def build_conditions
association_conditions = @reflection.options[:conditions]
through_conditions = build_through_conditions
source_conditions = @reflection.source_reflection.options[:conditions]
uses_sti = !@reflection.through_reflection.klass.descends_from_active_record?
if association_conditions || through_conditions || source_conditions || uses_sti
all = []
[association_conditions, source_conditions].each do |conditions|
all << interpolate_sql(sanitize_sql(conditions)) if conditions
end
all << through_conditions if through_conditions
all << build_sti_condition if uses_sti
all.map { |sql| "(#{sql})" } * ' AND '
end
end