nil的未定义方法`gsub'：NilClass让我在轨道上的红宝石中疯狂

Question

I don't know what is up, but I was experimenting with GSUB then decided I didn't want to use it anymore so changed my link_to arguments back to:

<%= link_to root_url(@user.username), @user.username %>

Now I keep getting this error: undefined method `gsub' for nil:NilClass

and when I remove that whole line from my show file everything is fine.

or if I change it to this:

<%= link_to root_url(:user => @user.username), @user.username %>

It's like it has been confused some how and thinks I'm still using the gsub method when I'm not. I've tested or url helpers such as login, password_reset etc and they all work fine. It seems to only be doing this with root_url.

I also cloned a repo of my site from yesterday before I got this issue and guess what? Same error..

I've never been this frustrated with my programming.

Is there something I can clear? I've tried clearing everything inthe tmp folder still no luck.

routes:

Mysite::Application.routes.draw do

  resources :users
  resources :sessions
  resources :passwords


  root :to                   => "users#new"
  match 'success'            => "users#success"
  match 'login'              => "sessions#new"
  match 'logout'             => "sessions#destroy"
  match 'reset_password'     => "passwords#new"
  match 'setup_new_password' => "passwords#edit"
  match ':username'          => "users#show"

end

Answer 1

I think you have your arguments for link_to backwards. It should be:

link_to(label, url)

The gsub method can be triggered by something else deeper inside of Rails. When you get an error, usually you get a stack trace that helps to explain the chain of events leading up to the failure.

Answer 2

这应该可以解决问题，因为root_url（和root_path）没有参数：

<%= link_to @user.username, root_url %>