CODEWITHSUNDEEP
ruby-on-railsactiverecordruby-on-rails-5
Ole Spaarmann
Ole Spaarmann

Reputation: 16771

saved_change_to_attribute? always returns false when called inside method

So I have an after_update callback in an ActiveRecord model to notify an external service. This should only be called if a couple of attributes are being updated. So I encapsulated the saved_change_to_attribute? calls in a method that is then used in the callback filter:

after_update :tell_service!, if: :update_for_service?

def update_for_service?
  saved_change_to_name? ||
  saved_change_to_city? 
end

Now update_for_service? always returns false and I don't understand why.

In the console:

> p = Person.last
> p.name = 'Tom'
> p.save
true
> p.saved_change_to_name?
true
> p.update_for_service?
false

What is going on here?

Upvotes: 5

Views: 4607

Answers (1)

coreyward
coreyward

Reputation: 80140

This is due to when after_update runs in the callback lifecycle. This answer by pan.goth explains:

after_save, after_create, after_update are called within the transaction block, so they will be executed before executing the SQL statement.

If you want to do something when the statement execution is completed, you should use after_commit callback.

Upvotes: 3

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