+=head1 NAME
+
+Catalyst::Upgrading - Instructions for upgrading to the latest Catalyst
+
=head1 Upgrading to Catalyst 5.80
Most applications and plugins should run unaltered on Catalyst 5.80.
-However as a lot of refactoring work has taken place, several changes
-have been made which could cause incompatibilities, if your application
-or plugin is using deprecated code, or relying on side-effects then
-there could be incompatibility.
+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<Catalyst::Manual::ExtendingCatalyst> for more information about using
+L<Moose> in your applications.
+
+=head2 Controller actions in Moose roles
+
+Declaring actions in Roles is currently unsupported.
+
+=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<Components which inherit from Moose::Object before Catalyst::Component>.
-Most issues found with pre-existing components have been easy to solve,
-and a complete description of behavior changes which may cause compatibility
-issues, or warnings to be emitted is included below to help if you have
-problems.
+=head1 Known backwards compatibility breakages
-If you think you have found an upgrade related issue which is not covered in
-this document, then please email the Catalyst list to discuss the problem.
+=head2 Applications in a single file
-=head1 Known backwards compatibility breakages.
+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<Algorithm::C3> method dispatch order. This is
+built into Perl 5.10, and comes via L<Class::C3> for Perl 5.8. This
+replaces L<NEXT> with L<Class::C3::Adopt::NEXT>, forcing all components
+to resolve methods using C3, rather than the unpredictable dispatch
+order of L<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
+L<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
+L<Class::C3::Adopt::NEXT>.
=head2 Components which inherit from Moose::Object before Catalyst::Component
use Moose;
extends qw/Moose::Object Catalyst::Component/;
-to use the constructor provided by Moose, whilst working if you do some hacks
-with the C< BUILDARGS > method, will not work with Catalyst 5.80 as
+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<Catalyst::Component> inherits from C<Moose::Object>, and so C< @ISA > fails
-to linearise.
+to linearize.
-The fix for this, is to not inherit directly from C<Moose::Object>
+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<attributes> to operate correctly.
+
+This way you do not inherit directly from C<Moose::Object>
yourself. Having components which do not inherit their constructor from
C<Catalyst::Component> is B<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 with and deal
+to detect the version of Catalyst your application is running, and deal
with it appropriately.
+You also don't get the L<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 B<all> Moose features work as expected.
+
You will also see this issue if you do the following:
package TestApp::Controller::Example;
as C< use base > appends to @ISA.
-The correct way to use Moose in a component in a both forward and backwards
-compatible way is:
+=head3 use Moose in MyApp
- package TestApp::Controller::Root;
+Similar to the above, this will also fail:
+
+ package MyApp;
use Moose;
- BEGIN { extends 'Catalyst::Component' }; # Or ::Controller, or whatever
+ use Catalyst qw/
+ ConfigLoader
+ /;
+ __PACKAGE__->setup;
-Note that the C< extends > decleration needs to occur in a begin block for
-L<attributes> to operate correctly.
+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
into the symbol table, you may encounter breakages. The simplest solution is
to use L<Sub::Name> to name the subroutine. Example:
- #Originalcode, likely to break:
- my $full_method_name = join('::',$package_name, $method_name);
+ # Original code, likely to break:
+ my $full_method_name = join('::', $package_name, $method_name);
*$full_method_name = sub { ... };
- #Fixed Code
+ # Fixed Code
use Sub::Name 'subname';
my $full_method_name = join('::',$package_name, $method_name);
*$full_method_name = subname $full_method_name, sub { ... };
my $metaclass = Moose::Meta::Class->initialize($package_name);
$metaclass->add_method($method_name => sub { ... });
-=head2 Components whos new method returns false
+=head2 Hooking into application setup
-Previously if your new method returned a false value,
+To execute code during application start-up, the following snippet in MyApp.pm
+used to work:
-Previously, if you had a component which inherited from Catalyst::COMPONENT, but
-overrode the new method, to return false, then your class' configuration would be blessed into a hash on your behalf,
-and this would be returned from the COMPONENT method. T
+ sub setup {
+ my ($class, @args) = @_;
+ $class->NEXT::setup(@args);
+ ... # things to do after the actual setup
+ }
-This behaviour makes no sense, and so has been removed.. You are recommended to implement your own new method
-in components, instead, you should inherit the new method from Catalyst::Component, and use Moose's BUILD functionality
-to perform any construction work necessary for your sub-class.
+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<NEXT> remembers what methods have already
+been called, and will not call them again.
-=head2 __PACKAGE__->mk_accessor('meta');
+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
-Won't work due to a limitation of L<Moose>
+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 is currently being fixed inside core Moose.
+This behavior makes no sense, and so has been removed. Implementing your own
+C< new > method in components is B<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.
+
+=head2 __PACKAGE__->mk_accessor('meta');
+
+Won't work due to a limitation of L<Moose>. 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.
+Previously, writing to a class data accessor would copy the accessor method
+down into your package.
-This behavior has been removed. Whilst the class data is still stored per-class, it is stored on
-the metaclass of the class defining the accessor.
+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.
+Therefore anything relying on the side effect of the accessor being copied down
+will be broken.
-=head2 Extending Catalyst::Request or other classes in an ad-hoc manor using mk_accessors
+The following test demonstrates the problem:
-Previously, it was possible to add additional accessors to Catalyst::Request (or other classes)
-by calling the mk_accessors class method.
+ {
+ package BaseClass;
+ use base qw/Class::Data::Inheritable/;
+ __PACKAGE__->mk_classdata('foo');
+ }
-This is no longer supported - users should make a sub-class of the class who's behavior they would
-like to change, rather than globally polluting the Catalyst objects.
+ {
+ package Child;
+ use base qw/BaseClass/;
+ }
-=head2 Confused multiple inheritance with Catalyst::Component::COMPONENT
+ BaseClass->foo('base class');
+ Child->foo('sub class');
-Warning message:
+ use Test::More;
+ isnt(BaseClass->can('foo'), Child->can('foo'));
- There is a COMPONENT method resolving after Catalyst::Component
- in ${next_package}.
-
-This means that one of the packages on the right hand side of
-Catalyst::Component in your Class' inheritance hierarchy defines
-a COMPONENT method.
+=head2 Extending Catalyst::Request or other classes in an ad-hoc manner using mk_accessors
-Previously, Catalyst's COMPONENT method would delegate to the
-method on the right hand side, which could then delegate back again
-with NEXT. This (as it is insane), is no longer supported, as it
-makes no sense with C3 method dispatch order.
+Previously, it was possible to add additional accessors to Catalyst::Request
+(or other classes) by calling the mk_accessors class method.
-Therefore the correct fix is to re-arrange your class' inheritance
-hierarchy so that the COMPONENT method you would like to inherit is
-the first COMPONENT method in your @ISA.
+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 Assigning lists to accessors
+=head2 Confused multiple inheritance with Catalyst::Component::COMPONENT
-Accessors generated by Class::Accessor::Fast will, when multiple values
-are assigned to them, store a reference to a list automatically for you.
+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.
-This is not currently supported by MooseX::Emulate::Class::Accessor::Fast,
-and only the first value in the list will be stored.
+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:
-If you are relying on this behavior, and inheriting mk_accessors from a
-Catalyst component, then your code will fail.
+ 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 Catalyst::Base
+
+Any code using L<Catalyst::Base> 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 likely to change
-significantly in the 5.8X release series, and therefore their use is highly
-deprecated.
+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 tree
-=item dispatch_types
+=item dispatch_types
-=item registered_dispatch_types
+=item registered_dispatch_types
-=item method_action_class
+=item method_action_class
-=item action_hash
+=item action_hash
=item 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,\n"
- . "this will be removed in Catalyst 5.9X"
+ Class $class is calling the deprecated method Catalyst::Dispatcher::$public_method_name,
+ this will be removed in Catalyst 5.9X
You should B<NEVER> be calling any of these methods from application code.
-Plugins authors and maintainers whos plugins need to call these methods
-should email the development list to discuss your use-case, and what a
-better API should look like.
+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
-=head2 require $class was successful but the package is not defined.
+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:
-In this version of Catalyst, if a component is loaded from disk, but no symbols are defined in that component's namespace
-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 mis-typing package names.
+This is to protect against confusing bugs caused by mistyping package names,
+and will become a fatal error in a future version.
-This will become a fatal error in a future version.
+Please note that 'inner packages' (via L<Devel::InnerPackage>) are still fully
+supported; this warning is only issued when component file naming does not map
+to B<any> of the packages defined within that component.
=head2 $c->plugin method
-Calling the plugin method is deprecated, and calling it at runtime is B<highly deprecated>.
+Calling the plugin method is deprecated, and calling it at run time is B<highly
+deprecated>.
-Instead you are recommended to use L< Catalyst::Model::Adaptor > or similar to compose the functionality
-you need outside of the main application namespace.
+Instead you are recommended to use L< 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.
=cut
+
projects / catagits/Catalyst-Runtime.git / blobdiff