我正在建立一个带有评论的简单博客。有一个 Post 模型和一个 Comment 模型。除了创建新评论外，两者之间的每一次互动都很好。尝试发表新评论时，我在 Rails 中遇到问题：
wrong number of arguments (1 for 0)
以下是请求参数（来自堆栈跟踪）：
{"commit"=>"Post My Comment",
"post_id"=>"1",
"authenticity_token"=>"5a7b3ad3dda771d4ef5eb5850018649a8be2af11",
"comment"=>{"name"=>"bj",
"website"=>"asdf.com",
"comment"=>"asdf",
"email"=>"asdf@asdf.com"}}
以及完整的堆栈跟踪：
/Library/Ruby/Gems/1.8/gems/activerecord-2.1.0/lib/active_record/callbacks.rb:296:in `notify'
/Library/Ruby/Gems/1.8/gems/activerecord-2.1.0/lib/active_record/callbacks.rb:296:in `callback'
/Library/Ruby/Gems/1.8/gems/activerecord-2.1.0/lib/active_record/callbacks.rb:263:in `valid?'
/Library/Ruby/Gems/1.8/gems/activerecord-2.1.0/lib/active_record/validations.rb:900:in `save_without_dirty'
/Library/Ruby/Gems/1.8/gems/activerecord-2.1.0/lib/active_record/dirty.rb:75:in `save_without_transactions'
/Library/Ruby/Gems/1.8/gems/activerecord-2.1.0/lib/active_record/transactions.rb:106:in `save'
/Library/Ruby/Gems/1.8/gems/activerecord-2.1.0/lib/active_record/connection_adapters/abstract/database_statements.rb:66:in `transaction'
/Library/Ruby/Gems/1.8/gems/activerecord-2.1.0/lib/active_record/transactions.rb:79:in `transaction'
/Library/Ruby/Gems/1.8/gems/activerecord-2.1.0/lib/active_record/transactions.rb:98:in `transaction'
/Library/Ruby/Gems/1.8/gems/activerecord-2.1.0/lib/active_record/transactions.rb:106:in `save'
/Library/Ruby/Gems/1.8/gems/activerecord-2.1.0/lib/active_record/transactions.rb:118:in `rollback_active_record_state!'
/Library/Ruby/Gems/1.8/gems/activerecord-2.1.0/lib/active_record/transactions.rb:106:in `save'
app/controllers/comments_controller.rb:39:in `create'
/Library/Ruby/Gems/1.8/gems/actionpack-2.1.0/lib/action_controller/base.rb:1162:in `send'
/Library/Ruby/Gems/1.8/gems/actionpack-2.1.0/lib/action_controller/base.rb:1162:in `perform_action_without_filters'
/Library/Ruby/Gems/1.8/gems/actionpack-2.1.0/lib/action_controller/filters.rb:580:in `call_filters'
/Library/Ruby/Gems/1.8/gems/actionpack-2.1.0/lib/action_controller/filters.rb:573:in `perform_action_without_benchmark'
/Library/Ruby/Gems/1.8/gems/actionpack-2.1.0/lib/action_controller/benchmarking.rb:68:in `perform_action_without_rescue'
/Library/Ruby/Gems/1.8/gems/actionpack-2.1.0/lib/action_controller/benchmarking.rb:68:in `perform_action_without_rescue'
/Library/Ruby/Gems/1.8/gems/actionpack-2.1.0/lib/action_controller/rescue.rb:201:in `perform_action_without_caching'
/Library/Ruby/Gems/1.8/gems/actionpack-2.1.0/lib/action_controller/caching/sql_cache.rb:13:in `perform_action'
/Library/Ruby/Gems/1.8/gems/activerecord-2.1.0/lib/active_record/connection_adapters/abstract/query_cache.rb:33:in `cache'
/Library/Ruby/Gems/1.8/gems/activerecord-2.1.0/lib/active_record/query_cache.rb:8:in `cache'
/Library/Ruby/Gems/1.8/gems/actionpack-2.1.0/lib/action_controller/caching/sql_cache.rb:12:in `perform_action'
/Library/Ruby/Gems/1.8/gems/actionpack-2.1.0/lib/action_controller/base.rb:529:in `send'
/Library/Ruby/Gems/1.8/gems/actionpack-2.1.0/lib/action_controller/base.rb:529:in `process_without_filters'
/Library/Ruby/Gems/1.8/gems/actionpack-2.1.0/lib/action_controller/filters.rb:569:in `process_without_session_management_support'
/Library/Ruby/Gems/1.8/gems/actionpack-2.1.0/lib/action_controller/session_management.rb:130:in `process'
/Library/Ruby/Gems/1.8/gems/actionpack-2.1.0/lib/action_controller/base.rb:389:in `process'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel/rails.rb:76:in `process'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel/rails.rb:74:in `synchronize'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel/rails.rb:74:in `process'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:159:in `process_client'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:158:in `each'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:158:in `process_client'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `run'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `initialize'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `new'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `run'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in `initialize'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in `new'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in `run'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:282:in `run'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:281:in `each'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:281:in `run'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/bin/mongrel_rails:128:in `run'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel/command.rb:212:in `run'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/bin/mongrel_rails:281
/Library/Ruby/Gems/1.8/gems/activesupport-2.1.0/lib/active_support/dependencies.rb:502:in `load'
/Library/Ruby/Gems/1.8/gems/activesupport-2.1.0/lib/active_support/dependencies.rb:502:in `load'
/Library/Ruby/Gems/1.8/gems/activesupport-2.1.0/lib/active_support/dependencies.rb:354:in `new_constants_in'
/Library/Ruby/Gems/1.8/gems/activesupport-2.1.0/lib/active_support/dependencies.rb:502:in `load'
/Library/Ruby/Gems/1.8/gems/rails-2.1.0/lib/commands/servers/mongrel.rb:64
/Library/Ruby/Gems/1.8/gems/activesupport-2.1.0/lib/active_support/dependencies.rb:509:in `require'
/Library/Ruby/Gems/1.8/gems/activesupport-2.1.0/lib/active_support/dependencies.rb:354:in `new_constants_in'
/Library/Ruby/Gems/1.8/gems/activesupport-2.1.0/lib/active_support/dependencies.rb:509:in `require'
/Library/Ruby/Gems/1.8/gems/rails-2.1.0/lib/commands/server.rb:39
我已将错误缩小到我在评论模型上调用的保存方法：
/Library/Ruby/Gems/1.8/gems/activerecord-2.1.0/lib/active_record/transactions.rb:106:in `save'
app/controllers/comments_controller.rb:39:in `create'
我部分中生成错误的表单（当我发布时）如下（form_row 是我创建的一个简单的辅助方法，用于创建一个表单行）：
<% form_for [post, new_comment] do |f| %>
<%= form_row('Name', f.text_field(:name, :size => 30), 'comment_name') %>
<%= form_row('Email', f.text_field(:email, :size => 30) + content_tag(:span, "*", :class => "required"), 'comment_email') %>
<%= form_row('Website', f.text_field(:website, :size => 30) + content_tag(:span, "*", :class => "required"), 'comment_website') %>
<%= form_row('Comment', f.text_area(:comment, { :rows => 10, :cols => 40 }), 'comment_comment') %>
<%= form_row('', '<span class="sm-text"><span class="required">*</span> Denotes fields that will not be displayed on your comment</span>') %>
<%= form_row('', submit_tag("Post My Comment")) %>
<% end -%>
我怀疑问题出在我的使用方式form_for上，但我已经尝试了所有可能的组合和咒语，但仍然无法弄清楚这一点。我的帖子和评论模型如下：
class Post < ActiveRecord::Base
has_many :comments
has_many :tags, :through => :posts_tags
belongs_to :user
validates_presence_of :user_id, :title, :body
validates_numericality_of :user_id
end
class Comment < ActiveRecord::Base
belongs_to :posts
validates_presence_of :post_id, :name, :email, :comment
validates_numericality_of :post_id
end
最后，执行保存的控制器代码：
def create
begin
@comment = Comment.new(params[:comment])
@comment.name = 'Anonymous' if @comment.name.nil?
if @comment.save # the error occurs here
...
我真的很难过。提前感谢您的帮助。