Catalyst::Upgrading(3pUser Contributed Perl DocumentatiCatalyst::Upgrading(3p)



NAME
       Catalyst::Upgrading - Instructions for upgrading to the latest Catalyst

Upgrading to Catalyst 5.80
       Most applications and plugins should run unaltered on Catalyst 5.80.

       However, a lot of refactoring work has taken place, and several changes
       have been made which could cause incompatibilities. If your application
       or plugin is using deprecated code, or relying on side effects, then
       you could have issues upgrading to this release.

       Most issues found with pre-existing components have been easy to solve.
       This document provides a complete description of behavior changes which
       may cause compatibility issues, and of new Catalyst warnings which be
       unclear.

       If you think you have found an upgrade-related issue which is not
       covered in this document, please email the Catalyst list to discuss the
       problem.

Moose features
   Application class roles
       You can only apply method modifiers after the application's "->setup"
       method has been called. This means that modifiers will not work with
       methods which run during the call to "->setup".

       See Catalyst::Manual::ExtendingCatalyst for more information about
       using Moose in your applications.

   Controller actions in Moose roles
       You can use MooseX::MethodAttributes::Role if you want to declare
       actions inside Moose roles.

   Using Moose in Components
       The correct way to use Moose in a component in a both forward and
       backwards compatible way is:

           package TestApp::Controller::Root;
           use Moose;
           BEGIN { extends 'Catalyst::Component' }; # Or ::Controller, or whatever

       See "Components which inherit from Moose::Object before
       Catalyst::Component".

Known backwards compatibility breakages
   Applications in a single file
       Applications must be in their own file, and loaded at compile time.
       This issue generally only affects the tests of CPAN distributions. Your
       application will fail if you try to define an application inline in a
       block, and use plugins which supply a " new " method, then use that
       application latter in tests within the same file.

       This is due to the fact that Catalyst is inlining a new method on your
       application class allowing it to be compatible with Moose. The method
       used to do this changed in 5.80004 to avoid the possibility of
       reporting an 'Unknown Error' if your application failed to compile.

   Issues with Class::C3
       Catalyst 5.80 uses the Algorithm::C3 method dispatch order. This is
       built into Perl 5.10, and comes via Class::C3 for Perl 5.8. This
       replaces NEXT with Class::C3::Adopt::NEXT, forcing all components to
       resolve methods using C3, rather than the unpredictable dispatch order
       of NEXT.

       This issue is characterised by your application failing to start due to
       an error message about having a non-linear @ISA.

       The Catalyst plugin most often causing this is
       Catalyst::Plugin::Session::Store::FastMmap - if you are using this
       plugin and see issues, then please upgrade your plugins, as it has been
       fixed. Note that Makefile.PL in the distribution will warn about known
       incompatible components.

       This issue can, however, be found in your own application - the only
       solution is to go through each base class of the class the error was
       reported against, until you identify the ones in conflict, and resolve
       them.

       To be able to generate a linear @ISA, the list of superclasses for each
       class must be resolvable using the C3 algorithm. Unfortunately, when
       superclasses are being used as mixins (to add functionality used in
       your class), and with multiple inheritence, it is easy to get this
       wrong.

       Most common is the case of:

           package Component1; # Note, this is the common case
           use base qw/Class::Accessor::Fast Class::Data::Inheritable/;

           package Component2; # Accidentally saying it this way causes a failure
           use base qw/Class::Data::Inheritable Class::Accessor::Fast/;

           package GoesBang;
           use base qw/Component1 Component2/;

       Any situation like this will cause your application to fail to start.

       For additional documentation about this issue, and how to resolve it,
       see Class::C3::Adopt::NEXT.

   Components which inherit from Moose::Object before Catalyst::Component
       Moose components which say:

           package TestApp::Controller::Example;
           use Moose;
           extends qw/Moose::Object Catalyst::Component/;

       to use the constructor provided by Moose, while working (if you do some
       hacks with the " BUILDARGS " method), will not work with Catalyst 5.80
       as "Catalyst::Component" inherits from "Moose::Object", and so  @ISA
       fails to linearize.

       The correct way to use Moose in a component in a both forward and
       backwards compatible way is:

           package TestApp::Controller::Root;
           use Moose;
           BEGIN { extends 'Catalyst::Component' }; # Or ::Controller, or whatever

       Note that the " extends " declaration needs to occur in a begin block
       for attributes to operate correctly.

       This way you do not inherit directly from "Moose::Object" yourself.
       Having components which do not inherit their constructor from
       "Catalyst::Component" is unsupported, and has never been recommended,
       therefore you're on your own if you're using this technique. You'll
       need to detect the version of Catalyst your application is running, and
       deal with it appropriately.

       You also don't get the Moose::Object constructor, and therefore
       attribute initialization will not work as normally expected. If you
       want to use Moose attributes, then they need to be made lazy to
       correctly initialize.

       Note that this only applies if your component needs to maintain
       component backwards compatibility for Catalyst versions before 5.71001
       - in 5.71001 attributes work as expected, and the BUILD method is
       called normally (although BUILDARGS is not).

       If you depend on Catalyst 5.8, then all Moose features work as
       expected.

       You will also see this issue if you do the following:

           package TestApp::Controller::Example;
           use Moose;
           use base 'Catalyst::Controller';

       as " use base " appends to @ISA.

       use Moose in MyApp

       Similar to the above, this will also fail:

           package MyApp;
           use Moose;
           use Catalyst qw/
             ConfigLoader
           /;
           __PACKAGE__->setup;

       If you need to use Moose in your application class (e.g. for method
       modifiers etc.) then the correct technique is:

           package MyApp;
           use Moose;
           use Catalyst;

           extends 'Catalyst';

           __PACKAGE__->config( name => 'MyApp' );
           __PACKAGE__->setup(qw/
               ConfigLoader
           /);

   Anonymous closures installed directly into the symbol table
       If you have any code which installs anonymous subroutine references
       directly into the symbol table, you may encounter breakages. The
       simplest solution is to use Sub::Name to name the subroutine. Example:

           # Original code, likely to break:
           my $full_method_name = join('::', $package_name, $method_name);
           *$full_method_name = sub { ... };

           # Fixed Code
           use Sub::Name 'subname';
           my $full_method_name = join('::',$package_name, $method_name);
           *$full_method_name = subname $full_method_name, sub { ... };

       Additionally, you can take advantage of Catalyst's use of Class::MOP
       and install the closure using the appropriate metaclass. Example:

           use Class::MOP;
           my $metaclass = Moose::Meta::Class->initialize($package_name);
           $metaclass->add_method($method_name => sub { ... });

   Hooking into application setup
       To execute code during application start-up, the following snippet in
       MyApp.pm used to work:

           sub setup {
               my ($class, @args) = @_;
               $class->NEXT::setup(@args);
               ... # things to do after the actual setup
           }

       With Catalyst 5.80 this won't work anymore, because Catalyst no longer
       uses NEXT.pm for method resolution. The functionality was only ever
       originally operational as NEXT remembers what methods have already been
       called, and will not call them again.

       Using this now causes infinite recursion between MyApp::setup and
       Catalyst::setup, due to other backwards compatibility issues related to
       how plugin setup works. Moose method modifiers like
       "before|after|around setup => sub { ... };" also will not operate
       correctly on the setup method.

       The right way to do it is this:

           after setup_finalize => sub {
               ... # things to do after the actual setup
           };

       The setup_finalize hook was introduced as a way to avoid this issue.

   Components with a new method which returns false
       Previously, if you had a component which inherited from
       Catalyst::COMPONENT, but overrode the new method to return false, then
       your class's configuration would be blessed into a hash on your behalf,
       and this would be returned from the COMPONENT method.

       This behavior makes no sense, and so has been removed. Implementing
       your own " new " method in components is highly discouraged. Instead,
       you should inherit the new method from Catalyst::Component, and use
       Moose's BUILD functionality and/or Moose attributes to perform any
       construction work necessary for your class.

   __PACKAGE__->mk_accessor('meta');
       Won't work due to a limitation of Moose. This is currently being fixed
       inside Moose.

   Class::Data::Inheritable side effects
       Previously, writing to a class data accessor would copy the accessor
       method down into your package.

       This behavior has been removed. While the class data is still stored
       per-class, it is stored on the metaclass of the class defining the
       accessor.

       Therefore anything relying on the side effect of the accessor being
       copied down will be broken.

       The following test demonstrates the problem:

           {
               package BaseClass;
               use base qw/Class::Data::Inheritable/;
               __PACKAGE__->mk_classdata('foo');
           }

           {
               package Child;
               use base qw/BaseClass/;
           }

           BaseClass->foo('base class');
           Child->foo('sub class');

           use Test::More;
           isnt(BaseClass->can('foo'), Child->can('foo'));

   Extending Catalyst::Request or other classes in an ad-hoc manner using
       mk_accessors
       Previously, it was possible to add additional accessors to
       Catalyst::Request (or other classes) by calling the mk_accessors class
       method.

       This is no longer supported - users should make a subclass of the class
       whose behavior they would like to change, rather than globally
       polluting the Catalyst objects.

   Confused multiple inheritance with Catalyst::Component::COMPONENT
       Previously, Catalyst's COMPONENT method would delegate to the method on
       the right hand side, which could then delegate back again with NEXT.
       This is poor practice, and in addition, makes no sense with C3 method
       dispatch order, and is therefore no longer supported.

       If a COMPONENT method is detected in the inheritance hierarchy to the
       right hand side of Catalyst::Component::COMPONENT, then the following
       warning message will be emitted:

           There is a COMPONENT method resolving after Catalyst::Component
           in ${next_package}.

       The correct fix is to re-arrange your class's inheritance hierarchy so
       that the COMPONENT method you would like to inherit is the first (left-
       hand most) COMPONENT method in your @ISA.

WARNINGS
   Actions in your application class
       Having actions in your application class will now emit a warning at
       application startup as this is deprecated. It is highly recommended
       that these actions are moved into a MyApp::Controller::Root (as
       demonstrated by the scaffold application generated by catalyst.pl).

       This warning, also affects tests. You should move actions in your test,
       creating a myTest::Controller::Root, like the following example:

           package MyTest::Controller::Root;

           use strict;
           use warnings;

           use parent 'Catalyst::Controller';

           __PACKAGE__->config(namespace => '');

           sub action : Local {
               my ( $self, $c ) = @_;
               $c->do_something;
           }

           1;

   ::[MVC]:: naming scheme
       Having packages called MyApp::[MVC]::XX is deprecated and can no longer
       be generated by catalyst.pl

       This is still supported, but it is recommended that you rename your
       application components to Model/View/Controller.

       A warning will be issued at application startup if the ::[MVC]:: naming
       scheme is in use.

   Catalyst::Base
       Any code using Catalyst::Base will now emit a warning; this module will
       be removed in a future release.

   Methods in Catalyst::Dispatcher
       The following methods in Catalyst::Dispatcher are implementation
       details, which may change in the 5.8X release series, and therefore
       their use is highly deprecated.

       tree
       dispatch_types
       registered_dispatch_types
       method_action_class
       action_hash
       container_hash

       The first time one of these methods is called, a warning will be
       emitted:

           Class $class is calling the deprecated method Catalyst::Dispatcher::$public_method_name,
           this will be removed in Catalyst 5.9X

       You should NEVER be calling any of these methods from application code.

       Plugin authors and maintainers whose plugins currently call these
       methods should change to using the public API, or, if you do not feel
       the public API adequately supports your use case, please email the
       development list to discuss what API features you need so that you can
       be appropriately supported.

   Class files with names that don't correspond to the packages they define
       In this version of Catalyst, if a component is loaded from disk, but no
       symbols are defined in that component's name space after it is loaded,
       this warning will be issued:

           require $class was successful but the package is not defined.

       This is to protect against confusing bugs caused by mistyping package
       names, and will become a fatal error in a future version.

       Please note that 'inner packages' (via Devel::InnerPackage) are still
       fully supported; this warning is only issued when component file naming
       does not map to any of the packages defined within that component.

   $c->plugin method
       Calling the plugin method is deprecated, and calling it at run time is
       highly deprecated.

       Instead you are recommended to use Catalyst::Model::Adaptor or similar
       to compose the functionality you need outside of the main application
       name space.

       Calling the plugin method will not be supported past Catalyst 5.81.



perl v5.12.2                      2010-03-03           Catalyst::Upgrading(3p)
