Question

I’ve recently added a ‘preferences’ field for my users which uses thw ActiveRecord serialize method in my rails app. This works fine for existing users but when I try initializing a new user model in the console I get an error:

u = User.new
#=> 
ActiveRecord::SerializationTypeMismatch: preferences was supposed to be a Hash, but was a String

I’ve added the field like this in the migration:

add_column :users, :preferences, :text, :default => { :allows_public_contributions => false }.to_yaml

And in the model, user.rb:

serialize :preferences, Hash

Any ideas?

Answer 1

Rails handles the serialization by itself. Remove the to_yaml method call from the default option in your migration. If you run this method on a hash you get a string.

{ :key => "value" } 
# => "---\n:key: value\n" 

That is the reason why you get the exception.