ruby-on-rails - 查看 Rails 模型页面适用于第一个 View ，但不适用于后续 View

Question

这是使用 Rails 2.2.2

我有一个使用 acts_as_flaggable 插件的模型，在我用来显示模型实例的页面上，我列出了该模型具有的所有标志。

当我使用标准脚本/服务器命令启动我的 Rails 开发服务器 (mongrel) 时，加载包含以下代码的页面，它加载正常:

<% @object.flags.each do |flag| %>
<tr>
<td><%= time_ago_in_words(flag.created_at) %> ago</td>
<td><%= flag.flag %></td>
<td><%= link_to flag.user.login, user_path(flag.user) %></td>
</tr>
<% end %>

如果我重新加载页面(以及任何后续 View )，我会收到以下 NoMethodError 错误:

You have a nil object when you didn't expect it!
You might have expected an instance of Array.
The error occurred while evaluating nil.include?

如果我重新启动开发服务器，页面会再次正常加载一次，然后后续 View 会产生同样的奇怪现象。

如果我删除该行:

<td><%= link_to flag.user.login, user_path(flag.user) %></td>

页面加载正常，并且从那时起将重新加载正常。

似乎可标记插件由于某种原因在用户模型方面出现问题，但为什么它在第一页加载时起作用？我似乎也无法使用脚本/控制台重复该问题。

--编辑--

添加每个请求的堆栈跟踪。在正常情况下，我通常可以处理这个特定的错误，但让我感到困惑的部分是为什么它第一次起作用。

这是在我看来的错误页面/跟踪，我希望这被证明是有帮助的:

NoMethodError in Admin#list_flagged

Showing app/views/admin/list_flagged.html.erb where line #65 raised:

You have a nil object when you didn't expect it!
You might have expected an instance of Array.
The error occurred while evaluating nil.include?

Extracted source (around line #65):

62:                   <tr>
63:                     <td><%= time_ago_in_words(flag.created_at) %> ago</td>
64:                     <td><%= flag.flag %></td>
65:                     <td><%= link_to flag.user.login, user_path(flag.user) %></td>
66:                   </tr>
67:                 <% end %>

RAILS_ROOT: /dev/trunk
Application Trace | Framework Trace | Full Trace

/usr/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/attribute_methods.rb:142:in `create_time_zone_conversion_attribute?'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/attribute_methods.rb:75:in `define_attribute_methods'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/attribute_methods.rb:71:in `each'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/attribute_methods.rb:71:in `define_attribute_methods'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/attribute_methods.rb:350:in `respond_to?'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/associations/association_proxy.rb:209:in `method_missing'
app/views/admin/list_flagged.html.erb:65
app/views/admin/list_flagged.html.erb:61
app/views/admin/list_flagged.html.erb:24:in `each'
app/views/admin/list_flagged.html.erb:24
app/views/admin/list_flagged.html.erb:14

/usr/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/attribute_methods.rb:142:in `create_time_zone_conversion_attribute?'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/attribute_methods.rb:75:in `define_attribute_methods'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/attribute_methods.rb:71:in `each'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/attribute_methods.rb:71:in `define_attribute_methods'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/attribute_methods.rb:350:in `respond_to?'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/associations/association_proxy.rb:209:in `method_missing'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/associations/association_collection.rb:359:in `method_missing_without_paginate'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/associations/association_proxy.rb:212:in `method_missing'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/associations/association_proxy.rb:212:in `each'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/associations/association_proxy.rb:212:in `send'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/associations/association_proxy.rb:212:in `method_missing'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/associations/association_collection.rb:359:in `method_missing_without_paginate'
/usr/lib/ruby/gems/1.8/gems/mislav-will_paginate-2.3.6/lib/will_paginate/finder.rb:167:in `method_missing'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_view/helpers/form_helper.rb:313:in `fields_for'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_view/helpers/form_helper.rb:253:in `form_for'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_view/renderable.rb:39:in `send'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_view/renderable.rb:39:in `render'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_view/template.rb:73:in `render_template'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_view/base.rb:256:in `render'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_view/base.rb:367:in `_render_with_layout'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_view/base.rb:254:in `render'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/base.rb:1174:in `render_for_file'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/base.rb:896:in `render_without_benchmark'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/benchmarking.rb:51:in `render'
/usr/lib/ruby/gems/1.8/gems/activesupport-2.2.2/lib/active_support/core_ext/benchmark.rb:8:in `realtime'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/benchmarking.rb:51:in `render'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/base.rb:868:in `render_without_benchmark'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/benchmarking.rb:51:in `render'
/usr/lib/ruby/gems/1.8/gems/activesupport-2.2.2/lib/active_support/core_ext/benchmark.rb:8:in `realtime'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/benchmarking.rb:51:in `render'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/base.rb:1248:in `default_render'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/base.rb:1254:in `perform_action_without_filters'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/filters.rb:617:in `call_filters'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/filters.rb:610:in `perform_action_without_benchmark'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/benchmarking.rb:68:in `perform_action_without_rescue'
/usr/lib/ruby/1.8/benchmark.rb:293:in `measure'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/benchmarking.rb:68:in `perform_action_without_rescue'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/rescue.rb:136:in `perform_action_without_caching'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/caching/sql_cache.rb:13:in `perform_action'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/connection_adapters/abstract/query_cache.rb:34:in `cache'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/query_cache.rb:8:in `cache'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/caching/sql_cache.rb:12:in `perform_action'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/base.rb:524:in `send'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/base.rb:524:in `process_without_filters'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/filters.rb:606:in `process_without_session_management_support'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/session_management.rb:134:in `process'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/base.rb:392:in `process'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/dispatcher.rb:183:in `handle_request'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/dispatcher.rb:110:in `dispatch_unlocked'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/dispatcher.rb:123:in `dispatch'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/dispatcher.rb:122:in `synchronize'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/dispatcher.rb:122:in `dispatch'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/dispatcher.rb:132:in `dispatch_cgi'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/dispatcher.rb:39:in `dispatch'
/usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/rails.rb:76:in `process'
/usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/rails.rb:74:in `synchronize'
/usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/rails.rb:74:in `process'
/usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:159:in `process_client'
/usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:158:in `each'
/usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:158:in `process_client'
/usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `run'
/usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `initialize'
/usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `new'
/usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `run'
/usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in `initialize'
/usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in `new'
/usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in `run'
/usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:282:in `run'
/usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:281:in `each'
/usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:281:in `run'
/usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/bin/mongrel_rails:128:in `run'
/usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/command.rb:212:in `run'
/usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/bin/mongrel_rails:281
/usr/lib/ruby/gems/1.8/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:142:in `load_without_new_constant_marking'
/usr/lib/ruby/gems/1.8/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:142:in `load'
/usr/lib/ruby/gems/1.8/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:521:in `new_constants_in'
/usr/lib/ruby/gems/1.8/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:142:in `load'
/usr/lib/ruby/gems/1.8/gems/rails-2.2.2/lib/commands/servers/mongrel.rb:64
/usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require'
/usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:31:in `require'
/usr/lib/ruby/gems/1.8/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in `require'
/usr/lib/ruby/gems/1.8/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:521:in `new_constants_in'
/usr/lib/ruby/gems/1.8/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in `require'
/usr/lib/ruby/gems/1.8/gems/rails-2.2.2/lib/commands/server.rb:49
/usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require'
/usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:31:in `require'
script/server:3

/usr/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/attribute_methods.rb:142:in `create_time_zone_conversion_attribute?'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/attribute_methods.rb:75:in `define_attribute_methods'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/attribute_methods.rb:71:in `each'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/attribute_methods.rb:71:in `define_attribute_methods'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/attribute_methods.rb:350:in `respond_to?'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/associations/association_proxy.rb:209:in `method_missing'
app/views/admin/list_flagged.html.erb:65
/usr/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/associations/association_collection.rb:359:in `method_missing_without_paginate'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/associations/association_proxy.rb:212:in `method_missing'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/associations/association_proxy.rb:212:in `each'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/associations/association_proxy.rb:212:in `send'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/associations/association_proxy.rb:212:in `method_missing'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/associations/association_collection.rb:359:in `method_missing_without_paginate'
/usr/lib/ruby/gems/1.8/gems/mislav-will_paginate-2.3.6/lib/will_paginate/finder.rb:167:in `method_missing'
app/views/admin/list_flagged.html.erb:61
app/views/admin/list_flagged.html.erb:24:in `each'
app/views/admin/list_flagged.html.erb:24
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_view/helpers/form_helper.rb:313:in `fields_for'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_view/helpers/form_helper.rb:253:in `form_for'
app/views/admin/list_flagged.html.erb:14
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_view/renderable.rb:39:in `send'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_view/renderable.rb:39:in `render'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_view/template.rb:73:in `render_template'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_view/base.rb:256:in `render'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_view/base.rb:367:in `_render_with_layout'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_view/base.rb:254:in `render'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/base.rb:1174:in `render_for_file'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/base.rb:896:in `render_without_benchmark'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/benchmarking.rb:51:in `render'
/usr/lib/ruby/gems/1.8/gems/activesupport-2.2.2/lib/active_support/core_ext/benchmark.rb:8:in `realtime'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/benchmarking.rb:51:in `render'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/base.rb:868:in `render_without_benchmark'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/benchmarking.rb:51:in `render'
/usr/lib/ruby/gems/1.8/gems/activesupport-2.2.2/lib/active_support/core_ext/benchmark.rb:8:in `realtime'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/benchmarking.rb:51:in `render'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/base.rb:1248:in `default_render'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/base.rb:1254:in `perform_action_without_filters'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/filters.rb:617:in `call_filters'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/filters.rb:610:in `perform_action_without_benchmark'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/benchmarking.rb:68:in `perform_action_without_rescue'
/usr/lib/ruby/1.8/benchmark.rb:293:in `measure'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/benchmarking.rb:68:in `perform_action_without_rescue'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/rescue.rb:136:in `perform_action_without_caching'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/caching/sql_cache.rb:13:in `perform_action'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/connection_adapters/abstract/query_cache.rb:34:in `cache'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/query_cache.rb:8:in `cache'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/caching/sql_cache.rb:12:in `perform_action'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/base.rb:524:in `send'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/base.rb:524:in `process_without_filters'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/filters.rb:606:in `process_without_session_management_support'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/session_management.rb:134:in `process'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/base.rb:392:in `process'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/dispatcher.rb:183:in `handle_request'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/dispatcher.rb:110:in `dispatch_unlocked'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/dispatcher.rb:123:in `dispatch'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/dispatcher.rb:122:in `synchronize'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/dispatcher.rb:122:in `dispatch'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/dispatcher.rb:132:in `dispatch_cgi'
/usr/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/dispatcher.rb:39:in `dispatch'
/usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/rails.rb:76:in `process'
/usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/rails.rb:74:in `synchronize'
/usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/rails.rb:74:in `process'
/usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:159:in `process_client'
/usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:158:in `each'
/usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:158:in `process_client'
/usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `run'
/usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `initialize'
/usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `new'
/usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `run'
/usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in `initialize'
/usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in `new'
/usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in `run'
/usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:282:in `run'
/usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:281:in `each'
/usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:281:in `run'
/usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/bin/mongrel_rails:128:in `run'
/usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/command.rb:212:in `run'
/usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/bin/mongrel_rails:281
/usr/lib/ruby/gems/1.8/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:142:in `load_without_new_constant_marking'
/usr/lib/ruby/gems/1.8/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:142:in `load'
/usr/lib/ruby/gems/1.8/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:521:in `new_constants_in'
/usr/lib/ruby/gems/1.8/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:142:in `load'
/usr/lib/ruby/gems/1.8/gems/rails-2.2.2/lib/commands/servers/mongrel.rb:64
/usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require'
/usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:31:in `require'
/usr/lib/ruby/gems/1.8/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in `require'
/usr/lib/ruby/gems/1.8/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:521:in `new_constants_in'
/usr/lib/ruby/gems/1.8/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in `require'
/usr/lib/ruby/gems/1.8/gems/rails-2.2.2/lib/commands/server.rb:49
/usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require'
/usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:31:in `require'
script/server:3

Request

Parameters:

None

Show session dump

--- 
:user_id: 1
:last_page: http://localhost:3000/
flash: !map:ActionController::Flash::FlashHash {}

Response

Headers:

{"cookie"=>[],
 "Content-Type"=>"text/html",
 "Cache-Control"=>"no-cache"}

--编辑#2--

好吧，我已经“修复”了它。尽管在 Flag 模型中存在 belongs_to 关系，但我将以下代码添加到 acts_as_flaggable 的 Flag 模型中:

def user
  User.find(self.user_id)
end

此代码确实允许页面加载而不会出现错误，无论是第一次还是第 N 次出现在页面上。

我会添加这个作为答案，但我不知道我对此是否满意。

Answer 1

如果遇到类似问题，我会检查您的 /config/initializers 目录。它是否声明了一些方法或将一些模块包含到模型中？如果是这样，它将在第一次加载时发生，但模型将在后续请求中重新加载，而无需再次运行初始化程序。