I was going exactly through and I wanted a clean new object if it wasn't present(if you're doing this just so object.display
doesn't err maybe object.try(:display)
is better) this too and this is what I found:
1: alias/alias_method_chain
def profile_with_no_nill
profile_without_no_nill || NullProfile
end
alias_method_chain :profile, :no_nill
But since alias_method_chain is being deprecated, if you're staying on the edge you would have to do the pattern by yourself manually... The answer here seems to provide the better and more elegant solution
2(Simplified/practical version from the answer):
class User < ActiveRecord::Base
has_one :profile
accepts_nested_attributes_for :profile
module ProfileNullObject
def profile
super || NullProfile
end
end
include ProfileNullObject
end
note: The order you do this matter(explained in the linked answer)
On what you tried:
When you did
def profile
@profile || NullProfile
end
It won't behave as expected because the Association is lazily loaded(unless you told it to :include
it in the search), so @profile is nil, that's why you're always getting NullProfile
def profile
self.profile || NullProfile
end
It will fail because the method is calling itself, so it's sort like a recursive method, you get SystemStackError: stack level too deep