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単純なRailsアプリ：エラーは整数にアクセスできません

シンプルなRails app。Rails v3.2.22.5（それは要件です）を構築しようとしています。PostgreSQLで実行しています。サーバーを起動しますが、データベースから単純な投稿を読み取ろうとすると、次のエラーが発生します。

整数にアクセスできません

トレースにより、以下のshowメソッドが表示されます。より具体的には、2行目です。私はRailsに非常に慣れていないため、これを修正する方法についてはまったく手がかりがありません。すでにWebを検索して成功していません。どんなアイデアでも大歓迎です。

  def show
    @post = Post.find(params[:id])
    respond_to do |format|
      format.html # show.html.erb
      format.json { render json: @post }
    end
  end

完全なトレース：

arel (3.0.3) lib/arel/visitors/visitor.rb:25:in `rescue in visit'
arel (3.0.3) lib/arel/visitors/visitor.rb:19:in `visit'
arel (3.0.3) lib/arel/visitors/to_sql.rb:241:in `visit_Arel_Nodes_Limit'
arel (3.0.3) lib/arel/visitors/visitor.rb:19:in `visit'
arel (3.0.3) lib/arel/visitors/to_sql.rb:123:in `visit_Arel_Nodes_SelectStatement'
arel (3.0.3) lib/arel/visitors/visitor.rb:19:in `visit'
arel (3.0.3) lib/arel/visitors/visitor.rb:5:in `accept'
arel (3.0.3) lib/arel/visitors/to_sql.rb:19:in `accept'
activerecord (3.2.22.5) lib/active_record/connection_adapters/abstract/database_statements.rb:7:in `to_sql'
activerecord (3.2.22.5) lib/active_record/connection_adapters/abstract/query_cache.rb:60:in `select_all'
activerecord (3.2.22.5) lib/active_record/querying.rb:38:in `block in find_by_sql'
activerecord (3.2.22.5) lib/active_record/explain.rb:41:in `logging_query_plan'
activerecord (3.2.22.5) lib/active_record/querying.rb:37:in `find_by_sql'
activerecord (3.2.22.5) lib/active_record/relation.rb:171:in `exec_queries'
activerecord (3.2.22.5) lib/active_record/relation.rb:160:in `block in to_a'
activerecord (3.2.22.5) lib/active_record/explain.rb:34:in `logging_query_plan'
activerecord (3.2.22.5) lib/active_record/relation.rb:159:in `to_a'
activerecord (3.2.22.5) lib/active_record/relation/Finder_methods.rb:381:in `find_first'
activerecord (3.2.22.5) lib/active_record/relation/Finder_methods.rb:122:in `first'
app/controllers/posts_controller.rb:16:in `show'
actionpack (3.2.22.5) lib/action_controller/metal/implicit_render.rb:4:in `send_action'
actionpack (3.2.22.5) lib/abstract_controller/base.rb:167:in `process_action'
actionpack (3.2.22.5) lib/action_controller/metal/rendering.rb:10:in `process_action'
actionpack (3.2.22.5) lib/abstract_controller/callbacks.rb:18:in `block in process_action'
activesupport (3.2.22.5) lib/active_support/callbacks.rb:414:in `_run__2562463311931153568__process_action__1655262725222060869__callbacks'
activesupport (3.2.22.5) lib/active_support/callbacks.rb:405:in `__run_callback'
activesupport (3.2.22.5) lib/active_support/callbacks.rb:385:in `_run_process_action_callbacks'
activesupport (3.2.22.5) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (3.2.22.5) lib/abstract_controller/callbacks.rb:17:in `process_action'
actionpack (3.2.22.5) lib/action_controller/metal/rescue.rb:29:in `process_action'
actionpack (3.2.22.5) lib/action_controller/metal/instrumentation.rb:30:in `block in process_action'
activesupport (3.2.22.5) lib/active_support/notifications.rb:123:in `block in instrument'
activesupport (3.2.22.5) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activesupport (3.2.22.5) lib/active_support/notifications.rb:123:in `instrument'
actionpack (3.2.22.5) lib/action_controller/metal/instrumentation.rb:29:in `process_action'
actionpack (3.2.22.5) lib/action_controller/metal/params_wrapper.rb:207:in `process_action'
activerecord (3.2.22.5) lib/active_record/railties/controller_runtime.rb:18:in `process_action'
actionpack (3.2.22.5) lib/abstract_controller/base.rb:121:in `process'
actionpack (3.2.22.5) lib/abstract_controller/rendering.rb:46:in `process'
actionpack (3.2.22.5) lib/action_controller/metal.rb:203:in `dispatch'
actionpack (3.2.22.5) lib/action_controller/metal/rack_delegation.rb:14:in `dispatch'
actionpack (3.2.22.5) lib/action_controller/metal.rb:246:in `block in action'
actionpack (3.2.22.5) lib/action_dispatch/routing/route_set.rb:73:in `dispatch'
actionpack (3.2.22.5) lib/action_dispatch/routing/route_set.rb:36:in `call'
journey (1.0.4) lib/journey/router.rb:68:in `block in call'
journey (1.0.4) lib/journey/router.rb:56:in `each'
journey (1.0.4) lib/journey/router.rb:56:in `call'
actionpack (3.2.22.5) lib/action_dispatch/routing/route_set.rb:608:in `call'
actionpack (3.2.22.5) lib/action_dispatch/middleware/best_standards_support.rb:17:in `call'
rack (1.4.7) lib/rack/etag.rb:23:in `call'
rack (1.4.7) lib/rack/conditionalget.rb:25:in `call'
actionpack (3.2.22.5) lib/action_dispatch/middleware/head.rb:14:in `call'
actionpack (3.2.22.5) lib/action_dispatch/middleware/params_parser.rb:21:in `call'
actionpack (3.2.22.5) lib/action_dispatch/middleware/flash.rb:242:in `call'
rack (1.4.7) lib/rack/session/abstract/id.rb:210:in `context'
rack (1.4.7) lib/rack/session/abstract/id.rb:205:in `call'
actionpack (3.2.22.5) lib/action_dispatch/middleware/cookies.rb:341:in `call'
activerecord (3.2.22.5) lib/active_record/query_cache.rb:64:in `call'
activerecord (3.2.22.5) lib/active_record/connection_adapters/abstract/connection_pool.rb:479:in `call'
actionpack (3.2.22.5) lib/action_dispatch/middleware/callbacks.rb:28:in `block in call'
activesupport (3.2.22.5) lib/active_support/callbacks.rb:405:in `_run__2325253408966325104__call__3112622970942194936__callbacks'
activesupport (3.2.22.5) lib/active_support/callbacks.rb:405:in `__run_callback'
activesupport (3.2.22.5) lib/active_support/callbacks.rb:385:in `_run_call_callbacks'
activesupport (3.2.22.5) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (3.2.22.5) lib/action_dispatch/middleware/callbacks.rb:27:in `call'
actionpack (3.2.22.5) lib/action_dispatch/middleware/reloader.rb:65:in `call'
actionpack (3.2.22.5) lib/action_dispatch/middleware/remote_ip.rb:31:in `call'
actionpack (3.2.22.5) lib/action_dispatch/middleware/debug_exceptions.rb:16:in `call'
actionpack (3.2.22.5) lib/action_dispatch/middleware/show_exceptions.rb:56:in `call'
railties (3.2.22.5) lib/Rails/rack/logger.rb:32:in `call_app'
railties (3.2.22.5) lib/Rails/rack/logger.rb:16:in `block in call'
activesupport (3.2.22.5) lib/active_support/tagged_logging.rb:22:in `tagged'
railties (3.2.22.5) lib/Rails/rack/logger.rb:16:in `call'
actionpack (3.2.22.5) lib/action_dispatch/middleware/request_id.rb:22:in `call'
rack (1.4.7) lib/rack/methodoverride.rb:21:in `call'
rack (1.4.7) lib/rack/runtime.rb:17:in `call'
activesupport (3.2.22.5) lib/active_support/cache/strategy/local_cache.rb:72:in `call'
rack (1.4.7) lib/rack/lock.rb:15:in `call'
actionpack (3.2.22.5) lib/action_dispatch/middleware/static.rb:83:in `call'
railties (3.2.22.5) lib/Rails/engine.rb:484:in `call'
railties (3.2.22.5) lib/Rails/application.rb:231:in `call'
rack (1.4.7) lib/rack/content_length.rb:14:in `call'
railties (3.2.22.5) lib/Rails/rack/log_tailer.rb:17:in `call'
rack (1.4.7) lib/rack/handler/webrick.rb:59:in `service'
/Users/luishreis/.rbenv/versions/2.4.1/lib/Ruby/2.4.0/webrick/httpserver.rb:140:in `service'
/Users/luishreis/.rbenv/versions/2.4.1/lib/Ruby/2.4.0/webrick/httpserver.rb:96:in `run'
/Users/luishreis/.rbenv/versions/2.4.1/lib/Ruby/2.4.0/webrick/server.rb:290:in `block in start_thread'
ruby-on-railsrubypostgresql
27
luis reis

使用しているRubyのバージョン（2.4.1）は、使用しているRailsのバージョン（3.2.22.5）と互換性がありません。そのバージョンのRubyには、少なくともRailsが必要です。5. Ruby 2.3以下にダウングレードしてみてください。 Rubyバージョンマネージャ（つまり、rvm、rbenvまたはchruby）を使用して、起動時に使用するRubyを制御できます。あなたの申請。

編集する

スタックトレースのrbenvをすでに使用していることに気づきました。次の行を含む.Ruby-versionファイルをアプリケーションのディレクトリに追加します。

2.3.4

そのディレクトリに再度入ったら、次の方法でバージョンを確認します。

$> Ruby -v
Ruby 2.3.4p301 (2017-03-30 revision 58214) [x86_64-darwin16]

（または同様のバージョン）Railsを起動する前。

28
Aaron Breckenridge

昨日このエラーが発生し、Ruby 2.4およびRails 3.2。

私がアイデアを得たコミットは： https://github.com/Rails/arel/commit/dc85a6e9c74942945ad696f5da4d82490a85b865

Rails初期化子に以下を含めてください。

module Arel
  module Visitors
    class DepthFirst < Arel::Visitors::Visitor
      alias :visit_Integer :terminal
    end

    class Dot < Arel::Visitors::Visitor
      alias :visit_Integer :visit_String
    end

    class ToSql < Arel::Visitors::Visitor
      alias :visit_Integer :literal
    end
  end
end
27
Thomas Dziedzic

将来のGoogle社員向け。同じ問題がありましたが、Thomas Dziedzicソリューションのバリアントを適用する必要がありました。

システムでRuby 2.5.1とRails 4.2.10を実行しています。

this commit に示すように、ToSqlはArel::Visitors::VisitorからArel::Visitors::Reduceに変更されました

これが私の更新されたソリューションです。 Rails初期化子にこれを入れてください：

module Arel
  module Visitors
    class DepthFirst < Arel::Visitors::Visitor
      alias :visit_Integer :terminal
    end

    class Dot < Arel::Visitors::Visitor
      alias :visit_Integer :visit_String
    end

    class ToSql < Arel::Visitors::Reduce
      alias :visit_Integer :literal
    end
  end
end
7
jonnyjava.net