TypeError（无法将符号转换为字符串）：答案

【问题标题】：TypeError (can't convert Symbol into String):TypeError（无法将符号转换为字符串）：
【发布时间】：2012-03-25 14:37:05
【问题描述】：

当我尝试访问我的 Rails 应用程序中的页面时，我现在收到了

TypeError (can't convert Symbol into String):

这是完整的堆栈跟踪。在我看来，它就像带有 twitter-bootstrap-rails gem 的东西。我说的对吗？

TypeError (can't convert Symbol into String):
  twitter-bootstrap-rails (2.0.4) lib/twitter/bootstrap/rails/twitter-bootstrap-breadcrumbs.rb:20:in `eval'
  twitter-bootstrap-rails (2.0.4) lib/twitter/bootstrap/rails/twitter-bootstrap-breadcrumbs.rb:20:in `add_breadcrumb'
  twitter-bootstrap-rails (2.0.4) lib/twitter/bootstrap/rails/twitter-bootstrap-breadcrumbs.rb:11:in `block in add_breadcrumb'
  activesupport (3.2.2) lib/active_support/callbacks.rb:407:in `_run__1576526312124645203__process_action__39584884573935751__callbacks'
  activesupport (3.2.2) lib/active_support/callbacks.rb:405:in `__run_callback'
  activesupport (3.2.2) lib/active_support/callbacks.rb:385:in `_run_process_action_callbacks'
  activesupport (3.2.2) lib/active_support/callbacks.rb:81:in `run_callbacks'
  actionpack (3.2.2) lib/abstract_controller/callbacks.rb:17:in `process_action'
  actionpack (3.2.2) lib/action_controller/metal/rescue.rb:29:in `process_action'
  actionpack (3.2.2) lib/action_controller/metal/instrumentation.rb:30:in `block in process_action'
  activesupport (3.2.2) lib/active_support/notifications.rb:123:in `block in instrument'
  activesupport (3.2.2) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
  activesupport (3.2.2) lib/active_support/notifications.rb:123:in `instrument'
  actionpack (3.2.2) lib/action_controller/metal/instrumentation.rb:29:in `process_action'
  actionpack (3.2.2) lib/action_controller/metal/params_wrapper.rb:205:in `process_action'
  activerecord (3.2.2) lib/active_record/railties/controller_runtime.rb:18:in `process_action'
  actionpack (3.2.2) lib/abstract_controller/base.rb:121:in `process'
  actionpack (3.2.2) lib/abstract_controller/rendering.rb:45:in `process'
  actionpack (3.2.2) lib/action_controller/metal.rb:203:in `dispatch'
  actionpack (3.2.2) lib/action_controller/metal/rack_delegation.rb:14:in `dispatch'
  actionpack (3.2.2) lib/action_controller/metal.rb:246:in `block in action'
  actionpack (3.2.2) lib/action_dispatch/routing/route_set.rb:67:in `call'
  actionpack (3.2.2) lib/action_dispatch/routing/route_set.rb:67:in `dispatch'
  actionpack (3.2.2) lib/action_dispatch/routing/route_set.rb:30:in `call'
  journey (1.0.3) lib/journey/router.rb:68:in `block in call'
  journey (1.0.3) lib/journey/router.rb:56:in `each'
  journey (1.0.3) lib/journey/router.rb:56:in `call'
  actionpack (3.2.2) lib/action_dispatch/routing/route_set.rb:594:in `call'
  actionpack (3.2.2) lib/action_dispatch/middleware/best_standards_support.rb:17:in `call'
  rack (1.4.1) lib/rack/etag.rb:23:in `call'
  rack (1.4.1) lib/rack/conditionalget.rb:25:in `call'
  actionpack (3.2.2) lib/action_dispatch/middleware/head.rb:14:in `call'
  actionpack (3.2.2) lib/action_dispatch/middleware/params_parser.rb:21:in `call'
  actionpack (3.2.2) lib/action_dispatch/middleware/flash.rb:242:in `call'
  rack (1.4.1) lib/rack/session/abstract/id.rb:205:in `context'
  rack (1.4.1) lib/rack/session/abstract/id.rb:200:in `call'
  actionpack (3.2.2) lib/action_dispatch/middleware/cookies.rb:338:in `call'
  activerecord (3.2.2) lib/active_record/query_cache.rb:64:in `call'
  activerecord (3.2.2) lib/active_record/connection_adapters/abstract/connection_pool.rb:443:in `call'
  actionpack (3.2.2) lib/action_dispatch/middleware/callbacks.rb:28:in `block in call'
  activesupport (3.2.2) lib/active_support/callbacks.rb:405:in `_run__400543747363831273__call__3603336714283860524__callbacks'
  activesupport (3.2.2) lib/active_support/callbacks.rb:405:in `__run_callback'
  activesupport (3.2.2) lib/active_support/callbacks.rb:385:in `_run_call_callbacks'
  activesupport (3.2.2) lib/active_support/callbacks.rb:81:in `run_callbacks'
  actionpack (3.2.2) lib/action_dispatch/middleware/callbacks.rb:27:in `call'
  actionpack (3.2.2) lib/action_dispatch/middleware/reloader.rb:65:in `call'
  actionpack (3.2.2) lib/action_dispatch/middleware/remote_ip.rb:31:in `call'
  actionpack (3.2.2) lib/action_dispatch/middleware/debug_exceptions.rb:16:in `call'
  actionpack (3.2.2) lib/action_dispatch/middleware/show_exceptions.rb:56:in `call'
  railties (3.2.2) lib/rails/rack/logger.rb:26:in `call_app'
  railties (3.2.2) lib/rails/rack/logger.rb:16:in `call'
  actionpack (3.2.2) lib/action_dispatch/middleware/request_id.rb:22:in `call'
  rack (1.4.1) lib/rack/methodoverride.rb:21:in `call'
  rack (1.4.1) lib/rack/runtime.rb:17:in `call'
  activesupport (3.2.2) lib/active_support/cache/strategy/local_cache.rb:72:in `call'
  rack (1.4.1) lib/rack/lock.rb:15:in `call'
  actionpack (3.2.2) lib/action_dispatch/middleware/static.rb:61:in `call'
  railties (3.2.2) lib/rails/engine.rb:479:in `call'
  railties (3.2.2) lib/rails/application.rb:220:in `call'
  rack (1.4.1) lib/rack/content_length.rb:14:in `call'
  railties (3.2.2) lib/rails/rack/log_tailer.rb:14:in `call'
  rack (1.4.1) lib/rack/handler/webrick.rb:59:in `service'
  /Users/Kyle/.rvm/rubies/ruby-1.9.3-p125/lib/ruby/1.9.1/webrick/httpserver.rb:138:in `service'
  /Users/Kyle/.rvm/rubies/ruby-1.9.3-p125/lib/ruby/1.9.1/webrick/httpserver.rb:94:in `run'
  /Users/Kyle/.rvm/rubies/ruby-1.9.3-p125/lib/ruby/1.9.1/webrick/server.rb:191:in `block in start_thread'

【问题讨论】：

可以发一下lib/twitter/bootstrap/rails/twitter-bootstrap-breadcrumbs.rb的内容吗
由于eval中出现错误，您能否将代码与控制器中的插件一起使用？我猜你在某个地方有一些论点是错误的。如果您使用的是符号，请尝试使用 to_s 方法将其转换为字符串。

标签： ruby-on-rails ruby-on-rails-3 rubygems

【解决方案1】：

您可能没有使用您认为正在使用的 ruby 版本。你刚刚更新了 ruby 吗？

如果您使用的是 rbenv 或 rvm，请尝试切换您正在使用的版本，看看错误是否仍然存在。也许你正在使用 jruby？

您能否在此线程上发布以下命令的结果？

which ruby
ruby --version

【讨论】：