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 as 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,
-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.
+Most issues found with pre-existing components have been easy to solve, and a
+complete description of behaviour changes which may cause compatibility issues,
+or warnings which are now emitted is included below to help if you have problems.
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.
=head1 Known backwards compatibility breakages.
-=head2 Moose applications
+=head2 Issues with Class::C3
-Moose components for Catalyst 5.70 needed to do
+Catalyst 5.80 uses 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>.
+To be able to do this, however, entails that the graph of superclasses for each
+class must be linearizable using the C3 algorithm. Unfortunately, when
+superclasses are being used as mixins, 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 round causes fail.
+ use base qw/Class::Data::Inheritable Class::Accessor::Fast/;
+
+ package GoesBang;
+ use base qw/Component1 Component2/;
+
+And the Catalyst plugin most often causing this, is
+L<Catalyst::Plugin::Sesssion::Store::FastMMap> - if you are using this plugin
+and see issues, then please upgrade!
+
+This 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.
+
+=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 be able to use the constructor provided by Moose. In 5.80
-C<Catalyst::Component> already inherits from C<Moose::Object>. Therefore you
-shouldn't directly inherit from C<Moose::Object> yourself, otherwise your
-Class' @ISA will not linearize with C3.
+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
+C<Catalyst::Component> inherits from C<Moose::Object>, and so C< @ISA > fails
+to linearise.
+
+The fix for this is to 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
+with it appropriately.
You will also see this issue if you do the following:
- use Moose;
+ package TestApp::Controller::Example;
+ use Moose;
use base 'Catalyst::Controller';
as C< use base > appends to @ISA.
-FIXME - Add note about the appropriate magic to detect $Catalyst::VERSION
-and work around it at compile time.
+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.
+
+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.
+
+=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;
+ extends 'Catalyst';
+ __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 { ... };
-Additionally, you can take advantage of Catalyst's use of L<Class::MOP> and
+Additionally, you can take advantage of Catalysts use of L<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 { ... });
-=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 startup 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. Due to the fact that Catalyst is
+no longer using NEXT.pm for method resolution, this no longer works. 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.
-Won't work due to a limitation of L<Moose>
+The right way to do it is this:
-This is currently being fixed inside core Moose.
+ after setup_finalize => sub {
+ ... # things to do after the actual setup
+ };
-=head2 Class::Data::Inheritable side effects
+The setup_finalize hook was introduced as a way to avoid this issue.
-Previously, writing to a class data accessor would copy the accessor method down into your package.
+=head2 Components with a new method which returns false
-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.
+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.
-Therefore anything relying on the side-effect of the accessor being copied down will be broken.
+This behaviour 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 Mooses BUILD
+functionality and/or Moose attributes to perform any construction work
+necessary for your class.
-=head2 Extending Catalyst::Request or other classes in an ad-hoc manor using mk_accessors
+=head2 __PACKAGE__->mk_accessor('meta');
-Previously, it was possible to add additional accessors to Catalyst::Request (or other classes)
-by calling the mk_accessors class method.
+Won't work due to a limitation of L<Moose>. This is currently being fixed
+inside Moose.
-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.
+=head2 Class::Data::Inheritable side effects
-=head2 Confused multiple inheritance with Catalyst::Component::COMPONENT
+Previously, writing to a class data accessor would copy the accessor method
+down into your package.
-Warning message:
+This behaviour has been removed. Whilst the class data is still stored
+per-class, it is stored on the metaclass of the class defining the accessor.
- There is a COMPONENT method resolving after Catalyst::Component
- in ${next_package}.
+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');
-This means that one of the packages on the right hand side of
-Catalyst::Component in your Class' inheritance hierarchy defines
-a COMPONENT method.
+ use Test::More;
+ isnt(BaseClass->can('foo'), Child->can('foo'));
-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.
+=head2 Extending Catalyst::Request or other classes in an ad-hoc manor using mk_accessors
+
+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 sub-class of the class whose
+behaviour 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 (as it
+is insane AND 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:
+
+ There is a COMPONENT method resolving after Catalyst::Component
+ in ${next_package}.
-If you are relying on this behavior, and inheriting mk_accessors from a
-Catalyst component, then your code will fail.
+The correct fix is to re-arrange your class' 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 warn, and 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 both an implementation
+detail, 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.
+Plugins 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 naming to packages defined does not correspond.
-=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 mis-typing 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 runtime 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