Rails - Strange Behavior After Adding Field to Model

Question

I have a very simple user model. When I first created it, it had three fields email, password_hash, and password_salt.

I recently added a field to that model, in order to allow the user to set a display name, the field being called display. I used the method as outlined in this answer. So what I typed into terminal would look like this:

script/rails g migration add_display_to_users display:string

and then

rake db:migrate

This worked fine, and after modifying my signup form, I was able to add this data into the database.

In my application layout, I then want to display the user's display name in the header. So, in my application controller, there is a method I call in every controller in order to get the nav bar, called nav_bar. In this method I also set a @user instance variable, if they are logged in.

Because the nav_bar method is called in the application controller, I can then access it from the application layout. So, I tried to show their email in the header as a test, like so:

<% if @user %>
    <div class="ac_button">
        <%= @user.email %>
    </div>
<% end %>

This works fine, and displays their email in the header. However, if I change it to

 <%= @user.display %>

It doesn't display anything.

The strangest part, is if I call @user.email, or any other property of the user somewhere in my application controller or layout. It works, and shows their display name. I have no idea why that would make it work, but it does.

For example, if after finding the user in the application controller, I call @user.email, it will then show their display name in the layout fine.

def nav_bar
    if session[:user_id]
      @user = User.find(session[:user_id])
      @user.email
    end
    # create and return the navbar
end

Or if in the layout, I call a property of the user anywhere, it also works.

<div class="ac_button">
    <% @user.password_hash %>
    <%= @user.display %>
</div>

If anyone can explain this very strange behavior I will be amazed!

score 5 · Accepted Answer · answered Nov 18 '11 at 09:06

The name display is an inherited method from ActiveRecord::Base so when you create a column called display the method displayand display= are created. So you overweite an ActiveRecord method by creating the column display. Had this problem earlier,... renamed the column to display_name and everything was fine! ;)

Rails - Strange Behavior After Adding Field to Model

1 Answers1