Add dirty methods for store accessors

[palkan]

Example:

class User < AR:Base
  store_accessor :settings, :color
end

u = User.new
u.color_changed? #=> false

u.color = 'red-n-white'
# Or
u.settings['color'] = 'red-n-white'

u.color_changed? #=> true
u.color_was #=> nil
u.color_change #=> [nil, 'red-n-white']

Also, force Model.stored_attributes[:store] array to contain string keys.

[palkan]

@rafaelfranca @sgrif Any feedback on that?

[sgrif]

I think that this falls into the bucket of "we should just promote store accessors to proper attributes".

[palkan]

@sgrif Interesting. Is anyone struggling with that?

[palkan]

Just found myself struggling with the absence of accessors dirty methods. Maybe, we should revamp this PR? It's pretty simple but useful change, IMO.

/cc @rafaelfranca @matthewd

[palkan]

Years have passed. I'm still missing this 😢

Maybe, Rails 6 is a good place for this feature? @kaspth WDYT?

[kaspth]

Let's go with &.dig(key) instead of the try.

[kaspth]

These'll also get change tracking too, right?

[palkan]

Could you please explain, what did you mean here?

[kaspth]

It's basically what you demonstrate in your PR description. I'm just asking if store_accessor :color also adds color_changed? etc. or if we missed it and only store :settings, accessors: %i( color ) would get it.

[palkan]

@kaspth Hey! Thanks for the feedback!

I've addressed all the comments and actualized the PR by adding saved changes helpers as well.

[LucasArruda]

This feature proves you should never ever give up! 👍

[wbcasey]

What's the easiest way to backport this to Rails 4.2?

[palkan]

@wbcasey You can patch ActiveRecord::Store::ClassMethods#store_accessor method to add additional methods. Smth like:

ActiveSupport.on_load(:active_record) do
  ActiveRecord::Store::ClassMethods.prepend(Module.new do
    def store_accessor(store_name, *keys)
      super
      keys = keys.flatten
      _store_accessors_module.module_eval do
          keys.each do |key|
            define_method("#{key}_changed?") do
              return false unless attribute_changed?(store_name)
              prev_store, new_store = changes[store_name]
              prev_store&.dig(key) != new_store&.dig(key)
            end
          end
          # ...
       end
    end
  end)
end

[LucasArruda]

@wbcasey defining those methods there?

[wbcasey]

@LucasArruda basically back-porting the "dirty" functionality. I tried just bringing it in, but some of the API surface has changed between 4.2 and 6.x