=head1 NAME Catalyst::Upgrading - Instructions for upgrading to the latest Catalyst =head1 Upgrading to Catalyst 5.90 The major change is that L now replaces most of the subclasses of L. If you are using one of the standard subclasses of L this should be a straightforward upgrade for you. It was a design goal for this release to be as backwardly compatible as possible. However since L is different from L it would be possible that edge case differences would exist. Therefore we recommend care be taken with this upgrade and that testing should be greater than would be the case with a minor point update. It is highly recommended that you become familar with the L ecosystem and documentation. Being able to take advantage of L development and middleware is a major bonus to this upgrade. If you have created a custom subclass of L you will need to convert it to be a subclass of L. If you are using the L engine, L, this new release supercedes that code. If you are using a subclass of L that is aimed at nonstandard or internal / testing uses, such as L you should still be able to continue using that engine. Advice for specific subclasses of L follows: =head2 Upgrading the FastCGI Engine No upgrade needed if your myapp_fastcgi.pl script is already upgraded enough to use L. =head2 Upgrading the mod_perl / Apache Engines The engines that are build upon the various iterations of mod_perl, L and L should be seemless upgrades and will work using using L or L as required. L, is however no longer supported, as Plack does not support mod_perl version 1.99??? FIXME - is this true? =head2 Upgrading the HTTP Engine The default development server that comes with the L distribution should continue to work as expected with no changes as long as your C script is upgraded to use L. =head2 Upgrading the CGI Engine If you were using L there is no upgrade needed if your myapp_cgi.pl script is already upgraded enough to use L. =head2 Upgrading the Preforking Engine If you were using L then L is automatically loaded. =head2 Upgrading the PSGI Engine If you were using L this new release supercedes this engine in supporting L. By default the Engine is now always L. As a result, you can stop depending on L in your C. Additionally, if you have an C script you no longer need to specify the PSGI engine. Instead, the L application class now has a new method C which returns a L compatible coderef. For example, if you were using L in the past, you may have written an C file similar to this one: use Plack::Builder; use MyCatalytApp; MyCatalystApp->setup_engine('PSGI'); builder { enable ... # enable your desired middleware sub { MyCatalystApp->run(@_) }; }; Instead, you now just do use Plack::Builder; use MyCatalystApp; builder { enable ... #enable your desired middleware MyCatalystApp->psgi_app; }; =head2 Engines with unknown status The following engines have untested or unknown compatibility. Reports are highly welcomed: Catalyst::Engine::Embeddable Catalyst::Engine::XMPP2 Catalyst::Engine::SCGI Catalyst::Engine::Mojo Catalyst::Engine::Zeus Catalyst::Engine::JobQueue::POE Catalyst::Engine::Wx Catalyst::Engine::Stomp Catalyst::Engine::Server (Marked as Deprecated) Catalyst::Engine::HTTP::POE (Marked as Deprecated) =head2 Using middleware XXX Should this be here or elsewhere? =head2 Making an app.psgi file =head2 Running with plackup? =head1 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. =head1 Moose features =head2 Application class roles You can only apply method modifiers after the application's C<< ->setup >> method has been called. This means that modifiers will not work with methods which run during the call to C<< ->setup >>. See L for more information about using L in your applications. =head2 Controller actions in Moose roles You can use L if you want to declare actions inside Moose roles. =head2 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 L. =head1 Known backwards compatibility breakages =head2 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 C< 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. =head2 Issues with Class::C3 Catalyst 5.80 uses the L method dispatch order. This is built into Perl 5.10, and comes via L for Perl 5.8. This replaces L with L, forcing all components to resolve methods using C3, rather than the unpredictable dispatch order of L. 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 L - 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 L. =head2 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 C< BUILDARGS > method), will not work with Catalyst 5.80 as C inherits from C, and so C< @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 C< extends > declaration needs to occur in a begin block for L to operate correctly. This way you do not inherit directly from C yourself. Having components which do not inherit their constructor from C is B, 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 L 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 B 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 C< use base > appends to @ISA. =head3 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 /); =head2 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 L 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 L 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 { ... }); =head2 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 L 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 C<< 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. =head2 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 C< new > method in components is B 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. =head2 __PACKAGE__->mk_accessor('meta'); Won't work due to a limitation of L. This is currently being fixed inside Moose. =head2 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')); =head2 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. =head2 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. =head1 WARNINGS =head2 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; =head2 ::[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. =head2 Catalyst::Base Any code using L will now emit a warning; this module will be removed in a future release. =head2 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. =over =item tree =item dispatch_types =item registered_dispatch_types =item method_action_class =item action_hash =item container_hash =back 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 B 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. =head2 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 L) are still fully supported; this warning is only issued when component file naming does not map to B of the packages defined within that component. =head2 $c->plugin method Calling the plugin method is deprecated, and calling it at run time is B. Instead you are recommended to use L 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. =cut