phpBB3インポートが現在のDiscourseバージョンでZeitwerk::NameErrorにより失敗

移行
1

phpBB3 フォーラムをインポートしようとしていますが、公式の移行ガイドに従っているにもかかわらず、スクリプトが Zeitwerk::NameError で即座に失敗します。

環境

  • Discourse バージョン: v2026.2.0-latest-324 (また stable/esr ブランチも試しました)
  • インストール: Docker ベースのインポートコンテナ
  • 以前: 2026年1月上旬に同じ phpBB フォーラムを問題なくインポートできました

エラー

/var/www/discourse/vendor/bundle/ruby/3.4.0/gems/zeitwerk-2.7.3/lib/zeitwerk/loader/callbacks.rb:31:in 'Zeitwerk::Loader::Callbacks#on_file_autoloaded': expected file /var/www/discourse/lib/freedom_patches/safe_migrations.rb to define constant FreedomPatches::SafeMigrations, but didn't (Zeitwerk::NameError)
完全なエラー追跡を展開 
discourse@vps116136-import-from-app:/var/www/discourse/script/import_scripts$ bundle exec ruby phpbb3.rb /shared/import/settings.yml
/var/www/discourse/vendor/bundle/ruby/3.4.0/gems/zeitwerk-2.7.3/lib/zeitwerk/loader/callbacks.rb:31:in 'Zeitwerk::Loader::Callbacks#on_file_autoloaded': expected file /var/www/discourse/lib/freedom_patches/safe_migrations.rb to define constant FreedomPatches::SafeMigrations, but didn't (Zeitwerk::NameError)

      raise Zeitwerk::NameError.new(msg, cref.cname)
      ^^^^^
        from /var/www/discourse/vendor/bundle/ruby/3.4.0/gems/zeitwerk-2.7.3/lib/zeitwerk/core_ext/kernel.rb:27:in 'Kernel#require'
        from /var/www/discourse/config/initializers/002-freedom_patches.rb:11:in 'block (2 levels) in <main>'
        from /var/www/discourse/config/initializers/002-freedom_patches.rb:9:in 'Array#each'
        from /var/www/discourse/config/initializers/002-freedom_patches.rb:9:in 'block in <main>'
        from /var/www/discourse/vendor/bundle/ruby/3.4.0/gems/activesupport-8.0.4/lib/active_support/callbacks.rb:406:in 'BasicObject#instance_exec'
        from /var/www/discourse/vendor/bundle/ruby/3.4.0/gems/activesupport-8.0.4/lib/active_support/callbacks.rb:406:in 'block in ActiveSupport::Callbacks::CallTemplate::InstanceExec0#make_lambda'
        from /var/www/discourse/vendor/bundle/ruby/3.4.0/gems/activesupport-8.0.4/lib/active_support/callbacks.rb:178:in 'block in ActiveSupport::Callbacks::Filters::Before#call'
        from /var/www/discourse/vendor/bundle/ruby/3.4.0/gems/activesupport-8.0.4/lib/active_support/callbacks.rb:668:in 'block (2 levels) in ActiveSupport::Callbacks::CallbackChain#default_terminator'
        from /var/www/discourse/vendor/bundle/ruby/3.4.0/gems/activesupport-8.0.4/lib/active_support/callbacks.rb:667:in 'Kernel#catch'
        from /var/www/discourse/vendor/bundle/ruby/3.4.0/gems/activesupport-8.0.4/lib/active_support/callbacks.rb:667:in 'block in ActiveSupport::Callbacks::CallbackChain#default_terminator'
        from /var/www/discourse/vendor/bundle/ruby/3.4.0/gems/activesupport-8.0.4/lib/active_support/callbacks.rb:179:in 'ActiveSupport::Callbacks::Filters::Before#call'
        from /var/www/discourse/vendor/bundle/ruby/3.4.0/gems/activesupport-8.0.4/lib/active_support/callbacks.rb:559:in 'block in ActiveSupport::Callbacks::CallbackSequence#invoke_before'
        from /var/www/discourse/vendor/bundle/ruby/3.4.0/gems/activesupport-8.0.4/lib/active_support/callbacks.rb:559:in 'Array#each'
        from /var/www/discourse/vendor/bundle/ruby/3.4.0/gems/activesupport-8.0.4/lib/active_support/callbacks.rb:559:in 'ActiveSupport::Callbacks::CallbackSequence#invoke_before'
        from /var/www/discourse/vendor/bundle/ruby/3.4.0/gems/activesupport-8.0.4/lib/active_support/callbacks.rb:108:in 'ActiveSupport::Callbacks#run_callbacks'
        from /var/www/discourse/vendor/bundle/ruby/3.4.0/gems/activesupport-8.0.4/lib/active_support/reloader.rb:96:in 'ActiveSupport::Reloader.prepare!'
        from /var/www/discourse/vendor/bundle/ruby/3.4.0/gems/railties-8.0.4/lib/rails/application/finisher.rb:73:in 'block in <module:Finisher>'
        from /var/www/discourse/vendor/bundle/ruby/3.4.0/gems/railties-8.0.4/lib/rails/initializable.rb:32:in 'BasicObject#instance_exec'
        from /var/www/discourse/vendor/bundle/ruby/3.4.0/gems/railties-8.0.4/lib/rails/initializable.rb:32:in 'Rails::Initializable::Initializer#run'
        from /var/www/discourse/vendor/bundle/ruby/3.4.0/gems/railties-8.0.4/lib/rails/initializable.rb:61:in 'block in Rails::Initializable#run_initializers'
        from /var/www/discourse/vendor/bundle/ruby/3.4.0/gems/tsort-0.2.0/lib/tsort.rb:231:in 'block in TSort.tsort_each'
        from /var/www/discourse/vendor/bundle/ruby/3.4.0/gems/tsort-0.2.0/lib/tsort.rb:353:in 'block (2 levels) in TSort.each_strongly_connected_component'
        from /var/www/discourse/vendor/bundle/ruby/3.4.0/gems/tsort-0.2.0/lib/tsort.rb:434:in 'TSort.each_strongly_connected_component_from'
        from /var/www/discourse/vendor/bundle/ruby/3.4.0/gems/tsort-0.2.0/lib/tsort.rb:352:in 'block in TSort.each_strongly_connected_component'
        from /var/www/discourse/vendor/bundle/ruby/3.4.0/gems/tsort-0.2.0/lib/tsort.rb:350:in 'Rails::Initializable::Collection#each'
        from /var/www/discourse/vendor/bundle/ruby/3.4.0/gems/tsort-0.2.0/lib/tsort.rb:350:in 'Method#call'
        from /var/www/discourse/vendor/bundle/ruby/3.4.0/gems/tsort-0.2.0/lib/tsort.rb:350:in 'TSort.each_strongly_connected_component'
        from /var/www/discourse/vendor/bundle/ruby/3.4.0/gems/tsort-0.2.0/lib/tsort.rb:229:in 'TSort#tsort_each'
        from /var/www/discourse/vendor/bundle/ruby/3.4.0/gems/tsort-0.2.0/lib/tsort.rb:208:in 'TSort#tsort_each'
        from /var/www/discourse/vendor/bundle/ruby/3.4.0/gems/railties-8.0.4/lib/rails/initializable.rb:60:in 'Rails::Initializable#run_initializers'
        from /var/www/discourse/vendor/bundle/ruby/3.4.0/gems/railties-8.0.4/lib/rails/application.rb:444:in 'Rails::Application#initialize!'
        from /var/www/discourse/config/environment.rb:7:in '<top (required)>'
        from /var/www/discourse/script/import_scripts/base.rb:16:in 'Kernel#require_relative'
        from /var/www/discourse/script/import_scripts/base.rb:16:in '<top (required)>'
        from /var/www/discourse/script/import_scripts/phpbb3/support/settings.rb:5:in 'Kernel#require_relative'
        from /var/www/discourse/script/import_scripts/phpbb3/support/settings.rb:5:in '<top (required)>'
        from phpbb3.rb:17:in 'Kernel#require_relative'
        from phpbb3.rb:17:in '<module:PhpBB3>'
        from phpbb3.rb:16:in '<module:ImportScripts>'
        from phpbb3.rb:15:in '<main>'

試したこと

  1. 異なる Discourse バージョン: latest、stable、esr ブランチを試しましたが、すべて同じエラーで失敗します。
  2. 異なる Rails 環境: RAILS_ENV=production と RAILS_ENV=development の両方を試しました。
  3. コンテナのクリーンビルド: インポートコンテナを複数回破棄して再構築しました。
  4. Bundle install: bundle install を実行して依存関係を更新しました。

原因分析

ファイル /var/www/discourse/lib/freedom_patches/safe_migrations.rb は、RAILS_ENV != "production" の場合にのみ SafeMigrations 定数を定義します。

if ENV["RAILS_ENV"] != "production"
  require_dependency "migration/safe_migrate"
  Migration::SafeMigrate.patch_active_record!
end

しかし、initializer /var/www/discourse/config/initializers/002-freedom_patches.rb は、このファイルを無条件に require しようとするため、production モードでは Zeitwerk エラーが発生します。

質問

  1. 最近の Discourse バージョンで、これに遭遇した人はいますか？
  2. 既知の回避策や修正はありますか？
  3. phpBB のインポートに現在推奨されている Discourse バージョンはどれですか？
  4. 1月に動作していたのに、今回失敗するという事実は、インポートに影響を与える Discourse コアの最近の破壊的変更を示唆しています。何かご指導いただけると幸いです！