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，我列出了模型的所有标志。
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（以及任何后续视图），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，页面会再次加载一次，然后后续视图会产生同样的陌生感。
如果我删除该行：
<td><%= link_to flag.user.login, user_path(flag.user) %></td>
页面加载正常，从那时起将重新加载。
似乎可标记的插件由于某种原因出现了用户模型的问题，但是为什么它在第一页加载时有效呢？我似乎也无法使用脚本/控制台重复这个问题。
- 编辑 -
按请求添加堆栈跟踪。在正常情况下，我通常可以处理这个特殊的错误，但令我困惑的部分是它第一次工作的原因。
这是我看来的错误页面/跟踪，我希望这证明是有用的：
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“修复”了它。尽管Flag模型中存在belongs_to关系，但我从acts_as_flaggable向Flag模型添加了以下代码：
def user
User.find(self.user_id)
end
此代码允许页面无错误地加载，无论是第一次在页面上还是第N次。
我会补充这个作为答案，但我不知道我对此感到满意。
答案 0 :(得分：1)
遇到类似的问题，我会检查你的/config/initializers目录。它是否声明了一些方法或在模型中包含一些模块？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不会再次运行初始化器。
答案 1 :(得分：0)
这意味着你有一个零对象，你期望一个真实的对象。这听起来像是在你的插件内部崩溃了。查看堆栈跟踪，看看你是否可以在你的代码中查明它的位置，然后在它周围包装一些调试原则，以检查你的对象是否应该是nil。
如果不知道该插件是如何工作的，请不要认为我们可以提供更多帮助。
答案 2 :(得分：0)
我知道这是rails世界中的一个异端，但安装netbeans并使用他们的调试工具来看看发生了什么。你可以在html中加入断点。它非常令人印象深刻（虽然非常慢）。
答案 3 :(得分：0)
没有真正的解决方法，但这是一个解决方法。它与development.rb文件中的config.cache_classes设置有关。
变化：
config.cache_classes = false
到...
config.cache_classes = true
问题就消失了。
不是一个很好的解决方案，但似乎自2.2.2以来（我在2.3.12）。
很多background and a possible patch here。
这是我的first clue。