Merge pull request rails#46877 from eileencodes/minor-improvements-to-pr-43487

Add documentation for rails#43487

Author: eileencodes

actionpack/CHANGELOG.md

@@ -1,3 +1,11 @@
+*   Allow raising an error when a callback's only/unless symbols aren't existing methods.
+
+    When `before_action :callback, only: :action_name` is declared on a controller that doesn't respond to `action_name`, raise an exception at request time. This is a safety measure to ensure that typos or forgetfulness don't prevent a crucial callback from being run when it should.
+
+    For new applications, raising an error for undefined actions is turned on by default. If you do not want to opt-in to this behavior set `config.action_pack.raise_on_missing_callback_actions` to `false` in your application configuration. See #43487 for more details.
+
+    *Jess Bees*
+
 *   Allow cookie options[:domain] to accept a proc to set the cookie domain on a more flexible per-request basis
 
     *RobL*

actionpack/lib/abstract_controller/callbacks.rb

@@ -48,7 +48,17 @@ def match?(controller)
           missing_action = @actions.find { |action| !controller.available_action?(action) }
           if missing_action
             filter_names = @filters.length == 1 ? @filters.first.inspect : @filters.inspect
-            message = "The #{missing_action} action could not be found for the #{filter_names} callback on #{controller.class.name}, but it is listed in its #{@conditional_key.inspect} option"
+
+            message = <<~MSG
+              The #{missing_action} action could not be found for the #{filter_names}
+              callback on #{controller.class.name}, but it is listed in the controller's
+              #{@conditional_key.inspect} option.
+
+              Raising for missing callback actions is a new default in Rails 7.1, if you'd
+              like to turn this off you can delete the option from the environment configurations
+              or set `config.action_pack.raise_on_missing_callback_actions` to `false`.
+            MSG
+
             raise ActionNotFound.new(message, controller, missing_action)
           end
         end