Question

Is there a way to ensure that a given before_save callback is executed after all other before_save callbacks in ActiveRecord short of actually ordering them so in the code?

I’m writing an external library that includes some before_save functionality but in order to be effective it really needs to be called after all others. I can get around it but it involves giving up dirty attributes which I really don’t want to!

— edit —

I didn’t realise in this that dirty attributes are maintained after the save of the model. So @page.attribute_was will still work after the yield in an around_save.

Answer 1

You could make the callback you want executed last an around_save callback. Check out the list of available callbacks and see if you can simply use a different callback “bucket” for some of your callbacks to ensure they are executed in the desired order.

If you still end up with multiple before_save callbacks and need one to trigger last, you may want to create custom callbacks, like maybe define_model_callbacks :split_save, registering your regular before_save callbacks as before_split_save callbacks, the one you want executed last as a after_split_save callback, and then just a single before_save callback that runs those two groups of callbacks (run_callbacks :split_save). See ActiveModel::Callbacks for more on how to do this.