X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FCatalyst%2FUpgrading.pod;h=0e4b76f2568599fb8112894cbc9a30fa65472f42;hb=5b6f82d2a814300635703289c910683f4133ebdc;hp=d7a3266518c81c42af80638f04d54f7d504715ad;hpb=c571d2c84b0acd26c540bba4b604e7ce8e01e426;p=catagits%2FCatalyst-Runtime.git diff --git a/lib/Catalyst/Upgrading.pod b/lib/Catalyst/Upgrading.pod index d7a3266..0e4b76f 100644 --- a/lib/Catalyst/Upgrading.pod +++ b/lib/Catalyst/Upgrading.pod @@ -1,23 +1,139 @@ +=head1 NAME + +Catalyst::Upgrading - Instructions for upgrading to the latest Catalyst + =head1 Upgrading to Catalyst 5.80 -Work in progress +Most applications and plugins should run unaltered on Catalyst 5.80. + +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 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 Catalyst::Plugin::Authentication +=head2 Issues with Class::C3 + +Catalyst 5.80 uses 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 - and please try upgrading your plugins +if you have this issue, 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 round causes fail. + 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. + +Please see additional documentation about this issue, and how to resolve it in +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, whilst 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 fix for this is to 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 with and deal +with it appropriately. + +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. + +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. + +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. -You need at least version FIXME of Catalyst::Plugin::Authentication. +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). -=head2 Moose applications +If you depend on Catalyst 5.8, then B Moose features work as expected. -Applications made by early adopters, which say: +=head3 use Moose in MyApp - extends qw/Moose::Object Catalyst::Component/ +Similar to the above, this will also fail: -need the C removing to run with Catalyst 5.80, otherwise -your Class' @ISA will not linearise with C3. + package MyApp; + use Moose; + use Catalyst qw/ + ConfigLoader + /; + __PACKAGE__->setup; -rafl to fix this bit :) +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 @@ -25,79 +141,150 @@ 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: - #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 and -install the closure using the appropriate metaclass. Example: +Additionally, you can take advantage of Catalysts use of L and +install the closure using the appropriate meta class. Example: use Class::MOP; my $metaclass = Moose::Meta::Class->initialize($package_name); $metaclass->add_method($method_name => sub { ... }); -=head2 Components without new methods +=head2 Hooking into application setup -FIXME +To execute code during application start-up the following snippet in MyApp.pm +used to work: -=head2 Components without COMPONENT methods + sub setup { + my ($class, @args) = @_; + $class->NEXT::setup(@args); + ... # things to do after the actual setup + } -FIXME +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 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 + }; -Won't work due to a limitation of L +The setup_finalize hook was introduced as a way to avoid this issue. -FIXME +=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 +would be blessed into a hash on your behalf, and this would be returned from +the COMPONENT method. + +This behaviour 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 Mooses 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 -FIXME +Previously, writing to a class data accessor would copy the accessor method +down into your package. -=head2 Extending Catalyst::Request or other classes in an ad-hoc manor using mk_accessor +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. -FIXME +Therefore anything relying on the side-effect of the accessor being copied down +will be broken. -=head2 require $class was successful but the package is not defined. +The following test demonstrates the problem: -FIXME Warning + { + package BaseClass; + use base qw/Class::Data::Inheritable/; + __PACKAGE__->mk_classdata('foo'); + } -=head2 $c->plugin method + { + package Child; + use base qw/BaseClass/; + } + + BaseClass->foo('base class'); + Child->foo('sub class'); -Deprecated + use Test::More; + isnt(BaseClass->can('foo'), Child->can('foo')); -=head2 Components which inherit Catalyst::Component's COMPONENT method, who's new method does not return a true value. +=head2 Extending Catalyst::Request or other classes in an ad-hoc manor using mk_accessors -Previously if your new method returned a false value, then your class' configuration would be blessed into a hash on your behalf, -and this would be returned from the COMPONENT method. This is no longer supported. You are not 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. +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 whose +behaviour 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 (as it +is insane AND 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' 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 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 @@ -105,34 +292,40 @@ deprecated. 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 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 Confused multiple inheritence with Catalyst::Component::COMPONENT +=head2 Class files with names that don't correspond to the packages they define -Warning message: +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: - 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. + require $class was successful but the package is not defined. -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. +This is to protect against confusing bugs caused by mis-typing package names, +and will become a fatal error in a future version. -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. +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< 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 +