lib/active_support/callbacks.rb in activesupport-5.1.2 vs lib/active_support/callbacks.rb in activesupport-5.1.3.rc1

@@ -662,11 +662,13 @@
         def set_callback(name, *filter_list, &block)
           type, filters, options = normalize_callback_params(filter_list, block)
 
           if options[:if].is_a?(String) || options[:unless].is_a?(String)
             ActiveSupport::Deprecation.warn(<<-MSG.squish)
-              Passing string to :if and :unless conditional options is deprecated
-              and will be removed in Rails 5.2 without replacement.
+              Passing string to be evaluated in :if and :unless conditional
+              options is deprecated and will be removed in Rails 5.2 without
+              replacement. Pass a symbol for an instance method, or a lambda,
+              proc or block, instead.
             MSG
           end
 
           self_chain = get_callbacks name
           mapped = filters.map do |filter|