ruby-on-rails - Rails time_ago_in_words 为 nil :NilClass 给出错误未定义的方法 `>'

Question

这是一个单独的帖子部分，作为提要部分的一部分呈现。所以它是部分中的部分。

除了 time_ago_in_words 行之外，一切正常。错误是

ActionView::Template::Error:
   undefined method `>' for nil:NilClass

这没有意义，因为 feed_post 不是零。它在错误出现之前渲染了 3 次。有一个 created_at 因为相同的帖子显示在不同的 View 中，所以我知道它在数据库中。此外，如果我删除 time_ago_in_words 并且只有 feed_post.created_at 它工作正常。我被难住了。

#shared/_feed_post.html.erb

  <li>
  <%= link_to gravatar(feed_post.user), feed_post.user %>
  <span class="user">
    <%= link_to feed_post.user.email, feed_post.user %>
  </span>
  <span class="post_text">
    <%= feed_post.text %>
  </span>
  <span class="timestamp">
    <%= time_ago_in_words(feed_post.created_at) %> #### Here is the trouble
  </span>
</li>

这里我用集合 @feed_posts

渲染部分

#shared/_feed.html.erb

<% if @feed_posts.any? %>
  <ol class="posts">
    <%= render partial: 'shared/feed_post', collection: @feed_posts %>
  </ol>
<% end %>

这是 Controller Action

def home
  @feed_posts = current_user.feed
end

希望这是一个可以帮助解决的简单错误。我只是没看到。任何帮助表示赞赏。谢谢

编辑这是完整的跟踪

app/views/shared/_feed_post.html.erb:10:in `_app_views_shared__feed_post_html_erb___559710345292053670_70357988998940'
actionpack (4.0.0.rc2) lib/action_view/template.rb:143:in `block in render'
activesupport (4.0.0.rc2) lib/active_support/notifications.rb:161:in `instrument'
actionpack (4.0.0.rc2) lib/action_view/template.rb:141:in `render'
actionpack (4.0.0.rc2) lib/action_view/renderer/partial_renderer.rb:399:in `block in collection_with_template'
actionpack (4.0.0.rc2) lib/action_view/renderer/partial_renderer.rb:395:in `map'
actionpack (4.0.0.rc2) lib/action_view/renderer/partial_renderer.rb:395:in `collection_with_template'
actionpack (4.0.0.rc2) lib/action_view/renderer/partial_renderer.rb:291:in `render_collection'
actionpack (4.0.0.rc2) lib/action_view/renderer/partial_renderer.rb:275:in `block in render'
actionpack (4.0.0.rc2) lib/action_view/renderer/abstract_renderer.rb:38:in `block in instrument'
activesupport (4.0.0.rc2) lib/active_support/notifications.rb:159:in `block in instrument'
activesupport (4.0.0.rc2) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activesupport (4.0.0.rc2) lib/active_support/notifications.rb:159:in `instrument'
actionpack (4.0.0.rc2) lib/action_view/renderer/abstract_renderer.rb:38:in `instrument'
actionpack (4.0.0.rc2) lib/action_view/renderer/partial_renderer.rb:274:in `render'
actionpack (4.0.0.rc2) lib/action_view/renderer/renderer.rb:47:in `render_partial'
actionpack (4.0.0.rc2) lib/action_view/renderer/renderer.rb:21:in `render'
actionpack (4.0.0.rc2) lib/action_view/helpers/rendering_helper.rb:24:in `render'
app/views/shared/_feed.html.erb:3:in `_app_views_shared__feed_html_erb__1326961751106757393_70357968045160'
actionpack (4.0.0.rc2) lib/action_view/template.rb:143:in `block in render'
activesupport (4.0.0.rc2) lib/active_support/notifications.rb:161:in `instrument'
actionpack (4.0.0.rc2) lib/action_view/template.rb:141:in `render'
actionpack (4.0.0.rc2) lib/action_view/renderer/partial_renderer.rb:306:in `render_partial'
actionpack (4.0.0.rc2) lib/action_view/renderer/partial_renderer.rb:279:in `block in render'
actionpack (4.0.0.rc2) lib/action_view/renderer/abstract_renderer.rb:38:in `block in instrument'
activesupport (4.0.0.rc2) lib/active_support/notifications.rb:159:in `block in instrument'
activesupport (4.0.0.rc2) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activesupport (4.0.0.rc2) lib/active_support/notifications.rb:159:in `instrument'
actionpack (4.0.0.rc2) lib/action_view/renderer/abstract_renderer.rb:38:in `instrument'
actionpack (4.0.0.rc2) lib/action_view/renderer/partial_renderer.rb:278:in `render'
actionpack (4.0.0.rc2) lib/action_view/renderer/renderer.rb:47:in `render_partial'
actionpack (4.0.0.rc2) lib/action_view/helpers/rendering_helper.rb:27:in `render'
app/views/pages/home.html.erb:12:in `_app_views_pages_home_html_erb__4035833185189931772_70357967633720'
actionpack (4.0.0.rc2) lib/action_view/template.rb:143:in `block in render'
activesupport (4.0.0.rc2) lib/active_support/notifications.rb:161:in `instrument'
actionpack (4.0.0.rc2) lib/action_view/template.rb:141:in `render'
actionpack (4.0.0.rc2) lib/action_view/renderer/template_renderer.rb:49:in `block (2 levels) in render_template'
actionpack (4.0.0.rc2) lib/action_view/renderer/abstract_renderer.rb:38:in `block in instrument'
activesupport (4.0.0.rc2) lib/active_support/notifications.rb:159:in `block in instrument'
activesupport (4.0.0.rc2) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activesupport (4.0.0.rc2) lib/active_support/notifications.rb:159:in `instrument'
actionpack (4.0.0.rc2) lib/action_view/renderer/abstract_renderer.rb:38:in `instrument'
actionpack (4.0.0.rc2) lib/action_view/renderer/template_renderer.rb:48:in `block in render_template'
actionpack (4.0.0.rc2) lib/action_view/renderer/template_renderer.rb:56:in `render_with_layout'
actionpack (4.0.0.rc2) lib/action_view/renderer/template_renderer.rb:47:in `render_template'
actionpack (4.0.0.rc2) lib/action_view/renderer/template_renderer.rb:17:in `render'
actionpack (4.0.0.rc2) lib/action_view/renderer/renderer.rb:42:in `render_template'
actionpack (4.0.0.rc2) lib/action_view/renderer/renderer.rb:23:in `render'
actionpack (4.0.0.rc2) lib/abstract_controller/rendering.rb:127:in `_render_template'
actionpack (4.0.0.rc2) lib/action_controller/metal/streaming.rb:219:in `_render_template'
actionpack (4.0.0.rc2) lib/abstract_controller/rendering.rb:120:in `render_to_body'
actionpack (4.0.0.rc2) lib/action_controller/metal/rendering.rb:33:in `render_to_body'
actionpack (4.0.0.rc2) lib/action_controller/metal/renderers.rb:26:in `render_to_body'
actionpack (4.0.0.rc2) lib/abstract_controller/rendering.rb:97:in `render'
actionpack (4.0.0.rc2) lib/action_controller/metal/rendering.rb:16:in `render'
actionpack (4.0.0.rc2) lib/action_controller/metal/instrumentation.rb:41:in `block (2 levels) in render'
activesupport (4.0.0.rc2) lib/active_support/core_ext/benchmark.rb:12:in `block in ms'
/Users/Brian/.rvm/rubies/ruby-2.0.0-p0/lib/ruby/2.0.0/benchmark.rb:296:in `realtime'
activesupport (4.0.0.rc2) lib/active_support/core_ext/benchmark.rb:12:in `ms'
actionpack (4.0.0.rc2) lib/action_controller/metal/instrumentation.rb:41:in `block in render'
actionpack (4.0.0.rc2) lib/action_controller/metal/instrumentation.rb:84:in `cleanup_view_runtime'
activerecord (4.0.0.rc2) lib/active_record/railties/controller_runtime.rb:25:in `cleanup_view_runtime'
actionpack (4.0.0.rc2) lib/action_controller/metal/instrumentation.rb:40:in `render'
actionpack (4.0.0.rc2) lib/action_controller/metal/implicit_render.rb:10:in `default_render'
actionpack (4.0.0.rc2) lib/action_controller/metal/implicit_render.rb:5:in `send_action'
actionpack (4.0.0.rc2) lib/abstract_controller/base.rb:189:in `process_action'
actionpack (4.0.0.rc2) lib/action_controller/metal/rendering.rb:10:in `process_action'
actionpack (4.0.0.rc2) lib/abstract_controller/callbacks.rb:18:in `block in process_action'
activesupport (4.0.0.rc2) lib/active_support/callbacks.rb:403:in `_run__533002015063756194__process_action__callbacks'
activesupport (4.0.0.rc2) lib/active_support/callbacks.rb:80:in `run_callbacks'
actionpack (4.0.0.rc2) lib/abstract_controller/callbacks.rb:17:in `process_action'
actionpack (4.0.0.rc2) lib/action_controller/metal/rescue.rb:29:in `process_action'
actionpack (4.0.0.rc2) lib/action_controller/metal/instrumentation.rb:31:in `block in process_action'
activesupport (4.0.0.rc2) lib/active_support/notifications.rb:159:in `block in instrument'
activesupport (4.0.0.rc2) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activesupport (4.0.0.rc2) lib/active_support/notifications.rb:159:in `instrument'
actionpack (4.0.0.rc2) lib/action_controller/metal/instrumentation.rb:30:in `process_action'
actionpack (4.0.0.rc2) lib/action_controller/metal/params_wrapper.rb:245:in `process_action'
activerecord (4.0.0.rc2) lib/active_record/railties/controller_runtime.rb:18:in `process_action'
actionpack (4.0.0.rc2) lib/abstract_controller/base.rb:136:in `process'
actionpack (4.0.0.rc2) lib/abstract_controller/rendering.rb:44:in `process'
actionpack (4.0.0.rc2) lib/action_controller/metal.rb:195:in `dispatch'
actionpack (4.0.0.rc2) lib/action_controller/metal/rack_delegation.rb:13:in `dispatch'
actionpack (4.0.0.rc2) lib/action_controller/metal.rb:231:in `block in action'
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warden (1.2.3) lib/warden/manager.rb:34:in `call'
rack (1.5.2) lib/rack/etag.rb:23:in `call'
rack (1.5.2) lib/rack/conditionalget.rb:25:in `call'
rack (1.5.2) lib/rack/head.rb:11:in `call'
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actionpack (4.0.0.rc2) lib/action_dispatch/middleware/flash.rb:241:in `call'
rack (1.5.2) lib/rack/session/abstract/id.rb:225:in `context'
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actionpack (4.0.0.rc2) lib/action_dispatch/middleware/cookies.rb:486:in `call'
activerecord (4.0.0.rc2) lib/active_record/query_cache.rb:36:in `call'
activerecord (4.0.0.rc2) lib/active_record/connection_adapters/abstract/connection_pool.rb:626:in `call'
activerecord (4.0.0.rc2) lib/active_record/migration.rb:369:in `call'
actionpack (4.0.0.rc2) lib/action_dispatch/middleware/callbacks.rb:29:in `block in call'
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activesupport (4.0.0.rc2) lib/active_support/callbacks.rb:80:in `run_callbacks'
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actionpack (4.0.0.rc2) lib/action_dispatch/middleware/remote_ip.rb:76:in `call'
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activesupport (4.0.0.rc2) lib/active_support/tagged_logging.rb:67:in `block in tagged'
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railties (4.0.0.rc2) lib/rails/rack/logger.rb:21:in `call'
actionpack (4.0.0.rc2) lib/action_dispatch/middleware/request_id.rb:21:in `call'
rack (1.5.2) lib/rack/methodoverride.rb:21:in `call'
rack (1.5.2) lib/rack/runtime.rb:17:in `call'
activesupport (4.0.0.rc2) lib/active_support/cache/strategy/local_cache.rb:83:in `call'
rack (1.5.2) lib/rack/lock.rb:17:in `call'
actionpack (4.0.0.rc2) lib/action_dispatch/middleware/static.rb:64:in `call'
railties (4.0.0.rc2) lib/rails/engine.rb:511:in `call'
railties (4.0.0.rc2) lib/rails/application.rb:97:in `call'
rack (1.5.2) lib/rack/lock.rb:17:in `call'
rack (1.5.2) lib/rack/content_length.rb:14:in `call'
rack (1.5.2) lib/rack/handler/webrick.rb:60:in `service'
/Users/Brian/.rvm/rubies/ruby-2.0.0-p0/lib/ruby/2.0.0/webrick/httpserver.rb:138:in `service'
/Users/Brian/.rvm/rubies/ruby-2.0.0-p0/lib/ruby/2.0.0/webrick/httpserver.rb:94:in `run'
/Users/Brian/.rvm/rubies/ruby-2.0.0-p0/lib/ruby/2.0.0/webrick/server.rb:295:in `block in start_thread'

Answer 1

试试这个

<li>
  <%= link_to gravatar(feed_post.user), feed_post.user %>
  <span class="user">
    <%= link_to feed_post.user.email, feed_post.user %>
  </span>
  <span class="post_text">
    <%= feed_post.text %>
  </span>
  <span class="timestamp">
    <%= time_ago_in_words(feed_post.created_at) unless feed_post.created_at.blank?%> #### Here is the trouble
  </span>
</li>