Catalyst::Delta - Overview of changes between versions of Catalyst


This is an overview of the user-visible changes to Catalyst in version 5.8.


Please see Catalyst::Upgrading for a full description of how changes in the framework may affect your application.

Below is a brief list of features which have been deprecated in this release:

::[MVC]:: style naming scheme has been deprecated and will warn
NEXT is deprecated for all applications and components, use MRO::Compat
Dispatcher methods which are an implementation detail made private, public versions now warn.
MyApp->plugin method is deprecated, use Catalyst::Model::Adaptor instead.
__PACKAGE__->mk_accessors() is supported for backward compatibility only, use Moose attributes instead in new code.
Use of Catalyst::Base now warns

New features


Fix forwarding to Catalyst::Action objects.
Add the dispatch_type method


The development server restarter has been improved to be compatible with immutable Moose classes, and also to optionally use B::Hooks::OP::Check::StashChange to handle more complex application layouts correctly.

$c->uri_for_action method.

Give a private path to the Catalyst action you want to create a URI for.


Log levels have been made additive.


Change to use Sub::Exporter.
Support mocking multiple virtual hosts
New methods like action_ok and action_redirect to write more compact tests


  • New print method which prints @data to the output stream, separated by $,. This lets you pass the response object to functions that want to write to an IO::Handle.

  • Added code method as an alias for $res->status

Consequences of the Moose back end

  • Components are fully compatible with Moose, and all Moose features, such as method modifiers, attributes, roles, BUILD and BUILDARGS methods are fully supported and may be used in components and applications.

  • Many reusable extensions which would previously have been plugins or base classes are better implemented as Moose roles.

  • MooseX::MethodAttributes::Inheritable is used to contain action attributes. This means that attributes are represented in the MOP, and decouples action creation from attributes.

  • There is a reasonable API in Catalyst::Controller for working with and registering actions, allowing a controller sub-class to replace subroutine attributes for action declarations with an alternate syntax.

  • Refactored capturing of $app from Catalyst::Controller into Catalyst::Component::ApplicationAttribute for easier reuse in other components.

  • Your application class is forced to become immutable at the end of compilation.

Bug fixes

  • Don't ignore SIGCHLD while handling requests with the development server, so that system() and other ways of creating child processes work as expected.

  • Fixes for FastCGI when used with IIS 6.0

  • Fix a bug in uri_for which could cause it to generate paths with multiple slashes in them.

  • Fix a bug in Catalyst::Stats, stopping garbage being inserted into the stats if a user calls begin => but no end