+=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.
+
+=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<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/;
-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.
+ package Component2; # Accidentally saying it this way causes a failure
+ use base qw/Class::Data::Inheritable Class::Accessor::Fast/;
-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.
+ package GoesBang;
+ use base qw/Component1 Component2/;
-=head1 Known backwards compatibility breakages.
+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 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
+to detect the version of Catalyst your application is running, and deal
with it appropriately.
You will also see this issue if you do the following:
use Moose;
BEGIN { extends 'Catalyst::Component' }; # Or ::Controller, or whatever
-Note that the C< extends > decleration needs to occur in a begin block for
+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;
+ 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<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 { ... };
=head2 Hooking into application setup
-To execute code during application startup the following snippet in MyApp.pm
+To execute code during application start-up, the following snippet in MyApp.pm
used to work:
sub setup {
... # things to do after the actual setup
}
-With Catalyst 5.80 this won't work anymore. Because instead of using NEXT.pm it
-relies on Class::C3::Adopt::NEXT, which doesn't remember what methods it
-already called, like NEXT does and therefore goes into a deep recursion between
-MyApp::setup and Catalyst::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<NEXT> remembers what methods have already
+been called, and will not call them again.
-Moose method modifiers line C<< before|after|around 'setup => sub { ... }; >>
-won't work either because of backward compatibility issues related to plugin
-setup methods.
+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:
... # things to do after the actual setup
};
-=head2 Components whos new method returns false
+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' configuration
+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. T
+the COMPONENT method.
-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.
+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 core Moose.
+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.
-This behavior has been removed. Whilst the class data is still stored
+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
+Therefore anything relying on the side effect of the accessor being copied down
will be broken.
-The following example demonstrates the problem:
+The following test demonstrates the problem:
{
package 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 manor using mk_accessors
+=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 sub-class of the class who's
-behavior they would like to change, rather than globally polluting the Catalyst
-objects.
+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
-Warning message:
+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}.
-This means that one of the packages on the right hand side of
-Catalyst::Component in your Class' inheritance hierarchy defines
-a COMPONENT method.
+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.
-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.
+=head1 WARNINGS
-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.
+=head2 Catalyst::Base
-=head1 WARNINGS
+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
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
+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.
+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