reflect_on_association can be mistakenly nil for inherited classes

[denzelem]

rails g migration createFoos
rails g migration createBars

Working example:

Bar = Class.new(ApplicationRecord)

class Foo < ApplicationRecord
  belongs_to :bar 
  Foo::Child # after association is no problem
end

class Foo::Child < Foo
  assignable_values_for :bar do
    []
  end
end

Foo::Child.reflect_on_association(:bar) # =>
 <ActiveRecord::Reflection::BelongsToReflection:0x00000004dc4e58 ... > 

Broken example:

Bar = Class.new(ApplicationRecord)

class Foo < ApplicationRecord
  Foo::Child # this will cause Foo::Child to not have the correct reflect_on_association for bar
  belongs_to :bar
end

class Foo::Child < Foo
  assignable_values_for :bar do
    []
  end
end

Foo::Child.reflect_on_association(:bar) # => nil

This only happens if the child class is loaded in the parent class before the association evaluation (here belongs_to).

Maybe we can super reflect_on_association if it is nil.

[triskweline]

@denzelem Why did you need to refer to Foo::Child inside the class definition of Foo?

[denzelem]

@triskweline It was a trait, which took a class as argument. Something like

class Foo < ApplicationRecord
  include DoesTakeSnapshots[
    as: Foo::Child
  ]

  belongs_to :bar
end

[triskweline]

I'm assuming this is a limitation of ActiveRecord, which probably copies association definitions at inheritance. It's probably also the reason why when you use has_many, the :class_name option takes a string, not a class. This would also be a workaround for the code sample above.

I'm considering this to be out of scope for this gem, sorry.