2 files changed, 49 insertions, 0 deletions
diff --git a/activesupport/lib/active_support.rb b/activesupport/lib/active_support.rb
index 5589c71281..9e242ddeaa 100644
--- a/activesupport/lib/active_support.rb
+++ b/activesupport/lib/active_support.rb
@@ -34,6 +34,7 @@ module ActiveSupport
   extend ActiveSupport::Autoload
 
   autoload :Concern
+  autoload :ActionableError
   autoload :CurrentAttributes
   autoload :Dependencies
   autoload :DescendantsTracker
diff --git a/activesupport/lib/active_support/actionable_error.rb b/activesupport/lib/active_support/actionable_error.rb
new file mode 100644
index 0000000000..7db14cd178
--- /dev/null
+++ b/activesupport/lib/active_support/actionable_error.rb
@@ -0,0 +1,48 @@
+# frozen_string_literal: true
+
+module ActiveSupport
+  # Actionable errors let's you define actions to resolve an error.
+  #
+  # To make an error actionable, include the <tt>ActiveSupport::ActionableError</tt>
+  # module and invoke the +action+ class macro to define the action. An action
+  # needs a name and a block to execute.
+  module ActionableError
+    extend Concern
+
+    class NonActionable < StandardError; end
+
+    included do
+      class_attribute :_actions, default: {}
+    end
+
+    def self.actions(error) # :nodoc:
+      case error
+      when ActionableError, -> it { Class === it && it < ActionableError }
+        error._actions
+      else
+        {}
+      end
+    end
+
+    def self.dispatch(error, name) # :nodoc:
+      actions(error).fetch(name).call
+    rescue KeyError
+      raise NonActionable, "Cannot find action \"#{name}\""
+    end
+
+    module ClassMethods
+      # Defines an action that can resolve the error.
+      #
+      #   class PendingMigrationError < MigrationError
+      #     include ActiveSupport::ActionableError
+      #
+      #     action "Run pending migrations" do
+      #       ActiveRecord::Tasks::DatabaseTasks.migrate
+      #     end
+      #   end
+      def action(name, &block)
+        _actions[name] = block
+      end
+    end
+  end
+end