_id, :version_no)
-        .to_a
-        .group_by(&:tag_id)
-        .transform_values(&:first)
-    rows = []
-
-    MigrationTag.find_each do |tag|
-      next if (tag.category == 'nico') != nico
-
-      first_version = first_versions[tag.id]
-      next unless first_version
-      next if valid_initial_version?(first_version)
-
-      assert_inferable_initial_version!(tag, first_version)
-      rows << initial_version_row(tag, first_version, nico:)
-    end
-
-    rows
-  end
-
-  def valid_initial_version? version
-    version.version_no == 1 && version.event_type == 'create'
-  end
-
-  def assert_inferable_initial_version! tag, version
-    inferable =
-        version.version_no == 2 &&
-        version.event_type == 'discard' &&
-        tag.created_at < version.created_at
-    return if inferable
-
-    details = [
-        "tag_id=#{ tag.id }",
-        "version_no=#{ version.version_no }",
-        "event_type=#{ version.event_type.inspect }",
-        "tag_created_at=#{ tag.created_at.iso8601(6) }",
-        "version_created_at=#{ version.created_at.iso8601(6) }"]
-
-    raise "Cannot infer initial tag version: #{ details.join(', ') }"
-  end
-
-  def initial_version_row tag, discard_version, nico:
-    row = {
-        tag_id: tag.id,
-        version_no: 1,
-        event_type: 'create',
-        name: discard_version.name,
-        created_at: tag.created_at,
-        created_by_user_id: nil }
-
-    if nico
-      return row.merge(linked_tags: discard_version.linked_tags)
-    end
-
-    row.merge(
-        category: discard_version.category,
-        aliases: discard_version.aliases,
-        parent_tag_ids: discard_version.parent_tag_ids,
-        deprecated_at: discard_version.deprecated_at)
-  end
-
-  def build_intervals_by_name
-    intervals_by_name = Hash.new { |hash, name| hash[name] = [] }
-    versions_by_kind = {
-        tag: versions_by_tag_id(MigrationTagVersion),
-        nico: versions_by_tag_id(MigrationNicoTagVersion) }
-    current_names = current_names_by_tag_id
-
-    MigrationTag.find_each do |tag|
-      nico = tag.category == 'nico'
-      kind = nico ? :nico : :tag
-      versions = versions_by_kind.fetch(kind).fetch(tag.id, [])
-
-      intervals_for(
-          tag,
-          versions,
-          current_name: current_names.fetch(tag.id),
-          nico:).each do |interval|
-        name = interval.delete(:name)
-        intervals_by_name[name] << interval
-      end
-    end
-
-    intervals_by_name
-  end
-
-  def versions_by_tag_id version_class
-    version_class
-        .order(:tag_id, :version_no)
-        .to_a
-        .group_by(&:tag_id)
-  end
-
-  def current_names_by_tag_id
-    MigrationTagName
-        .joins('INNER JOIN tags ON tags.tag_name_id = tag_names.id')
-        .pluck('tags.id', 'tag_names.name')
-        .to_h
-  end
-
-  def intervals_for tag, versions, current_name:, nico:
-    if versions.empty?
-      return [{
-          name: current_name,
-          tag_id: tag.id,
-          version_no: tag.version_no,
-          category: nico ? 'nico' : tag.category,
-          from: tag.created_at,
-          to: tag.discarded_at }]
-    end
-
-    versions.each_with_index.filter_map do |version, index|
-      next if version.event_type == 'discard'
-
-      {
-          name: version.name,
-          tag_id: tag.id,
-          version_no: version.version_no,
-          category: nico ? 'nico' : version.category,
-          from: version.created_at,
-          to: versions[index + 1]&.created_at || tag.discarded_at }
-    end
-  end
-
-  def build_tags_json version, intervals_by_name
-    entries = version.tags.to_s.split.map do |literal|
-      name = tag_name_from_literal(literal)
-      interval = resolve_tag!(intervals_by_name.fetch(name, []), name:, version:)
-
-      { 'id' => interval.fetch(:tag_id),
-        'version_no' => interval.fetch(:version_no),
-        'name' => name,
-        'category' => interval.fetch(:category),
-        'sections' => [] }
-    end
-
-    assert_unique_tag_ids!(version, entries)
-
-    entries.sort_by { |entry| entry.fetch('id') }
-  end
-
-  def tag_name_from_literal literal
-    name = literal.dup
-    name.sub!(SECTION_LITERAL_PATTERN, '') while name.match?(
-        SECTION_LITERAL_PATTERN)
-
-    if name.empty? || name.include?('[') || name.include?(']')
-      raise "Invalid legacy tag literal: #{ literal.inspect }"
-    end
-
-    name
-  end
-
-  def resolve_tag! intervals, name:, version:
-    time = version.created_at
-    candidates = intervals.select do |interval|
-      interval.fetch(:from) <= time &&
-        (interval[:to].nil? || time < interval.fetch(:to))
-    end
-
-    candidates = future_candidates(intervals, time) if candidates.empty?
-
-    return candidates.first if candidates.one?
-
-    candidate_versions = candidates.map do |candidate|
-      [candidate.fetch(:tag_id), candidate.fetch(:version_no)]
-    end
-    details = [
-        "post_version_id=#{ version.id }",
-        "post_id=#{ version.post_id }",
-        "name=#{ name.inspect }",
-        "created_at=#{ time.iso8601(6) }",
-        "candidates=#{ candidate_versions.inspect }"].join(', ')
-
-    raise "Could not resolve tag snapshot: #{ details }"
-  end
-
-  def future_candidates intervals, time
-    candidates = intervals.select do |interval|
-      interval.fetch(:from) > time &&
-        interval.fetch(:from) <= time + RESOLUTION_GRACE
-    end
-    return [] if candidates.empty?
-
-    nearest_from = candidates.map { |interval| interval.fetch(:from) }.min
-
-    candidates.select do |interval|
-      interval.fetch(:from) == nearest_from
-    end
-  end
-
-  def assert_unique_tag_ids! version, entries
-    duplicate_tag_ids =
-        entries
-        .map { |entry| entry.fetch('id') }
-        .tally
-        .select { |_tag_id, count| count > 1 }
-        .keys
-    return if duplicate_tag_ids.empty?
-
-    details = [
-        "post_version_id=#{ version.id }",
-        "duplicate_tag_ids=#{ duplicate_tag_ids.inspect }"].join(', ')
-
-    raise "Duplicate tag IDs: #{ details }"
-  end
-
-  def assert_backfill_complete!
-    missing_count = MigrationPostVersion.where(tags_json: nil).count
-    return if missing_count.zero?
-
-    raise "#{ missing_count } post versions were not backfilled"
-  end
-end

backend/db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[8.0].define(version: 2026_07_27_123600) do
+ActiveRecord::Schema[8.0].define(version: 2026_07_13_000000) do
   create_table "active_storage_attachments", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.string "name", null: false
     t.string "record_type", null: false
@@ -349,7 +349,6 @@ ActiveRecord::Schema[8.0].define(version: 2026_07_27_123600) do
     t.string "url", limit: 768, null: false
     t.string "thumbnail_base", limit: 2000
     t.text "tags", null: false
-    t.json "tags_json", null: false
     t.text "parent_post_ids", null: false
     t.datetime "original_created_from"
     t.datetime "original_created_before"