Method: ActiveRecord::Reflection::AbstractReflection#inverse_which_updates_counter_cache

Defined in:
activerecord/lib/active_record/reflection.rb

#inverse_which_updates_counter_cache ⇒ Object Also known as: inverse_updates_counter_cache?

We need to avoid the following situation:

* An associated record is deleted via record.destroy
* Hence the callbacks run, and they find a belongs_to on the record with a
  :counter_cache options which points back at our owner. So they update the
  counter cache.
* In which case, we must make sure to *not* update the counter cache, or else
  it will be decremented twice.

Hence this method.



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# File 'activerecord/lib/active_record/reflection.rb', line 285

def inverse_which_updates_counter_cache
  unless @inverse_which_updates_counter_cache_defined
    if counter_cache_column
      inverse_candidates = inverse_of ? [inverse_of] : klass.reflect_on_all_associations(:belongs_to)
      @inverse_which_updates_counter_cache = inverse_candidates.find do |inverse|
        inverse.counter_cache_column == counter_cache_column && (inverse.polymorphic? || inverse.klass == active_record)
      end
    end
    @inverse_which_updates_counter_cache_defined = true
  end
  @inverse_which_updates_counter_cache
end