path: root/activerecord/lib/active_record/associations/singular_association.rb

# frozen_string_literal: true

module ActiveRecord
  module Associations
    class SingularAssociation < Association #:nodoc:
      # Implements the reader method, e.g. foo.bar for Foo.has_one :bar
      def reader
        if !loaded? || stale_target?
          reload
        end

        target
      end

      # Implements the writer method, e.g. foo.bar= for Foo.belongs_to :bar
      def writer(record)
        replace(record)
      end

      def build(attributes = {}, &block)
        record = build_record(attributes, &block)
        set_new_record(record)
        record
      end

      # Implements the reload reader method, e.g. foo.reload_bar for
      # Foo.has_one :bar
      def force_reload_reader
        reload(true)
        target
      end

      private
        def scope_for_create
          super.except!(klass.primary_key)
        end

        def find_target
          super.first
        end

        def replace(record)
          raise NotImplementedError, "Subclasses must implement a replace(record) method"
        end

        def set_new_record(record)
          replace(record)
        end

        def _create_record(attributes, raise_error = false, &block)
          record = build_record(attributes, &block)
          saved = record.save
          set_new_record(record)
          raise RecordInvalid.new(record) if !saved && raise_error
          record
        end
    end
  end
end